[PATCH] TTY layer buffering revamp

The API and code have been through various bits of initial review by
serial driver people but they definitely need to live somewhere for a
while so the unconverted drivers can get knocked into shape, existing
drivers that have been updated can be better tuned and bugs whacked out.

This replaces the tty flip buffers with kmalloc objects in rings. In the
normal situation for an IRQ driven serial port at typical speeds the
behaviour is pretty much the same, two buffers end up allocated and the
kernel cycles between them as before.

When there are delays or at high speed we now behave far better as the
buffer pool can grow a bit rather than lose characters. This also means
that we can operate at higher speeds reliably.

For drivers that receive characters in blocks (DMA based, USB and
especially virtualisation) the layer allows a lot of driver specific
code that works around the tty layer with private secondary queues to be
removed. The IBM folks need this sort of layer, the smart serial port
people do, the virtualisers do (because a virtualised tty typically
operates at infinite speed rather than emulating 9600 baud).

Finally many drivers had invalid and unsafe attempts to avoid buffer
overflows by directly invoking tty methods extracted out of the innards
of work queue structs. These are no longer needed and all go away. That
fixes various random hangs with serial ports on overflow.

The other change in here is to optimise the receive_room path that is
used by some callers. It turns out that only one ldisc uses receive room
except asa constant and it updates it far far less than the value is
read. We thus make it a variable not a function call.

I expect the code to contain bugs due to the size alone but I'll be
watching and squashing them and feeding out new patches as it goes.

Because the buffers now dynamically expand you should only run out of
buffering when the kernel runs out of memory for real. That means a lot of
the horrible hacks high performance drivers used to do just aren't needed any
more.

Description:

tty_insert_flip_char is an old API and continues to work as before, as does
tty_flip_buffer_push() [this is why many drivers dont need modification]. It
does now also return the number of chars inserted

There are also

tty_buffer_request_room(tty, len)

which asks for a buffer block of the length requested and returns the space
found. This improves efficiency with hardware that knows how much to
transfer.

and tty_insert_flip_string_flags(tty, str, flags, len)

to insert a string of characters and flags

For a smart interface the usual code is

len = tty_request_buffer_room(tty, amount_hardware_says);
tty_insert_flip_string(tty, buffer_from_card, len);

More description!

At the moment tty buffers are attached directly to the tty. This is causing a
lot of the problems related to tty layer locking, also problems at high speed
and also with bursty data (such as occurs in virtualised environments)

I'm working on ripping out the flip buffers and replacing them with a pool of
dynamically allocated buffers. This allows both for old style "byte I/O"
devices and also helps virtualisation and smart devices where large blocks of
data suddenely materialise and need storing.

So far so good. Lots of drivers reference tty->flip.*. Several of them also
call directly and unsafely into function pointers it provides. This will all
break. Most drivers can use tty_insert_flip_char which can be kept as an API
but others need more.

At the moment I've added the following interfaces, if people think more will
be needed now is a good time to say

int tty_buffer_request_room(tty, size)

Try and ensure at least size bytes are available, returns actual room (may be
zero). At the moment it just uses the flipbuf space but that will change.
Repeated calls without characters being added are not cumulative. (ie if you
call it with 1, 1, 1, and then 4 you'll have four characters of space. The
other functions will also try and grow buffers in future but this will be a
more efficient way when you know block sizes.

int tty_insert_flip_char(tty, ch, flag)

As before insert a character if there is room. Now returns 1 for success, 0
for failure.

int tty_insert_flip_string(tty, str, len)

Insert a block of non error characters. Returns the number inserted.

int tty_prepare_flip_string(tty, strptr, len)

Adjust the buffer to allow len characters to be added. Returns a buffer
pointer in strptr and the length available. This allows for hardware that
needs to use functions like insl or mencpy_fromio.

Signed-off-by: Alan Cox <[e-mail]>
Cc: Paul Fulghum <[e-mail]>
Signed-off-by: Hirokazu Takata <[e-mail]>
Signed-off-by: Serge Hallyn <[e-mail]>
Signed-off-by: Jeff Dike <[e-mail]>
Signed-off-by: John Hawkes <[e-mail]>
Signed-off-by: Martin Schwidefsky <[e-mail]>
Signed-off-by: Adrian Bunk <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

arch/um/drivers/chan_kern.c

···
 		}
 	}
 
-	if((tty->flip.flag_buf_ptr == NULL) ||
-	   (tty->flip.char_buf_ptr == NULL))
-		return;
 	tty_insert_flip_char(tty, ch, TTY_NORMAL);
 }
 
···
 		chan = list_entry(ele, struct chan, list);
 		if(!chan->input || (chan->ops->read == NULL)) continue;
 		do {
-			if((tty != NULL) &&
-			   (tty->flip.count >= TTY_FLIPBUF_SIZE)){
+			if (tty && !tty_buffer_request_room(tty, 1)) {
 				schedule_delayed_work(task, 1);
 				goto out;
 			}

drivers/bluetooth/hci_ldisc.c

···
 
 	tty->disc_data = hu;
 	hu->tty = tty;
+	tty->receive_room = 65536;
 
 	spin_lock_init(&hu->rx_lock);
 
···
 
 	if (test_bit(HCI_UART_PROTO_SET, &hu->flags))
 		hci_uart_tx_wakeup(hu);
-}
-
-/* hci_uart_tty_room()
- * 
- *    Callback function from tty driver. Return the amount of 
- *    space left in the receiver's buffer to decide if remote
- *    transmitter is to be throttled.
- *
- * Arguments:        tty    pointer to associated tty instance data
- * Return Value:    number of bytes left in receive buffer
- */
-static int hci_uart_tty_room (struct tty_struct *tty)
-{
-	return 65536;
 }
 
 /* hci_uart_tty_receive()
···
 	hci_uart_ldisc.write		= hci_uart_tty_write;
 	hci_uart_ldisc.ioctl		= hci_uart_tty_ioctl;
 	hci_uart_ldisc.poll		= hci_uart_tty_poll;
-	hci_uart_ldisc.receive_room	= hci_uart_tty_room;
 	hci_uart_ldisc.receive_buf	= hci_uart_tty_receive;
 	hci_uart_ldisc.write_wakeup	= hci_uart_tty_wakeup;
 	hci_uart_ldisc.owner		= THIS_MODULE;

drivers/char/Kconfig

···
 
 config COMPUTONE
 	tristate "Computone IntelliPort Plus serial support"
-	depends on SERIAL_NONSTANDARD && BROKEN_ON_SMP
+	depends on SERIAL_NONSTANDARD
 	---help---
 	  This driver supports the entire family of Intelliport II/Plus
 	  controllers with the exception of the MicroChannel controllers and
···
 
 config ESPSERIAL
 	tristate "Hayes ESP serial port support"
-	depends on SERIAL_NONSTANDARD && ISA && BROKEN_ON_SMP && ISA_DMA_API
+	depends on SERIAL_NONSTANDARD && ISA && ISA_DMA_API
 	help
 	  This is a driver which supports Hayes ESP serial ports.  Both single
 	  port cards and multiport cards are supported.  Make sure to read
···
 
 config MOXA_INTELLIO
 	tristate "Moxa Intellio support"
-	depends on SERIAL_NONSTANDARD && BROKEN_ON_SMP
+	depends on SERIAL_NONSTANDARD
 	help
 	  Say Y here if you have a Moxa Intellio multiport serial card.
 

drivers/char/amiserial.c

···
         int status;
 	int serdatr;
 	struct tty_struct *tty = info->tty;
-	unsigned char ch;
+	unsigned char ch, flag;
 	struct	async_icount *icount;
+	int oe = 0;
 
 	icount = &info->state->icount;
 
···
 	    status |= UART_LSR_OE;
 
 	ch = serdatr & 0xff;
-	if (tty->flip.count >= TTY_FLIPBUF_SIZE)
-	  goto ignore_char;
-	*tty->flip.char_buf_ptr = ch;
 	icount->rx++;
 
 #ifdef SERIAL_DEBUG_INTR
 	printk("DR%02x:%02x...", ch, status);
 #endif
-	*tty->flip.flag_buf_ptr = 0;
+	flag = TTY_NORMAL;
 
 	/*
 	 * We don't handle parity or frame errors - but I have left
···
 	   * should be ignored.
 	   */
 	  if (status & info->ignore_status_mask)
-	    goto ignore_char;
+	    goto out;
 
 	  status &= info->read_status_mask;
 
···
 #ifdef SERIAL_DEBUG_INTR
 	    printk("handling break....");
 #endif
-	    *tty->flip.flag_buf_ptr = TTY_BREAK;
+	    flag = TTY_BREAK;
 	    if (info->flags & ASYNC_SAK)
 	      do_SAK(tty);
 	  } else if (status & UART_LSR_PE)
-	    *tty->flip.flag_buf_ptr = TTY_PARITY;
+	    flag = TTY_PARITY;
 	  else if (status & UART_LSR_FE)
-	    *tty->flip.flag_buf_ptr = TTY_FRAME;
+	    flag = TTY_FRAME;
 	  if (status & UART_LSR_OE) {
 	    /*
 	     * Overrun is special, since it's
 	     * reported immediately, and doesn't
 	     * affect the current character
 	     */
-	    if (tty->flip.count < TTY_FLIPBUF_SIZE) {
-	      tty->flip.count++;
-	      tty->flip.flag_buf_ptr++;
-	      tty->flip.char_buf_ptr++;
-	      *tty->flip.flag_buf_ptr = TTY_OVERRUN;
-	    }
+	     oe = 1;
 	  }
 	}
-	tty->flip.flag_buf_ptr++;
-	tty->flip.char_buf_ptr++;
-	tty->flip.count++;
- ignore_char:
-
+	tty_insert_flip_char(tty, ch, flag);
+	if (oe == 1)
+		tty_insert_flip_char(tty, 0, TTY_OVERRUN);
 	tty_flip_buffer_push(tty);
+out:
+	return;
 }
 
 static _INLINE_ void transmit_chars(struct async_struct *info)

drivers/char/cyclades.c

···
 #include <linux/timer.h>
 #include <linux/interrupt.h>
 #include <linux/tty.h>
+#include <linux/tty_flip.h>
 #include <linux/serial.h>
 #include <linux/major.h>
 #include <linux/string.h>
···
   int had_work;
   int mdm_change;
   int mdm_status;
-
+  int len;
     if((cinfo = (struct cyclades_card *)dev_id) == 0){
 #ifdef CY_DEBUG_INTERRUPTS
 	printk("cyy_interrupt: spurious interrupt %d\n\r", irq);
···
 				info->icount.rx++;
                                 continue;
                             }
-                            if (tty->flip.count < TTY_FLIPBUF_SIZE){
-                                tty->flip.count++;
+                            if (tty_buffer_request_room(tty, 1)) {
                                 if (data & info->read_status_mask){
                                     if(data & CyBREAK){
-                                        *tty->flip.flag_buf_ptr++ =
-	    						    TTY_BREAK;
-                                        *tty->flip.char_buf_ptr++ =
-					  cy_readb(base_addr+(CyRDSR<<index));
+                                        tty_insert_flip_char(tty, cy_readb(base_addr+(CyRDSR<<index)), TTY_BREAK);
 					info->icount.rx++;
                                         if (info->flags & ASYNC_SAK){
                                             do_SAK(tty);
                                         }
                                     }else if(data & CyFRAME){
-                                        *tty->flip.flag_buf_ptr++ =
-							    TTY_FRAME;
-                                        *tty->flip.char_buf_ptr++ =
-					  cy_readb(base_addr+(CyRDSR<<index));
+                                        tty_insert_flip_char(tty, cy_readb(base_addr+(CyRDSR<<index)), TTY_FRAME);
 					info->icount.rx++;
 					info->idle_stats.frame_errs++;
                                     }else if(data & CyPARITY){
-                                        *tty->flip.flag_buf_ptr++ =
-							    TTY_PARITY;
-                                        *tty->flip.char_buf_ptr++ =
-					  cy_readb(base_addr+(CyRDSR<<index));
+					/* Pieces of seven... */
+                                        tty_insert_flip_char(tty, cy_readb(base_addr+(CyRDSR<<index)), TTY_PARITY);
 					info->icount.rx++;
 					info->idle_stats.parity_errs++;
                                     }else if(data & CyOVERRUN){
-                                        *tty->flip.flag_buf_ptr++ =
-							    TTY_OVERRUN;
-                                        *tty->flip.char_buf_ptr++ = 0;
+                                        tty_insert_flip_char(tty, 0, TTY_OVERRUN);
 					info->icount.rx++;
                                         /* If the flip buffer itself is
                                            overflowing, we still lose
                                            the next incoming character.
                                          */
-                                        if(tty->flip.count
-					           < TTY_FLIPBUF_SIZE){
-                                            tty->flip.count++;
-                                            *tty->flip.flag_buf_ptr++ =
-							     TTY_NORMAL;
-                                           *tty->flip.char_buf_ptr++ =
-					    cy_readb(base_addr+(CyRDSR<<index));
-					    info->icount.rx++;
-                                        }
+                                        tty_insert_flip_char(tty, cy_readb(base_addr+(CyRDSR<<index)), TTY_FRAME);
+				        info->icount.rx++;
 					info->idle_stats.overruns++;
                                     /* These two conditions may imply */
                                     /* a normal read should be done. */
                                     /* }else if(data & CyTIMEOUT){ */
                                     /* }else if(data & CySPECHAR){ */
-                                    }else{
-                                        *tty->flip.flag_buf_ptr++ = 0;
-                                        *tty->flip.char_buf_ptr++ = 0;
-					info->icount.rx++;
+                                    }else {
+					tty_insert_flip_char(tty, 0, TTY_NORMAL);
+				        info->icount.rx++;
                                     }
                                 }else{
-                                    *tty->flip.flag_buf_ptr++ = 0;
-                                    *tty->flip.char_buf_ptr++ = 0;
+				    tty_insert_flip_char(tty, 0, TTY_NORMAL);
 				    info->icount.rx++;
                                 }
                             }else{
···
                                info->mon.char_max = char_count;
                             info->mon.char_last = char_count;
 #endif
-                            while(char_count--){
-                                if (tty->flip.count >= TTY_FLIPBUF_SIZE){
-                                        break;
-                                }
-                                tty->flip.count++;
+			    len = tty_buffer_request_room(tty, char_count);
+                            while(len--){
                                 data = cy_readb(base_addr+(CyRDSR<<index));
-                                *tty->flip.flag_buf_ptr++ = TTY_NORMAL;
-                                *tty->flip.char_buf_ptr++ = data;
+				tty_insert_flip_char(tty, data, TTY_NORMAL);
 				info->idle_stats.recv_bytes++;
 				info->icount.rx++;
 #ifdef CY_16Y_HACK
···
                             }
                              info->idle_stats.recv_idle = jiffies;
                         }
-                        schedule_delayed_work(&tty->flip.work, 1);
+                        schedule_delayed_work(&tty->buf.work, 1);
                     }
                     /* end of service */
                     cy_writeb(base_addr+(CyRIR<<index), (save_xir & 0x3f));
···
   struct cyclades_card *cinfo = &cy_card[info->card];
   struct tty_struct *tty = info->tty;
   volatile int char_count;
+  int len;
 #ifdef BLOCKMOVE
   int small_count;
 #else
···
 		tty->flip.count += small_count;
 	    }
 #else
-	    while(char_count--){
-		if (tty->flip.count >= N_TTY_BUF_SIZE - tty->read_cnt)
-                    break;
-
-		if (tty->flip.count >= TTY_FLIPBUF_SIZE)
-		    break;
-
+	    len = tty_buffer_request_room(tty, char_count);
+	    while(len--){
 		data = cy_readb(cinfo->base_addr + rx_bufaddr + new_rx_get);
 		new_rx_get = (new_rx_get + 1) & (rx_bufsize - 1);
-		tty->flip.count++;
-		*tty->flip.flag_buf_ptr++ = TTY_NORMAL;
-		*tty->flip.char_buf_ptr++ = data;
+		tty_insert_flip_char(tty, data, TTY_NORMAL);
 		info->idle_stats.recv_bytes++;
 		info->icount.rx++;
 	    }
···
 	    }
 #endif
 	    info->idle_stats.recv_idle = jiffies;
-	    schedule_delayed_work(&tty->flip.work, 1);
+	    schedule_delayed_work(&tty->buf.work, 1);
 	}
 	/* Update rx_get */
 	cy_writel(&buf_ctrl->rx_get, new_rx_get);
···
 
 	switch(cmd) {
 	    case C_CM_PR_ERROR:
-		tty->flip.count++;
-		*tty->flip.flag_buf_ptr++ = TTY_PARITY;
-		*tty->flip.char_buf_ptr++ = 0;
+		tty_insert_flip_char(tty, 0, TTY_PARITY);
 		info->icount.rx++;
 		special_count++;
 		break;
 	    case C_CM_FR_ERROR:
-		tty->flip.count++;
-		*tty->flip.flag_buf_ptr++ = TTY_FRAME;
-		*tty->flip.char_buf_ptr++ = 0;
+		tty_insert_flip_char(tty, 0, TTY_FRAME);
 		info->icount.rx++;
 		special_count++;
 		break;
 	    case C_CM_RXBRK:
-		tty->flip.count++;
-		*tty->flip.flag_buf_ptr++ = TTY_BREAK;
-		*tty->flip.char_buf_ptr++ = 0;
+		tty_insert_flip_char(tty, 0, TTY_BREAK);
 		info->icount.rx++;
 		special_count++;
 		break;
···
 	if(delta_count)
 	    cy_sched_event(info, Cy_EVENT_DELTA_WAKEUP);
 	if(special_count)
-	    schedule_delayed_work(&tty->flip.work, 1);
+	    schedule_delayed_work(&tty->buf.work, 1);
     }
 }
 

drivers/char/epca.c

···
 		if (tty)  { /* Begin if valid tty */
 			if (event & BREAK_IND)  { /* Begin if BREAK_IND */
 				/* A break has been indicated */
-				tty->flip.count++;
-				*tty->flip.flag_buf_ptr++ = TTY_BREAK;
-				*tty->flip.char_buf_ptr++ = 0;
+				tty_insert_flip_char(tty, 0, TTY_BREAK);
 				tty_schedule_flip(tty); 
 			} else if (event & LOWTX_IND)  { /* Begin LOWTX_IND */
 				if (ch->statusflags & LOWWAIT) 
···
 	int dataToRead, wrapgap, bytesAvailable;
 	unsigned int tail, head;
 	unsigned int wrapmask;
-	int rc;
 
 	/* ---------------------------------------------------------------
 		This routine is called by doint when a receive data event 
···
 		return;
 	}
 
-	if (tty->flip.count == TTY_FLIPBUF_SIZE) 
+	if (tty_buffer_request_room(tty, bytesAvailable + 1) == 0)
 		return;
 
 	if (readb(&bc->orun)) {
 		writeb(0, &bc->orun);
 		printk(KERN_WARNING "epca; overrun! DigiBoard device %s\n",tty->name);
+		tty_insert_flip_char(tty, 0, TTY_OVERRUN);
 	}
 	rxwinon(ch);
-	rptr = tty->flip.char_buf_ptr;
-	rc = tty->flip.count;
 	while (bytesAvailable > 0)  { /* Begin while there is data on the card */
 		wrapgap = (head >= tail) ? head - tail : ch->rxbufsize - tail;
 		/* ---------------------------------------------------------------
···
 		/* --------------------------------------------------------------
 		   Make sure we don't overflow the buffer
 		----------------------------------------------------------------- */
-		if ((rc + dataToRead) > TTY_FLIPBUF_SIZE)
-			dataToRead = TTY_FLIPBUF_SIZE - rc;
+		dataToRead = tty_prepare_flip_string(tty, &rptr, dataToRead);
 		if (dataToRead == 0)
 			break;
 		/* ---------------------------------------------------------------
···
 			for translation if necessary.
 		------------------------------------------------------------------ */
 		memcpy_fromio(rptr, ch->rxptr + tail, dataToRead);
-		rc   += dataToRead;
-		rptr += dataToRead;
 		tail = (tail + dataToRead) & wrapmask;
 		bytesAvailable -= dataToRead;
 	} /* End while there is data on the card */
-	tty->flip.count = rc;
-	tty->flip.char_buf_ptr = rptr;
 	globalwinon(ch);
 	writew(tail, &bc->rout);
 	/* Must be called with global data */

drivers/char/esp.c

···
 
 	for (i = 0; i < num_bytes; i++) {
 		if (!(err_buf->data[i] & status_mask)) {
-			*(tty->flip.char_buf_ptr++) = pio_buf->data[i];
+			int flag = 0;
 
 			if (err_buf->data[i] & 0x04) {
-				*(tty->flip.flag_buf_ptr++) = TTY_BREAK;
-
+				flag = TTY_BREAK;
 				if (info->flags & ASYNC_SAK)
 					do_SAK(tty);
 			}
 			else if (err_buf->data[i] & 0x02)
-				*(tty->flip.flag_buf_ptr++) = TTY_FRAME;
+				flag = TTY_FRAME;
 			else if (err_buf->data[i] & 0x01)
-				*(tty->flip.flag_buf_ptr++) = TTY_PARITY;
-			else
-				*(tty->flip.flag_buf_ptr++) = 0;
-		
-			tty->flip.count++;
+				flag = TTY_PARITY;
+			tty_insert_flip_char(tty, pio_buf->data[i], flag);
 		}
 	}
 
-	schedule_delayed_work(&tty->flip.work, 1);
+	schedule_delayed_work(&tty->buf.work, 1);
 
 	info->stat_flags &= ~ESP_STAT_RX_TIMEOUT;
 	release_pio_buffer(pio_buf);
···
 	int num_bytes;
 	unsigned long flags;
 	
-	
 	flags=claim_dma_lock();
 	disable_dma(dma);
 	clear_dma_ff(dma);
···
 	
 	info->icount.rx += num_bytes;
 
-	memcpy(tty->flip.char_buf_ptr, dma_buffer, num_bytes);
-	tty->flip.char_buf_ptr += num_bytes;
-	tty->flip.count += num_bytes;
-	memset(tty->flip.flag_buf_ptr, 0, num_bytes);
-	tty->flip.flag_buf_ptr += num_bytes;
-
 	if (num_bytes > 0) {
-		tty->flip.flag_buf_ptr--;
+		tty_insert_flip_string(tty, dma_buffer, num_bytes - 1);
 
 		status &= (0x1c & info->read_status_mask);
-
-		if (status & info->ignore_status_mask) {
-			tty->flip.count--;
-			tty->flip.char_buf_ptr--;
-			tty->flip.flag_buf_ptr--;
-		} else if (status & 0x10) {
-			*tty->flip.flag_buf_ptr = TTY_BREAK;
-			(info->icount.brk)++;
-			if (info->flags & ASYNC_SAK)
-				do_SAK(tty);
-		} else if (status & 0x08) {
-			*tty->flip.flag_buf_ptr = TTY_FRAME;
-			(info->icount.frame)++;
-		}
-		else if (status & 0x04) {
-			*tty->flip.flag_buf_ptr = TTY_PARITY;
-			(info->icount.parity)++;
-		}
-
-		tty->flip.flag_buf_ptr++;
 		
-		schedule_delayed_work(&tty->flip.work, 1);
+		/* Is the status significant or do we throw the last byte ? */
+		if (!(status & info->ignore_status_mask)) {
+			int statflag = 0;
+
+			if (status & 0x10) {
+				statflag = TTY_BREAK;
+				(info->icount.brk)++;
+				if (info->flags & ASYNC_SAK)
+					do_SAK(tty);
+			} else if (status & 0x08) {
+				statflag = TTY_FRAME;
+				(info->icount.frame)++;
+			}
+			else if (status & 0x04) {
+				statflag = TTY_PARITY;
+				(info->icount.parity)++;
+			}
+			tty_insert_flip_char(tty, dma_buffer[num_bytes - 1], statflag);
+		}
+		schedule_delayed_work(&tty->buf.work, 1);
 	}
 
 	if (dma_bytes != num_bytes) {
···
 		num_bytes = serial_in(info, UART_ESI_STAT1) << 8;
 		num_bytes |= serial_in(info, UART_ESI_STAT2);
 
-		if (num_bytes > (TTY_FLIPBUF_SIZE - info->tty->flip.count))
-		  num_bytes = TTY_FLIPBUF_SIZE - info->tty->flip.count;
+		num_bytes = tty_buffer_request_room(info->tty, num_bytes);
 
 		if (num_bytes) {
 			if (dma_bytes ||

drivers/char/hvc_console.c

···
 
 	/* Read data if any */
 	for (;;) {
-		int count = N_INBUF;
-		if (count > (TTY_FLIPBUF_SIZE - tty->flip.count))
-			count = TTY_FLIPBUF_SIZE - tty->flip.count;
+		int count = tty_buffer_request_room(tty, N_INBUF);
 
 		/* If flip is full, just reschedule a later read */
 		if (count == 0) {
···
 			tty_insert_flip_char(tty, buf[i], 0);
 		}
 
-		if (tty->flip.count)
+		if (count)
 			tty_schedule_flip(tty);
 
 		/*

drivers/char/hvcs.c

···
 	/* remove the read masks */
 	hvcsd->todo_mask &= ~(HVCS_READ_MASK);
 
-	if ((tty->flip.count + HVCS_BUFF_LEN) < TTY_FLIPBUF_SIZE) {
+	if (tty_buffer_request_room(tty, HVCS_BUFF_LEN) >= HVCS_BUFF_LEN) {
 		got = hvc_get_chars(unit_address,
 				&buf[0],
 				HVCS_BUFF_LEN);
-		for (i=0;got && i<got;i++)
-			tty_insert_flip_char(tty, buf[i], TTY_NORMAL);
+		tty_insert_flip_string(tty, buf, got);
 	}
 
 	/* Give the TTY time to process the data we just sent. */
···
 		hvcsd->todo_mask |= HVCS_QUICK_READ;
 
 	spin_unlock_irqrestore(&hvcsd->lock, flags);
-	if (tty->flip.count) {
-		/* This is synch because tty->low_latency == 1 */
+	/* This is synch because tty->low_latency == 1 */
+	if(got)
 		tty_flip_buffer_push(tty);
-	}
 
 	if (!got) {
 		/* Do this _after_ the flip_buffer_push */

drivers/char/isicom.c

···
 #include <linux/module.h>
 #include <linux/kernel.h>
 #include <linux/tty.h>
+#include <linux/tty_flip.h>
 #include <linux/termios.h>
 #include <linux/fs.h>
 #include <linux/sched.h>
···
 	unsigned short base, header, word_count, count;
 	unsigned char channel;
 	short byte_count;
+	unsigned char *rp;
 	
 	card = (struct isi_board *) dev_id;
 
···
 				break;
 				
 			case 1:	/* Received Break !!!	 */
-				if (tty->flip.count >= TTY_FLIPBUF_SIZE)
-					break;
-				*tty->flip.flag_buf_ptr++ = TTY_BREAK;
-				*tty->flip.char_buf_ptr++ = 0;
-				tty->flip.count++;
+				tty_insert_flip_char(tty, 0, TTY_BREAK);
 				if (port->flags & ASYNC_SAK)
 					do_SAK(tty);
-				schedule_delayed_work(&tty->flip.work, 1);
+				tty_flip_buffer_push(tty);
 				break;
 				
 			case 2:	/* Statistics		 */
···
 		}	 
 	}
 	else {				/* Data   Packet */
-		count = min_t(unsigned short, byte_count, (TTY_FLIPBUF_SIZE - tty->flip.count));
+
+		count = tty_prepare_flip_string(tty, &rp, byte_count & ~1);
 #ifdef ISICOM_DEBUG
 		printk(KERN_DEBUG "ISICOM: Intr: Can rx %d of %d bytes.\n", 
 					count, byte_count);
 #endif			
 		word_count = count >> 1;
-		insw(base, tty->flip.char_buf_ptr, word_count);
-		tty->flip.char_buf_ptr += (word_count << 1);		
+		insw(base, rp, word_count);
 		byte_count -= (word_count << 1);
 		if (count & 0x0001) {
-			*tty->flip.char_buf_ptr++ = (char)(inw(base) & 0xff);
+			tty_insert_flip_char(tty,  inw(base) & 0xff, TTY_NORMAL);
 			byte_count -= 2;
 		}	
-		memset(tty->flip.flag_buf_ptr, 0, count);
-		tty->flip.flag_buf_ptr += count;
-		tty->flip.count += count;
-		
 		if (byte_count > 0) {
 			printk(KERN_DEBUG "ISICOM: Intr(0x%x:%d): Flip buffer overflow! dropping bytes...\n",
 					base, channel+1);
···
 				byte_count -= 2;
 			}
 		}
-		schedule_delayed_work(&tty->flip.work, 1);
+		tty_flip_buffer_push(tty);
 	}
 	if (card->isa == YES)
 		ClearInterrupt(base);

drivers/char/istallion.c

···
 		stlen = size - tail;
 	}
 
-	len = MIN(len, (TTY_FLIPBUF_SIZE - tty->flip.count));
+	len = tty_buffer_request_room(tty, len);
+	/* FIXME : iomap ? */
 	shbuf = (volatile char *) EBRDGETMEMPTR(brdp, portp->rxoffset);
 
 	while (len > 0) {
 		stlen = MIN(len, stlen);
-		memcpy(tty->flip.char_buf_ptr, (char *) (shbuf + tail), stlen);
-		memset(tty->flip.flag_buf_ptr, 0, stlen);
-		tty->flip.char_buf_ptr += stlen;
-		tty->flip.flag_buf_ptr += stlen;
-		tty->flip.count += stlen;
-
+		tty_insert_flip_string(tty, (char *)(shbuf + tail), stlen);
 		len -= stlen;
 		tail += stlen;
 		if (tail >= size) {
···
 
 		if ((nt.data & DT_RXBREAK) && (portp->rxmarkmsk & BRKINT)) {
 			if (tty != (struct tty_struct *) NULL) {
-				if (tty->flip.count < TTY_FLIPBUF_SIZE) {
-					tty->flip.count++;
-					*tty->flip.flag_buf_ptr++ = TTY_BREAK;
-					*tty->flip.char_buf_ptr++ = 0;
-					if (portp->flags & ASYNC_SAK) {
-						do_SAK(tty);
-						EBRDENABLE(brdp);
-					}
-					tty_schedule_flip(tty);
+				tty_insert_flip_char(tty, 0, TTY_BREAK);
+				if (portp->flags & ASYNC_SAK) {
+					do_SAK(tty);
+					EBRDENABLE(brdp);
 				}
+				tty_schedule_flip(tty);
 			}
 		}
 
···
 	if (portp->tty != (struct tty_struct *) NULL) {
 		if (portp->tty->driver_data == portp) {
 			stli_comstats.ttystate = portp->tty->flags;
-			stli_comstats.rxbuffered = portp->tty->flip.count;
+			stli_comstats.rxbuffered = -1 /*portp->tty->flip.count*/;
 			if (portp->tty->termios != (struct termios *) NULL) {
 				stli_comstats.cflags = portp->tty->termios->c_cflag;
 				stli_comstats.iflags = portp->tty->termios->c_iflag;

drivers/char/moxa.c

···
 static int MoxaPortDCDON(int);
 static void MoxaPortFlushData(int, int);
 static int MoxaPortWriteData(int, unsigned char *, int);
-static int MoxaPortReadData(int, unsigned char *, int);
+static int MoxaPortReadData(int, struct tty_struct *tty);
 static int MoxaPortTxQueue(int);
 static int MoxaPortRxQueue(int);
 static int MoxaPortTxFree(int);
···
 	.tiocmget = moxa_tiocmget,
 	.tiocmset = moxa_tiocmset,
 };
+
+static spinlock_t moxa_lock = SPIN_LOCK_UNLOCKED;
 
 #ifdef CONFIG_PCI
 static int moxa_get_PCI_conf(struct pci_dev *p, int board_type, moxa_board_conf * board)
···
 	if (ch == NULL)
 		return (0);
 	port = ch->port;
-	save_flags(flags);
-	cli();
+
+	spin_lock_irqsave(&moxa_lock, flags);
 	len = MoxaPortWriteData(port, (unsigned char *) buf, count);
-	restore_flags(flags);
+	spin_unlock_irqrestore(&moxa_lock, flags);
 
 	/*********************************************
 	if ( !(ch->statusflags & LOWWAIT) &&
···
 	if (ch == NULL)
 		return;
 	port = ch->port;
-	save_flags(flags);
-	cli();
+	spin_lock_irqsave(&moxa_lock, flags);
 	moxaXmitBuff[0] = c;
 	MoxaPortWriteData(port, moxaXmitBuff, 1);
-	restore_flags(flags);
+	spin_unlock_irqrestore(&moxa_lock, flags);
 	/************************************************
 	if ( !(ch->statusflags & LOWWAIT) && (MoxaPortTxFree(port) <= 100) )
 	*************************************************/
···
 	printk("block_til_ready before block: ttys%d, count = %d\n",
 	       ch->line, ch->count);
 #endif
-	save_flags(flags);
-	cli();
+	spin_lock_irqsave(&moxa_lock, flags);
 	if (!tty_hung_up_p(filp))
 		ch->count--;
-	restore_flags(flags);
 	ch->blocked_open++;
+	spin_unlock_irqrestore(&moxa_lock, flags);
+
 	while (1) {
 		set_current_state(TASK_INTERRUPTIBLE);
 		if (tty_hung_up_p(filp) ||
···
 	}
 	set_current_state(TASK_RUNNING);
 	remove_wait_queue(&ch->open_wait, &wait);
+
+	spin_lock_irqsave(&moxa_lock, flags);
 	if (!tty_hung_up_p(filp))
 		ch->count++;
 	ch->blocked_open--;
+	spin_unlock_irqrestore(&moxa_lock, flags);
 #ifdef SERIAL_DEBUG_OPEN
 	printk("block_til_ready after blocking: ttys%d, count = %d\n",
 	       ch->line, ch->count);
 #endif
 	if (retval)
 		return (retval);
+	/* FIXME: review to see if we need to use set_bit on these */
 	ch->asyncflags |= ASYNC_NORMAL_ACTIVE;
-	return (0);
+	return 0;
 }
 
 static void setup_empty_event(struct tty_struct *tty)
···
 	struct moxa_str *ch = tty->driver_data;
 	unsigned long flags;
 
-	save_flags(flags);
-	cli();
+	spin_lock_irqsave(&moxa_lock, flags);
 	ch->statusflags |= EMPTYWAIT;
 	moxaEmptyTimer_on[ch->port] = 0;
 	del_timer(&moxaEmptyTimer[ch->port]);
 	moxaEmptyTimer[ch->port].expires = jiffies + HZ;
 	moxaEmptyTimer_on[ch->port] = 1;
 	add_timer(&moxaEmptyTimer[ch->port]);
-	restore_flags(flags);
+	spin_unlock_irqrestore(&moxa_lock, flags);
 }
 
 static void check_xmit_empty(unsigned long data)
···
 {
 	struct tty_struct *tp;
 	struct termios *ts;
-	int i, count, rc, space;
-	unsigned char *charptr, *flagptr;
 	unsigned long flags;
 
 	ts = NULL;
···
 		MoxaPortFlushData(ch->port, 0);
 		return;
 	}
-	space = TTY_FLIPBUF_SIZE - tp->flip.count;
-	if (space <= 0)
-		return;
-	charptr = tp->flip.char_buf_ptr;
-	flagptr = tp->flip.flag_buf_ptr;
-	rc = tp->flip.count;
-	save_flags(flags);
-	cli();
-	count = MoxaPortReadData(ch->port, charptr, space);
-	restore_flags(flags);
-	for (i = 0; i < count; i++)
-		*flagptr++ = 0;
-	charptr += count;
-	rc += count;
-	tp->flip.count = rc;
-	tp->flip.char_buf_ptr = charptr;
-	tp->flip.flag_buf_ptr = flagptr;
-	tty_schedule_flip(ch->tty);
+	spin_lock_irqsave(&moxa_lock, flags);
+	MoxaPortReadData(ch->port, tp);
+	spin_unlock_irqrestore(&moxa_lock, flags);
+	tty_schedule_flip(tp);
 }
 
 #define Magic_code	0x404
···
  *	14. MoxaPortDCDON(int port);					     *
  *	15. MoxaPortFlushData(int port, int mode);	                     *
  *	16. MoxaPortWriteData(int port, unsigned char * buffer, int length); *
- *	17. MoxaPortReadData(int port, unsigned char * buffer, int length);  *
+ *	17. MoxaPortReadData(int port, struct tty_struct *tty); 	     *
  *	18. MoxaPortTxBufSize(int port);				     *
  *	19. MoxaPortRxBufSize(int port);				     *
  *	20. MoxaPortTxQueue(int port);					     *
···
  *
  *      Function 21:    Read data.
  *      Syntax:
- *      int  MoxaPortReadData(int port, unsigned char * buffer, int length);
+ *      int  MoxaPortReadData(int port, struct tty_struct *tty);
  *           int port           : port number (0 - 127)
- *           unsigned char * buffer     : pointer to read data buffer.
- *           int length         : read data buffer length
+ *	     struct tty_struct *tty : tty for data
  *
  *           return:    0 - length      : real read data length
  *
···
 	return (total);
 }
 
-int MoxaPortReadData(int port, unsigned char * buffer, int space)
+int MoxaPortReadData(int port, struct tty_struct *tty)
 {
 	register ushort head, pageofs;
 	int i, count, cnt, len, total, remain;
···
 	count = (tail >= head) ? (tail - head)
 	    : (tail - head + rx_mask + 1);
 	if (count == 0)
-		return (0);
+		return 0;
 
-	total = (space > count) ? count : space;
+	total = count;
 	remain = count - total;
 	moxaLog.rxcnt[port] += total;
 	count = total;
···
 			len = (count > len) ? len : count;
 			ofs = baseAddr + DynPage_addr + bufhead + head;
 			for (i = 0; i < len; i++)
-				*buffer++ = readb(ofs + i);
+				tty_insert_flip_char(tty, readb(ofs + i), TTY_NORMAL);
 			head = (head + len) & rx_mask;
 			count -= len;
 		}
···
 			writew(pageno, baseAddr + Control_reg);
 			ofs = baseAddr + DynPage_addr + pageofs;
 			for (i = 0; i < cnt; i++)
-				*buffer++ = readb(ofs + i);
+				tty_insert_flip_char(tty, readb(ofs + i), TTY_NORMAL);
 			if (count == 0) {
 				writew((head + len) & rx_mask, ofsAddr + RXrptr);
 				break;

drivers/char/mxser.c

···
 
 	spin_lock_irqsave(&info->slock, flags);
 
-	recv_room = tty->ldisc.receive_room(tty);
+	recv_room = tty->receive_room;
 	if ((recv_room == 0) && (!info->ldisc_stop_rx)) {
 		//mxser_throttle(tty);
 		mxser_stoprx(tty);

drivers/char/n_hdlc.c

···
 	.ioctl		= n_hdlc_tty_ioctl,
 	.poll		= n_hdlc_tty_poll,
 	.receive_buf	= n_hdlc_tty_receive,
-	.receive_room	= n_hdlc_tty_room,
 	.write_wakeup	= n_hdlc_tty_wakeup,
 };
 
···
 		
 	tty->disc_data = n_hdlc;
 	n_hdlc->tty    = tty;
+	tty->receive_room = 65536;
 	
 #if defined(TTY_NO_WRITE_SPLIT)
 	/* change tty_io write() to not split large writes into 8K chunks */
···
 	n_hdlc_send_frames (n_hdlc, tty);
 		
 }	/* end of n_hdlc_tty_wakeup() */
-
-/**
- * n_hdlc_tty_room - Return the amount of space left in the receiver's buffer
- * @tty	- pointer to associated tty instance data
- *
- * Callback function from tty driver. Return the amount of space left in the
- * receiver's buffer to decide if remote transmitter is to be throttled.
- */
-static int n_hdlc_tty_room(struct tty_struct *tty)
-{
-	if (debuglevel >= DEBUG_LEVEL_INFO)	
-		printk("%s(%d)n_hdlc_tty_room() called\n",__FILE__,__LINE__);
-	/* always return a larger number to prevent */
-	/* throttling of remote transmitter. */
-	return 65536;
-}	/* end of n_hdlc_tty_root() */
 
 /**
  * n_hdlc_tty_receive - Called by tty driver when receive data is available

drivers/char/n_r3964.c

···
 		      struct poll_table_struct  *wait);
 static void r3964_receive_buf(struct tty_struct *tty, const unsigned char *cp,
                               char *fp, int count);
-static int  r3964_receive_room(struct tty_struct *tty);
 
 static struct tty_ldisc tty_ldisc_N_R3964 = {
 	.owner	 = THIS_MODULE,
···
 	.set_termios = r3964_set_termios,
 	.poll	= r3964_poll,            
 	.receive_buf = r3964_receive_buf,
-	.receive_room = r3964_receive_room,
 };
 
 
···
    pInfo->nRetry = 0;
    
    tty->disc_data = pInfo;
+   tty->receive_room = 65536;
 
    init_timer(&pInfo->tmr);
    pInfo->tmr.data = (unsigned long)pInfo;
···
         
     }
 }
-
-static int r3964_receive_room(struct tty_struct *tty)
-{
-   TRACE_L("receive_room");
-   return -1;
-}
-
 
 MODULE_LICENSE("GPL");
 MODULE_ALIAS_LDISC(N_R3964);

drivers/char/n_tty.c

···
 		free_page((unsigned long) buf);
 }
 
-static inline void put_tty_queue_nolock(unsigned char c, struct tty_struct *tty)
+/**
+ *	n_tty_set__room	-	receive space
+ *	@tty: terminal
+ *
+ *	Called by the driver to find out how much data it is
+ *	permitted to feed to the line discipline without any being lost
+ *	and thus to manage flow control. Not serialized. Answers for the
+ *	"instant".
+ */
+
+static void n_tty_set_room(struct tty_struct *tty)
+{
+	int	left = N_TTY_BUF_SIZE - tty->read_cnt - 1;
+
+	/*
+	 * If we are doing input canonicalization, and there are no
+	 * pending newlines, let characters through without limit, so
+	 * that erase characters will be handled.  Other excess
+	 * characters will be beeped.
+	 */
+	if (left <= 0)
+		left = tty->icanon && !tty->canon_data;
+	tty->receive_room = left;
+}
+
+static void put_tty_queue_nolock(unsigned char c, struct tty_struct *tty)
 {
 	if (tty->read_cnt < N_TTY_BUF_SIZE) {
 		tty->read_buf[tty->read_head] = c;
···
 	}
 }
 
-static inline void put_tty_queue(unsigned char c, struct tty_struct *tty)
+static void put_tty_queue(unsigned char c, struct tty_struct *tty)
 {
 	unsigned long flags;
 	/*
···
 	spin_unlock_irqrestore(&tty->read_lock, flags);
 	tty->canon_head = tty->canon_data = tty->erasing = 0;
 	memset(&tty->read_flags, 0, sizeof tty->read_flags);
+	n_tty_set_room(tty);
 	check_unthrottle(tty);
 }
 
···
 	put_tty_queue(c, tty);
 }	
 
-/**
- *	n_tty_receive_room	-	receive space
- *	@tty: terminal
- *
- *	Called by the driver to find out how much data it is
- *	permitted to feed to the line discipline without any being lost
- *	and thus to manage flow control. Not serialized. Answers for the
- *	"instant".
- */
- 
-static int n_tty_receive_room(struct tty_struct *tty)
-{
-	int	left = N_TTY_BUF_SIZE - tty->read_cnt - 1;
-
-	/*
-	 * If we are doing input canonicalization, and there are no
-	 * pending newlines, let characters through without limit, so
-	 * that erase characters will be handled.  Other excess
-	 * characters will be beeped.
-	 */
-	if (left <= 0)
-		left = tty->icanon && !tty->canon_data;
-	return left;
-}
 
 /**
  *	n_tty_write_wakeup	-	asynchronous I/O notifier
···
 			tty->driver->flush_chars(tty);
 	}
 
+	n_tty_set_room(tty);
+
 	if (!tty->icanon && (tty->read_cnt >= tty->minimum_to_wake)) {
 		kill_fasync(&tty->fasync, SIGIO, POLL_IN);
 		if (waitqueue_active(&tty->read_wait))
···
 	 * mode.  We don't want to throttle the driver if we're in
 	 * canonical mode and don't have a newline yet!
 	 */
-	if (n_tty_receive_room(tty) < TTY_THRESHOLD_THROTTLE) {
+	if (tty->receive_room < TTY_THRESHOLD_THROTTLE) {
 		/* check TTY_THROTTLED first so it indicates our state */
 		if (!test_and_set_bit(TTY_THROTTLED, &tty->flags) &&
 		    tty->driver->throttle)
···
 	if (test_bit(TTY_HW_COOK_IN, &tty->flags)) {
 		tty->raw = 1;
 		tty->real_raw = 1;
+		n_tty_set_room(tty);
 		return;
 	}
 	if (I_ISTRIP(tty) || I_IUCLC(tty) || I_IGNCR(tty) ||
···
 		else
 			tty->real_raw = 0;
 	}
+	n_tty_set_room(tty);
 }
 
 /**
···
  *
  */
  
-static inline int copy_from_read_buf(struct tty_struct *tty,
+static int copy_from_read_buf(struct tty_struct *tty,
 				      unsigned char __user **b,
 				      size_t *nr)
 
···
 				retval = -ERESTARTSYS;
 				break;
 			}
+			n_tty_set_room(tty);
 			clear_bit(TTY_DONT_FLIP, &tty->flags);
 			timeout = schedule_timeout(timeout);
 			set_bit(TTY_DONT_FLIP, &tty->flags);
···
 	       		clear_bit(TTY_PUSH, &tty->flags);
 	} else if (test_and_clear_bit(TTY_PUSH, &tty->flags))
 		 goto do_it_again;
+
+	n_tty_set_room(tty);
 
 	return retval;
 }
···
 	normal_poll,		/* poll */
 	NULL,			/* hangup */
 	n_tty_receive_buf,	/* receive_buf */
-	n_tty_receive_room,	/* receive_room */
 	n_tty_write_wakeup	/* write_wakeup */
 };
 

drivers/char/pcmcia/synclink_cs.c

···
 
 static void rx_ready_async(MGSLPC_INFO *info, int tcd)
 {
-	unsigned char data, status;
+	unsigned char data, status, flag;
 	int fifo_count;
+	int work = 0;
  	struct tty_struct *tty = info->tty;
  	struct mgsl_icount *icount = &info->icount;
 
···
 			fifo_count = 32;
 	} else
 		fifo_count = 32;
-	
+
+	tty_buffer_request_room(tty, fifo_count);
 	/* Flush received async data to receive data buffer. */ 
 	while (fifo_count) {
 		data   = read_reg(info, CHA + RXFIFO);
 		status = read_reg(info, CHA + RXFIFO);
 		fifo_count -= 2;
 
-		if (tty->flip.count >= TTY_FLIPBUF_SIZE)
-			break;
-			
-		*tty->flip.char_buf_ptr = data;
 		icount->rx++;
-		
-		*tty->flip.flag_buf_ptr = 0;
+		flag = TTY_NORMAL;
 
 		// if no frameing/crc error then save data
 		// BIT7:parity error
···
 			status &= info->read_status_mask;
 
 			if (status & BIT7)
-				*tty->flip.flag_buf_ptr = TTY_PARITY;
+				flag = TTY_PARITY;
 			else if (status & BIT6)
-				*tty->flip.flag_buf_ptr = TTY_FRAME;
+				flag = TTY_FRAME;
 		}
-		
-		tty->flip.flag_buf_ptr++;
-		tty->flip.char_buf_ptr++;
-		tty->flip.count++;
+		work += tty_insert_flip_char(tty, data, flag);
 	}
 	issue_command(info, CHA, CMD_RXFIFO);
 
 	if (debug_level >= DEBUG_LEVEL_ISR) {
-		printk("%s(%d):rx_ready_async count=%d\n",
-			__FILE__,__LINE__,tty->flip.count);
+		printk("%s(%d):rx_ready_async",
+			__FILE__,__LINE__);
 		printk("%s(%d):rx=%d brk=%d parity=%d frame=%d overrun=%d\n",
 			__FILE__,__LINE__,icount->rx,icount->brk,
 			icount->parity,icount->frame,icount->overrun);
 	}
 			
-	if (tty->flip.count)
+	if (work)
 		tty_flip_buffer_push(tty);
 }
 

drivers/char/pty.c

···
 	if (!to || tty->stopped)
 		return 0;
 
-	c = to->ldisc.receive_room(to);
+	c = to->receive_room;
 	if (c > count)
 		c = count;
 	to->ldisc.receive_buf(to, buf, NULL, c);
···
 	if (!to || tty->stopped)
 		return 0;
 
-	return to->ldisc.receive_room(to);
+	return to->receive_room;
 }
 
 /*

drivers/char/rio/riointr.c

···
 #include <linux/slab.h>
 #include <linux/errno.h>
 #include <linux/tty.h>
+#include <linux/tty_flip.h>
 #include <asm/io.h>
 #include <asm/system.h>
 #include <asm/string.h>
···
   struct PKT *PacketP;
   register uint	DataCnt;
   uchar *	ptr;
+  unsigned char *buf;
   int copied =0;
 
   static int intCount, RxIntCnt;
···
 	  ** and available space.
 	  */
 			
-	  transCount = min_t(unsigned int, PacketP->len & PKT_LEN_MASK,
-			   TTY_FLIPBUF_SIZE - TtyP->flip.count);
+	  transCount = tty_buffer_request_room(TtyP, PacketP->len & PKT_LEN_MASK);
 	  rio_dprintk (RIO_DEBUG_REC,  "port %d: Copy %d bytes\n", 
 				      PortP->PortNum, transCount);
 	  /*
···
 #endif
 	  ptr = (uchar *) PacketP->data + PortP->RxDataStart;
 
-	  rio_memcpy_fromio (TtyP->flip.char_buf_ptr, ptr, transCount);
-	  memset(TtyP->flip.flag_buf_ptr, TTY_NORMAL, transCount);
-
+	  tty_prepare_flip_string(TtyP, &buf, transCount);
+	  rio_memcpy_fromio (buf, ptr, transCount);
 #ifdef STATS
 	  /*
 	  ** keep a count for statistical purposes
···
 	  PortP->RxDataStart	+= transCount;
 	  PacketP->len		-= transCount;
 	  copied += transCount;
-	  TtyP->flip.count += transCount;
-	  TtyP->flip.char_buf_ptr += transCount;
-	  TtyP->flip.flag_buf_ptr += transCount;
 
 
 #ifdef ___DEBUG_IT___

drivers/char/riscom8.c

···
 #include <linux/major.h>
 #include <linux/init.h>
 #include <linux/delay.h>
+#include <linux/tty_flip.h>
 
 #include <asm/uaccess.h>
 
···
 	struct riscom_port *port;
 	struct tty_struct *tty;
 	unsigned char status;
-	unsigned char ch;
+	unsigned char ch, flag;
 	
 	if (!(port = rc_get_port(bp, "Receive")))
 		return;
 
 	tty = port->tty;
-	if (tty->flip.count >= TTY_FLIPBUF_SIZE)  {
-		printk(KERN_WARNING "rc%d: port %d: Working around flip "
-				    "buffer overflow.\n",
-		       board_No(bp), port_No(port));
-		return;
-	}
 	
 #ifdef RC_REPORT_OVERRUN	
 	status = rc_in(bp, CD180_RCSR);
-	if (status & RCSR_OE)  {
+	if (status & RCSR_OE)
 		port->overrun++;
-#if 0		
-		printk(KERN_ERR "rc%d: port %d: Overrun. Total %ld overruns\n", 
-		       board_No(bp), port_No(port), port->overrun);
-#endif		
-	}
 	status &= port->mark_mask;
 #else	
 	status = rc_in(bp, CD180_RCSR) & port->mark_mask;
···
 	} else if (status & RCSR_BREAK)  {
 		printk(KERN_INFO "rc%d: port %d: Handling break...\n",
 		       board_No(bp), port_No(port));
-		*tty->flip.flag_buf_ptr++ = TTY_BREAK;
+		flag = TTY_BREAK;
 		if (port->flags & ASYNC_SAK)
 			do_SAK(tty);
 		
 	} else if (status & RCSR_PE) 
-		*tty->flip.flag_buf_ptr++ = TTY_PARITY;
+		flag = TTY_PARITY;
 	
 	else if (status & RCSR_FE) 
-		*tty->flip.flag_buf_ptr++ = TTY_FRAME;
+		flag = TTY_FRAME;
 	
         else if (status & RCSR_OE)
-		*tty->flip.flag_buf_ptr++ = TTY_OVERRUN;
+		flag = TTY_OVERRUN;
 	
 	else
-		*tty->flip.flag_buf_ptr++ = 0;
+		flag = TTY_NORMAL;
 	
-	*tty->flip.char_buf_ptr++ = ch;
-	tty->flip.count++;
-	schedule_delayed_work(&tty->flip.work, 1);
+	tty_insert_flip_char(tty, ch, flag);
+	tty_flip_buffer_push(tty);
 }
 
 static inline void rc_receive(struct riscom_board const * bp)
···
 #endif	
 	
 	while (count--)  {
-		if (tty->flip.count >= TTY_FLIPBUF_SIZE)  {
+		if (tty_buffer_request_room(tty, 1) == 0)  {
 			printk(KERN_WARNING "rc%d: port %d: Working around "
 					    "flip buffer overflow.\n",
 			       board_No(bp), port_No(port));
 			break;
 		}
-		*tty->flip.char_buf_ptr++ = rc_in(bp, CD180_RDR);
-		*tty->flip.flag_buf_ptr++ = 0;
-		tty->flip.count++;
+		tty_insert_flip_char(tty, rc_in(bp, CD180_RDR), TTY_NORMAL);
 	}
-	schedule_delayed_work(&tty->flip.work, 1);
+	tty_flip_buffer_push(tty);
 }
 
 static inline void rc_transmit(struct riscom_board const * bp)

drivers/char/rocket.c

···
 {
 	unsigned int CharNStat;
 	int ToRecv, wRecv, space = 0, count;
-	unsigned char *cbuf;
-	char *fbuf;
+	unsigned char *cbuf, *chead;
+	char *fbuf, *fhead;
 	struct tty_ldisc *ld;
 
 	ld = tty_ldisc_ref(tty);
 
 	ToRecv = sGetRxCnt(cp);
-	if (ld)
-		space = ld->receive_room(tty);
+	space = tty->receive_room;
 	if (space > 2 * TTY_FLIPBUF_SIZE)
 		space = 2 * TTY_FLIPBUF_SIZE;
-	cbuf = tty->flip.char_buf;
-	fbuf = tty->flip.flag_buf;
 	count = 0;
 #ifdef ROCKET_DEBUG_INTR
 	printk(KERN_INFO "rp_do_receive(%d, %d)...", ToRecv, space);
···
 	if (ToRecv > space)
 		ToRecv = space;
 
+	ToRecv = tty_prepare_flip_string_flags(tty, &chead, &fhead, ToRecv);
 	if (ToRecv <= 0)
 		goto done;
+
+	cbuf = chead;
+	fbuf = fhead;
 
 	/*
 	 * if status indicates there are errored characters in the
···
 			else if (CharNStat & STMRCVROVRH)
 				*fbuf++ = TTY_OVERRUN;
 			else
-				*fbuf++ = 0;
+				*fbuf++ = TTY_NORMAL;
 			*cbuf++ = CharNStat & 0xff;
 			count++;
 			ToRecv--;
···
 			sInStrW(sGetTxRxDataIO(cp), (unsigned short *) cbuf, wRecv);
 		if (ToRecv & 1)
 			cbuf[ToRecv - 1] = sInB(sGetTxRxDataIO(cp));
-		memset(fbuf, 0, ToRecv);
+		memset(fbuf, TTY_NORMAL, ToRecv);
 		cbuf += ToRecv;
 		fbuf += ToRecv;
 		count += ToRecv;
 	}
 	/*  Push the data up to the tty layer */
-	ld->receive_buf(tty, tty->flip.char_buf, tty->flip.flag_buf, count);
+	ld->receive_buf(tty, cbuf, fbuf, count);
 done:
 	tty_ldisc_deref(ld);
 }

drivers/char/selection.c

···
 int paste_selection(struct tty_struct *tty)
 {
 	struct vc_data *vc = (struct vc_data *)tty->driver_data;
-	int	pasted = 0, count;
+	int	pasted = 0;
+	unsigned int count;
 	struct  tty_ldisc *ld;
 	DECLARE_WAITQUEUE(wait, current);
 
···
 			continue;
 		}
 		count = sel_buffer_lth - pasted;
-		count = min(count, tty->ldisc.receive_room(tty));
+		count = min(count, tty->receive_room);
 		tty->ldisc.receive_buf(tty, sel_buffer + pasted, NULL, count);
 		pasted += count;
 	}

drivers/char/ser_a2232.c

···
 */
 	struct tty_struct *tty = port->gs.tty;
 
-	if (tty->flip.count >= TTY_FLIPBUF_SIZE)
-		return;
-
-	tty->flip.count++;
-
 #if 0
 	switch(err) {
 	case TTY_BREAK:
···
 	}
 #endif
 
-	*tty->flip.flag_buf_ptr++ = err;
-	*tty->flip.char_buf_ptr++ = ch;
+	tty_insert_flip_char(tty, ch, err);
 	tty_flip_buffer_push(tty);
 }
 

drivers/char/serial167.c

···
 	    base_addr[CyREOIR] = rfoc ? 0 : CyNOTRANS;
 	    return IRQ_HANDLED;
 	}
-	if (tty->flip.count < TTY_FLIPBUF_SIZE){
-	    tty->flip.count++;
+	if (tty_buffer_request_room(tty, 1) != 0){
 	    if (err & info->read_status_mask){
 		if(err & CyBREAK){
-		    *tty->flip.flag_buf_ptr++ = TTY_BREAK;
-		    *tty->flip.char_buf_ptr++ = data;
+		    tty_insert_flip_char(tty, data, TTY_BREAK);
 		    if (info->flags & ASYNC_SAK){
 			do_SAK(tty);
 		    }
 		}else if(err & CyFRAME){
-		    *tty->flip.flag_buf_ptr++ = TTY_FRAME;
-		    *tty->flip.char_buf_ptr++ = data;
+		    tty_insert_flip_char(tty, data, TTY_FRAME);
 		}else if(err & CyPARITY){
-		    *tty->flip.flag_buf_ptr++ = TTY_PARITY;
-		    *tty->flip.char_buf_ptr++ = data;
+		    tty_insert_flip_char(tty, data, TTY_PARITY);
 		}else if(err & CyOVERRUN){
-		    *tty->flip.flag_buf_ptr++ = TTY_OVERRUN;
-		    *tty->flip.char_buf_ptr++ = 0;
+		    tty_insert_flip_char(tty, 0, TTY_OVERRUN);
 		    /*
 		       If the flip buffer itself is
 		       overflowing, we still loose
 		       the next incoming character.
 		     */
-		    if(tty->flip.count < TTY_FLIPBUF_SIZE){
-			tty->flip.count++;
-			*tty->flip.flag_buf_ptr++ = TTY_NORMAL;
-			*tty->flip.char_buf_ptr++ = data;
-		    }
+		    tty_insert_flip_char(tty, data, TTY_NORMAL);
+		}
 		/* These two conditions may imply */
 		/* a normal read should be done. */
 		/* else if(data & CyTIMEOUT) */
 		/* else if(data & CySPECHAR) */
 		}else{
-		    *tty->flip.flag_buf_ptr++ = 0;
-		    *tty->flip.char_buf_ptr++ = 0;
+		    tty_insert_flip_char(tty, 0, TTY_NORMAL);
 		}
 	    }else{
-		*tty->flip.flag_buf_ptr++ = 0;
-		*tty->flip.char_buf_ptr++ = 0;
+		    tty_insert_flip_char(tty, data, TTY_NORMAL);
 	    }
 	}else{
 	    /* there was a software buffer overrun
···
 #endif
 	while(char_count--){
 	    data = base_addr[CyRDR];
-	    if (tty->flip.count >= TTY_FLIPBUF_SIZE){
-		continue;
-	    }
-	    tty->flip.count++;
-	    *tty->flip.flag_buf_ptr++ = TTY_NORMAL;
-	    *tty->flip.char_buf_ptr++ = data;
+	    tty_insert_flip_char(tty, data, TTY_NORMAL);
 #ifdef CYCLOM_16Y_HACK
 	    udelay(10L);
 #endif

drivers/char/specialix.c

···
 #include <linux/interrupt.h>
 #include <linux/errno.h>
 #include <linux/tty.h>
+#include <linux/tty_flip.h>
 #include <linux/mm.h>
 #include <linux/serial.h>
 #include <linux/fcntl.h>
···
 	struct specialix_port *port;
 	struct tty_struct *tty;
 	unsigned char status;
-	unsigned char ch;
+	unsigned char ch, flag;
 
 	func_enter();
 
···
 		return;
 	}
 	tty = port->tty;
-	dprintk (SX_DEBUG_RX, "port: %p count: %d BUFF_SIZE: %d\n",
-		 port,  tty->flip.count, TTY_FLIPBUF_SIZE);
 
 	status = sx_in(bp, CD186x_RCSR);
 
···
 
 	/* This flip buffer check needs to be below the reading of the
 	   status register to reset the chip's IRQ.... */
-	if (tty->flip.count >= TTY_FLIPBUF_SIZE) {
+	if (tty_buffer_request_room(tty, 1) == 0) {
 		dprintk(SX_DEBUG_FIFO, "sx%d: port %d: Working around flip buffer overflow.\n",
 		       board_No(bp), port_No(port));
 		func_exit();
···
 	} else if (status & RCSR_BREAK) {
 		dprintk(SX_DEBUG_RX, "sx%d: port %d: Handling break...\n",
 		       board_No(bp), port_No(port));
-		*tty->flip.flag_buf_ptr++ = TTY_BREAK;
+		flag = TTY_BREAK;
 		if (port->flags & ASYNC_SAK)
 			do_SAK(tty);
 
 	} else if (status & RCSR_PE)
-		*tty->flip.flag_buf_ptr++ = TTY_PARITY;
+		flag = TTY_PARITY;
 
 	else if (status & RCSR_FE)
-		*tty->flip.flag_buf_ptr++ = TTY_FRAME;
+		flag = TTY_FRAME;
 
 	else if (status & RCSR_OE)
-		*tty->flip.flag_buf_ptr++ = TTY_OVERRUN;
+		flag = TTY_OVERRUN;
 
 	else
-		*tty->flip.flag_buf_ptr++ = 0;
+		flag = TTY_NORMAL;
 
-	*tty->flip.char_buf_ptr++ = ch;
-	tty->flip.count++;
-	schedule_delayed_work(&tty->flip.work, 1);
-
+	if(tty_insert_flip_char(tty, ch, flag))
+		tty_flip_buffer_push(tty);
 	func_exit();
 }
 
···
 	dprintk (SX_DEBUG_RX, "port: %p: count: %d\n", port, count);
 	port->hits[count > 8 ? 9 : count]++;
 
-	while (count--) {
-		if (tty->flip.count >= TTY_FLIPBUF_SIZE) {
-			printk(KERN_INFO "sx%d: port %d: Working around flip buffer overflow.\n",
-			       board_No(bp), port_No(port));
-			break;
-		}
-		*tty->flip.char_buf_ptr++ = sx_in(bp, CD186x_RDR);
-		*tty->flip.flag_buf_ptr++ = 0;
-		tty->flip.count++;
-	}
-	schedule_delayed_work(&tty->flip.work, 1);
+	tty_buffer_request_room(tty, count);
 
+	while (count--)
+		tty_insert_flip_char(tty, sx_in(bp, CD186x_RDR), TTY_NORMAL);
+	tty_flip_buffer_push(tty);
 	func_exit();
 }
 

drivers/char/stallion.c

···
 	if (portp->tty != (struct tty_struct *) NULL) {
 		if (portp->tty->driver_data == portp) {
 			portp->stats.ttystate = portp->tty->flags;
-			portp->stats.rxbuffered = portp->tty->flip.count;
+			/* No longer available as a statistic */
+			portp->stats.rxbuffered = 1; /*portp->tty->flip.count; */
 			if (portp->tty->termios != (struct termios *) NULL) {
 				portp->stats.cflags = portp->tty->termios->c_cflag;
 				portp->stats.iflags = portp->tty->termios->c_iflag;
···
 	if ((ioack & ACK_TYPMASK) == ACK_TYPRXGOOD) {
 		outb((RDCR + portp->uartaddr), ioaddr);
 		len = inb(ioaddr + EREG_DATA);
-		if ((tty == (struct tty_struct *) NULL) ||
-		    (tty->flip.char_buf_ptr == (char *) NULL) ||
-		    ((buflen = TTY_FLIPBUF_SIZE - tty->flip.count) == 0)) {
+		if (tty == NULL || (buflen = tty_buffer_request_room(tty, len)) == 0) {
 			len = MIN(len, sizeof(stl_unwanted));
 			outb((RDSR + portp->uartaddr), ioaddr);
 			insb((ioaddr + EREG_DATA), &stl_unwanted[0], len);
···
 		} else {
 			len = MIN(len, buflen);
 			if (len > 0) {
+				unsigned char *ptr;
 				outb((RDSR + portp->uartaddr), ioaddr);
-				insb((ioaddr + EREG_DATA), tty->flip.char_buf_ptr, len);
-				memset(tty->flip.flag_buf_ptr, 0, len);
-				tty->flip.flag_buf_ptr += len;
-				tty->flip.char_buf_ptr += len;
-				tty->flip.count += len;
+				tty_prepare_flip_string(tty, &ptr, len);
+				insb((ioaddr + EREG_DATA), ptr, len);
 				tty_schedule_flip(tty);
 				portp->stats.rxtotal += len;
 			}
···
 				portp->stats.txxoff++;
 			goto stl_rxalldone;
 		}
-		if ((tty != (struct tty_struct *) NULL) &&
-		    ((portp->rxignoremsk & status) == 0)) {
+		if (tty != NULL && (portp->rxignoremsk & status) == 0) {
 			if (portp->rxmarkmsk & status) {
 				if (status & ST_BREAK) {
 					status = TTY_BREAK;
···
 			} else {
 				status = 0;
 			}
-			if (tty->flip.char_buf_ptr != (char *) NULL) {
-				if (tty->flip.count < TTY_FLIPBUF_SIZE) {
-					*tty->flip.flag_buf_ptr++ = status;
-					*tty->flip.char_buf_ptr++ = ch;
-					tty->flip.count++;
-				}
-				tty_schedule_flip(tty);
-			}
+			tty_insert_flip_char(tty, ch, status);
+			tty_schedule_flip(tty);
 		}
 	} else {
 		printk("STALLION: bad RX interrupt ack value=%x\n", ioack);
···
 	len = inb(ioaddr + XP_DATA) + 1;
 
 	if ((iack & IVR_TYPEMASK) == IVR_RXDATA) {
-		if ((tty == (struct tty_struct *) NULL) ||
-		    (tty->flip.char_buf_ptr == (char *) NULL) ||
-		    ((buflen = TTY_FLIPBUF_SIZE - tty->flip.count) == 0)) {
+		if (tty == NULL || (buflen = tty_buffer_request_room(tty, len)) == 0) {
 			len = MIN(len, sizeof(stl_unwanted));
 			outb(GRXFIFO, (ioaddr + XP_ADDR));
 			insb((ioaddr + XP_DATA), &stl_unwanted[0], len);
···
 		} else {
 			len = MIN(len, buflen);
 			if (len > 0) {
+				unsigned char *ptr;
 				outb(GRXFIFO, (ioaddr + XP_ADDR));
-				insb((ioaddr + XP_DATA), tty->flip.char_buf_ptr, len);
-				memset(tty->flip.flag_buf_ptr, 0, len);
-				tty->flip.flag_buf_ptr += len;
-				tty->flip.char_buf_ptr += len;
-				tty->flip.count += len;
+				tty_prepare_flip_string(tty, &ptr, len);
+				insb((ioaddr + XP_DATA), ptr, len);
 				tty_schedule_flip(tty);
 				portp->stats.rxtotal += len;
 			}
···
 			status = 0;
 		}
 
-		if (tty->flip.char_buf_ptr != (char *) NULL) {
-			if (tty->flip.count < TTY_FLIPBUF_SIZE) {
-				*tty->flip.flag_buf_ptr++ = status;
-				*tty->flip.char_buf_ptr++ = ch;
-				tty->flip.count++;
-			}
-			tty_schedule_flip(tty);
-		}
+		tty_insert_flip_char(tty, ch, status);
+		tty_schedule_flip(tty);
 
 		if (status == 0)
 			portp->stats.rxtotal++;

drivers/char/sx.c

···
 	int rx_op;
 	struct tty_struct *tty;
 	int copied=0;
+	unsigned char *rp;
 
 	func_enter2 ();
 	tty = port->gs.tty;
···
 		sx_dprintk (SX_DEBUG_RECEIVE, "rxop=%d, c = %d.\n", rx_op, c); 
 
 		/* Don't copy more bytes than there is room for in the buffer */
-		if (tty->flip.count + c > TTY_FLIPBUF_SIZE) 
-			c = TTY_FLIPBUF_SIZE - tty->flip.count;
+
+		c = tty_prepare_flip_string(tty, &rp, c);
 
 		sx_dprintk (SX_DEBUG_RECEIVE, "c = %d.\n", c); 
 
···
 		sx_dprintk (SX_DEBUG_RECEIVE , "Copying over %d chars. First is %d at %lx\n", c, 
 		            read_sx_byte (port->board, CHAN_OFFSET(port,hi_rxbuf) + rx_op),
 		            CHAN_OFFSET(port, hi_rxbuf)); 
-		memcpy_fromio (tty->flip.char_buf_ptr, 
+		memcpy_fromio (rp,
 		               port->board->base + CHAN_OFFSET(port,hi_rxbuf) + rx_op, c);
-		memset(tty->flip.flag_buf_ptr, TTY_NORMAL, c);
-
-		/* Update the kernel buffer end */
-		tty->flip.count += c;
-		tty->flip.char_buf_ptr += c;
-		tty->flip.flag_buf_ptr += c;
 
 		/* This one last. ( Not essential.)
 		   It allows the card to start putting more data into the buffer! 

drivers/char/synclink.c

···
 {
 	int Fifocount;
 	u16 status;
+	int work = 0;
 	unsigned char DataByte;
  	struct tty_struct *tty = info->tty;
  	struct	mgsl_icount *icount = &info->icount;
···
 	/* flush the receive FIFO */
 
 	while( (Fifocount = (usc_InReg(info,RICR) >> 8)) ) {
+		int flag;
+
 		/* read one byte from RxFIFO */
 		outw( (inw(info->io_base + CCAR) & 0x0780) | (RDR+LSBONLY),
 		      info->io_base + CCAR );
···
 				RXSTATUS_OVERRUN + RXSTATUS_BREAK_RECEIVED) )
 			usc_UnlatchRxstatusBits(info,RXSTATUS_ALL);
 		
-		if (tty->flip.count >= TTY_FLIPBUF_SIZE)
-			continue;
-			
-		*tty->flip.char_buf_ptr = DataByte;
 		icount->rx++;
 		
-		*tty->flip.flag_buf_ptr = 0;
+		flag = 0;
 		if ( status & (RXSTATUS_FRAMING_ERROR + RXSTATUS_PARITY_ERROR +
 				RXSTATUS_OVERRUN + RXSTATUS_BREAK_RECEIVED) ) {
 			printk("rxerr=%04X\n",status);					
···
 			status &= info->read_status_mask;
 		
 			if (status & RXSTATUS_BREAK_RECEIVED) {
-				*tty->flip.flag_buf_ptr = TTY_BREAK;
+				flag = TTY_BREAK;
 				if (info->flags & ASYNC_SAK)
 					do_SAK(tty);
 			} else if (status & RXSTATUS_PARITY_ERROR)
-				*tty->flip.flag_buf_ptr = TTY_PARITY;
+				flag = TTY_PARITY;
 			else if (status & RXSTATUS_FRAMING_ERROR)
-				*tty->flip.flag_buf_ptr = TTY_FRAME;
-			if (status & RXSTATUS_OVERRUN) {
-				/* Overrun is special, since it's
-				 * reported immediately, and doesn't
-				 * affect the current character
-				 */
-				if (tty->flip.count < TTY_FLIPBUF_SIZE) {
-					tty->flip.count++;
-					tty->flip.flag_buf_ptr++;
-					tty->flip.char_buf_ptr++;
-					*tty->flip.flag_buf_ptr = TTY_OVERRUN;
-				}
-			}
+				flag = TTY_FRAME;
 		}	/* end of if (error) */
-		
-		tty->flip.flag_buf_ptr++;
-		tty->flip.char_buf_ptr++;
-		tty->flip.count++;
+		tty_insert_flip_char(tty, DataByte, flag);
+		if (status & RXSTATUS_OVERRUN) {
+			/* Overrun is special, since it's
+			 * reported immediately, and doesn't
+			 * affect the current character
+			 */
+			work += tty_insert_flip_char(tty, 0, TTY_OVERRUN);
+		}
 	}
 
 	if ( debug_level >= DEBUG_LEVEL_ISR ) {
-		printk("%s(%d):mgsl_isr_receive_data flip count=%d\n",
-			__FILE__,__LINE__,tty->flip.count);
 		printk("%s(%d):rx=%d brk=%d parity=%d frame=%d overrun=%d\n",
 			__FILE__,__LINE__,icount->rx,icount->brk,
 			icount->parity,icount->frame,icount->overrun);
 	}
 			
-	if ( tty->flip.count )
+	if(work)
 		tty_flip_buffer_push(tty);
 }
 

drivers/char/synclink_gt.c

···
 	unsigned char status;
 	struct slgt_desc *bufs = info->rbufs;
 	int i, count;
+	int chars = 0;
+	int stat;
+	unsigned char ch;
 
 	start = end = info->rbuf_current;
 
···
 		DBGDATA(info, p, count, "rx");
 
 		for(i=0 ; i < count; i+=2, p+=2) {
-			if (tty) {
-				if (tty->flip.count >= TTY_FLIPBUF_SIZE)
-					tty_flip_buffer_push(tty);
-				if (tty->flip.count >= TTY_FLIPBUF_SIZE)
-					break;
-				*tty->flip.char_buf_ptr = *p;
-				*tty->flip.flag_buf_ptr = 0;
+			if (tty && chars) {
+				tty_flip_buffer_push(tty);
+				chars = 0;
 			}
+			ch = *p;
 			icount->rx++;
+
+			stat = 0;
 
 			if ((status = *(p+1) & (BIT9 + BIT8))) {
 				if (status & BIT9)
···
 				/* discard char if tty control flags say so */
 				if (status & info->ignore_status_mask)
 					continue;
-				if (tty) {
-					if (status & BIT9)
-						*tty->flip.flag_buf_ptr = TTY_PARITY;
-					else if (status & BIT8)
-						*tty->flip.flag_buf_ptr = TTY_FRAME;
-				}
+				if (status & BIT9)
+					stat = TTY_PARITY;
+				else if (status & BIT8)
+					stat = TTY_FRAME;
 			}
 			if (tty) {
-				tty->flip.flag_buf_ptr++;
-				tty->flip.char_buf_ptr++;
-				tty->flip.count++;
+				tty_insert_flip_char(tty, ch, stat);
+				chars++;
 			}
 		}
 
···
 			break;
 	}
 
-	if (tty && tty->flip.count)
+	if (tty && chars)
 		tty_flip_buffer_push(tty);
 }
 
···
 			if (info->tty) {
 				if (!(status & info->ignore_status_mask)) {
 					if (info->read_status_mask & MASK_BREAK) {
-						*info->tty->flip.flag_buf_ptr = TTY_BREAK;
+						tty_insert_flip_char(info->tty, 0, TTY_BREAK);
 						if (info->flags & ASYNC_SAK)
 							do_SAK(info->tty);
 					}

drivers/char/synclinkmp.c

···
 			if ( tty ) {
 				if (!(status & info->ignore_status_mask1)) {
 					if (info->read_status_mask1 & BRKD) {
-						*tty->flip.flag_buf_ptr = TTY_BREAK;
+						tty_insert_flip_char(tty, 0, TTY_BREAK);
 						if (info->flags & ASYNC_SAK)
 							do_SAK(tty);
 					}
···
 
 	while((status = read_reg(info,CST0)) & BIT0)
 	{
+		int flag = 0;
+		int over = 0;
 		DataByte = read_reg(info,TRB);
-
-		if ( tty ) {
-			if (tty->flip.count >= TTY_FLIPBUF_SIZE)
-				continue;
-
-			*tty->flip.char_buf_ptr = DataByte;
-			*tty->flip.flag_buf_ptr = 0;
-		}
 
 		icount->rx++;
 
···
 
 			if ( tty ) {
 				if (status & PE)
-					*tty->flip.flag_buf_ptr = TTY_PARITY;
+					flag = TTY_PARITY;
 				else if (status & FRME)
-					*tty->flip.flag_buf_ptr = TTY_FRAME;
+					flag = TTY_FRAME;
 				if (status & OVRN) {
 					/* Overrun is special, since it's
 					 * reported immediately, and doesn't
 					 * affect the current character
 					 */
-					if (tty->flip.count < TTY_FLIPBUF_SIZE) {
-						tty->flip.count++;
-						tty->flip.flag_buf_ptr++;
-						tty->flip.char_buf_ptr++;
-						*tty->flip.flag_buf_ptr = TTY_OVERRUN;
-					}
+					over = 1;
 				}
 			}
 		}	/* end of if (error) */
 
 		if ( tty ) {
-			tty->flip.flag_buf_ptr++;
-			tty->flip.char_buf_ptr++;
-			tty->flip.count++;
+			tty_insert_flip_char(tty, DataByte, flag);
+			if (over)
+				tty_insert_flip_char(tty, 0, TTY_OVERRUN);
 		}
 	}
 
 	if ( debug_level >= DEBUG_LEVEL_ISR ) {
-		printk("%s(%d):%s isr_rxrdy() flip count=%d\n",
-			__FILE__,__LINE__,info->device_name,
-			tty ? tty->flip.count : 0);
 		printk("%s(%d):%s rx=%d brk=%d parity=%d frame=%d overrun=%d\n",
 			__FILE__,__LINE__,info->device_name,
 			icount->rx,icount->brk,icount->parity,
 			icount->frame,icount->overrun);
 	}
 
-	if ( tty && tty->flip.count )
+	if ( tty )
 		tty_flip_buffer_push(tty);
 }
 

drivers/char/tty_io.c

···
 	return tty;
 }
 
+static void tty_buffer_free_all(struct tty_struct *);
+
 static inline void free_tty_struct(struct tty_struct *tty)
 {
 	kfree(tty->write_buf);
+	tty_buffer_free_all(tty);
 	kfree(tty);
 }
 
···
 #endif
 	return 0;
 }
+
+/*
+ * Tty buffer allocation management
+ */
+
+static void tty_buffer_free_all(struct tty_struct *tty)
+{
+	struct tty_buffer *thead;
+	while((thead = tty->buf.head) != NULL) {
+		tty->buf.head = thead->next;
+		kfree(thead);
+	}
+	while((thead = tty->buf.free) != NULL) {
+		tty->buf.free = thead->next;
+		kfree(thead);
+	}
+	tty->buf.tail = NULL;
+}
+
+static void tty_buffer_init(struct tty_struct *tty)
+{
+	tty->buf.head = NULL;
+	tty->buf.tail = NULL;
+	tty->buf.free = NULL;
+}
+
+static struct tty_buffer *tty_buffer_alloc(size_t size)
+{
+	struct tty_buffer *p = kmalloc(sizeof(struct tty_buffer) + 2 * size, GFP_ATOMIC);
+	if(p == NULL)
+		return NULL;
+	p->used = 0;
+	p->size = size;
+	p->next = NULL;
+	p->char_buf_ptr = (char *)(p->data);
+	p->flag_buf_ptr = (unsigned char *)p->char_buf_ptr + size;
+/* 	printk("Flip create %p\n", p); */
+	return p;
+}
+
+/* Must be called with the tty_read lock held. This needs to acquire strategy
+   code to decide if we should kfree or relink a given expired buffer */
+
+static void tty_buffer_free(struct tty_struct *tty, struct tty_buffer *b)
+{
+	/* Dumb strategy for now - should keep some stats */
+/* 	printk("Flip dispose %p\n", b); */
+	if(b->size >= 512)
+		kfree(b);
+	else {
+		b->next = tty->buf.free;
+		tty->buf.free = b;
+	}
+}
+
+static struct tty_buffer *tty_buffer_find(struct tty_struct *tty, size_t size)
+{
+	struct tty_buffer **tbh = &tty->buf.free;
+	while((*tbh) != NULL) {
+		struct tty_buffer *t = *tbh;
+		if(t->size >= size) {
+			*tbh = t->next;
+			t->next = NULL;
+			t->used = 0;
+			/* DEBUG ONLY */
+			memset(t->data, '*', size);
+/* 			printk("Flip recycle %p\n", t); */
+			return t;
+		}
+		tbh = &((*tbh)->next);
+	}
+	/* Round the buffer size out */
+	size = (size + 0xFF) & ~ 0xFF;
+	return tty_buffer_alloc(size);
+	/* Should possibly check if this fails for the largest buffer we
+	   have queued and recycle that ? */
+}
+
+int tty_buffer_request_room(struct tty_struct *tty, size_t size)
+{
+	struct tty_buffer *b = tty->buf.head, *n;
+	int left = 0;
+
+	/* OPTIMISATION: We could keep a per tty "zero" sized buffer to
+	   remove this conditional if its worth it. This would be invisible
+	   to the callers */
+	if(b != NULL)
+		left = b->size - b->used;
+	if(left >= size)
+		return size;
+	/* This is the slow path - looking for new buffers to use */
+	n = tty_buffer_find(tty, size);
+	if(n == NULL)
+		return left;
+	n->next = b;
+	if(b != NULL)
+		b->next = n;
+	else
+		tty->buf.head = n;
+	tty->buf.tail = n;
+	return size;
+}
+
+EXPORT_SYMBOL_GPL(tty_buffer_request_room);
+
+int tty_insert_flip_string(struct tty_struct *tty, unsigned char *chars, size_t size)
+{
+	int copied = 0;
+	do {
+		int space = tty_buffer_request_room(tty, size - copied);
+		struct tty_buffer *tb = tty->buf.tail;
+		/* If there is no space then tb may be NULL */
+		if(unlikely(space == 0))
+			break;
+		memcpy(tb->char_buf_ptr + tb->used, chars, space);
+		memset(tb->flag_buf_ptr + tb->used, TTY_NORMAL, space);
+		tb->used += space;
+		copied += space;
+		chars += space;
+/* 		printk("Flip insert %d.\n", space); */
+	}
+	/* There is a small chance that we need to split the data over
+	   several buffers. If this is the case we must loop */
+	while (unlikely(size > copied));
+	return copied;
+}
+
+EXPORT_SYMBOL_GPL(tty_insert_flip_string);
+
+int tty_insert_flip_string_flags(struct tty_struct *tty, unsigned char *chars, char *flags, size_t size)
+{
+	int copied = 0;
+	do {
+		int space = tty_buffer_request_room(tty, size - copied);
+		struct tty_buffer *tb = tty->buf.tail;
+		/* If there is no space then tb may be NULL */
+		if(unlikely(space == 0))
+			break;
+		memcpy(tb->char_buf_ptr + tb->used, chars, space);
+		memcpy(tb->flag_buf_ptr + tb->used, flags, space);
+		tb->used += space;
+		copied += space;
+		chars += space;
+		flags += space;
+	}
+	/* There is a small chance that we need to split the data over
+	   several buffers. If this is the case we must loop */
+	while (unlikely(size > copied));
+	return copied;
+}
+
+EXPORT_SYMBOL_GPL(tty_insert_flip_string_flags);
+
+
+/*
+ *	Prepare a block of space in the buffer for data. Returns the length
+ *	available and buffer pointer to the space which is now allocated and
+ *	accounted for as ready for normal characters. This is used for drivers
+ *	that need their own block copy routines into the buffer. There is no
+ *	guarantee the buffer is a DMA target!
+ */
+
+int tty_prepare_flip_string(struct tty_struct *tty, unsigned char **chars, size_t size)
+{
+	int space = tty_buffer_request_room(tty, size);
+	struct tty_buffer *tb = tty->buf.tail;
+	*chars = tb->char_buf_ptr + tb->used;
+	memset(tb->flag_buf_ptr + tb->used, TTY_NORMAL, space);
+	tb->used += space;
+	return space;
+}
+
+EXPORT_SYMBOL_GPL(tty_prepare_flip_string);
+
+/*
+ *	Prepare a block of space in the buffer for data. Returns the length
+ *	available and buffer pointer to the space which is now allocated and
+ *	accounted for as ready for characters. This is used for drivers
+ *	that need their own block copy routines into the buffer. There is no
+ *	guarantee the buffer is a DMA target!
+ */
+
+int tty_prepare_flip_string_flags(struct tty_struct *tty, unsigned char **chars, char **flags, size_t size)
+{
+	int space = tty_buffer_request_room(tty, size);
+	struct tty_buffer *tb = tty->buf.tail;
+	*chars = tb->char_buf_ptr + tb->used;
+	*flags = tb->flag_buf_ptr + tb->used;
+	tb->used += space;
+	return space;
+}
+
+EXPORT_SYMBOL_GPL(tty_prepare_flip_string_flags);
+
+
 
 /*
  *	This is probably overkill for real world processors but
···
 	if (ld == NULL)
 		return -EINVAL;
 
+	/*
+	 *	No more input please, we are switching. The new ldisc
+	 *	will update this value in the ldisc open function
+	 */
+
+	tty->receive_room = 0;
+
+	/*
+	 *	Problem: What do we do if this blocks ?
+	 */
+
 	tty_wait_until_sent(tty, 0);
 
 	if (tty->ldisc.num == ldisc) {
···
 	 *	we say so later on.
 	 */
 
-	work = cancel_delayed_work(&tty->flip.work);
+	work = cancel_delayed_work(&tty->buf.work);
 	/*
-	 * Wait for ->hangup_work and ->flip.work handlers to terminate
+	 * Wait for ->hangup_work and ->buf.work handlers to terminate
 	 */
 	 
 	flush_scheduled_work();
···
 	/* Restart it in case no characters kick it off. Safe if
 	   already running */
 	if (work)
-		schedule_delayed_work(&tty->flip.work, 1);
+		schedule_delayed_work(&tty->buf.work, 1);
 	return retval;
 }
 
···
 	 */
 	clear_bit(TTY_LDISC, &tty->flags);
 	clear_bit(TTY_DONT_FLIP, &tty->flags);
-	cancel_delayed_work(&tty->flip.work);
+	cancel_delayed_work(&tty->buf.work);
 
 	/*
-	 * Wait for ->hangup_work and ->flip.work handlers to terminate
+	 * Wait for ->hangup_work and ->buf.work handlers to terminate
 	 */
 	 
 	flush_scheduled_work();
···
 
 /*
  * This routine is called out of the software interrupt to flush data
- * from the flip buffer to the line discipline. 
+ * from the buffer chain to the line discipline.
  */
  
 static void flush_to_ldisc(void *private_)
 {
 	struct tty_struct *tty = (struct tty_struct *) private_;
-	unsigned char	*cp;
-	char		*fp;
-	int		count;
 	unsigned long 	flags;
 	struct tty_ldisc *disc;
+	struct tty_buffer *tbuf;
 
 	disc = tty_ldisc_ref(tty);
 	if (disc == NULL)	/*  !TTY_LDISC */
···
 		/*
 		 * Do it after the next timer tick:
 		 */
-		schedule_delayed_work(&tty->flip.work, 1);
+		schedule_delayed_work(&tty->buf.work, 1);
 		goto out;
 	}
 	spin_lock_irqsave(&tty->read_lock, flags);
-	if (tty->flip.buf_num) {
-		cp = tty->flip.char_buf + TTY_FLIPBUF_SIZE;
-		fp = tty->flip.flag_buf + TTY_FLIPBUF_SIZE;
-		tty->flip.buf_num = 0;
-		tty->flip.char_buf_ptr = tty->flip.char_buf;
-		tty->flip.flag_buf_ptr = tty->flip.flag_buf;
-	} else {
-		cp = tty->flip.char_buf;
-		fp = tty->flip.flag_buf;
-		tty->flip.buf_num = 1;
-		tty->flip.char_buf_ptr = tty->flip.char_buf + TTY_FLIPBUF_SIZE;
-		tty->flip.flag_buf_ptr = tty->flip.flag_buf + TTY_FLIPBUF_SIZE;
+	while((tbuf = tty->buf.head) != NULL) {
+		tty->buf.head = tbuf->next;
+		spin_unlock_irqrestore(&tty->read_lock, flags);
+		/* printk("Process buffer %p for %d\n", tbuf, tbuf->used); */
+		disc->receive_buf(tty, tbuf->char_buf_ptr,
+				       tbuf->flag_buf_ptr,
+				       tbuf->used);
+		spin_lock_irqsave(&tty->read_lock, flags);
+		tty_buffer_free(tty, tbuf);
 	}
-	count = tty->flip.count;
-	tty->flip.count = 0;
+	tty->buf.tail = NULL;
 	spin_unlock_irqrestore(&tty->read_lock, flags);
-
-	disc->receive_buf(tty, cp, fp, count);
 out:
 	tty_ldisc_deref(disc);
 }
···
 	if (tty->low_latency)
 		flush_to_ldisc((void *) tty);
 	else
-		schedule_delayed_work(&tty->flip.work, 1);
+		schedule_delayed_work(&tty->buf.work, 1);
 }
 
 EXPORT_SYMBOL(tty_flip_buffer_push);
+
 
 /*
  * This subroutine initializes a tty structure.
···
 	tty_ldisc_assign(tty, tty_ldisc_get(N_TTY));
 	tty->pgrp = -1;
 	tty->overrun_time = jiffies;
-	tty->flip.char_buf_ptr = tty->flip.char_buf;
-	tty->flip.flag_buf_ptr = tty->flip.flag_buf;
-	INIT_WORK(&tty->flip.work, flush_to_ldisc, tty);
-	init_MUTEX(&tty->flip.pty_sem);
+	tty->buf.head = tty->buf.tail = NULL;
+	tty_buffer_init(tty);
+	INIT_WORK(&tty->buf.work, flush_to_ldisc, tty);
+	init_MUTEX(&tty->buf.pty_sem);
 	init_MUTEX(&tty->termios_sem);
 	init_waitqueue_head(&tty->write_wait);
 	init_waitqueue_head(&tty->read_wait);

drivers/char/viocons.c

···
 		 * Don't attempt to copy more data into the buffer than we
 		 * have room for because it would fail without indication.
 		 */
-		if ((tty->flip.count + 1) > TTY_FLIPBUF_SIZE) {
+		if(tty_insert_flip_char(tty, cevent->data[index], TTY_NORMAL) == 0) {
 			printk(VIOCONS_KERN_WARN "input buffer overflow!\n");
 			break;
 		}
-		tty_insert_flip_char(tty, cevent->data[index], TTY_NORMAL);
 	}
 
 	/* if cevent->len == 0 then no data was added to the buffer and flip.count == 0 */

drivers/char/vme_scc.c

···
 		SCCwrite_NB(COMMAND_REG, CR_HIGHEST_IUS_RESET);
 		return IRQ_HANDLED;
 	}
-	if (tty->flip.count < TTY_FLIPBUF_SIZE) {
-		*tty->flip.char_buf_ptr = ch;
-		*tty->flip.flag_buf_ptr = 0;
-		tty->flip.flag_buf_ptr++;
-		tty->flip.char_buf_ptr++;
-		tty->flip.count++;
-	}
+	tty_insert_flip_char(tty, ch, 0);
 
 	/* Check if another character is already ready; in that case, the
 	 * spcond_int() function must be used, because this character may have an
···
 		else
 			err = 0;
 
-		if (tty->flip.count < TTY_FLIPBUF_SIZE) {
-			*tty->flip.char_buf_ptr = ch;
-			*tty->flip.flag_buf_ptr = err;
-			tty->flip.flag_buf_ptr++;
-			tty->flip.char_buf_ptr++;
-			tty->flip.count++;
-		}
+		tty_insert_flip_char(tty, ch, err);
 
 		/* ++TeSche: *All* errors have to be cleared manually,
 		 * else the condition persists for the next chars

drivers/input/serio/serport.c

···
 	init_waitqueue_head(&serport->wait);
 
 	tty->disc_data = serport;
+	tty->receive_room = 256;
 	set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
 
 	return 0;
···
 
 out:
 	spin_unlock_irqrestore(&serport->lock, flags);
-}
-
-/*
- * serport_ldisc_room() reports how much room we do have for receiving data.
- * Although we in fact have infinite room, we need to specify some value
- * here, and 256 seems to be reasonable.
- */
-
-static int serport_ldisc_room(struct tty_struct *tty)
-{
-	return 256;
 }
 
 /*
···
 	.read =		serport_ldisc_read,
 	.ioctl =	serport_ldisc_ioctl,
 	.receive_buf =	serport_ldisc_receive,
-	.receive_room =	serport_ldisc_room,
 	.write_wakeup =	serport_ldisc_write_wakeup
 };
 

drivers/isdn/capi/capi.c

···
 #endif
 		goto bad;
 	}
-	if (ld->receive_room &&
-	    ld->receive_room(mp->tty) < datalen) {
+	if (mp->tty->receive_room < datalen) {
 #if defined(_DEBUG_DATAFLOW) || defined(_DEBUG_TTYFUNCS)
 		printk(KERN_DEBUG "capi: no room in tty\n");
 #endif

drivers/isdn/i4l/isdn_common.c

···
 	return count;
 }
 
+/*
+ * isdn_readbchan_tty() tries to get data from the read-queue.
+ * It MUST be called with interrupts off.
+ *
+ * Be aware that this is not an atomic operation when sleep != 0, even though
+ * interrupts are turned off! Well, like that we are currently only called
+ * on behalf of a read system call on raw device files (which are documented
+ * to be dangerous and for for debugging purpose only). The inode semaphore
+ * takes care that this is not called for the same minor device number while
+ * we are sleeping, but access is not serialized against simultaneous read()
+ * from the corresponding ttyI device. Can other ugly events, like changes
+ * of the mapping (di,ch)<->minor, happen during the sleep? --he
+ */
+int
+isdn_readbchan_tty(int di, int channel, struct tty_struct *tty, int cisco_hack)
+{
+	int count;
+	int count_pull;
+	int count_put;
+	int dflag;
+	struct sk_buff *skb;
+	char last = 0;
+	int len;
+
+	if (!dev->drv[di])
+		return 0;
+	if (skb_queue_empty(&dev->drv[di]->rpqueue[channel]))
+			return 0;
+
+	len = tty_buffer_request_room(tty, dev->drv[di]->rcvcount[channel]);
+	if(len == 0)
+		return len;
+
+	count = 0;
+	while (len) {
+		if (!(skb = skb_peek(&dev->drv[di]->rpqueue[channel])))
+			break;
+#ifdef CONFIG_ISDN_AUDIO
+		if (ISDN_AUDIO_SKB_LOCK(skb))
+			break;
+		ISDN_AUDIO_SKB_LOCK(skb) = 1;
+		if ((ISDN_AUDIO_SKB_DLECOUNT(skb)) || (dev->drv[di]->DLEflag & (1 << channel))) {
+			char *p = skb->data;
+			unsigned long DLEmask = (1 << channel);
+
+			dflag = 0;
+			count_pull = count_put = 0;
+			while ((count_pull < skb->len) && (len > 0)) {
+				len--;
+				if (dev->drv[di]->DLEflag & DLEmask) {
+					last = DLE;
+					dev->drv[di]->DLEflag &= ~DLEmask;
+				} else {
+					last = *p;
+					if (last == DLE) {
+						dev->drv[di]->DLEflag |= DLEmask;
+						(ISDN_AUDIO_SKB_DLECOUNT(skb))--;
+					}
+					p++;
+					count_pull++;
+				}
+				count_put++;
+			}
+			if (count_pull >= skb->len)
+				dflag = 1;
+		} else {
+#endif
+			/* No DLE's in buff, so simply copy it */
+			dflag = 1;
+			if ((count_pull = skb->len) > len) {
+				count_pull = len;
+				dflag = 0;
+			}
+			count_put = count_pull;
+			if(count_put > 1)
+				tty_insert_flip_string(tty, skb->data, count_put - 1);
+			last = skb->data[count_put] - 1;
+			len -= count_put;
+#ifdef CONFIG_ISDN_AUDIO
+		}
+#endif
+		count += count_put;
+		if (dflag) {
+			/* We got all the data in this buff.
+			 * Now we can dequeue it.
+			 */
+			if(cisco_hack)
+				tty_insert_flip_char(tty, last, 0xFF);
+			else
+				tty_insert_flip_char(tty, last, TTY_NORMAL);
+#ifdef CONFIG_ISDN_AUDIO
+			ISDN_AUDIO_SKB_LOCK(skb) = 0;
+#endif
+			skb = skb_dequeue(&dev->drv[di]->rpqueue[channel]);
+			dev_kfree_skb(skb);
+		} else {
+			tty_insert_flip_char(tty, last, TTY_NORMAL);
+			/* Not yet emptied this buff, so it
+			 * must stay in the queue, for further calls
+			 * but we pull off the data we got until now.
+			 */
+			skb_pull(skb, count_pull);
+#ifdef CONFIG_ISDN_AUDIO
+			ISDN_AUDIO_SKB_LOCK(skb) = 0;
+#endif
+		}
+		dev->drv[di]->rcvcount[channel] -= count_put;
+	}
+	return count;
+}
+
+
 static __inline int
 isdn_minor2drv(int minor)
 {

drivers/isdn/i4l/isdn_common.h

···
 extern void isdn_unexclusive_channel(int di, int ch);
 extern int  isdn_getnum(char **);
 extern int  isdn_readbchan(int, int, u_char *, u_char *, int, wait_queue_head_t *);
+extern int  isdn_readbchan_tty(int, int, struct tty_struct *, int);
 extern int  isdn_get_free_channel(int, int, int, int, int, char *);
 extern int  isdn_writebuf_skb_stub(int, int, int, struct sk_buff *);
 extern int  register_isdn(isdn_if * i);

drivers/isdn/i4l/isdn_tty.c

···
 	int c;
 	int len;
 	struct tty_struct *tty;
+	char last;
 
 	if (info->online) {
 		if ((tty = info->tty)) {
 			if (info->mcr & UART_MCR_RTS) {
-				c = TTY_FLIPBUF_SIZE - tty->flip.count;
 				len = skb->len
 #ifdef CONFIG_ISDN_AUDIO
 					+ ISDN_AUDIO_SKB_DLECOUNT(skb)
 #endif
 					;
+
+				c = tty_buffer_request_room(tty, len);
 				if (c >= len) {
 #ifdef CONFIG_ISDN_AUDIO
-					if (ISDN_AUDIO_SKB_DLECOUNT(skb))
-						while (skb->len--) {
+					if (ISDN_AUDIO_SKB_DLECOUNT(skb)) {
+						int l = skb->len;
+						unsigned char *dp = skb->data;
+						while (--l) {
 							if (*skb->data == DLE)
 								tty_insert_flip_char(tty, DLE, 0);
-							tty_insert_flip_char(tty, *skb->data++, 0);
+							tty_insert_flip_char(tty, *dp++, 0);
+						}
+						last = *dp;
 					} else {
 #endif
-						memcpy(tty->flip.char_buf_ptr,
-						       skb->data, len);
-						tty->flip.count += len;
-						tty->flip.char_buf_ptr += len;
-						memset(tty->flip.flag_buf_ptr, 0, len);
-						tty->flip.flag_buf_ptr += len;
+						if(len > 1)
+							tty_insert_flip_string(tty, skb->data, len - 1);
+						last = skb->data[len - 1];
 #ifdef CONFIG_ISDN_AUDIO
 					}
 #endif
 					if (info->emu.mdmreg[REG_CPPP] & BIT_CPPP)
-						tty->flip.flag_buf_ptr[len - 1] = 0xff;
-					schedule_delayed_work(&tty->flip.work, 1);
+						tty_insert_flip_char(tty, last, 0xFF);
+					else
+						tty_insert_flip_char(tty, last, TTY_NORMAL);
+					tty_flip_buffer_push(tty);
 					kfree_skb(skb);
 					return 1;
 				}
···
 	int resched = 0;
 	int midx;
 	int i;
-	int c;
 	int r;
 	struct tty_struct *tty;
 	modem_info *info;
···
 #endif
 				if ((tty = info->tty)) {
 					if (info->mcr & UART_MCR_RTS) {
-						c = TTY_FLIPBUF_SIZE - tty->flip.count;
-						if (c > 0) {
-							r = isdn_readbchan(info->isdn_driver, info->isdn_channel,
-									   tty->flip.char_buf_ptr,
-									   tty->flip.flag_buf_ptr, c, NULL);
-							/* CISCO AsyncPPP Hack */
-							if (!(info->emu.mdmreg[REG_CPPP] & BIT_CPPP))
-								memset(tty->flip.flag_buf_ptr, 0, r);
-							tty->flip.count += r;
-							tty->flip.flag_buf_ptr += r;
-							tty->flip.char_buf_ptr += r;
-							if (r)
-								schedule_delayed_work(&tty->flip.work, 1);
-						}
+						/* CISCO AsyncPPP Hack */
+						if (!(info->emu.mdmreg[REG_CPPP] & BIT_CPPP))
+							r = isdn_readbchan_tty(info->isdn_driver, info->isdn_channel, tty, 0);
+						else
+							r = isdn_readbchan_tty(info->isdn_driver, info->isdn_channel, tty, 1);
+						if (r)
+							tty_flip_buffer_push(tty);
 					} else
 						r = 1;
 				} else
···
 	}
 #endif
 #endif
-	/* Try to deliver directly via tty-flip-buf if queue is empty */
+	/* Try to deliver directly via tty-buf if queue is empty */
 	spin_lock_irqsave(&info->readlock, flags);
 	if (skb_queue_empty(&dev->drv[di]->rpqueue[channel]))
 		if (isdn_tty_try_read(info, skb)) {
···
 /* The next routine is called once from within timer-interrupt
  * triggered within isdn_tty_modem_ncarrier(). It calls
  * isdn_tty_modem_result() to stuff a "NO CARRIER" Message
- * into the tty's flip-buffer.
+ * into the tty's buffer.
  */
 static void
 isdn_tty_modem_do_ncarrier(unsigned long data)
···
 	u_long flags;
 	struct sk_buff *skb = NULL;
 	char *sp = NULL;
+	int l = strlen(msg);
 
 	if (!msg) {
 		printk(KERN_WARNING "isdn_tty: Null-Message in isdn_tty_at_cout\n");
···
 		return;
 	}
 
-	/* use queue instead of direct flip, if online and */
-	/* data is in queue or flip buffer is full */
-	if ((info->online) && (((tty->flip.count + strlen(msg)) >= TTY_FLIPBUF_SIZE) ||
-	    (!skb_queue_empty(&dev->drv[info->isdn_driver]->rpqueue[info->isdn_channel])))) {
-		skb = alloc_skb(strlen(msg), GFP_ATOMIC);
+	/* use queue instead of direct, if online and */
+	/* data is in queue or buffer is full */
+	if ((info->online && tty_buffer_request_room(tty, l) < l) ||
+	    (!skb_queue_empty(&dev->drv[info->isdn_driver]->rpqueue[info->isdn_channel]))) {
+		skb = alloc_skb(l, GFP_ATOMIC);
 		if (!skb) {
 			spin_unlock_irqrestore(&info->readlock, flags);
 			return;
 		}
-		sp = skb_put(skb, strlen(msg));
+		sp = skb_put(skb, l);
 #ifdef CONFIG_ISDN_AUDIO
 		ISDN_AUDIO_SKB_DLECOUNT(skb) = 0;
 		ISDN_AUDIO_SKB_LOCK(skb) = 0;
···
 		if (skb) {
 			*sp++ = c;
 		} else {
-			if (tty->flip.count >= TTY_FLIPBUF_SIZE)
+			if(tty_insert_flip_char(tty, c, TTY_NORMAL) == 0)
 				break;
-			tty_insert_flip_char(tty, c, 0);
 		}
 	}
 	if (skb) {
···
 		dev->drv[info->isdn_driver]->rcvcount[info->isdn_channel] += skb->len;
 		spin_unlock_irqrestore(&info->readlock, flags);
 		/* Schedule dequeuing */
-		if ((dev->modempoll) && (info->rcvsched))
+		if (dev->modempoll && info->rcvsched)
 			isdn_timer_ctrl(ISDN_TIMER_MODEMREAD, 1);
 
 	} else {
 		spin_unlock_irqrestore(&info->readlock, flags);
-		schedule_delayed_work(&tty->flip.work, 1);
+		tty_flip_buffer_push(tty);
 	}
 }
 

drivers/net/hamradio/6pack.c

···
 
 /* ----------------------------------------------------------------------- */
 
-static int sixpack_receive_room(struct tty_struct *tty)
-{
-	return 65536;  /* We can handle an infinite amount of data. :-) */
-}
-
 /*
  * Handle the 'receiver data ready' interrupt.
  * This function is called by the 'tty_io' module in the kernel when
···
 
 	/* Done.  We have linked the TTY line to a channel. */
 	tty->disc_data = sp;
+	tty->receive_room = 65536;
 
 	/* Now we're ready to register. */
 	if (register_netdev(dev))
···
 	.close		= sixpack_close,
 	.ioctl		= sixpack_ioctl,
 	.receive_buf	= sixpack_receive_buf,
-	.receive_room	= sixpack_receive_room,
 	.write_wakeup	= sixpack_write_wakeup,
 };
 

drivers/net/hamradio/mkiss.c

···
 
 	ax->tty = tty;
 	tty->disc_data = ax;
+	tty->receive_room = 65535;
 
 	if (tty->driver->flush_buffer)
 		tty->driver->flush_buffer(tty);
···
 		tty->driver->unthrottle(tty);
 }
 
-static int mkiss_receive_room(struct tty_struct *tty)
-{
-	return 65536;  /* We can handle an infinite amount of data. :-) */
-}
-
 /*
  * Called by the driver when there's room for more data.  If we have
  * more packets to send, we send them here.
···
 	.close		= mkiss_close,
 	.ioctl		= mkiss_ioctl,
 	.receive_buf	= mkiss_receive_buf,
-	.receive_room	= mkiss_receive_room,
 	.write_wakeup	= mkiss_write_wakeup
 };
 

drivers/net/irda/irtty-sir.c

···
 }
 
 /*
- * Function irtty_receive_room (tty)
- *
- *    Used by the TTY to find out how much data we can receive at a time
- * 
-*/
-static int irtty_receive_room(struct tty_struct *tty) 
-{
-	struct sirtty_cb *priv = tty->disc_data;
-
-	IRDA_ASSERT(priv != NULL, return 0;);
-	IRDA_ASSERT(priv->magic == IRTTY_MAGIC, return 0;);
-
-	return 65536;  /* We can handle an infinite amount of data. :-) */
-}
-
-/*
  * Function irtty_write_wakeup (tty)
  *
  *    Called by the driver when there's room for more data.  If we have
···
 
 	dev->priv = priv;
 	tty->disc_data = priv;
+	tty->receive_room = 65536;
 
 	up(&irtty_sem);
 
···
 	.ioctl		= irtty_ioctl,
  	.poll		= NULL,
 	.receive_buf	= irtty_receive_buf,
-	.receive_room	= irtty_receive_room,
 	.write_wakeup	= irtty_write_wakeup,
 	.owner		= THIS_MODULE,
 };

drivers/net/ppp_async.c

···
 		goto out_free;
 
 	tty->disc_data = ap;
-
+	tty->receive_room = 65536;
 	return 0;
 
  out_free:
···
 	return 0;
 }
 
-static int
-ppp_asynctty_room(struct tty_struct *tty)
-{
-	return 65535;
-}
-
 /*
  * This can now be called from hard interrupt level as well
  * as soft interrupt level or mainline.
···
 	.write	= ppp_asynctty_write,
 	.ioctl	= ppp_asynctty_ioctl,
 	.poll	= ppp_asynctty_poll,
-	.receive_room = ppp_asynctty_room,
 	.receive_buf = ppp_asynctty_receive,
 	.write_wakeup = ppp_asynctty_wakeup,
 };

drivers/net/ppp_synctty.c

···
 		goto out_free;
 
 	tty->disc_data = ap;
-
+	tty->receive_room = 65536;
 	return 0;
 
  out_free:
···
 	return 0;
 }
 
-static int
-ppp_sync_room(struct tty_struct *tty)
-{
-	return 65535;
-}
-
 /*
  * This can now be called from hard interrupt level as well
  * as soft interrupt level or mainline.
···
 	.write	= ppp_sync_write,
 	.ioctl	= ppp_synctty_ioctl,
 	.poll	= ppp_sync_poll,
-	.receive_room = ppp_sync_room,
 	.receive_buf = ppp_sync_receive,
 	.write_wakeup = ppp_sync_wakeup,
 };

drivers/net/slip.c

···
  ******************************************/
 
 
-static int slip_receive_room(struct tty_struct *tty)
-{
-	return 65536;  /* We can handle an infinite amount of data. :-) */
-}
-
 /*
  * Handle the 'receiver data ready' interrupt.
  * This function is called by the 'tty_io' module in the kernel when
···
 	sl->line = tty_devnum(tty);
 	sl->pid = current->pid;
 	
-	/* FIXME: already done before we were called - seems this can go */
-	if (tty->driver->flush_buffer)
-		tty->driver->flush_buffer(tty);
-		
 	if (!test_bit(SLF_INUSE, &sl->flags)) {
 		/* Perform the low-level SLIP initialization. */
 		if ((err = sl_alloc_bufs(sl, SL_MTU)) != 0)
···
 
 	/* Done.  We have linked the TTY line to a channel. */
 	rtnl_unlock();
+	tty->receive_room = 65536;	/* We don't flow control */
 	return sl->dev->base_addr;
 
 err_free_bufs:
···
 	.close	 	= slip_close,
 	.ioctl		= slip_ioctl,
 	.receive_buf	= slip_receive_buf,
-	.receive_room	= slip_receive_room,
 	.write_wakeup	= slip_write_wakeup,
 };
 

drivers/net/wan/pc300_tty.c

···
 					}
 				}	
 				cpc_tty->buf_rx.first = cpc_tty->buf_rx.first->next;
-				kfree(buf);
+				kfree((void *)buf);
 				buf = cpc_tty->buf_rx.first;
 				flg_rx = 1;
 			}

drivers/net/wan/x25_asy.c

···
 	return 0;
 }
 
-static int x25_asy_receive_room(struct tty_struct *tty)
-{
-	return 65536;  /* We can handle an infinite amount of data. :-) */
-}
-
 /*
  * Handle the 'receiver data ready' interrupt.
  * This function is called by the 'tty_io' module in the kernel when
···
 
 	sl->tty = tty;
 	tty->disc_data = sl;
+	tty->receive_room = 65536;
 	if (tty->driver->flush_buffer)  {
 		tty->driver->flush_buffer(tty);
 	}
···
 	.close		= x25_asy_close_tty,
 	.ioctl		= x25_asy_ioctl,
 	.receive_buf	= x25_asy_receive_buf,
-	.receive_room	= x25_asy_receive_room,
 	.write_wakeup	= x25_asy_write_wakeup,
 };
 

drivers/net/wireless/strip.c

···
 /************************************************************************/
 /* Receiving routines							*/
 
-static int strip_receive_room(struct tty_struct *tty)
-{
-	return 0x10000;		/* We can handle an infinite amount of data. :-) */
-}
-
 /*
  * This function parses the response to the ATS300? command,
  * extracting the radio version and serial number.
···
 /*
  * Here's the order things happen:
  * When the user runs "slattach -p strip ..."
- *  1. The TTY module calls strip_open
+ *  1. The TTY module calls strip_open;;
  *  2. strip_open calls strip_alloc
  *  3.                  strip_alloc calls register_netdev
  *  4.                  register_netdev calls strip_dev_init
···
 
 	strip_info->tty = tty;
 	tty->disc_data = strip_info;
+	tty->receive_room = 65536;
+
 	if (tty->driver->flush_buffer)
 		tty->driver->flush_buffer(tty);
 
···
 	.close = strip_close,
 	.ioctl = strip_ioctl,
 	.receive_buf = strip_receive_buf,
-	.receive_room = strip_receive_room,
 	.write_wakeup = strip_write_some_more,
 };
 

drivers/s390/char/con3215.c

···
 #include <linux/types.h>
 #include <linux/kdev_t.h>
 #include <linux/tty.h>
+#include <linux/tty_flip.h>
 #include <linux/vt_kern.h>
 #include <linux/init.h>
 #include <linux/console.h>
···
 				if (count > slen)
 					count = slen;
 			} else
-			if (count >= TTY_FLIPBUF_SIZE - tty->flip.count)
-				count = TTY_FLIPBUF_SIZE - tty->flip.count - 1;
 			EBCASC(raw->inbuf, count);
 			cchar = ctrlchar_handle(raw->inbuf, count, tty);
 			switch (cchar & CTRLCHAR_MASK) {
···
 				break;
 
 			case CTRLCHAR_CTRL:
-				tty->flip.count++;
-				*tty->flip.flag_buf_ptr++ = TTY_NORMAL;
-				*tty->flip.char_buf_ptr++ = cchar;
+				tty_insert_flip_char(tty, cchar, TTY_NORMAL);
 				tty_flip_buffer_push(raw->tty);
 				break;
 
 			case CTRLCHAR_NONE:
-				memcpy(tty->flip.char_buf_ptr,
-				       raw->inbuf, count);
 				if (count < 2 ||
-				    (strncmp(raw->inbuf+count-2, "^n", 2) &&
-				    strncmp(raw->inbuf+count-2, "\252n", 2)) ) {
-					/* don't add the auto \n */
-					tty->flip.char_buf_ptr[count] = '\n';
-					memset(tty->flip.flag_buf_ptr,
-					       TTY_NORMAL, count + 1);
+				    (strncmp(raw->inbuf+count-2, "\252n", 2) &&
+				     strncmp(raw->inbuf+count-2, "^n", 2)) ) {
+					/* add the auto \n */
+					raw->inbuf[count] = '\n';
 					count++;
 				} else
-					count-=2;
-				tty->flip.char_buf_ptr += count;
-				tty->flip.flag_buf_ptr += count;
-				tty->flip.count += count;
+					count -= 2;
+				tty_insert_flip_string(tty, raw->inbuf, count);
 				tty_flip_buffer_push(raw->tty);
 				break;
 			}

drivers/s390/char/sclp_tty.c

···
 #include <linux/kmod.h>
 #include <linux/tty.h>
 #include <linux/tty_driver.h>
+#include <linux/tty_flip.h>
 #include <linux/sched.h>
 #include <linux/wait.h>
 #include <linux/slab.h>
···
 	case CTRLCHAR_SYSRQ:
 		break;
 	case CTRLCHAR_CTRL:
-		sclp_tty->flip.count++;
-		*sclp_tty->flip.flag_buf_ptr++ = TTY_NORMAL;
-		*sclp_tty->flip.char_buf_ptr++ = cchar;
+		tty_insert_flip_char(sclp_tty, cchar, TTY_NORMAL);
 		tty_flip_buffer_push(sclp_tty);
 		break;
 	case CTRLCHAR_NONE:
 		/* send (normal) input to line discipline */
-		memcpy(sclp_tty->flip.char_buf_ptr, buf, count);
 		if (count < 2 ||
-		    (strncmp ((const char *) buf + count - 2, "^n", 2) &&
-		     strncmp ((const char *) buf + count - 2, "\0252n", 2))) {
-			sclp_tty->flip.char_buf_ptr[count] = '\n';
-			count++;
+		    (strncmp((const char *) buf + count - 2, "^n", 2) &&
+		     strncmp((const char *) buf + count - 2, "\252n", 2))) {
+			/* add the auto \n */
+			tty_insert_flip_string(sclp_tty, buf, count);
+			tty_insert_flip_char(sclp_tty, '\n', TTY_NORMAL);
 		} else
-			count -= 2;
-		memset(sclp_tty->flip.flag_buf_ptr, TTY_NORMAL, count);
-		sclp_tty->flip.char_buf_ptr += count;
-		sclp_tty->flip.flag_buf_ptr += count;
-		sclp_tty->flip.count += count;
+			tty_insert_flip_string(sclp_tty, buf, count - 2);
 		tty_flip_buffer_push(sclp_tty);
 		break;
 	}

drivers/s390/char/sclp_vt220.c

···
 #include <linux/kernel.h>
 #include <linux/tty.h>
 #include <linux/tty_driver.h>
+#include <linux/tty_flip.h>
 #include <linux/sched.h>
 #include <linux/errno.h>
 #include <linux/mm.h>
···
 		/* Send input to line discipline */
 		buffer++;
 		count--;
-		/* Prevent buffer overrun by discarding input. Note that
-		 * because buffer_push works asynchronously, we cannot wait
-		 * for the buffer to be emptied. */
-		if (count + sclp_vt220_tty->flip.count > TTY_FLIPBUF_SIZE)
-			count = TTY_FLIPBUF_SIZE - sclp_vt220_tty->flip.count;
-		memcpy(sclp_vt220_tty->flip.char_buf_ptr, buffer, count);
-		memset(sclp_vt220_tty->flip.flag_buf_ptr, TTY_NORMAL, count);
-		sclp_vt220_tty->flip.char_buf_ptr += count;
-		sclp_vt220_tty->flip.flag_buf_ptr += count;
-		sclp_vt220_tty->flip.count += count;
+		tty_insert_flip_string(sclp_vt220_tty, buffer, count);
 		tty_flip_buffer_push(sclp_vt220_tty);
 		break;
 	}

drivers/s390/net/ctctty.c

···
 #include <linux/config.h>
 #include <linux/module.h>
 #include <linux/tty.h>
+#include <linux/tty_flip.h>
 #include <linux/serial_reg.h>
 #include <linux/interrupt.h>
 #include <linux/delay.h>
···
 static int
 ctc_tty_try_read(ctc_tty_info * info, struct sk_buff *skb)
 {
-	int c;
 	int len;
 	struct tty_struct *tty;
 
 	DBF_TEXT(trace, 5, __FUNCTION__);
 	if ((tty = info->tty)) {
 		if (info->mcr & UART_MCR_RTS) {
-			c = TTY_FLIPBUF_SIZE - tty->flip.count;
 			len = skb->len;
-			if (c >= len) {
-				memcpy(tty->flip.char_buf_ptr, skb->data, len);
-				memset(tty->flip.flag_buf_ptr, 0, len);
-				tty->flip.count += len;
-				tty->flip.char_buf_ptr += len;
-				tty->flip.flag_buf_ptr += len;
-				tty_flip_buffer_push(tty);
-				kfree_skb(skb);
-				return 1;
-			}
+			tty_insert_flip_string(tty, skb->data, len);
+			tty_flip_buffer_push(tty);
+			kfree_skb(skb);
+			return 1;
 		}
 	}
 	return 0;
···
 	DBF_TEXT(trace, 5, __FUNCTION__);
 	if ((tty = info->tty)) {
 		if (info->mcr & UART_MCR_RTS) {
-			int c = TTY_FLIPBUF_SIZE - tty->flip.count;
 			struct sk_buff *skb;
 			
-			if ((c > 0) && (skb = skb_dequeue(&info->rx_queue))) {
+			if ((skb = skb_dequeue(&info->rx_queue))) {
 				int len = skb->len;
-				if (len > c)
-					len = c;
-				memcpy(tty->flip.char_buf_ptr, skb->data, len);
+				tty_insert_flip_string(tty, skb->data, len);
 				skb_pull(skb, len);
-				memset(tty->flip.flag_buf_ptr, 0, len);
-				tty->flip.count += len;
-				tty->flip.char_buf_ptr += len;
-				tty->flip.flag_buf_ptr += len;
 				tty_flip_buffer_push(tty);
 				if (skb->len > 0)
 					skb_queue_head(&info->rx_queue, skb);

drivers/serial/21285.c

···
 
 	status = *CSR_UARTFLG;
 	while (!(status & 0x10) && max_count--) {
-		if (tty->flip.count >= TTY_FLIPBUF_SIZE) {
-			if (tty->low_latency)
-				tty_flip_buffer_push(tty);
-			/*
-			 * If this failed then we will throw away the
-			 * bytes but must do so to clear interrupts
-			 */
-		}
-
 		ch = *CSR_UARTDR;
 		flag = TTY_NORMAL;
 		port->icount.rx++;

drivers/serial/68328serial.c

···
 {
 	struct tty_struct *tty = info->tty;
 	m68328_uart *uart = &uart_addr[info->line];
-	unsigned char ch;
+	unsigned char ch, flag;
 
 	/*
 	 * This do { } while() loop will get ALL chars out of Rx FIFO 
···
 		/*
 		 * Make sure that we do not overflow the buffer
 		 */
-		if (tty->flip.count >= TTY_FLIPBUF_SIZE) {
+		if (tty_request_buffer_room(tty, 1) == 0) {
 			schedule_work(&tty->flip.work);
 			return;
 		}
 
+		flag = TTY_NORMAL;
+
 		if(rx & URX_PARITY_ERROR) {
-			*tty->flip.flag_buf_ptr++ = TTY_PARITY;
+			flag = TTY_PARITY;
 			status_handle(info, rx);
 		} else if(rx & URX_OVRUN) {
-			*tty->flip.flag_buf_ptr++ = TTY_OVERRUN;
+			flag = TTY_OVERRUN;
 			status_handle(info, rx);
 		} else if(rx & URX_FRAME_ERROR) {
-			*tty->flip.flag_buf_ptr++ = TTY_FRAME;
+			flag = TTY_FRAME;
 			status_handle(info, rx);
-		} else {
-			*tty->flip.flag_buf_ptr++ = 0; /* XXX */
 		}
-                *tty->flip.char_buf_ptr++ = ch;
-		tty->flip.count++;
-
+		tty_insert_flip_char(tty, ch, flag);
 #ifndef CONFIG_XCOPILOT_BUGS
 	} while((rx = uart->urx.w) & URX_DATA_READY);
 #endif

drivers/serial/68360serial.c

···
 static _INLINE_ void receive_chars(ser_info_t *info)
 {
 	struct tty_struct *tty = info->tty;
-	unsigned char ch, *cp;
+	unsigned char ch, flag, *cp;
 	/*int	ignored = 0;*/
 	int	i;
 	ushort	status;
···
 		cp = (char *)bdp->buf;
 		status = bdp->status;
 
-		/* Check to see if there is room in the tty buffer for
-		 * the characters in our BD buffer.  If not, we exit
-		 * now, leaving the BD with the characters.  We'll pick
-		 * them up again on the next receive interrupt (which could
-		 * be a timeout).
-		 */
-		if ((tty->flip.count + i) >= TTY_FLIPBUF_SIZE)
-			break;
-
 		while (i-- > 0) {
 			ch = *cp++;
-			*tty->flip.char_buf_ptr = ch;
 			icount->rx++;
 
 #ifdef SERIAL_DEBUG_INTR
 			printk("DR%02x:%02x...", ch, status);
 #endif
-			*tty->flip.flag_buf_ptr = 0;
+			flag = TTY_NORMAL;
+
 			if (status & (BD_SC_BR | BD_SC_FR |
 				       BD_SC_PR | BD_SC_OV)) {
 				/*
···
 					if (info->flags & ASYNC_SAK)
 						do_SAK(tty);
 				} else if (status & BD_SC_PR)
-					*tty->flip.flag_buf_ptr = TTY_PARITY;
+					flag = TTY_PARITY;
 				else if (status & BD_SC_FR)
-					*tty->flip.flag_buf_ptr = TTY_FRAME;
-				if (status & BD_SC_OV) {
-					/*
-					 * Overrun is special, since it's
-					 * reported immediately, and doesn't
-					 * affect the current character
-					 */
-					if (tty->flip.count < TTY_FLIPBUF_SIZE) {
-						tty->flip.count++;
-						tty->flip.flag_buf_ptr++;
-						tty->flip.char_buf_ptr++;
-						*tty->flip.flag_buf_ptr =
-								TTY_OVERRUN;
-					}
-				}
+					flag = TTY_FRAME;
 			}
-			if (tty->flip.count >= TTY_FLIPBUF_SIZE)
-				break;
-
-			tty->flip.flag_buf_ptr++;
-			tty->flip.char_buf_ptr++;
-			tty->flip.count++;
+			tty_insert_flip_char(tty, ch, flag);
+			if (status & BD_SC_OV)
+				/*
+				 * Overrun is special, since it's
+				 * reported immediately, and doesn't
+				 * affect the current character
+				 */
+				tty_insert_flip_char(tty, 0, TTY_OVERRUN);
 		}
 
 		/* This BD is ready to be used again.  Clear status.
···
 	/* Check to see if there is room in the tty buffer for
 	 * the break.  If not, we exit now, losing the break.  FIXME
 	 */
-	if ((tty->flip.count + 1) >= TTY_FLIPBUF_SIZE)
-		return;
-	*(tty->flip.flag_buf_ptr++) = TTY_BREAK;
-	*(tty->flip.char_buf_ptr++) = 0;
-	tty->flip.count++;
-
+	tty_insert_flip_char(tty, 0, TTY_BREAK);
 	schedule_work(&tty->flip.work);
 }
 

drivers/serial/8250.c

···
 	char flag;
 
 	do {
-		/* The following is not allowed by the tty layer and
-		   unsafe. It should be fixed ASAP */
-		if (unlikely(tty->flip.count >= TTY_FLIPBUF_SIZE)) {
-			if (tty->low_latency) {
-				spin_unlock(&up->port.lock);
-				tty_flip_buffer_push(tty);
-				spin_lock(&up->port.lock);
-			}
-			/*
-			 * If this failed then we will throw away the
-			 * bytes but must do so to clear interrupts
-			 */
-		}
 		ch = serial_inp(up, UART_RX);
 		flag = TTY_NORMAL;
 		up->port.icount.rx++;

drivers/serial/amba-pl010.c

···
 
 	status = UART_GET_FR(port);
 	while (UART_RX_DATA(status) && max_count--) {
-		if (tty->flip.count >= TTY_FLIPBUF_SIZE) {
-			if (tty->low_latency)
-				tty_flip_buffer_push(tty);
-			/*
-			 * If this failed then we will throw away the
-			 * bytes but must do so to clear interrupts.
-			 */
-		}
-
 		ch = UART_GET_CHAR(port);
 		flag = TTY_NORMAL;
 

drivers/serial/amba-pl011.c

···
 
 	status = readw(uap->port.membase + UART01x_FR);
 	while ((status & UART01x_FR_RXFE) == 0 && max_count--) {
-		if (tty->flip.count >= TTY_FLIPBUF_SIZE) {
-			if (tty->low_latency)
-				tty_flip_buffer_push(tty);
-			/*
-			 * If this failed then we will throw away the
-			 * bytes but must do so to clear interrupts
-			 */
-		}
-
 		ch = readw(uap->port.membase + UART01x_DR) | UART_DUMMY_DR_RX;
 		flag = TTY_NORMAL;
 		uap->port.icount.rx++;

drivers/serial/au1x00_uart.c

···
 receive_chars(struct uart_8250_port *up, int *status, struct pt_regs *regs)
 {
 	struct tty_struct *tty = up->port.info->tty;
-	unsigned char ch;
+	unsigned char ch, flag;
 	int max_count = 256;
 
 	do {
-		if (unlikely(tty->flip.count >= TTY_FLIPBUF_SIZE)) {
-			tty->flip.work.func((void *)tty);
-			if (tty->flip.count >= TTY_FLIPBUF_SIZE)
-				return; // if TTY_DONT_FLIP is set
-		}
 		ch = serial_inp(up, UART_RX);
-		*tty->flip.char_buf_ptr = ch;
-		*tty->flip.flag_buf_ptr = TTY_NORMAL;
+		flag = TTY_NORMAL;
 		up->port.icount.rx++;
 
 		if (unlikely(*status & (UART_LSR_BI | UART_LSR_PE |
···
 #endif
 			if (*status & UART_LSR_BI) {
 				DEBUG_INTR("handling break....");
-				*tty->flip.flag_buf_ptr = TTY_BREAK;
+				flag = TTY_BREAK;
 			} else if (*status & UART_LSR_PE)
-				*tty->flip.flag_buf_ptr = TTY_PARITY;
+				flag = TTY_PARITY;
 			else if (*status & UART_LSR_FE)
-				*tty->flip.flag_buf_ptr = TTY_FRAME;
+				flag = TTY_FRAME;
 		}
 		if (uart_handle_sysrq_char(&up->port, ch, regs))
 			goto ignore_char;
-		if ((*status & up->port.ignore_status_mask) == 0) {
-			tty->flip.flag_buf_ptr++;
-			tty->flip.char_buf_ptr++;
-			tty->flip.count++;
-		}
-		if ((*status & UART_LSR_OE) &&
-		    tty->flip.count < TTY_FLIPBUF_SIZE) {
+		if ((*status & up->port.ignore_status_mask) == 0)
+			tty_insert_flip_char(tty, ch, flag);
+		if (*status & UART_LSR_OE)
 			/*
 			 * Overrun is special, since it's reported
 			 * immediately, and doesn't affect the current
 			 * character.
 			 */
-			*tty->flip.flag_buf_ptr = TTY_OVERRUN;
-			tty->flip.flag_buf_ptr++;
-			tty->flip.char_buf_ptr++;
-			tty->flip.count++;
+			tty_insert_flip_char(tty, 0, TTY_OVERRUN);
 		}
 	ignore_char:
 		*status = serial_inp(up, UART_LSR);

drivers/serial/clps711x.c

···
 	while (!(status & SYSFLG_URXFE)) {
 		ch = clps_readl(UARTDR(port));
 
-		if (tty->flip.count >= TTY_FLIPBUF_SIZE)
-			goto ignore_char;
 		port->icount.rx++;
 
 		flg = TTY_NORMAL;

drivers/serial/dz.c

···
 
 		if (!tty)
 			break;
-		if (tty->flip.count >= TTY_FLIPBUF_SIZE)
-			break;
 
 		icount->rx++;
 

drivers/serial/icom.c

···
 	unsigned short int status;
 	struct uart_icount *icount;
 	unsigned long offset;
+	unsigned char flag;
 
 	trace(icom_port, "RCV_COMPLETE", 0);
 	rcv_buff = icom_port->next_rcv;
 
 	status = cpu_to_le16(icom_port->statStg->rcv[rcv_buff].flags);
 	while (status & SA_FL_RCV_DONE) {
+		int first = -1;
 
 		trace(icom_port, "FID_STATUS", status);
 		count = cpu_to_le16(icom_port->statStg->rcv[rcv_buff].leLength);
 
+                count = tty_buffer_request_room(tty, count);
 		trace(icom_port, "RCV_COUNT", count);
-		if (count > (TTY_FLIPBUF_SIZE - tty->flip.count))
-			count = TTY_FLIPBUF_SIZE - tty->flip.count;
 
 		trace(icom_port, "REAL_COUNT", count);
 
···
 			cpu_to_le32(icom_port->statStg->rcv[rcv_buff].leBuffer) -
 			icom_port->recv_buf_pci;
 
-		memcpy(tty->flip.char_buf_ptr,(unsigned char *)
-		       ((unsigned long)icom_port->recv_buf + offset), count);
-
+		/* Block copy all but the last byte as this may have status */
 		if (count > 0) {
-			tty->flip.count += count - 1;
-			tty->flip.char_buf_ptr += count - 1;
-
-			memset(tty->flip.flag_buf_ptr, 0, count);
-			tty->flip.flag_buf_ptr += count - 1;
+			first = icom_port->recv_buf[offset];
+			tty_insert_flip_string(tty, icom_port->recv_buf + offset, count - 1);
 		}
 
 		icount = &icom_port->uart_port.icount;
···
 
 		/* Break detect logic */
 		if ((status & SA_FLAGS_FRAME_ERROR)
-		    && (tty->flip.char_buf_ptr[0] == 0x00)) {
+		    && first == 0) {
 			status &= ~SA_FLAGS_FRAME_ERROR;
 			status |= SA_FLAGS_BREAK_DET;
 			trace(icom_port, "BREAK_DET", 0);
 		}
+
+		flag = TTY_NORMAL;
 
 		if (status &
 		    (SA_FLAGS_BREAK_DET | SA_FLAGS_PARITY_ERROR |
···
 			status &= icom_port->read_status_mask;
 
 			if (status & SA_FLAGS_BREAK_DET) {
-				*tty->flip.flag_buf_ptr = TTY_BREAK;
+				flag = TTY_BREAK;
 			} else if (status & SA_FLAGS_PARITY_ERROR) {
 				trace(icom_port, "PARITY_ERROR", 0);
-				*tty->flip.flag_buf_ptr = TTY_PARITY;
+				flag = TTY_PARITY;
 			} else if (status & SA_FLAGS_FRAME_ERROR)
-				*tty->flip.flag_buf_ptr = TTY_FRAME;
+				flag = TTY_FRAME;
 
-			if (status & SA_FLAGS_OVERRUN) {
-				/*
-				 * Overrun is special, since it's
-				 * reported immediately, and doesn't
-				 * affect the current character
-				 */
-				if (tty->flip.count < TTY_FLIPBUF_SIZE) {
-					tty->flip.count++;
-					tty->flip.flag_buf_ptr++;
-					tty->flip.char_buf_ptr++;
-					*tty->flip.flag_buf_ptr = TTY_OVERRUN;
-				}
-			}
 		}
 
-		tty->flip.flag_buf_ptr++;
-		tty->flip.char_buf_ptr++;
-		tty->flip.count++;
-		ignore_char:
-			icom_port->statStg->rcv[rcv_buff].flags = 0;
+		tty_insert_flip_char(tty, *(icom_port->recv_buf + offset + count - 1), flag);
+
+		if (status & SA_FLAGS_OVERRUN)
+			/*
+			 * Overrun is special, since it's
+			 * reported immediately, and doesn't
+			 * affect the current character
+			 */
+			tty_insert_flip_char(tty, 0, TTY_OVERRUN);
+ignore_char:
+		icom_port->statStg->rcv[rcv_buff].flags = 0;
 		icom_port->statStg->rcv[rcv_buff].leLength = 0;
 		icom_port->statStg->rcv[rcv_buff].WorkingLength =
 			(unsigned short int) cpu_to_le16(RCV_BUFF_SZ);

drivers/serial/imx.c

···
 	error_return:
 		tty_insert_flip_char(tty, rx, flg);
 
-		if (tty->flip.count >= TTY_FLIPBUF_SIZE)
-			goto out;
-
 	ignore_char:
 		rx = URXD0((u32)sport->port.membase);
 	} while(rx & URXD_CHARRDY);

drivers/serial/ioc4_serial.c

···
 	spin_lock_irqsave(&the_port->lock, pflags);
 	tty = info->tty;
 
-	if (request_count > TTY_FLIPBUF_SIZE - tty->flip.count)
-		request_count = TTY_FLIPBUF_SIZE - tty->flip.count;
+	request_count = tty_buffer_request_room(tty, IOC4_MAX_CHARS - 2);
 
 	if (request_count > 0) {
 		icount = &the_port->icount;
 		read_count = do_read(the_port, ch, request_count);
 		if (read_count > 0) {
-			flip = 1;
-			memcpy(tty->flip.char_buf_ptr, ch, read_count);
-			memset(tty->flip.flag_buf_ptr, TTY_NORMAL, read_count);
-			tty->flip.char_buf_ptr += read_count;
-			tty->flip.flag_buf_ptr += read_count;
-			tty->flip.count += read_count;
+			tty_insert_flip_string(tty, ch, read_count);
 			icount->rx += read_count;
 		}
 	}

drivers/serial/ip22zilog.c

···
 	struct tty_struct *tty = up->port.info->tty;	/* XXX info==NULL? */
 
 	while (1) {
-		unsigned char ch, r1;
-
-		if (unlikely(tty->flip.count >= TTY_FLIPBUF_SIZE)) {
-			tty->flip.work.func((void *)tty);
-			if (tty->flip.count >= TTY_FLIPBUF_SIZE)
-				return;		/* XXX Ignores SysRq when we need it most. Fix. */
-		}
+		unsigned char ch, r1, flag;
 
 		r1 = read_zsreg(channel, R1);
 		if (r1 & (PAR_ERR | Rx_OVR | CRC_ERR)) {
···
 		}
 
 		/* A real serial line, record the character and status.  */
-		*tty->flip.char_buf_ptr = ch;
-		*tty->flip.flag_buf_ptr = TTY_NORMAL;
+		flag = TTY_NORMAL;
 		up->port.icount.rx++;
 		if (r1 & (BRK_ABRT | PAR_ERR | Rx_OVR | CRC_ERR)) {
 			if (r1 & BRK_ABRT) {
···
 				up->port.icount.overrun++;
 			r1 &= up->port.read_status_mask;
 			if (r1 & BRK_ABRT)
-				*tty->flip.flag_buf_ptr = TTY_BREAK;
+				flag = TTY_BREAK;
 			else if (r1 & PAR_ERR)
-				*tty->flip.flag_buf_ptr = TTY_PARITY;
+				flag = TTY_PARITY;
 			else if (r1 & CRC_ERR)
-				*tty->flip.flag_buf_ptr = TTY_FRAME;
+				flag = TTY_FRAME;
 		}
 		if (uart_handle_sysrq_char(&up->port, ch, regs))
 			goto next_char;
 
 		if (up->port.ignore_status_mask == 0xff ||
-		    (r1 & up->port.ignore_status_mask) == 0) {
-			tty->flip.flag_buf_ptr++;
-			tty->flip.char_buf_ptr++;
-			tty->flip.count++;
-		}
-		if ((r1 & Rx_OVR) &&
-		    tty->flip.count < TTY_FLIPBUF_SIZE) {
-			*tty->flip.flag_buf_ptr = TTY_OVERRUN;
-			tty->flip.flag_buf_ptr++;
-			tty->flip.char_buf_ptr++;
-			tty->flip.count++;
-		}
+		    (r1 & up->port.ignore_status_mask) == 0)
+		    	tty_insert_flip_char(tty, ch, flag);
+
+		if (r1 & Rx_OVR)
+			tty_insert_flip_char(tty, 0, TTY_OVERRUN);
 	next_char:
 		ch = readb(&channel->control);
 		ZSDELAY();

drivers/serial/m32r_sio.c

···
 {
 	struct tty_struct *tty = up->port.info->tty;
 	unsigned char ch;
+	unsigned char flag;
 	int max_count = 256;
 
 	do {
-		if (unlikely(tty->flip.count >= TTY_FLIPBUF_SIZE)) {
-			tty->flip.work.func((void *)tty);
-			if (tty->flip.count >= TTY_FLIPBUF_SIZE)
-				return; // if TTY_DONT_FLIP is set
-		}
 		ch = sio_in(up, SIORXB);
-		*tty->flip.char_buf_ptr = ch;
-		*tty->flip.flag_buf_ptr = TTY_NORMAL;
+		flag = TTY_NORMAL;
 		up->port.icount.rx++;
 
 		if (unlikely(*status & (UART_LSR_BI | UART_LSR_PE |
···
 
 			if (*status & UART_LSR_BI) {
 				DEBUG_INTR("handling break....");
-				*tty->flip.flag_buf_ptr = TTY_BREAK;
+				flag = TTY_BREAK;
 			} else if (*status & UART_LSR_PE)
-				*tty->flip.flag_buf_ptr = TTY_PARITY;
+				flag = TTY_PARITY;
 			else if (*status & UART_LSR_FE)
-				*tty->flip.flag_buf_ptr = TTY_FRAME;
+				flag = TTY_FRAME;
 		}
 		if (uart_handle_sysrq_char(&up->port, ch, regs))
 			goto ignore_char;
-		if ((*status & up->port.ignore_status_mask) == 0) {
-			tty->flip.flag_buf_ptr++;
-			tty->flip.char_buf_ptr++;
-			tty->flip.count++;
-		}
-		if ((*status & UART_LSR_OE) &&
-		    tty->flip.count < TTY_FLIPBUF_SIZE) {
+		if ((*status & up->port.ignore_status_mask) == 0)
+			tty_insert_flip_char(tty, ch, flag);
+
+		if (*status & UART_LSR_OE) {
 			/*
 			 * Overrun is special, since it's reported
 			 * immediately, and doesn't affect the current
 			 * character.
 			 */
-			*tty->flip.flag_buf_ptr = TTY_OVERRUN;
-			tty->flip.flag_buf_ptr++;
-			tty->flip.char_buf_ptr++;
-			tty->flip.count++;
+			tty_insert_flip_char(tty, 0, TTY_OVERRUN);
 		}
 	ignore_char:
 		*status = serial_in(up, UART_LSR);

drivers/serial/mcfserial.c

···
 {
 	volatile unsigned char	*uartp;
 	struct tty_struct	*tty = info->tty;
-	unsigned char		status, ch;
+	unsigned char		status, ch, flag;
 
 	if (!tty)
 		return;
···
 	uartp = info->addr;
 
 	while ((status = uartp[MCFUART_USR]) & MCFUART_USR_RXREADY) {
-
-		if (tty->flip.count >= TTY_FLIPBUF_SIZE)
-			break;
-
 		ch = uartp[MCFUART_URB];
 		info->stats.rx++;
 
···
 		}
 #endif
 
-		tty->flip.count++;
+		flag = TTY_NORMAL;
 		if (status & MCFUART_USR_RXERR) {
 			uartp[MCFUART_UCR] = MCFUART_UCR_CMDRESETERR;
 			if (status & MCFUART_USR_RXBREAK) {
 				info->stats.rxbreak++;
-				*tty->flip.flag_buf_ptr++ = TTY_BREAK;
+				flag = TTY_BREAK;
 			} else if (status & MCFUART_USR_RXPARITY) {
 				info->stats.rxparity++;
-				*tty->flip.flag_buf_ptr++ = TTY_PARITY;
+				flag = TTY_PARITY;
 			} else if (status & MCFUART_USR_RXOVERRUN) {
 				info->stats.rxoverrun++;
-				*tty->flip.flag_buf_ptr++ = TTY_OVERRUN;
+				flag = TTY_OVERRUN;
 			} else if (status & MCFUART_USR_RXFRAMING) {
 				info->stats.rxframing++;
-				*tty->flip.flag_buf_ptr++ = TTY_FRAME;
-			} else {
-				/* This should never happen... */
-				*tty->flip.flag_buf_ptr++ = 0;
+				flag = TTY_FRAME;
 			}
-		} else {
-			*tty->flip.flag_buf_ptr++ = 0;
 		}
-		*tty->flip.char_buf_ptr++ = ch;
+		tty_insert_flip_char(tty, ch, flag);
 	}
 
 	schedule_work(&tty->flip.work);

drivers/serial/mpc52xx_uart.c

···
 mpc52xx_uart_int_rx_chars(struct uart_port *port, struct pt_regs *regs)
 {
 	struct tty_struct *tty = port->info->tty;
-	unsigned char ch;
+	unsigned char ch, flag;
 	unsigned short status;
 
 	/* While we can read, do so ! */
 	while ( (status = in_be16(&PSC(port)->mpc52xx_psc_status)) &
 	        MPC52xx_PSC_SR_RXRDY) {
 
-		/* If we are full, just stop reading */
-		if (tty->flip.count >= TTY_FLIPBUF_SIZE)
-			break;
-		
 		/* Get the char */
 		ch = in_8(&PSC(port)->mpc52xx_psc_buffer_8);
 
···
 #endif
 
 		/* Store it */
-		*tty->flip.char_buf_ptr = ch;
-		*tty->flip.flag_buf_ptr = 0;
+
+		flag = TTY_NORMAL;
 		port->icount.rx++;
 	
 		if ( status & (MPC52xx_PSC_SR_PE |
 		               MPC52xx_PSC_SR_FE |
-		               MPC52xx_PSC_SR_RB |
-		               MPC52xx_PSC_SR_OE) ) {
+		               MPC52xx_PSC_SR_RB) ) {
 			
 			if (status & MPC52xx_PSC_SR_RB) {
-				*tty->flip.flag_buf_ptr = TTY_BREAK;
+				flag = TTY_BREAK;
 				uart_handle_break(port);
 			} else if (status & MPC52xx_PSC_SR_PE)
-				*tty->flip.flag_buf_ptr = TTY_PARITY;
+				flag = TTY_PARITY;
 			else if (status & MPC52xx_PSC_SR_FE)
-				*tty->flip.flag_buf_ptr = TTY_FRAME;
-			if (status & MPC52xx_PSC_SR_OE) {
-				/*
-				 * Overrun is special, since it's
-				 * reported immediately, and doesn't
-				 * affect the current character
-				 */
-				if (tty->flip.count < (TTY_FLIPBUF_SIZE-1)) {
-					tty->flip.flag_buf_ptr++;
-					tty->flip.char_buf_ptr++;
-					tty->flip.count++;
-				}
-				*tty->flip.flag_buf_ptr = TTY_OVERRUN;
-			}
+				flag = TTY_FRAME;
 
 			/* Clear error condition */
 			out_8(&PSC(port)->command,MPC52xx_PSC_RST_ERR_STAT);
 
 		}
-
-		tty->flip.char_buf_ptr++;
-		tty->flip.flag_buf_ptr++;
-		tty->flip.count++;
-
+		tty_insert_flip_char(tty, ch, flag);
+		if (status & MPC52xx_PSC_SR_OE) {
+			/*
+			 * Overrun is special, since it's
+			 * reported immediately, and doesn't
+			 * affect the current character
+			 */
+			tty_insert_flip_char(tty, 0, TTY_OVERRUN);
+		}
 	}
 
 	tty_flip_buffer_push(tty);

drivers/serial/mpsc.c

···
 		bytes_in = be16_to_cpu(rxre->bytecnt);
 
 		/* Following use of tty struct directly is deprecated */
-		if (unlikely((tty->flip.count + bytes_in) >= TTY_FLIPBUF_SIZE)){
+		if (unlikely(tty_buffer_request_room(tty, bytes_in) < bytes_in)) {
 			if (tty->low_latency)
 				tty_flip_buffer_push(tty);
 			/*
-			 * If this failed then we will throw awa the bytes
-			 * but mst do so to clear interrupts.
+			 * If this failed then we will throw away the bytes
+			 * but must do so to clear interrupts.
 			 */
 		}
 

drivers/serial/mux.c

···
 		if (MUX_EOFIFO(data))
 			break;
 
-		if (tty->flip.count >= TTY_FLIPBUF_SIZE)
-			continue;
-
-		*tty->flip.char_buf_ptr = data & 0xffu;
-		*tty->flip.flag_buf_ptr = TTY_NORMAL;
 		port->icount.rx++;
 
 		if (MUX_BREAK(data)) {
···
 		if (uart_handle_sysrq_char(port, data & 0xffu, NULL))
 			continue;
 
-		tty->flip.flag_buf_ptr++;
-		tty->flip.char_buf_ptr++;
-		tty->flip.count++;
+		tty_insert_flip_char(tty, data & 0xFF, TTY_NORMAL);
 	}
 	
 	if (start_count != port->icount.rx) {

drivers/serial/pmac_zilog.c

···
 					    struct pt_regs *regs)
 {
 	struct tty_struct *tty = NULL;
-	unsigned char ch, r1, drop, error;
+	unsigned char ch, r1, drop, error, flag;
 	int loops = 0;
 
- retry:
 	/* The interrupt can be enabled when the port isn't open, typically
 	 * that happens when using one port is open and the other closed (stale
 	 * interrupt) or when one port is used as a console.
···
 	while (1) {
 		error = 0;
 		drop = 0;
-
-		if (unlikely(tty->flip.count >= TTY_FLIPBUF_SIZE)) {
-			/* Have to drop the lock here */
-			pmz_debug("pmz: flip overflow\n");
-			spin_unlock(&uap->port.lock);
-			tty->flip.work.func((void *)tty);
-			spin_lock(&uap->port.lock);
-			if (tty->flip.count >= TTY_FLIPBUF_SIZE)
-				drop = 1;
-			if (ZS_IS_ASLEEP(uap))
-				return NULL;
-			if (!ZS_IS_OPEN(uap))
-				goto retry;
-		}
 
 		r1 = read_zsreg(uap, R1);
 		ch = read_zsdata(uap);
···
 		if (drop)
 			goto next_char;
 
-		*tty->flip.char_buf_ptr = ch;
-		*tty->flip.flag_buf_ptr = TTY_NORMAL;
+		flag = TTY_NORMAL;
 		uap->port.icount.rx++;
 
 		if (r1 & (PAR_ERR | Rx_OVR | CRC_ERR | BRK_ABRT)) {
···
 				uap->port.icount.overrun++;
 			r1 &= uap->port.read_status_mask;
 			if (r1 & BRK_ABRT)
-				*tty->flip.flag_buf_ptr = TTY_BREAK;
+				flag = TTY_BREAK;
 			else if (r1 & PAR_ERR)
-				*tty->flip.flag_buf_ptr = TTY_PARITY;
+				flag = TTY_PARITY;
 			else if (r1 & CRC_ERR)
-				*tty->flip.flag_buf_ptr = TTY_FRAME;
+				flag = TTY_FRAME;
 		}
 
 		if (uap->port.ignore_status_mask == 0xff ||
 		    (r1 & uap->port.ignore_status_mask) == 0) {
-			tty->flip.flag_buf_ptr++;
-			tty->flip.char_buf_ptr++;
-			tty->flip.count++;
+		    	tty_insert_flip_char(tty, ch, flag);
 		}
-		if ((r1 & Rx_OVR) &&
-		    tty->flip.count < TTY_FLIPBUF_SIZE) {
-			*tty->flip.flag_buf_ptr = TTY_OVERRUN;
-			tty->flip.flag_buf_ptr++;
-			tty->flip.char_buf_ptr++;
-			tty->flip.count++;
-		}
+		if (r1 & Rx_OVR)
+			tty_insert_flip_char(tty, 0, TTY_OVERRUN);
 	next_char:
 		/* We can get stuck in an infinite loop getting char 0 when the
 		 * line is in a wrong HW state, we break that here.

drivers/serial/pxa.c

···
 	int max_count = 256;
 
 	do {
-		if (unlikely(tty->flip.count >= TTY_FLIPBUF_SIZE)) {
-			if (tty->low_latency)
-				tty_flip_buffer_push(tty);
-			/*
-			 * If this failed then we will throw away the
-			 * bytes but must do so to clear interrupts
-			 */
-		}
 		ch = serial_in(up, UART_RX);
 		flag = TTY_NORMAL;
 		up->port.icount.rx++;

drivers/serial/s3c2410.c

···
 		if (s3c24xx_serial_rx_fifocnt(ourport, ufstat) == 0)
 			break;
 
-		if (tty->flip.count >= TTY_FLIPBUF_SIZE) {
-			if (tty->low_latency)
-				tty_flip_buffer_push(tty);
-
-			/*
-			 * If this failed then we will throw away the
-			 * bytes but must do so to clear interrupts
-			 */
-		}
-
 		uerstat = rd_regl(port, S3C2410_UERSTAT);
 		ch = rd_regb(port, S3C2410_URXH);
 

drivers/serial/sa1100.c

···
 	while (status & UTSR1_TO_SM(UTSR1_RNE)) {
 		ch = UART_GET_CHAR(sport);
 
-		if (tty->flip.count >= TTY_FLIPBUF_SIZE)
-			goto ignore_char;
 		sport->port.icount.rx++;
 
 		flg = TTY_NORMAL;

drivers/serial/serial_lh7a40x.c

···
 	unsigned int data, flag;/* Received data and status */
 
 	while (!(UR (port, UART_R_STATUS) & nRxRdy) && --cbRxMax) {
-		if (tty->flip.count >= TTY_FLIPBUF_SIZE) {
-			if (tty->low_latency)
-				tty_flip_buffer_push(tty);
-			/*
-			 * If this failed then we will throw away the
-			 * bytes but must do so to clear interrupts
-			 */
-		}
-
 		data = UR (port, UART_R_DATA);
 		flag = TTY_NORMAL;
 		++port->icount.rx;

drivers/serial/serial_txx9.c

···
 	char flag;
 
 	do {
-		/* The following is not allowed by the tty layer and
-		   unsafe. It should be fixed ASAP */
-		if (unlikely(tty->flip.count >= TTY_FLIPBUF_SIZE)) {
-			if (tty->low_latency) {
-				spin_unlock(&up->port.lock);
-				tty_flip_buffer_push(tty);
-				spin_lock(&up->port.lock);
-			}
-			/* If this failed then we will throw away the
-			   bytes but must do so to clear interrupts */
-		}
 		ch = sio_in(up, TXX9_SIRFIFO);
 		flag = TTY_NORMAL;
 		up->port.icount.rx++;

drivers/serial/sh-sci.c

···
 	struct tty_struct *tty = port->info->tty;
 	int i, count, copied = 0;
 	unsigned short status;
+	unsigned char flag;
 
 	status = sci_in(port, SCxSR);
 	if (!(status & SCxSR_RDxF(port)))
···
 #endif
 
 		/* Don't copy more bytes than there is room for in the buffer */
-		if (tty->flip.count + count > TTY_FLIPBUF_SIZE)
-			count = TTY_FLIPBUF_SIZE - tty->flip.count;
+		count = tty_buffer_request_room(tty, count);
 
 		/* If for any reason we can't copy more data, we're done! */
 		if (count == 0)
···
 			    || uart_handle_sysrq_char(port, c, regs)) {
 				count = 0;
 			} else {
-			    tty->flip.char_buf_ptr[0] = c;
-			    tty->flip.flag_buf_ptr[0] = TTY_NORMAL;
+			    tty_insert_flip_char(tty, c, TTY_NORMAL);
 			}
 		} else {
 			for (i=0; i<count; i++) {
···
 				}
 
 				/* Store data and status */
-				tty->flip.char_buf_ptr[i] = c;
 				if (status&SCxSR_FER(port)) {
-					tty->flip.flag_buf_ptr[i] = TTY_FRAME;
+					flag = TTY_FRAME;
 					pr_debug("sci: frame error\n");
 				} else if (status&SCxSR_PER(port)) {
-					tty->flip.flag_buf_ptr[i] = TTY_PARITY;
+					flag = TTY_PARITY;
 					pr_debug("sci: parity error\n");
-				} else {
-					tty->flip.flag_buf_ptr[i] = TTY_NORMAL;
-				}
+				} else
+					flag = TTY_NORMAL;
+				tty_insert_flip_char(tty, c, flag);
 			}
 		}
 
 		sci_in(port, SCxSR); /* dummy read */
 		sci_out(port, SCxSR, SCxSR_RDxF_CLEAR(port));
 
-		/* Update the kernel buffer end */
-		tty->flip.count += count;
-		tty->flip.char_buf_ptr += count;
-		tty->flip.flag_buf_ptr += count;
 		copied += count;
 		port->icount.rx += count;
 	}
···
 	unsigned short status = sci_in(port, SCxSR);
 	struct tty_struct *tty = port->info->tty;
 
-	if (status&SCxSR_ORER(port) && tty->flip.count<TTY_FLIPBUF_SIZE) {
+	if (status&SCxSR_ORER(port)) {
 		/* overrun error */
-		copied++;
-		*tty->flip.flag_buf_ptr++ = TTY_OVERRUN;
+		if(tty_insert_flip_char(tty, 0, TTY_OVERRUN))
+			copied++;
 		pr_debug("sci: overrun error\n");
 	}
 
-	if (status&SCxSR_FER(port) && tty->flip.count<TTY_FLIPBUF_SIZE) {
+	if (status&SCxSR_FER(port)) {
 		if (sci_rxd_in(port) == 0) {
 			/* Notify of BREAK */
 			struct sci_port * sci_port = (struct sci_port *)port;
-                       if(!sci_port->break_flag) {
-	                        sci_port->break_flag = 1;
-                               sci_schedule_break_timer((struct sci_port *)port);
+			if(!sci_port->break_flag) {
+	                	sci_port->break_flag = 1;
+	                	sci_schedule_break_timer((struct sci_port *)port);
 				/* Do sysrq handling. */
-				if(uart_handle_break(port)) {
+				if(uart_handle_break(port))
 					return 0;
-				}
 			        pr_debug("sci: BREAK detected\n");
-			        copied++;
-			        *tty->flip.flag_buf_ptr++ = TTY_BREAK;
+			        if(tty_insert_flip_char(tty, 0, TTY_BREAK))
+				        copied++;
                        }
 		}
 		else {
 			/* frame error */
-			copied++;
-			*tty->flip.flag_buf_ptr++ = TTY_FRAME;
+			if(tty_insert_flip_char(tty, 0, TTY_FRAME))
+				copied++;
 			pr_debug("sci: frame error\n");
 		}
 	}
 
-	if (status&SCxSR_PER(port) && tty->flip.count<TTY_FLIPBUF_SIZE) {
+	if (status&SCxSR_PER(port)) {
+		if(tty_insert_flip_char(tty, 0, TTY_PARITY))
+			copied++;
 		/* parity error */
-		copied++;
-		*tty->flip.flag_buf_ptr++ = TTY_PARITY;
 		pr_debug("sci: parity error\n");
 	}
 
-	if (copied) {
-		tty->flip.count += copied;
+	if (copied)
 		tty_flip_buffer_push(tty);
-	}
 
 	return copied;
 }
···
 	struct tty_struct *tty = port->info->tty;
 	struct sci_port *s = &sci_ports[port->line];
 
-	if (!s->break_flag && status & SCxSR_BRK(port) &&
-	    tty->flip.count < TTY_FLIPBUF_SIZE) {
+	if (!s->break_flag && status & SCxSR_BRK(port))
 #if defined(CONFIG_CPU_SH3)
 		/* Debounce break */
 		s->break_flag = 1;
 #endif
 		/* Notify of BREAK */
-		copied++;
-		*tty->flip.flag_buf_ptr++ = TTY_BREAK;
+		if(tty_insert_flip_char(tty, 0, TTY_BREAK))
+			copied++;
 		pr_debug("sci: BREAK detected\n");
 	}
 
···
 	/* XXX: Handle SCIF overrun error */
 	if (port->type == PORT_SCIF && (sci_in(port, SCLSR) & SCIF_ORER) != 0) {
 		sci_out(port, SCLSR, 0);
-		if(tty->flip.count<TTY_FLIPBUF_SIZE) {
+		if(tty_insert_flip_char(tty, 0, TTY_OVERRUN)) {
 			copied++;
-			*tty->flip.flag_buf_ptr++ = TTY_OVERRUN;
 			pr_debug("sci: overrun error\n");
 		}
 	}
 #endif
 
-	if (copied) {
-		tty->flip.count += copied;
+	if (copied)
 		tty_flip_buffer_push(tty);
-	}
-
 	return copied;
 }
 
···
 			struct tty_struct *tty = port->info->tty;
 
 			sci_out(port, SCLSR, 0);
-			if(tty->flip.count<TTY_FLIPBUF_SIZE) {
-				*tty->flip.flag_buf_ptr++ = TTY_OVERRUN;
-				tty->flip.count++;
-				tty_flip_buffer_push(tty);
-				pr_debug("scif: overrun error\n");
-			}
+			tty_insert_flip_char(tty, 0, TTY_OVERRUN);
+			tty_flip_buffer_push(tty);
+			pr_debug("scif: overrun error\n");
 		}
 #endif
 		sci_rx_interrupt(irq, ptr, regs);

drivers/serial/sn_console.c

···
 
 		/* record the character to pass up to the tty layer */
 		if (tty) {
-			*tty->flip.char_buf_ptr = ch;
-			*tty->flip.flag_buf_ptr = TTY_NORMAL;
-			tty->flip.char_buf_ptr++;
-			tty->flip.count++;
-			if (tty->flip.count == TTY_FLIPBUF_SIZE)
+			if(tty_insert_flip_char(tty, ch, TTY_NORMAL) == 0)
 				break;
 		}
 		port->sc_port.icount.rx++;

drivers/serial/sunsab.c

···
 		saw_console_brk = 1;
 
 	for (i = 0; i < count; i++) {
-		unsigned char ch = buf[i];
+		unsigned char ch = buf[i], flag;
 
 		if (tty == NULL) {
 			uart_handle_sysrq_char(&up->port, ch, regs);
 			continue;
 		}
 
-		if (unlikely(tty->flip.count >= TTY_FLIPBUF_SIZE)) {
-			tty->flip.work.func((void *)tty);
-			if (tty->flip.count >= TTY_FLIPBUF_SIZE)
-				return tty; // if TTY_DONT_FLIP is set
-		}
-
-		*tty->flip.char_buf_ptr = ch;
-		*tty->flip.flag_buf_ptr = TTY_NORMAL;
+		flag = TTY_NORMAL;
 		up->port.icount.rx++;
 
 		if (unlikely(stat->sreg.isr0 & (SAB82532_ISR0_PERR |
···
 			stat->sreg.isr1 &= ((up->port.read_status_mask >> 8) & 0xff);
 
 			if (stat->sreg.isr1 & SAB82532_ISR1_BRK) {
-				*tty->flip.flag_buf_ptr = TTY_BREAK;
+				flag = TTY_BREAK;
 			} else if (stat->sreg.isr0 & SAB82532_ISR0_PERR)
-				*tty->flip.flag_buf_ptr = TTY_PARITY;
+				flag = TTY_PARITY;
 			else if (stat->sreg.isr0 & SAB82532_ISR0_FERR)
-				*tty->flip.flag_buf_ptr = TTY_FRAME;
+				flag = TTY_FRAME;
 		}
 
 		if (uart_handle_sysrq_char(&up->port, ch, regs))
 			continue;
 
 		if ((stat->sreg.isr0 & (up->port.ignore_status_mask & 0xff)) == 0 &&
-		    (stat->sreg.isr1 & ((up->port.ignore_status_mask >> 8) & 0xff)) == 0){
-			tty->flip.flag_buf_ptr++;
-			tty->flip.char_buf_ptr++;
-			tty->flip.count++;
-		}
-		if ((stat->sreg.isr0 & SAB82532_ISR0_RFO) &&
-		    tty->flip.count < TTY_FLIPBUF_SIZE) {
-			/*
-			 * Overrun is special, since it's reported
-			 * immediately, and doesn't affect the current
-			 * character.
-			 */
-			*tty->flip.flag_buf_ptr = TTY_OVERRUN;
-			tty->flip.flag_buf_ptr++;
-			tty->flip.char_buf_ptr++;
-			tty->flip.count++;
-		}
+		    (stat->sreg.isr1 & ((up->port.ignore_status_mask >> 8) & 0xff)) == 0)
+			tty_insert_flip_char(tty, ch, flag);
+		if (stat->sreg.isr0 & SAB82532_ISR0_RFO)
+			tty_insert_flip_char(tty, 0, TTY_OVERRUN);
 	}
 
 	if (saw_console_brk)

drivers/serial/sunsu.c

···
 receive_chars(struct uart_sunsu_port *up, unsigned char *status, struct pt_regs *regs)
 {
 	struct tty_struct *tty = up->port.info->tty;
-	unsigned char ch;
+	unsigned char ch, flag;
 	int max_count = 256;
 	int saw_console_brk = 0;
 
 	do {
-		if (unlikely(tty->flip.count >= TTY_FLIPBUF_SIZE)) {
-			tty->flip.work.func((void *)tty);
-			if (tty->flip.count >= TTY_FLIPBUF_SIZE)
-				return tty; // if TTY_DONT_FLIP is set
-		}
 		ch = serial_inp(up, UART_RX);
-		*tty->flip.char_buf_ptr = ch;
-		*tty->flip.flag_buf_ptr = TTY_NORMAL;
+		flag = TTY_NORMAL;
 		up->port.icount.rx++;
 
 		if (unlikely(*status & (UART_LSR_BI | UART_LSR_PE |
···
 			}
 
 			if (*status & UART_LSR_BI) {
-				*tty->flip.flag_buf_ptr = TTY_BREAK;
+				flag = TTY_BREAK;
 			} else if (*status & UART_LSR_PE)
-				*tty->flip.flag_buf_ptr = TTY_PARITY;
+				flag = TTY_PARITY;
 			else if (*status & UART_LSR_FE)
-				*tty->flip.flag_buf_ptr = TTY_FRAME;
+				flag = TTY_FRAME;
 		}
 		if (uart_handle_sysrq_char(&up->port, ch, regs))
 			goto ignore_char;
-		if ((*status & up->port.ignore_status_mask) == 0) {
-			tty->flip.flag_buf_ptr++;
-			tty->flip.char_buf_ptr++;
-			tty->flip.count++;
-		}
-		if ((*status & UART_LSR_OE) &&
-		    tty->flip.count < TTY_FLIPBUF_SIZE) {
+		if ((*status & up->port.ignore_status_mask) == 0)
+			tty_insert_flip_char(tty, ch, flag);
+		if (*status & UART_LSR_OE)
 			/*
 			 * Overrun is special, since it's reported
 			 * immediately, and doesn't affect the current
 			 * character.
 			 */
-			*tty->flip.flag_buf_ptr = TTY_OVERRUN;
-			tty->flip.flag_buf_ptr++;
-			tty->flip.char_buf_ptr++;
-			tty->flip.count++;
-		}
+			 tty_insert_flip_char(tty, 0, TTY_OVERRUN);
 	ignore_char:
 		*status = serial_inp(up, UART_LSR);
 	} while ((*status & UART_LSR_DR) && (max_count-- > 0));

drivers/serial/sunzilog.c

···
 		       struct pt_regs *regs)
 {
 	struct tty_struct *tty;
-	unsigned char ch, r1;
+	unsigned char ch, r1, flag;
 
 	tty = NULL;
 	if (up->port.info != NULL &&		/* Unopened serial console */
···
 			continue;
 		}
 
-		if (unlikely(tty->flip.count >= TTY_FLIPBUF_SIZE)) {
-			tty->flip.work.func((void *)tty);
-			/*
-			 * The 8250 bails out of the loop here,
-			 * but we need to read everything, or die.
-			 */
-			if (tty->flip.count >= TTY_FLIPBUF_SIZE)
-				continue;
-		}
-
 		/* A real serial line, record the character and status.  */
-		*tty->flip.char_buf_ptr = ch;
-		*tty->flip.flag_buf_ptr = TTY_NORMAL;
+		flag = TTY_NORMAL;
 		up->port.icount.rx++;
 		if (r1 & (BRK_ABRT | PAR_ERR | Rx_OVR | CRC_ERR)) {
 			if (r1 & BRK_ABRT) {
···
 				up->port.icount.overrun++;
 			r1 &= up->port.read_status_mask;
 			if (r1 & BRK_ABRT)
-				*tty->flip.flag_buf_ptr = TTY_BREAK;
+				flag = TTY_BREAK;
 			else if (r1 & PAR_ERR)
-				*tty->flip.flag_buf_ptr = TTY_PARITY;
+				flag = TTY_PARITY;
 			else if (r1 & CRC_ERR)
-				*tty->flip.flag_buf_ptr = TTY_FRAME;
+				flag = TTY_FRAME;
 		}
 		if (uart_handle_sysrq_char(&up->port, ch, regs))
 			continue;
 
 		if (up->port.ignore_status_mask == 0xff ||
 		    (r1 & up->port.ignore_status_mask) == 0) {
-			tty->flip.flag_buf_ptr++;
-			tty->flip.char_buf_ptr++;
-			tty->flip.count++;
+		    	tty_insert_flip_char(tty, ch, flag);
 		}
-		if ((r1 & Rx_OVR) &&
-		    tty->flip.count < TTY_FLIPBUF_SIZE) {
-			*tty->flip.flag_buf_ptr = TTY_OVERRUN;
-			tty->flip.flag_buf_ptr++;
-			tty->flip.char_buf_ptr++;
-			tty->flip.count++;
-		}
+		if (r1 & Rx_OVR)
+			tty_insert_flip_char(tty, 0, TTY_OVERRUN);
 	}
 
 	return tty;

drivers/serial/vr41xx_siu.c

···
 	lsr = *status;
 
 	do {
-		if (unlikely(tty->flip.count >= TTY_FLIPBUF_SIZE)) {
-			if (tty->low_latency)
-				tty_flip_buffer_push(tty);
-		}
-
 		ch = siu_read(port, UART_RX);
 		port->icount.rx++;
 		flag = TTY_NORMAL;

drivers/usb/class/cdc-acm.c

···
 
 	dbg("acm_rx_tasklet: procesing buf 0x%p, size = %d\n", buf, buf->size);
 
-	for (i = 0; i < buf->size && !acm->throttle; i++) {
-		/* if we insert more than TTY_FLIPBUF_SIZE characters,
-		   we drop them. */
-		if (tty->flip.count >= TTY_FLIPBUF_SIZE) {
-			tty_flip_buffer_push(tty);
- 		}
-		tty_insert_flip_char(tty, buf->base[i], 0);
- 	}
+	tty_buffer_request_room(tty, buf->size);
+	if (!acm->throttle)
+		tty_insert_flip_string(tty, buf->base, buf->size);
 	tty_flip_buffer_push(tty);
 
 	spin_lock(&acm->throttle_lock);

drivers/usb/gadget/serial.c

···
 	unsigned int len;
 	struct gs_port *port;
 	int ret;
+	struct tty_struct *tty;
 
 	/* TEMPORARY -- only port 0 is supported right now */
 	port = dev->dev_port[0];
···
 		goto exit;
 	}
 
-	if (port->port_tty == NULL) {
+
+	tty = port->port_tty;
+
+	if (tty == NULL) {
 		printk(KERN_ERR "gs_recv_packet: port=%d, NULL tty pointer\n",
 			port->port_num);
 		ret = -EIO;
···
 		goto exit;
 	}
 
-	len = (unsigned int)(TTY_FLIPBUF_SIZE - port->port_tty->flip.count);
-	if (len < size)
-		size = len;
-
-	if (size > 0) {
-		memcpy(port->port_tty->flip.char_buf_ptr, packet, size);
-		port->port_tty->flip.char_buf_ptr += size;
-		port->port_tty->flip.count += size;
+	len = tty_buffer_request_room(tty, size);
+	if (len > 0) {
+		tty_insert_flip_string(tty, packet, len);
 		tty_flip_buffer_push(port->port_tty);
 		wake_up_interruptible(&port->port_tty->read_wait);
 	}
-
 	ret = 0;
-
 exit:
 	spin_unlock(&port->port_lock);
 	return ret;

drivers/usb/serial/Kconfig

···
 
 config USB_SERIAL_WHITEHEAT
 	tristate "USB ConnectTech WhiteHEAT Serial Driver"
-	depends on USB_SERIAL && BROKEN_ON_SMP
+	depends on USB_SERIAL
 	help
 	  Say Y here if you want to use a ConnectTech WhiteHEAT 4 port
 	  USB to serial converter device.

drivers/usb/serial/cyberjack.c

···
 	struct tty_struct *tty;
 	unsigned char *data = urb->transfer_buffer;
 	short todo;
-	int i;
 	int result;
 
 	dbg("%s - port %d", __FUNCTION__, port->number);
···
 		return;
 	}
 	if (urb->actual_length) {
-		for (i = 0; i < urb->actual_length ; ++i) {
-			/* if we insert more than TTY_FLIPBUF_SIZE characters, we drop them. */
-			if(tty->flip.count >= TTY_FLIPBUF_SIZE) {
-				tty_flip_buffer_push(tty);
-			}
-			/* this doesn't actually push the data through unless tty->low_latency is set */
-			tty_insert_flip_char(tty, data[i], 0);
-		}
+		tty_buffer_request_room(tty, urb->actual_length);
+		tty_insert_flip_string(tty, data, urb->actual_length);
 	  	tty_flip_buffer_push(tty);
 	}
 

drivers/usb/serial/cypress_m8.c

···
 
 	/* process read if there is data other than line status */
 	if (tty && (bytes > i)) {
+		bytes = tty_buffer_request_room(tty, bytes);
 		for (; i < bytes ; ++i) {
 			dbg("pushing byte number %d - %d - %c", i, data[i],
 					data[i]);
-			if(tty->flip.count >= TTY_FLIPBUF_SIZE) {
-				tty_flip_buffer_push(tty);
-			}
 			tty_insert_flip_char(tty, data[i], tty_flag);
 		}
 		tty_flip_buffer_push(port->tty);

drivers/usb/serial/digi_acceleport.c

···
 	spin_lock_irqsave( &priv->dp_port_lock, flags );
 
 	/* send any buffered chars from throttle time on to tty subsystem */
-	len = min(priv->dp_in_buf_len, TTY_FLIPBUF_SIZE - tty->flip.count );
+
+	len = tty_buffer_request_room(tty, priv->dp_in_buf_len);
 	if( len > 0 ) {
-		memcpy( tty->flip.char_buf_ptr, priv->dp_in_buf, len );
-		memcpy( tty->flip.flag_buf_ptr, priv->dp_in_flag_buf, len );
-		tty->flip.char_buf_ptr += len;
-		tty->flip.flag_buf_ptr += len;
-		tty->flip.count += len;
+		tty_insert_flip_string_flags(tty, priv->dp_in_buf, priv->dp_in_flag_buf, len);
 		tty_flip_buffer_push( tty );
 	}
 
···
 	int status = ((unsigned char *)urb->transfer_buffer)[2];
 	unsigned char *data = ((unsigned char *)urb->transfer_buffer)+3;
 	int flag,throttled;
+	int i;
 
 	/* do not process callbacks on closed ports */
 	/* but do continue the read chain */
···
 			}
 
 		} else {
-
-			len = min( len, TTY_FLIPBUF_SIZE - tty->flip.count );
-
+			len = tty_buffer_request_room(tty, len);
 			if( len > 0 ) {
-				memcpy( tty->flip.char_buf_ptr, data, len );
-				memset( tty->flip.flag_buf_ptr, flag, len );
-				tty->flip.char_buf_ptr += len;
-				tty->flip.flag_buf_ptr += len;
-				tty->flip.count += len;
+				/* Hot path */
+				if(flag == TTY_NORMAL)
+					tty_insert_flip_string(tty, data, len);
+				else {
+					for(i = 0; i < len; i++)
+						tty_insert_flip_char(tty, data[i], flag);
+				}
 				tty_flip_buffer_push( tty );
 			}
-
 		}
-
 	}
 
 	spin_unlock( &priv->dp_port_lock );

drivers/usb/serial/empeg.c

···
 	struct usb_serial_port *port = (struct usb_serial_port *)urb->context;
 	struct tty_struct *tty;
 	unsigned char *data = urb->transfer_buffer;
-	int i;
 	int result;
 
 	dbg("%s - port %d", __FUNCTION__, port->number);
···
 	tty = port->tty;
 
 	if (urb->actual_length) {
-		for (i = 0; i < urb->actual_length ; ++i) {
-			/* gb - 2000/11/13
-			 * If we insert too many characters we'll overflow the buffer.
-			 * This means we'll lose bytes - Decidedly bad.
-			 */
-			if(tty->flip.count >= TTY_FLIPBUF_SIZE) {
-				tty_flip_buffer_push(tty);
-				}
-			tty_insert_flip_char(tty, data[i], 0);
-		}
-		/* gb - 2000/11/13
-		 * Goes straight through instead of scheduling - if tty->low_latency is set.
-		 */
+		tty_buffer_request_room(tty, urb->actual_length);
+		tty_insert_flip_string(tty, data, urb->actual_length);
 		tty_flip_buffer_push(tty);
 		bytes_in += urb->actual_length;
 	}

drivers/usb/serial/ftdi_sio.c

···
 			length = 0;
 		}
 
-		/* have to make sure we don't overflow the buffer
-		   with tty_insert_flip_char's */
-		if (tty->flip.count+length > TTY_FLIPBUF_SIZE) {
-			tty_flip_buffer_push(tty);
-			need_flip = 0;
-
-			if (tty->flip.count != 0) {
-				/* flip didn't work, this happens when ftdi_process_read() is
-				 * called from ftdi_unthrottle, because TTY_DONT_FLIP is set */
-				dbg("%s - flip buffer push failed", __FUNCTION__);
-				break;
-			}
-		}
 		if (priv->rx_flags & THROTTLED) {
 			dbg("%s - throttled", __FUNCTION__);
 			break;
 		}
-		if (tty->ldisc.receive_room(tty)-tty->flip.count < length) {
+		if (tty_buffer_request_room(tty, length) < length) {
 			/* break out & wait for throttling/unthrottling to happen */
 			dbg("%s - receive room low", __FUNCTION__);
 			break;

drivers/usb/serial/garmin_gps.c

···
                         char *data, unsigned int actual_length)
 {
 	struct tty_struct *tty = port->tty;
-	int i;
 
 	if (tty && actual_length) {
 
 		usb_serial_debug_data(debug, &port->dev, 
 					__FUNCTION__, actual_length, data);
 
-		for (i = 0; i < actual_length ; ++i) {
-			/* if we insert more than TTY_FLIPBUF_SIZE characters,
-			   we drop them. */
-			if(tty->flip.count >= TTY_FLIPBUF_SIZE) {
-				tty_flip_buffer_push(tty);
-			}
-			/* this doesn't actually push the data through unless
-			   tty->low_latency is set */
-			tty_insert_flip_char(tty, data[i], 0);
-		}
+		tty_buffer_request_room(tty, actual_length);
+		tty_insert_flip_string(tty, data, actual_length);
 		tty_flip_buffer_push(tty);
 	}
 }

drivers/usb/serial/generic.c

···
 	struct usb_serial *serial = port->serial;
 	struct tty_struct *tty;
 	unsigned char *data = urb->transfer_buffer;
-	int i;
 	int result;
 
 	dbg("%s - port %d", __FUNCTION__, port->number);
···
 
 	tty = port->tty;
 	if (tty && urb->actual_length) {
-		for (i = 0; i < urb->actual_length ; ++i) {
-			/* if we insert more than TTY_FLIPBUF_SIZE characters, we drop them. */
-			if(tty->flip.count >= TTY_FLIPBUF_SIZE) {
-				tty_flip_buffer_push(tty);
-			}
-			/* this doesn't actually push the data through unless tty->low_latency is set */
-			tty_insert_flip_char(tty, data[i], 0);
-		}
+		tty_buffer_request_room(tty, urb->actual_length);
+		tty_insert_flip_string(tty, data, urb->actual_length);
 	  	tty_flip_buffer_push(tty);
 	}
 

drivers/usb/serial/io_edgeport.c

···
 	int cnt;
 
 	do {
-		if (tty->flip.count >= TTY_FLIPBUF_SIZE) {
-			tty_flip_buffer_push(tty);
-			if (tty->flip.count >= TTY_FLIPBUF_SIZE) {
-				dev_err(dev, "%s - dropping data, %d bytes lost\n",
-					__FUNCTION__, length);
-				return;
-			}
+		cnt = tty_buffer_request_room(tty, length);
+		if (cnt < length) {
+			dev_err(dev, "%s - dropping data, %d bytes lost\n",
+					__FUNCTION__, length - cnt);
+			if(cnt == 0)
+				break;
 		}
-		cnt = min(length, TTY_FLIPBUF_SIZE - tty->flip.count);
-		memcpy(tty->flip.char_buf_ptr, data, cnt);
-		memset(tty->flip.flag_buf_ptr, 0, cnt);
-		tty->flip.char_buf_ptr += cnt;
-		tty->flip.flag_buf_ptr += cnt;
-		tty->flip.count += cnt;
+		tty_insert_flip_string(tty, data, cnt);
 		data += cnt;
 		length -= cnt;
 	} while (length > 0);

drivers/usb/serial/io_ti.c

···
 	int cnt;
 
 	do {
-		if (tty->flip.count >= TTY_FLIPBUF_SIZE) {
-			tty_flip_buffer_push(tty);
-			if (tty->flip.count >= TTY_FLIPBUF_SIZE) {
-				dev_err(dev, "%s - dropping data, %d bytes lost\n",
-					__FUNCTION__, length);
-				return;
-			}
+		cnt = tty_buffer_request_room(tty, length);
+		if (cnt < length) {
+			dev_err(dev, "%s - dropping data, %d bytes lost\n",
+				__FUNCTION__, length - cnt);
+			if(cnt == 0)
+				break;
 		}
-		cnt = min(length, TTY_FLIPBUF_SIZE - tty->flip.count);
-		memcpy(tty->flip.char_buf_ptr, data, cnt);
-		memset(tty->flip.flag_buf_ptr, 0, cnt);
-		tty->flip.char_buf_ptr += cnt;
-		tty->flip.flag_buf_ptr += cnt;
-		tty->flip.count += cnt;
+		tty_insert_flip_string(tty, data, cnt);
 		data += cnt;
 		length -= cnt;
 	} while (length > 0);

drivers/usb/serial/ipaq.c

···
 	struct usb_serial_port	*port = (struct usb_serial_port *)urb->context;
 	struct tty_struct	*tty;
 	unsigned char		*data = urb->transfer_buffer;
-	int			i, result;
+	int			result;
 
 	dbg("%s - port %d", __FUNCTION__, port->number);
 
···
 
 	tty = port->tty;
 	if (tty && urb->actual_length) {
-		for (i = 0; i < urb->actual_length ; ++i) {
-			/* if we insert more than TTY_FLIPBUF_SIZE characters, we drop them. */
-			if(tty->flip.count >= TTY_FLIPBUF_SIZE) {
-				tty_flip_buffer_push(tty);
-			}
-			/* this doesn't actually push the data through unless tty->low_latency is set */
-			tty_insert_flip_char(tty, data[i], 0);
-		}
+		tty_buffer_request_room(tty, urb->actual_length);
+		tty_insert_flip_string(tty, data, urb->actual_length);
 		tty_flip_buffer_push(tty);
 		bytes_in += urb->actual_length;
 	}

drivers/usb/serial/ipw.c

···
 	struct usb_serial_port *port = urb->context;
 	unsigned char *data = urb->transfer_buffer;
 	struct tty_struct *tty;
-	int i;
 	int result;
 
 	dbg("%s - port %d", __FUNCTION__, port->number);
···
 
 	tty = port->tty;
 	if (tty && urb->actual_length) {
-		for (i = 0; i < urb->actual_length ; ++i) {
-			/* if we insert more than TTY_FLIPBUF_SIZE characters, we drop them. */
-			if(tty->flip.count >= TTY_FLIPBUF_SIZE) {
-				tty_flip_buffer_push(tty);
-			}
-			/* this doesn't actually push the data through unless tty->low_latency is set */
-			tty_insert_flip_char(tty, data[i], 0);
-		}
+		tty_buffer_request_room(tty, urb->actual_length);
+		tty_insert_flip_string(tty, data, urb->actual_length);
 		tty_flip_buffer_push(tty);
 	}
 

drivers/usb/serial/kl5kusb105.c

···
 		usb_serial_debug_data(debug, &port->dev, __FUNCTION__,
 				      urb->actual_length, data);
 	} else {
-		int i;
 		int bytes_sent = ((__u8 *) data)[0] +
 				 ((unsigned int) ((__u8 *) data)[1] << 8);
 		tty = port->tty;
···
 			bytes_sent = urb->actual_length - 2;
 		}
 
-		for (i = 2; i < 2+bytes_sent; i++) {
-			/* if we insert more than TTY_FLIPBUF_SIZE characters,
-			 * we drop them. */
-			if(tty->flip.count >= TTY_FLIPBUF_SIZE) {
-				tty_flip_buffer_push(tty);
-			}
-			/* this doesn't actually push the data through unless 
-			 * tty->low_latency is set */
-			tty_insert_flip_char(tty, ((__u8*) data)[i], 0);
-		}
+		tty_buffer_request_room(tty, bytes_sent);
+		tty_insert_flip_string(tty, data + 2, bytes_sent);
 		tty_flip_buffer_push(tty);
 
 		/* again lockless, but debug info only */

drivers/usb/serial/kobil_sct.c

···
 
 static void kobil_read_int_callback( struct urb *purb, struct pt_regs *regs)
 {
-	int i;
 	int result;
 	struct usb_serial_port *port = (struct usb_serial_port *) purb->context;
 	struct tty_struct *tty;
···
 		*/
 		// END DEBUG
 
-		for (i = 0; i < purb->actual_length; ++i) {
-			// if we insert more than TTY_FLIPBUF_SIZE characters, we drop them.
-			if(tty->flip.count >= TTY_FLIPBUF_SIZE) {
-				tty_flip_buffer_push(tty);
-			}
-			// this doesn't actually push the data through unless tty->low_latency is set
-			tty_insert_flip_char(tty, data[i], 0);
-		}
+		tty_buffer_request_room(tty, purb->actual_length);
+		tty_insert_flip_string(tty, data, purb->actual_length);
 		tty_flip_buffer_push(tty);
 	}
 

drivers/usb/serial/option.c

···
 
 static void option_indat_callback(struct urb *urb, struct pt_regs *regs)
 {
-	int i, err;
+	int err;
 	int endpoint;
 	struct usb_serial_port *port;
 	struct tty_struct *tty;
···
 	} else {
 		tty = port->tty;
 		if (urb->actual_length) {
-			for (i = 0; i < urb->actual_length ; ++i) {
-				if (tty->flip.count >= TTY_FLIPBUF_SIZE)
-					tty_flip_buffer_push(tty);
-				tty_insert_flip_char(tty, data[i], 0);
-			}
+			tty_buffer_request_room(tty, urb->actual_length);
+			tty_insert_flip_string(tty, data, urb->actual_length);
 			tty_flip_buffer_push(tty);
 		} else {
 			dbg("%s: empty read urb received", __FUNCTION__);

drivers/usb/serial/pl2303.c

···
 
 	tty = port->tty;
 	if (tty && urb->actual_length) {
+		tty_buffer_request_room(tty, urb->actual_length + 1);
 		/* overrun is special, not associated with a char */
 		if (status & UART_OVERRUN_ERROR)
 			tty_insert_flip_char(tty, 0, TTY_OVERRUN);
-
-		for (i = 0; i < urb->actual_length; ++i) {
-			if (tty->flip.count >= TTY_FLIPBUF_SIZE) {
-				tty_flip_buffer_push(tty);
-			}
+		for (i = 0; i < urb->actual_length; ++i)
 			tty_insert_flip_char (tty, data[i], tty_flag);
-		}
 		tty_flip_buffer_push (tty);
 	}
 

drivers/usb/serial/ti_usb_3410_5052.c

···
 	int cnt;
 
 	do {
-		if (tty->flip.count >= TTY_FLIPBUF_SIZE) {
-			tty_flip_buffer_push(tty);
-			if (tty->flip.count >= TTY_FLIPBUF_SIZE) {
-				dev_err(dev, "%s - dropping data, %d bytes lost\n", __FUNCTION__, length);
-				return;
-			}
+		cnt = tty_buffer_request_room(tty, length);
+		if (cnt < length) {
+			dev_err(dev, "%s - dropping data, %d bytes lost\n", __FUNCTION__, length - cnt);
+			if(cnt == 0)
+				break;
 		}
-		cnt = min(length, TTY_FLIPBUF_SIZE - tty->flip.count);
-		memcpy(tty->flip.char_buf_ptr, data, cnt);
-		memset(tty->flip.flag_buf_ptr, 0, cnt);
-		tty->flip.char_buf_ptr += cnt;
-		tty->flip.flag_buf_ptr += cnt;
-		tty->flip.count += cnt;
+		tty_insert_flip_string(tty, data, cnt);
+		tty_flip_buffer_push(tty);
 		data += cnt;
 		length -= cnt;
 	} while (length > 0);
 
-	tty_flip_buffer_push(tty);
 }
 
 

drivers/usb/serial/visor.c

···
 	unsigned char *data = urb->transfer_buffer;
 	struct tty_struct *tty;
 	unsigned long flags;
-	int i;
 	int throttled;
 	int result;
 
···
 
 	tty = port->tty;
 	if (tty && urb->actual_length) {
-		for (i = 0; i < urb->actual_length ; ++i) {
-			/* if we insert more than TTY_FLIPBUF_SIZE characters, we drop them. */
-			if(tty->flip.count >= TTY_FLIPBUF_SIZE) {
-				tty_flip_buffer_push(tty);
-			}
-			/* this doesn't actually push the data through unless tty->low_latency is set */
-			tty_insert_flip_char(tty, data[i], 0);
-		}
+		tty_buffer_request_room(tty, urb->actual_length);
+		tty_insert_flip_string(tty, data, urb->actual_length);
 		tty_flip_buffer_push(tty);
 	}
 	spin_lock_irqsave(&priv->lock, flags);

drivers/usb/serial/whiteheat.c

···
 		urb = wrap->urb;
 
 		if (tty && urb->actual_length) {
-			if (urb->actual_length > TTY_FLIPBUF_SIZE - tty->flip.count) {
+			int len = tty_buffer_request_room(tty, urb->actual_length);
+			/* This stuff can go away now I suspect */
+			if (unlikely(len < urb->actual_length)) {
 				spin_lock_irqsave(&info->lock, flags);
 				list_add(tmp, &info->rx_urb_q);
 				spin_unlock_irqrestore(&info->lock, flags);
···
 				schedule_work(&info->rx_work);
 				return;
 			}
-
-			memcpy(tty->flip.char_buf_ptr, urb->transfer_buffer, urb->actual_length);
-			tty->flip.char_buf_ptr += urb->actual_length;
-			tty->flip.count += urb->actual_length;
-			sent += urb->actual_length;
+			tty_insert_flip_string(tty, urb->transfer_buffer, len);
+			sent += len;
 		}
 
 		urb->dev = port->serial->dev;

include/linux/kbd_kern.h

···
 
 static inline void con_schedule_flip(struct tty_struct *t)
 {
-	schedule_work(&t->flip.work);
+	schedule_work(&t->buf.work);
 }
 
 #endif

include/linux/tty.h

···
  */
 #define TTY_FLIPBUF_SIZE 512
 
-struct tty_flip_buffer {
+struct tty_buffer {
+	struct tty_buffer *next;
+	char *char_buf_ptr;
+	unsigned char *flag_buf_ptr;
+	int used;
+	int size;
+	/* Data points here */
+	unsigned long data[0];
+};
+
+struct tty_bufhead {
 	struct work_struct		work;
 	struct semaphore pty_sem;
-	char		*char_buf_ptr;
-	unsigned char	*flag_buf_ptr;
-	int		count;
-	int		buf_num;
-	unsigned char	char_buf[2*TTY_FLIPBUF_SIZE];
-	char		flag_buf[2*TTY_FLIPBUF_SIZE];
-	unsigned char	slop[4]; /* N.B. bug overwrites buffer by 1 */
+	struct tty_buffer *head;	/* Queue head */
+	struct tty_buffer *tail;	/* Active buffer */
+	struct tty_buffer *free;	/* Free queue head */
 };
 /*
  * The pty uses char_buf and flag_buf as a contiguous buffer
···
 	unsigned char stopped:1, hw_stopped:1, flow_stopped:1, packet:1;
 	unsigned char low_latency:1, warned:1;
 	unsigned char ctrl_status;
+	unsigned int receive_room;	/* Bytes free for queue */
 
 	struct tty_struct *link;
 	struct fasync_struct *fasync;
-	struct tty_flip_buffer flip;
+	struct tty_bufhead buf;
 	int max_flip_cnt;
 	int alt_speed;		/* For magic substitution of 38400 bps */
 	wait_queue_head_t write_wait;

include/linux/tty_flip.h

···
 #ifndef _LINUX_TTY_FLIP_H
 #define _LINUX_TTY_FLIP_H
 
+extern int tty_buffer_request_room(struct tty_struct *tty, size_t size);
+extern int tty_insert_flip_string(struct tty_struct *tty, unsigned char *chars, size_t size);
+extern int tty_insert_flip_string_flags(struct tty_struct *tty, unsigned char *chars, char *flags, size_t size);
+extern int tty_prepare_flip_string(struct tty_struct *tty, unsigned char **chars, size_t size);
+extern int tty_prepare_flip_string_flags(struct tty_struct *tty, unsigned char **chars, char **flags, size_t size);
+
 #ifdef INCLUDE_INLINE_FUNCS
 #define _INLINE_ extern
 #else
 #define _INLINE_ static __inline__
 #endif
 
-_INLINE_ void tty_insert_flip_char(struct tty_struct *tty,
+_INLINE_ int tty_insert_flip_char(struct tty_struct *tty,
 				   unsigned char ch, char flag)
 {
-	if (tty->flip.count < TTY_FLIPBUF_SIZE) {
-		tty->flip.count++;
-		*tty->flip.flag_buf_ptr++ = flag;
-		*tty->flip.char_buf_ptr++ = ch;
+	struct tty_buffer *tb = tty->buf.tail;
+	if (tb && tb->used < tb->size) {
+		tb->flag_buf_ptr[tb->used] = flag;
+		tb->char_buf_ptr[tb->used++] = ch;
+		return 1;
 	}
+	return tty_insert_flip_string_flags(tty, &ch, &flag, 1);
 }
 
 _INLINE_ void tty_schedule_flip(struct tty_struct *tty)
 {
-	schedule_delayed_work(&tty->flip.work, 1);
+	schedule_delayed_work(&tty->buf.work, 1);
 }
 
 #undef _INLINE_

include/linux/tty_ldisc.h

···
  * 	pointer of flag bytes which indicate whether a character was
  * 	received with a parity error, etc.
  * 
- * int	(*receive_room)(struct tty_struct *);
- *
- * 	This function is called by the low-level tty driver to
- * 	determine how many characters the line discpline can accept.
- * 	The low-level driver must not send more characters than was
- * 	indicated by receive_room, or the line discpline may drop
- * 	those characters.
- * 
  * void	(*write_wakeup)(struct tty_struct *);
  *
  * 	This function is called by the low-level tty driver to signal
···
 	 */
 	void	(*receive_buf)(struct tty_struct *, const unsigned char *cp,
 			       char *fp, int count);
-	int	(*receive_room)(struct tty_struct *);
 	void	(*write_wakeup)(struct tty_struct *);
 
 	struct  module *owner;

net/bluetooth/rfcomm/tty.c

···
 	BT_DBG("dlc %p tty %p len %d", dlc, tty, skb->len);
 
 	if (test_bit(TTY_DONT_FLIP, &tty->flags)) {
-		register int i;
-		for (i = 0; i < skb->len; i++) {
-			if (tty->flip.count >= TTY_FLIPBUF_SIZE)
-				tty_flip_buffer_push(tty);
-
-			tty_insert_flip_char(tty, skb->data[i], 0);
-		}
+		tty_buffer_request_room(tty, skb->len);
+		tty_insert_flip_string(tty, skb->data, skb->len);
 		tty_flip_buffer_push(tty);
 	} else
 		tty->ldisc.receive_buf(tty, skb->data, NULL, skb->len);