Gitweb:
http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=db99247ac68fc352100090ad7704fb5efb9327b6
Commit: db99247ac68fc352100090ad7704fb5efb9327b6
Parent: 870e6f7e15980d1a33615de572078406737ac22e
Author: Cory T. Tusar <[EMAIL PROTECTED]>
AuthorDate: Sun Dec 23 12:34:51 2007 -0800
Committer: Linus Torvalds <[EMAIL PROTECTED]>
CommitDate: Sun Dec 23 12:54:37 2007 -0800
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 <[EMAIL PROTECTED]>
Cc: Alan Cox <[EMAIL PROTECTED]>
Acked-by: Jiri Slaby <[EMAIL PROTECTED]>
Cc: <[EMAIL PROTECTED]>
Signed-off-by: Andrew Morton <[EMAIL PROTECTED]>
Signed-off-by: Linus Torvalds <[EMAIL PROTECTED]>
---
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);
-
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