Patch "tty: early return from send_break() on TTY_DRIVER_HARDWARE_BREAK" has been added to the 5.15-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    tty: early return from send_break() on TTY_DRIVER_HARDWARE_BREAK

to the 5.15-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     tty-early-return-from-send_break-on-tty_driver_hardw.patch
and it can be found in the queue-5.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 31c357c68b71dd039bbcfd4b427e5d85eb8b3684
Author: Jiri Slaby (SUSE) <jirislaby@xxxxxxxxxx>
Date:   Tue Sep 19 10:51:54 2023 +0200

    tty: early return from send_break() on TTY_DRIVER_HARDWARE_BREAK
    
    [ Upstream commit 66619686d187b4a6395316b7f39881e945dce4bc ]
    
    If the driver sets TTY_DRIVER_HARDWARE_BREAK, we leave ops->break_ctl()
    to the driver and return from send_break(). But we do it using a local
    variable and keep the code flowing through the end of the function.
    Instead, do 'return' immediately with the ops->break_ctl()'s return
    value.
    
    This way, we don't have to stuff the 'else' branch of the 'if' with the
    software break handling. And we can re-indent the function too.
    
    Signed-off-by: "Jiri Slaby (SUSE)" <jirislaby@xxxxxxxxxx>
    Link: https://lore.kernel.org/r/20230919085156.1578-14-jirislaby@xxxxxxxxxx
    Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
    Stable-dep-of: 66aad7d8d3ec ("usb: cdc-acm: return correct error code on unsupported break")
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index 12f6ef8d0f45..a18138ce67b2 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -2504,22 +2504,24 @@ static int send_break(struct tty_struct *tty, unsigned int duration)
 		return 0;
 
 	if (tty->driver->flags & TTY_DRIVER_HARDWARE_BREAK)
-		retval = tty->ops->break_ctl(tty, duration);
-	else {
-		/* Do the work ourselves */
-		if (tty_write_lock(tty, false) < 0)
-			return -EINTR;
-		retval = tty->ops->break_ctl(tty, -1);
-		if (retval)
-			goto out;
-		if (!signal_pending(current))
-			msleep_interruptible(duration);
-		retval = tty->ops->break_ctl(tty, 0);
+		return tty->ops->break_ctl(tty, duration);
+
+	/* Do the work ourselves */
+	if (tty_write_lock(tty, false) < 0)
+		return -EINTR;
+
+	retval = tty->ops->break_ctl(tty, -1);
+	if (retval)
+		goto out;
+	if (!signal_pending(current))
+		msleep_interruptible(duration);
+	retval = tty->ops->break_ctl(tty, 0);
 out:
-		tty_write_unlock(tty);
-		if (signal_pending(current))
-			retval = -EINTR;
-	}
+	tty_write_unlock(tty);
+
+	if (signal_pending(current))
+		retval = -EINTR;
+
 	return retval;
 }