[PATCH] remove down_tty_sem()

Remove the down_tty_sem() and up_tty_sem() and replace them with open-coded
up() and down().  This is an equivalent transformation.

I assume these functions were created to open the possibility of per-tty
semaphores at some time in the future.  But the code which is protected by
this lock deals with two tty's at the same time, and the next patch will need
to release the lock after the tty has been destroyed.

drivers/char/tty_io.c

@@ -122,6 +122,9 @@ EXPORT_SYMBOL(tty_std_termios);
 LIST_HEAD(tty_drivers);			/* linked list of tty drivers */
 struct tty_ldisc ldiscs[NR_LDISCS];	/* line disc dispatch table	*/
 
+/* Semaphore to protect creating and releasing a tty */
+static DECLARE_MUTEX(tty_sem);
+
 #ifdef CONFIG_UNIX98_PTYS
 extern struct tty_driver *ptm_driver;	/* Unix98 pty masters; for /dev/ptmx */
 extern int pty_limit;		/* Config limit on Unix98 ptys */
@@ -141,6 +144,8 @@ int tty_ioctl(struct inode * inode, struct file * file,
 	      unsigned int cmd, unsigned long arg);
 static int tty_fasync(int fd, struct file * filp, int on);
 extern void rs_360_init(void);
+static void release_mem(struct tty_struct *tty, int idx);
+
 
 static struct tty_struct *alloc_tty_struct(void)
 {
@@ -765,21 +770,6 @@ ssize_t redirected_tty_write(struct file * file, const char * buf, size_t count,
 	return tty_write(file, buf, count, ppos);
 }
 
-/* Semaphore to protect creating and releasing a tty */
-static DECLARE_MUTEX(tty_sem);
-
-static void down_tty_sem(int index)
-{
-	down(&tty_sem);
-}
-
-static void up_tty_sem(int index)
-{
-	up(&tty_sem);
-}
-
-static void release_mem(struct tty_struct *tty, int idx);
-
 static inline void tty_line_name(struct tty_driver *driver, int index, char *p)
 {
 	sprintf(p, "%s%d", driver->name, index + driver->name_base);
@@ -803,7 +793,7 @@ static int init_dev(struct tty_driver *driver, int idx,
 	 * Check whether we need to acquire the tty semaphore to avoid
 	 * race conditions.  For now, play it safe.
 	 */
-	down_tty_sem(idx);
+	down(&tty_sem);
 
 	/* check whether we're reopening an existing tty */
 	if (driver->flags & TTY_DRIVER_DEVPTS_MEM) {
@@ -987,7 +977,7 @@ static int init_dev(struct tty_driver *driver, int idx,
 	
 	/* All paths come through here to release the semaphore */
 end_init:
-	up_tty_sem(idx);
+	up(&tty_sem);
 	return retval;
 
 	/* Release locally allocated memory ... nothing placed in slots */