unix98 allocated_ptys_lock semaphore to mutex

Convert the unix98 allocated_ptys_lock to a mutex.
Signed-off-by: NDaniel Walker <dwalker@mvista.com>
Acked-by: NIngo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

drivers/char/tty_io.c

@@ -138,7 +138,7 @@ EXPORT_SYMBOL(tty_mutex);
 extern struct tty_driver *ptm_driver;	/* Unix98 pty masters; for /dev/ptmx */
 extern int pty_limit;		/* Config limit on Unix98 ptys */
 static DEFINE_IDR(allocated_ptys);
-static DECLARE_MUTEX(allocated_ptys_lock);
+static DEFINE_MUTEX(allocated_ptys_lock);
 static int ptmx_open(struct inode *, struct file *);
 #endif
 
@@ -2571,9 +2571,9 @@ static void release_dev(struct file * filp)
 #ifdef CONFIG_UNIX98_PTYS
 	/* Make this pty number available for reallocation */
 	if (devpts) {
-		down(&allocated_ptys_lock);
+		mutex_lock(&allocated_ptys_lock);
 		idr_remove(&allocated_ptys, idx);
-		up(&allocated_ptys_lock);
+		mutex_unlock(&allocated_ptys_lock);
 	}
 #endif
 
@@ -2737,24 +2737,24 @@ static int ptmx_open(struct inode * inode, struct file * filp)
 	nonseekable_open(inode, filp);
 
 	/* find a device that is not in use. */
-	down(&allocated_ptys_lock);
+	mutex_lock(&allocated_ptys_lock);
 	if (!idr_pre_get(&allocated_ptys, GFP_KERNEL)) {
-		up(&allocated_ptys_lock);
+		mutex_unlock(&allocated_ptys_lock);
 		return -ENOMEM;
 	}
 	idr_ret = idr_get_new(&allocated_ptys, NULL, &index);
 	if (idr_ret < 0) {
-		up(&allocated_ptys_lock);
+		mutex_unlock(&allocated_ptys_lock);
 		if (idr_ret == -EAGAIN)
 			return -ENOMEM;
 		return -EIO;
 	}
 	if (index >= pty_limit) {
 		idr_remove(&allocated_ptys, index);
-		up(&allocated_ptys_lock);
+		mutex_unlock(&allocated_ptys_lock);
 		return -EIO;
 	}
-	up(&allocated_ptys_lock);
+	mutex_unlock(&allocated_ptys_lock);
 
 	mutex_lock(&tty_mutex);
 	retval = init_dev(ptm_driver, index, &tty);
@@ -2781,9 +2781,9 @@ static int ptmx_open(struct inode * inode, struct file * filp)
 	release_dev(filp);
 	return retval;
 out:
-	down(&allocated_ptys_lock);
+	mutex_lock(&allocated_ptys_lock);
 	idr_remove(&allocated_ptys, index);
-	up(&allocated_ptys_lock);
+	mutex_unlock(&allocated_ptys_lock);
 	return retval;
 }
 #endif