diff options
| author | Cory T. Tusar <ctusar@videon-central.com> | 2007-12-23 20:34:51 (GMT) |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-12-23 20:54:37 (GMT) |
| commit | db99247ac68fc352100090ad7704fb5efb9327b6 (patch) | |
| tree | c18bbbb61eed5bb0be920cd2ece585cf070aef91 | |
| parent | 870e6f7e15980d1a33615de572078406737ac22e (diff) | |
| download | linux-fsl-qoriq-db99247ac68fc352100090ad7704fb5efb9327b6.tar.xz | |
tty: fix logic change introduced by wait_event_interruptible_timeout()
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@videon-central.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Acked-by: Jiri Slaby <jirislaby@gmail.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | drivers/char/tty_ioctl.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/char/tty_ioctl.c b/drivers/char/tty_ioctl.c index 1bdd2bf..e02d592 100644 --- a/drivers/char/tty_ioctl.c +++ b/drivers/char/tty_ioctl.c @@ -62,7 +62,7 @@ void tty_wait_until_sent(struct tty_struct * tty, long timeout) 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); |