Patch "mailbox: skip complete wait event if timer expired" has been added to the 4.4-stable tree

Patch "mailbox: skip complete wait event if timer expired" has been added to the 4.4-stable tree

[gregkh]

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

    mailbox: skip complete wait event if timer expired

to the 4.4-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:
     mailbox-skip-complete-wait-event-if-timer-expired.patch
and it can be found in the queue-4.4 subdirectory.

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


>From cc6eeaa3029a6dbcb4ad41b1f92876483bd88965 Mon Sep 17 00:00:00 2001
From: Sudeep Holla <sudeep.holla@arm.com>
Date: Tue, 21 Mar 2017 11:30:15 +0000
Subject: mailbox: skip complete wait event if timer expired

From: Sudeep Holla <sudeep.holla@arm.com>

commit cc6eeaa3029a6dbcb4ad41b1f92876483bd88965 upstream.

If a wait_for_completion_timeout() call returns due to a timeout,
complete() can get called after returning from the wait which is
incorrect and can cause subsequent transmissions on a channel to fail.
Since the wait_for_completion_timeout() sees the completion variable
is non-zero caused by the erroneous/spurious complete() call, and
it immediately returns without waiting for the time as expected by the
client.

This patch fixes the issue by skipping complete() call for the timer
expiry.

Fixes: 2b6d83e2b8b7 ("mailbox: Introduce framework for mailbox")
Reported-by: Alexey Klimov <alexey.klimov@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>
Signed-off-by: Amit Pundir <amit.pundir@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/mailbox/mailbox.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

--- a/drivers/mailbox/mailbox.c
+++ b/drivers/mailbox/mailbox.c
@@ -108,7 +108,7 @@ static void tx_tick(struct mbox_chan *ch
 	if (mssg && chan->cl->tx_done)
 		chan->cl->tx_done(chan->cl, mssg, r);
 
-	if (chan->cl->tx_block)
+	if (r != -ETIME && chan->cl->tx_block)
 		complete(&chan->tx_complete);
 }
 
@@ -272,8 +272,8 @@ int mbox_send_message(struct mbox_chan *
 
 		ret = wait_for_completion_timeout(&chan->tx_complete, wait);
 		if (ret == 0) {
-			t = -EIO;
-			tx_tick(chan, -EIO);
+			t = -ETIME;
+			tx_tick(chan, t);
 		}
 	}
 


Patches currently in stable-queue which might be from sudeep.holla@arm.com are

queue-4.4/mailbox-always-wait-in-mbox_send_message-for-blocking-tx-mode.patch
queue-4.4/mailbox-skip-complete-wait-event-if-timer-expired.patch
queue-4.4/mailbox-handle-empty-message-in-tx_tick.patch