[PATCH 3.18 21/50] mailbox: always wait in mbox_send_message for blocking Tx mode

[Greg Kroah-Hartman]

3.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Sudeep Holla <sudeep.holla@xxxxxxx>

commit c61b781ee084e69855477d23dd33e7e6caad652c upstream.

There exists a race when msg_submit return immediately as there was an
active request being processed which may have completed just before it's
checked again in mbox_send_message. This will result in return to the
caller without waiting in mbox_send_message even when it's blocking Tx.

This patch fixes the issue by waiting for the completion always if Tx
is in blocking mode.

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

---
 drivers/mailbox/mailbox.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/mailbox/mailbox.c
+++ b/drivers/mailbox/mailbox.c
@@ -255,7 +255,7 @@ int mbox_send_message(struct mbox_chan *
 	if (chan->txdone_method	== TXDONE_BY_POLL)
 		poll_txdone((unsigned long)chan->mbox);
 
-	if (chan->cl->tx_block && chan->active_req) {
+	if (chan->cl->tx_block) {
 		unsigned long wait;
 		int ret;