[PATCH 4.9 035/105] mailbox: handle empty message in tx_tick

From: Greg Kroah-Hartman
Date: Fri Aug 04 2017 - 20:12:56 EST


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

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

From: Sudeep Holla <sudeep.holla@xxxxxxx>

commit cb710ab1d8a23f68ff8f45aedf3e552bb90e70de upstream.

We already check if the message is empty before calling the client
tx_done callback. Calling completion on a wait event is also invalid
if the message is empty.

This patch moves the existing empty message check earlier.

Fixes: 2b6d83e2b8b7 ("mailbox: Introduce framework for mailbox")
Signed-off-by: Sudeep Holla <sudeep.holla@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 | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

--- a/drivers/mailbox/mailbox.c
+++ b/drivers/mailbox/mailbox.c
@@ -104,8 +104,11 @@ static void tx_tick(struct mbox_chan *ch
/* Submit next message */
msg_submit(chan);

+ if (!mssg)
+ return;
+
/* Notify the client */
- if (mssg && chan->cl->tx_done)
+ if (chan->cl->tx_done)
chan->cl->tx_done(chan->cl, mssg, r);

if (r != -ETIME && chan->cl->tx_block)