[PATCH] sem2mutex: tty

Semaphore to mutex conversion.

The conversion was generated via scripts, and the result was validated
automatically via a script as well.

Signed-off-by: Ingo Molnar <[e-mail]>
Cc: Alan Cox <[e-mail]>
Cc: Russell King <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

drivers/char/n_tty.c

···
  *	We test the TTY_THROTTLED bit first so that it always
  *	indicates the current state. The decision about whether
  *	it is worth allowing more input has been taken by the caller.
- *	Can sleep, may be called under the atomic_read semaphore but
+ *	Can sleep, may be called under the atomic_read_lock mutex but
  *	this is not guaranteed.
  */
  
···
  *	buffer, and once to drain the space from the (physical) beginning of
  *	the buffer to head pointer.
  *
- *	Called under the tty->atomic_read sem and with TTY_DONT_FLIP set
+ *	Called under the tty->atomic_read_lock sem and with TTY_DONT_FLIP set
  *
  */
  
···
 	 *	Internal serialization of reads.
 	 */
 	if (file->f_flags & O_NONBLOCK) {
-		if (down_trylock(&tty->atomic_read))
+		if (!mutex_trylock(&tty->atomic_read_lock))
 			return -EAGAIN;
 	}
 	else {
-		if (down_interruptible(&tty->atomic_read))
+		if (mutex_lock_interruptible(&tty->atomic_read_lock))
 			return -ERESTARTSYS;
 	}
 
···
 			timeout = time;
 	}
 	clear_bit(TTY_DONT_FLIP, &tty->flags);
-	up(&tty->atomic_read);
+	mutex_unlock(&tty->atomic_read_lock);
 	remove_wait_queue(&tty->read_wait, &wait);
 
 	if (!waitqueue_active(&tty->read_wait))

drivers/char/tty_io.c

···
 
 /* Semaphore to protect creating and releasing a tty. This is shared with
    vt.c for deeply disgusting hack reasons */
-DECLARE_MUTEX(tty_sem);
+DEFINE_MUTEX(tty_mutex);
 
 #ifdef CONFIG_UNIX98_PTYS
 extern struct tty_driver *ptm_driver;	/* Unix98 pty masters; for /dev/ptmx */
···
 
 	lock_kernel();
 
-	down(&tty_sem);
+	mutex_lock(&tty_mutex);
 	tty = current->signal->tty;
 	if (tty) {
 		tty_pgrp = tty->pgrp;
-		up(&tty_sem);
+		mutex_unlock(&tty_mutex);
 		if (on_exit && tty->driver->type != TTY_DRIVER_TYPE_PTY)
 			tty_vhangup(tty);
 	} else {
···
 			kill_pg(current->signal->tty_old_pgrp, SIGHUP, on_exit);
 			kill_pg(current->signal->tty_old_pgrp, SIGCONT, on_exit);
 		}
-		up(&tty_sem);
+		mutex_unlock(&tty_mutex);
 		unlock_kernel();	
 		return;
 	}
···
 	}
 
 	/* Must lock changes to tty_old_pgrp */
-	down(&tty_sem);
+	mutex_lock(&tty_mutex);
 	current->signal->tty_old_pgrp = 0;
 	tty->session = 0;
 	tty->pgrp = -1;
···
 		p->signal->tty = NULL;
 	} while_each_task_pid(current->signal->session, PIDTYPE_SID, p);
 	read_unlock(&tasklist_lock);
-	up(&tty_sem);
+	mutex_unlock(&tty_mutex);
 	unlock_kernel();
 }
 
···
 	ssize_t ret = 0, written = 0;
 	unsigned int chunk;
 	
-	if (down_interruptible(&tty->atomic_write)) {
+	if (mutex_lock_interruptible(&tty->atomic_write_lock)) {
 		return -ERESTARTSYS;
 	}
 
···
 	if (count < chunk)
 		chunk = count;
 
-	/* write_buf/write_cnt is protected by the atomic_write semaphore */
+	/* write_buf/write_cnt is protected by the atomic_write_lock mutex */
 	if (tty->write_cnt < chunk) {
 		unsigned char *buf;
 
···
 
 		buf = kmalloc(chunk, GFP_KERNEL);
 		if (!buf) {
-			up(&tty->atomic_write);
+			mutex_unlock(&tty->atomic_write_lock);
 			return -ENOMEM;
 		}
 		kfree(tty->write_buf);
···
 		inode->i_mtime = current_fs_time(inode->i_sb);
 		ret = written;
 	}
-	up(&tty->atomic_write);
+	mutex_unlock(&tty->atomic_write_lock);
 	return ret;
 }
 
···
 
 /*
  * WSH 06/09/97: Rewritten to remove races and properly clean up after a
- * failed open.  The new code protects the open with a semaphore, so it's
- * really quite straightforward.  The semaphore locking can probably be
+ * failed open.  The new code protects the open with a mutex, so it's
+ * really quite straightforward.  The mutex locking can probably be
  * relaxed for the (most common) case of reopening a tty.
  */
 static int init_dev(struct tty_driver *driver, int idx,
···
 success:
 	*ret_tty = tty;
 	
-	/* All paths come through here to release the semaphore */
+	/* All paths come through here to release the mutex */
 end_init:
 	return retval;
 
···
 		/* Guard against races with tty->count changes elsewhere and
 		   opens on /dev/tty */
 		   
-		down(&tty_sem);
+		mutex_lock(&tty_mutex);
 		tty_closing = tty->count <= 1;
 		o_tty_closing = o_tty &&
 			(o_tty->count <= (pty_master ? 1 : 0));
···
 
 		printk(KERN_WARNING "release_dev: %s: read/write wait queue "
 				    "active!\n", tty_name(tty, buf));
-		up(&tty_sem);
+		mutex_unlock(&tty_mutex);
 		schedule();
 	}	
 
···
 		read_unlock(&tasklist_lock);
 	}
 
-	up(&tty_sem);
+	mutex_unlock(&tty_mutex);
 
 	/* check whether both sides are closing ... */
 	if (!tty_closing || (o_tty && !o_tty_closing))
···
 	index  = -1;
 	retval = 0;
 	
-	down(&tty_sem);
+	mutex_lock(&tty_mutex);
 
 	if (device == MKDEV(TTYAUX_MAJOR,0)) {
 		if (!current->signal->tty) {
-			up(&tty_sem);
+			mutex_unlock(&tty_mutex);
 			return -ENXIO;
 		}
 		driver = current->signal->tty->driver;
···
 			noctty = 1;
 			goto got_driver;
 		}
-		up(&tty_sem);
+		mutex_unlock(&tty_mutex);
 		return -ENODEV;
 	}
 
 	driver = get_tty_driver(device, &index);
 	if (!driver) {
-		up(&tty_sem);
+		mutex_unlock(&tty_mutex);
 		return -ENODEV;
 	}
 got_driver:
 	retval = init_dev(driver, index, &tty);
-	up(&tty_sem);
+	mutex_unlock(&tty_mutex);
 	if (retval)
 		return retval;
 
···
 	}
 	up(&allocated_ptys_lock);
 
-	down(&tty_sem);
+	mutex_lock(&tty_mutex);
 	retval = init_dev(ptm_driver, index, &tty);
-	up(&tty_sem);
+	mutex_unlock(&tty_mutex);
 	
 	if (retval)
 		goto out;
···
 	init_waitqueue_head(&tty->write_wait);
 	init_waitqueue_head(&tty->read_wait);
 	INIT_WORK(&tty->hangup_work, do_tty_hangup, tty);
-	sema_init(&tty->atomic_read, 1);
-	sema_init(&tty->atomic_write, 1);
+	mutex_init(&tty->atomic_read_lock);
+	mutex_init(&tty->atomic_write_lock);
 	spin_lock_init(&tty->read_lock);
 	INIT_LIST_HEAD(&tty->tty_files);
 	INIT_WORK(&tty->SAK_work, NULL, NULL);

drivers/char/vt.c

···
 }
 
 /*
- * We take tty_sem in here to prevent another thread from coming in via init_dev
+ * We take tty_mutex in here to prevent another thread from coming in via init_dev
  * and taking a ref against the tty while we're in the process of forgetting
  * about it and cleaning things up.
  *
···
  */
 static void con_close(struct tty_struct *tty, struct file *filp)
 {
-	down(&tty_sem);
+	mutex_lock(&tty_mutex);
 	acquire_console_sem();
 	if (tty && tty->count == 1) {
 		struct vc_data *vc = tty->driver_data;
···
 		tty->driver_data = NULL;
 		release_console_sem();
 		vcs_remove_devfs(tty);
-		up(&tty_sem);
+		mutex_unlock(&tty_mutex);
 		/*
-		 * tty_sem is released, but we still hold BKL, so there is
+		 * tty_mutex is released, but we still hold BKL, so there is
 		 * still exclusion against init_dev()
 		 */
 		return;
 	}
 	release_console_sem();
-	up(&tty_sem);
+	mutex_unlock(&tty_mutex);
 }
 
 static void vc_init(struct vc_data *vc, unsigned int rows,
···
 }
 
 /*
- * We defer the timer blanking to work queue so it can take the console semaphore
+ * We defer the timer blanking to work queue so it can take the console mutex
  * (console operations can still happen at irq time, but only from printk which
- * has the console semaphore. Not perfect yet, but better than no locking
+ * has the console mutex. Not perfect yet, but better than no locking
  */
 static void blank_screen_t(unsigned long dummy)
 {

include/linux/tty.h

···
 #include <linux/tty_driver.h>
 #include <linux/tty_ldisc.h>
 #include <linux/screen_info.h>
+#include <linux/mutex.h>
 
 #include <asm/system.h>
 
···
 	int canon_data;
 	unsigned long canon_head;
 	unsigned int canon_column;
-	struct semaphore atomic_read;
-	struct semaphore atomic_write;
+	struct mutex atomic_read_lock;
+	struct mutex atomic_write_lock;
 	unsigned char *write_buf;
 	int write_cnt;
 	spinlock_t read_lock;
···
 extern void tty_wakeup(struct tty_struct *tty);
 extern void tty_ldisc_flush(struct tty_struct *tty);
 
-struct semaphore;
-extern struct semaphore tty_sem;
+extern struct mutex tty_mutex;
 
 /* n_tty.c */
 extern struct tty_ldisc tty_ldisc_N_TTY;

kernel/exit.c

···
 	exit_mm(current);
 
 	set_special_pids(1, 1);
-	down(&tty_sem);
+	mutex_lock(&tty_mutex);
 	current->signal->tty = NULL;
-	up(&tty_sem);
+	mutex_unlock(&tty_mutex);
 
 	/* Block and flush all signals */
 	sigfillset(&blocked);

kernel/sys.c

···
 	struct pid *pid;
 	int err = -EPERM;
 
-	down(&tty_sem);
+	mutex_lock(&tty_mutex);
 	write_lock_irq(&tasklist_lock);
 
 	pid = find_pid(PIDTYPE_PGID, group_leader->pid);
···
 	err = process_group(group_leader);
 out:
 	write_unlock_irq(&tasklist_lock);
-	up(&tty_sem);
+	mutex_unlock(&tty_mutex);
 	return err;
 }