The patch titled
tty: fix logic change introduced by wait_event_interruptible_timeout()
has been removed from the -mm tree. Its filename was
tty-fix-logic-change-introduced-by-wait_event_interruptible_timeout.patch
This patch was dropped because it was merged into mainline or a subsystem tree
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: tty: fix logic change introduced by wait_event_interruptible_timeout()
From: "Cory T. Tusar" <ctusar@xxxxxxxxxxxxxxxxxx>
Commit 5a52bd4a2dcb570333ce6fe2e16cd311650dbdc8 introduced a subtle logic
change in tty_wait_until_sent(). The original version would only error out
of the 'do { ... } while (timeout)' loop if signal_pending() evaluated to
true; a timeout or break due to an empty buffer would fall out of the loop
and into the tty->driver->wait_until_sent handling. The current
implementation will error out on either a pending signal or an empty
buffer, falling through to the tty->driver->wait_until_sent handling only
on a timeout.
The ->wait_until_sent() will not be reached if the buffer empties before
timeout jiffies have elapsed. This behavior differs from that prior to commit
5a52bd4a2dcb570333ce6fe2e16cd311650dbdc8.
I turned this up while using a little serial download utility to bootstrap an
ARM-based eval board. The util worked fine on 2.6.22.x, but consistently
failed on 2.6.23.x. Once I'd determined that, I narrowed things down with git
bisect, and found the above difference in logic in tty_wait_until_sent() by
inspection.
This change reverts the logic flow in tty_wait_until_sent() to match that
prior to the aforementioned commit.
Signed-off-by: Cory T. Tusar <ctusar@xxxxxxxxxxxxxxxxxx>
Cc: Alan Cox <alan@xxxxxxxxxxxxxxxxxxx>
Acked-by: Jiri Slaby <jirislaby@xxxxxxxxx>
Cc: <stable@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/char/tty_ioctl.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff -puN drivers/char/tty_ioctl.c~tty-fix-logic-change-introduced-by-wait_event_interruptible_timeout drivers/char/tty_ioctl.c
--- a/drivers/char/tty_ioctl.c~tty-fix-logic-change-introduced-by-wait_event_interruptible_timeout
+++ a/drivers/char/tty_ioctl.c
@@ -62,7 +62,7 @@ void tty_wait_until_sent(struct tty_stru
if (!timeout)
timeout = MAX_SCHEDULE_TIMEOUT;
if (wait_event_interruptible_timeout(tty->write_wait,
- !tty->driver->chars_in_buffer(tty), timeout))
+ !tty->driver->chars_in_buffer(tty), timeout) < 0)
return;
if (tty->driver->wait_until_sent)
tty->driver->wait_until_sent(tty, timeout);
_
Patches currently in -mm which might be from ctusar@xxxxxxxxxxxxxxxxxx are
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