tty: Replace ASYNC_NORMAL_ACTIVE bit and update atomically

Replace ASYNC_NORMAL_ACTIVE bit in the tty_port::flags field with
TTY_PORT_ACTIVE bit in the tty_port::iflags field. Introduce helpers
tty_port_set_active() and tty_port_active() to abstract atomic bit ops.

Extract state changes from port lock sections, as this usage is
broken and confused; the state transitions are protected by the
tty lock (which mutually excludes parallel open/close/hangup),
and no user tests the active state while holding the port lock.

Signed-off-by: Peter Hurley <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/isdn/i4l/isdn_tty.c

···
 		return;
 	isdn_tty_shutdown(info);
 	port->count = 0;
-	port->flags &= ~ASYNC_NORMAL_ACTIVE;
+	tty_port_set_active(port, 0);
 	port->tty = NULL;
 	wake_up_interruptible(&port->open_wait);
 }
···
 #endif
 			if (
 #ifndef FIX_FILE_TRANSFER
-				(info->port.flags & ASYNC_NORMAL_ACTIVE) &&
+			    tty_port_active(&info->port) &&
 #endif
 				(info->isdn_driver == -1) &&
 				(info->isdn_channel == -1) &&
···
 	       ((dev->drv[di]->flags & DRV_FLAG_REJBUS) && (wret != 2)) ? "rejected" : "ignored");
 	return (wret == 2) ? 3 : 0;
 }
-
-#define TTY_IS_ACTIVE(info)	(info->port.flags & ASYNC_NORMAL_ACTIVE)
 
 int
 isdn_tty_stat_callback(int i, isdn_ctrl *c)
···
 #ifdef ISDN_TTY_STAT_DEBUG
 			printk(KERN_DEBUG "tty_STAT_DCONN ttyI%d\n", info->line);
 #endif
-			if (TTY_IS_ACTIVE(info)) {
+			if (tty_port_active(&info->port)) {
 				if (info->dialing == 1) {
 					info->dialing = 2;
 					return 1;
···
 #ifdef ISDN_TTY_STAT_DEBUG
 			printk(KERN_DEBUG "tty_STAT_DHUP ttyI%d\n", info->line);
 #endif
-			if (TTY_IS_ACTIVE(info)) {
+			if (tty_port_active(&info->port)) {
 				if (info->dialing == 1)
 					isdn_tty_modem_result(RESULT_BUSY, info);
 				if (info->dialing > 1)
···
 			 * waiting for it and
 			 * set DCD-bit of its modem-status.
 			 */
-			if (TTY_IS_ACTIVE(info) ||
+			if (tty_port_active(&info->port) ||
 			    (info->port.blocked_open &&
 			     (info->emu.mdmreg[REG_DCD] & BIT_DCD))) {
 				info->msr |= UART_MSR_DCD;
···
 #ifdef ISDN_TTY_STAT_DEBUG
 			printk(KERN_DEBUG "tty_STAT_BHUP ttyI%d\n", info->line);
 #endif
-			if (TTY_IS_ACTIVE(info)) {
+			if (tty_port_active(&info->port)) {
 #ifdef ISDN_DEBUG_MODEM_HUP
 				printk(KERN_DEBUG "Mhup in ISDN_STAT_BHUP\n");
 #endif
···
 #ifdef ISDN_TTY_STAT_DEBUG
 			printk(KERN_DEBUG "tty_STAT_NODCH ttyI%d\n", info->line);
 #endif
-			if (TTY_IS_ACTIVE(info)) {
+			if (tty_port_active(&info->port)) {
 				if (info->dialing) {
 					info->dialing = 0;
 					info->last_l2 = -1;
···
 			return 1;
 #ifdef CONFIG_ISDN_TTY_FAX
 		case ISDN_STAT_FAXIND:
-			if (TTY_IS_ACTIVE(info)) {
+			if (tty_port_active(&info->port)) {
 				isdn_tty_fax_command(info, c);
 			}
 			break;
 #endif
 #ifdef CONFIG_ISDN_AUDIO
 		case ISDN_STAT_AUDIO:
-			if (TTY_IS_ACTIVE(info)) {
+			if (tty_port_active(&info->port)) {
 				switch (c->parm.num[0]) {
 				case ISDN_AUDIO_DTMF:
 					if (info->vonline) {

drivers/tty/amiserial.c

···
 	rs_flush_buffer(tty);
 	shutdown(tty, info);
 	info->tport.count = 0;
-	info->tport.flags &= ~ASYNC_NORMAL_ACTIVE;
+	tty_port_set_active(&info->tport, 0);
 	info->tport.tty = NULL;
 	wake_up_interruptible(&info->tport.open_wait);
 }

drivers/tty/rocket.c

···
 		}
 	}
 	spin_lock_irq(&port->lock);
-	info->port.flags &= ~(ASYNC_INITIALIZED | ASYNC_NORMAL_ACTIVE);
+	port->flags &= ~ASYNC_INITIALIZED;
 	tty->closing = 0;
 	spin_unlock_irq(&port->lock);
+	tty_port_set_active(port, 0);
 	mutex_unlock(&port->mutex);
 	tty_port_tty_set(port, NULL);
 
···
 	/*  Write remaining data into the port's xmit_buf */
 	while (1) {
 		/* Hung up ? */
-		if (!test_bit(ASYNCB_NORMAL_ACTIVE, &info->port.flags))
+		if (!tty_port_active(&info->port))
 			goto end;
 		c = min(count, XMIT_BUF_SIZE - info->xmit_cnt - 1);
 		c = min(c, XMIT_BUF_SIZE - info->xmit_head);

drivers/tty/serial/crisv10.c

···
 			schedule_timeout_interruptible(info->port.close_delay);
 		wake_up_interruptible(&info->port.open_wait);
 	}
-	info->port.flags &= ~ASYNC_NORMAL_ACTIVE;
 	local_irq_restore(flags);
+	tty_port_set_active(&info->port, 0);
 
 	/* port closed */
 
···
 	shutdown(info);
 	info->event = 0;
 	info->port.count = 0;
-	info->port.flags &= ~ASYNC_NORMAL_ACTIVE;
+	tty_port_set_active(&info->port, 0);
 	info->port.tty = NULL;
 	wake_up_interruptible(&info->port.open_wait);
 }
···
 	 * then make the check up front and then exit.
 	 */
 	if ((filp->f_flags & O_NONBLOCK) || tty_io_error(tty)) {
-		info->port.flags |= ASYNC_NORMAL_ACTIVE;
+		tty_port_set_active(&info->port, 1);
 		return 0;
 	}
 
···
 #endif
 	if (retval)
 		return retval;
-	info->port.flags |= ASYNC_NORMAL_ACTIVE;
+	tty_port_set_active(&info->port, 1);
 	return 0;
 }
 

drivers/tty/serial/serial_core.c

···
 		uart_change_pm(state, UART_PM_STATE_OFF);
 		spin_lock_irq(&port->lock);
 	}
+	spin_unlock_irq(&port->lock);
+	tty_port_set_active(port, 0);
 
 	/*
 	 * Wake up anyone trying to open this port.
 	 */
-	clear_bit(ASYNCB_NORMAL_ACTIVE, &port->flags);
-	spin_unlock_irq(&port->lock);
 	wake_up_interruptible(&port->open_wait);
 
 	mutex_unlock(&port->mutex);
···
 	pr_debug("uart_hangup(%d)\n", tty->index);
 
 	mutex_lock(&port->mutex);
-	if (port->flags & ASYNC_NORMAL_ACTIVE) {
+	if (tty_port_active(port)) {
 		uart_flush_buffer(tty);
 		uart_shutdown(tty, state);
 		spin_lock_irqsave(&port->lock, flags);
 		port->count = 0;
-		clear_bit(ASYNCB_NORMAL_ACTIVE, &port->flags);
 		spin_unlock_irqrestore(&port->lock, flags);
+		tty_port_set_active(port, 0);
 		tty_port_tty_set(port, NULL);
 		if (!uart_console(state->uart_port))
 			uart_change_pm(state, UART_PM_STATE_OFF);

drivers/tty/synclink.c

···
 	shutdown(info);
 	
 	info->port.count = 0;	
-	info->port.flags &= ~ASYNC_NORMAL_ACTIVE;
+	tty_port_set_active(&info->port, 0);
 	info->port.tty = NULL;
 
 	wake_up_interruptible(&info->port.open_wait);
···
 
 	if (filp->f_flags & O_NONBLOCK || tty_io_error(tty)) {
 		/* nonblock mode is set or port is not enabled */
-		port->flags |= ASYNC_NORMAL_ACTIVE;
+		tty_port_set_active(port, 1);
 		return 0;
 	}
 
···
 			 __FILE__,__LINE__, tty->driver->name, port->count );
 			 
 	if (!retval)
-		port->flags |= ASYNC_NORMAL_ACTIVE;
+		tty_port_set_active(port, 1);
 		
 	return retval;
 	

drivers/tty/synclink_gt.c

···
 
 	spin_lock_irqsave(&info->port.lock, flags);
 	info->port.count = 0;
-	info->port.flags &= ~ASYNC_NORMAL_ACTIVE;
 	info->port.tty = NULL;
 	spin_unlock_irqrestore(&info->port.lock, flags);
+	tty_port_set_active(&info->port, 0);
 	mutex_unlock(&info->port.mutex);
 
 	wake_up_interruptible(&info->port.open_wait);
···
 
 	if (filp->f_flags & O_NONBLOCK || tty_io_error(tty)) {
 		/* nonblock mode is set or port is not enabled */
-		port->flags |= ASYNC_NORMAL_ACTIVE;
+		tty_port_set_active(port, 1);
 		return 0;
 	}
 
···
 	port->blocked_open--;
 
 	if (!retval)
-		port->flags |= ASYNC_NORMAL_ACTIVE;
+		tty_port_set_active(port, 1);
 
 	DBGINFO(("%s block_til_ready ready, rc=%d\n", tty->driver->name, retval));
 	return retval;

drivers/tty/synclinkmp.c

···
 
 	spin_lock_irqsave(&info->port.lock, flags);
 	info->port.count = 0;
-	info->port.flags &= ~ASYNC_NORMAL_ACTIVE;
 	info->port.tty = NULL;
 	spin_unlock_irqrestore(&info->port.lock, flags);
+	tty_port_set_active(&info->port, 1);
 	mutex_unlock(&info->port.mutex);
 
 	wake_up_interruptible(&info->port.open_wait);
···
 	if (filp->f_flags & O_NONBLOCK || tty_io_error(tty)) {
 		/* nonblock mode is set or port is not enabled */
 		/* just verify that callout device is not active */
-		port->flags |= ASYNC_NORMAL_ACTIVE;
+		tty_port_set_active(port, 1);
 		return 0;
 	}
 
···
 			 __FILE__,__LINE__, tty->driver->name, port->count );
 
 	if (!retval)
-		port->flags |= ASYNC_NORMAL_ACTIVE;
+		tty_port_set_active(port, 1);
 
 	return retval;
 }

drivers/tty/tty_port.c

···
 
 	spin_lock_irqsave(&port->lock, flags);
 	port->count = 0;
-	port->flags &= ~ASYNC_NORMAL_ACTIVE;
 	tty = port->tty;
 	if (tty)
 		set_bit(TTY_IO_ERROR, &tty->flags);
 	port->tty = NULL;
 	spin_unlock_irqrestore(&port->lock, flags);
+	tty_port_set_active(port, 0);
 	tty_port_shutdown(port, tty);
 	tty_kref_put(tty);
 	wake_up_interruptible(&port->open_wait);
···
 	/* if non-blocking mode is set we can pass directly to open unless
 	   the port has just hung up or is in another error state */
 	if (tty_io_error(tty)) {
-		port->flags |= ASYNC_NORMAL_ACTIVE;
+		tty_port_set_active(port, 1);
 		return 0;
 	}
 	if (filp->f_flags & O_NONBLOCK) {
 		/* Indicate we are open */
 		if (C_BAUD(tty))
 			tty_port_raise_dtr_rts(port);
-		port->flags |= ASYNC_NORMAL_ACTIVE;
+		tty_port_set_active(port, 1);
 		return 0;
 	}
 
···
 	if (!tty_hung_up_p(filp))
 		port->count++;
 	port->blocked_open--;
-	if (retval == 0)
-		port->flags |= ASYNC_NORMAL_ACTIVE;
 	spin_unlock_irqrestore(&port->lock, flags);
+	if (retval == 0)
+		tty_port_set_active(port, 1);
 	return retval;
 }
 EXPORT_SYMBOL(tty_port_block_til_ready);
···
 		spin_lock_irqsave(&port->lock, flags);
 		wake_up_interruptible(&port->open_wait);
 	}
-	port->flags &= ~ASYNC_NORMAL_ACTIVE;
 	spin_unlock_irqrestore(&port->lock, flags);
+	tty_port_set_active(port, 0);
 }
 EXPORT_SYMBOL(tty_port_close_end);
 

include/linux/tty.h

···
 		clear_bit(TTY_PORT_CTS_FLOW, &port->iflags);
 }
 
+static inline bool tty_port_active(struct tty_port *port)
+{
+	return test_bit(TTY_PORT_ACTIVE, &port->iflags);
+}
+
+static inline void tty_port_set_active(struct tty_port *port, bool val)
+{
+	if (val)
+		set_bit(TTY_PORT_ACTIVE, &port->iflags);
+	else
+		clear_bit(TTY_PORT_ACTIVE, &port->iflags);
+}
 
 extern struct tty_struct *tty_port_tty_get(struct tty_port *port);
 extern void tty_port_tty_set(struct tty_port *port, struct tty_struct *tty);

net/irda/ircomm/ircomm_tty.c

···
 	 * then make the check up front and then exit.
 	 */
 	if (tty_io_error(tty)) {
-		port->flags |= ASYNC_NORMAL_ACTIVE;
+		tty_port_set_active(port, 1);
 		return 0;
 	}
 
···
 		/* nonblock mode is set */
 		if (C_BAUD(tty))
 			tty_port_raise_dtr_rts(port);
-		port->flags |= ASYNC_NORMAL_ACTIVE;
+		tty_port_set_active(port, 1);
 		pr_debug("%s(), O_NONBLOCK requested!\n", __func__);
 		return 0;
 	}
···
 		 __FILE__, __LINE__, tty->driver->name, port->count);
 
 	if (!retval)
-		port->flags |= ASYNC_NORMAL_ACTIVE;
+		tty_port_set_active(port, 1);
 
 	return retval;
 }
···
 	ircomm_tty_shutdown(self);
 
 	spin_lock_irqsave(&port->lock, flags);
-	port->flags &= ~ASYNC_NORMAL_ACTIVE;
 	if (port->tty) {
 		set_bit(TTY_IO_ERROR, &port->tty->flags);
 		tty_kref_put(port->tty);
···
 	port->tty = NULL;
 	port->count = 0;
 	spin_unlock_irqrestore(&port->lock, flags);
+	tty_port_set_active(port, 0);
 
 	wake_up_interruptible(&port->open_wait);
 }
···
 		seq_printf(m, "%cASYNC_LOW_LATENCY", sep);
 		sep = '|';
 	}
-	if (self->port.flags & ASYNC_NORMAL_ACTIVE) {
+	if (tty_port_active(&self->port)) {
 		seq_printf(m, "%cASYNC_NORMAL_ACTIVE", sep);
 		sep = '|';
 	}