tty: simplify throttling using guard()s

tty_throttle_safe() and tty_unthrottle_safe can be made less convoluted
using guard()s. Switch them.

Signed-off-by: Jiri Slaby (SUSE) <jirislaby@kernel.org>
Link: https://lore.kernel.org/r/20250425111315.1036184-2-jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/tty_ioctl.c b/drivers/tty/tty_ioctl.c
index 85de90eebc7bbf533e82df6a4ca3d83d0083afe6..90c70d8d14e3a0a64e4c070499d885d90698f08e 100644 (file)
--- a/drivers/tty/tty_ioctl.c
+++ b/drivers/tty/tty_ioctl.c
@@ -122,21 +122,19 @@ EXPORT_SYMBOL(tty_unthrottle);
  */
 bool tty_throttle_safe(struct tty_struct *tty)
 {
-       bool ret = true;
-
-       mutex_lock(&tty->throttle_mutex);
-       if (!tty_throttled(tty)) {
-               if (tty->flow_change != TTY_THROTTLE_SAFE)
-                       ret = false;
-               else {
-                       set_bit(TTY_THROTTLED, &tty->flags);
-                       if (tty->ops->throttle)
-                               tty->ops->throttle(tty);
-               }
-       }
-       mutex_unlock(&tty->throttle_mutex);
+       guard(mutex)(&tty->throttle_mutex);
 
-       return ret;
+       if (tty_throttled(tty))
+               return true;
+
+       if (tty->flow_change != TTY_THROTTLE_SAFE)
+               return false;
+
+       set_bit(TTY_THROTTLED, &tty->flags);
+       if (tty->ops->throttle)
+               tty->ops->throttle(tty);
+
+       return true;
 }
 
 /**
@@ -152,21 +150,19 @@ bool tty_throttle_safe(struct tty_struct *tty)
  */
 bool tty_unthrottle_safe(struct tty_struct *tty)
 {
-       bool ret = true;
+       guard(mutex)(&tty->throttle_mutex);
 
-       mutex_lock(&tty->throttle_mutex);
-       if (tty_throttled(tty)) {
-               if (tty->flow_change != TTY_UNTHROTTLE_SAFE)
-                       ret = false;
-               else {
-                       clear_bit(TTY_THROTTLED, &tty->flags);
-                       if (tty->ops->unthrottle)
-                               tty->ops->unthrottle(tty);
-               }
-       }
-       mutex_unlock(&tty->throttle_mutex);
+       if (!tty_throttled(tty))
+               return true;
 
-       return ret;
+       if (tty->flow_change != TTY_UNTHROTTLE_SAFE)
+               return false;
+
+       clear_bit(TTY_THROTTLED, &tty->flags);
+       if (tty->ops->unthrottle)
+               tty->ops->unthrottle(tty);
+
+       return true;
 }
 
 /**