[PATCH] tty: make termios_sem a mutex

[akpm@osdl.org: fix]
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Arjan van de Ven <arjan@infradead.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

3 files changed, 22 insertions, 20 deletions

diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c
index b4f37c65b95c..142427c6e8f3 100644
--- a/drivers/char/tty_io.c
+++ b/drivers/char/tty_io.c
@@ -618,9 +618,9 @@ EXPORT_SYMBOL_GPL(tty_prepare_flip_string_flags);
  
 static void tty_set_termios_ldisc(struct tty_struct *tty, int num)
 {
-        down(&tty->termios_sem);
+        mutex_lock(&tty->termios_mutex);
         tty->termios->c_line = num;
-        up(&tty->termios_sem);
+        mutex_unlock(&tty->termios_mutex);
 }
 
 /*
@@ -1338,9 +1338,9 @@ static void do_tty_hangup(void *data)
          */
         if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
         {
-                down(&tty->termios_sem);
+                mutex_lock(&tty->termios_mutex);
                 *tty->termios = tty->driver->init_termios;
-                up(&tty->termios_sem);
+                mutex_unlock(&tty->termios_mutex);
         }
         
         /* Defer ldisc switch */
@@ -2750,9 +2750,9 @@ static int tiocgwinsz(struct tty_struct *tty, struct winsize __user * arg)
 {
         int err;
 
-        down(&tty->termios_sem);
+        mutex_lock(&tty->termios_mutex);
         err = copy_to_user(arg, &tty->winsize, sizeof(*arg));
-        up(&tty->termios_sem);
+        mutex_unlock(&tty->termios_mutex);
 
         return err ? -EFAULT: 0;
 }
@@ -2782,14 +2782,15 @@ static int tiocswinsz(struct tty_struct *tty, struct tty_struct *real_tty,
         if (copy_from_user(&tmp_ws, arg, sizeof(*arg)))
                 return -EFAULT;
 
-        down(&tty->termios_sem);
+        mutex_lock(&tty->termios_mutex);
         if (!memcmp(&tmp_ws, &tty->winsize, sizeof(*arg)))
                 goto done;
 
 #ifdef CONFIG_VT
         if (tty->driver->type == TTY_DRIVER_TYPE_CONSOLE) {
-                if (vc_lock_resize(tty->driver_data, tmp_ws.ws_col, tmp_ws.ws_row)) {
-                        up(&tty->termios_sem);
+                if (vc_lock_resize(tty->driver_data, tmp_ws.ws_col,
+                                        tmp_ws.ws_row)) {
+                        mutex_unlock(&tty->termios_mutex);
                         return -ENXIO;
                 }
         }
@@ -2801,7 +2802,7 @@ static int tiocswinsz(struct tty_struct *tty, struct tty_struct *real_tty,
         tty->winsize = tmp_ws;
         real_tty->winsize = tmp_ws;
 done:
-        up(&tty->termios_sem);
+        mutex_unlock(&tty->termios_mutex);
         return 0;
 }
 
@@ -3576,7 +3577,7 @@ static void initialize_tty_struct(struct tty_struct *tty)
         tty_buffer_init(tty);
         INIT_WORK(&tty->buf.work, flush_to_ldisc, tty);
         init_MUTEX(&tty->buf.pty_sem);
-        init_MUTEX(&tty->termios_sem);
+        mutex_init(&tty->termios_mutex);
         init_waitqueue_head(&tty->write_wait);
         init_waitqueue_head(&tty->read_wait);
         INIT_WORK(&tty->hangup_work, do_tty_hangup, tty);
diff --git a/drivers/char/tty_ioctl.c b/drivers/char/tty_ioctl.c
index 4ad47d321bd4..4d540619ac84 100644
--- a/drivers/char/tty_ioctl.c
+++ b/drivers/char/tty_ioctl.c
@@ -20,6 +20,7 @@
 #include <linux/mm.h>
 #include <linux/module.h>
 #include <linux/bitops.h>
+#include <linux/mutex.h>
 
 #include <asm/io.h>
 #include <asm/uaccess.h>
@@ -131,7 +132,7 @@ static void change_termios(struct tty_struct * tty, struct termios * new_termios
 
         /* FIXME: we need to decide on some locking/ordering semantics
            for the set_termios notification eventually */
-        down(&tty->termios_sem);
+        mutex_lock(&tty->termios_mutex);
 
         *tty->termios = *new_termios;
         unset_locked_termios(tty->termios, &old_termios, tty->termios_locked);
@@ -176,7 +177,7 @@ static void change_termios(struct tty_struct * tty, struct termios * new_termios
                         (ld->set_termios)(tty, &old_termios);
                 tty_ldisc_deref(ld);
         }
-        up(&tty->termios_sem);
+        mutex_unlock(&tty->termios_mutex);
 }
 
 /**
@@ -284,13 +285,13 @@ static int get_sgttyb(struct tty_struct * tty, struct sgttyb __user * sgttyb)
 {
         struct sgttyb tmp;
 
-        down(&tty->termios_sem);
+        mutex_lock(&tty->termios_mutex);
         tmp.sg_ispeed = 0;
         tmp.sg_ospeed = 0;
         tmp.sg_erase = tty->termios->c_cc[VERASE];
         tmp.sg_kill = tty->termios->c_cc[VKILL];
         tmp.sg_flags = get_sgflags(tty);
-        up(&tty->termios_sem);
+        mutex_unlock(&tty->termios_mutex);
         
         return copy_to_user(sgttyb, &tmp, sizeof(tmp)) ? -EFAULT : 0;
 }
@@ -345,12 +346,12 @@ static int set_sgttyb(struct tty_struct * tty, struct sgttyb __user * sgttyb)
         if (copy_from_user(&tmp, sgttyb, sizeof(tmp)))
                 return -EFAULT;
 
-        down(&tty->termios_sem);                
+        mutex_lock(&tty->termios_mutex);
         termios =  *tty->termios;
         termios.c_cc[VERASE] = tmp.sg_erase;
         termios.c_cc[VKILL] = tmp.sg_kill;
         set_sgflags(&termios, tmp.sg_flags);
-        up(&tty->termios_sem);
+        mutex_unlock(&tty->termios_mutex);
         change_termios(tty, &termios);
         return 0;
 }
@@ -592,11 +593,11 @@ int n_tty_ioctl(struct tty_struct * tty, struct file * file,
                 case TIOCSSOFTCAR:
                         if (get_user(arg, (unsigned int __user *) arg))
                                 return -EFAULT;
-                        down(&tty->termios_sem);
+                        mutex_lock(&tty->termios_mutex);
                         tty->termios->c_cflag =
                                 ((tty->termios->c_cflag & ~CLOCAL) |
                                  (arg ? CLOCAL : 0));
-                        up(&tty->termios_sem);
+                        mutex_unlock(&tty->termios_mutex);
                         return 0;
                 default:
                         return -ENOIOCTLCMD;
diff --git a/include/linux/tty.h b/include/linux/tty.h
index d1dec3d0c814..ea4c2605f8da 100644
--- a/include/linux/tty.h
+++ b/include/linux/tty.h
@@ -174,7 +174,7 @@ struct tty_struct {
         struct tty_driver *driver;
         int index;
         struct tty_ldisc ldisc;
-        struct semaphore termios_sem;
+        struct mutex termios_mutex;
         struct termios *termios, *termios_locked;
         char name[64];
         int pgrp;