[PATCHv4 4/5] mailbox: Fix TX completion init

[Jassi Brar]

From: LeyFoon Tan <lftan.linux@xxxxxxxxx>

For fast TX the complete could be called before being initialized as follows
 mbox_send_message --> poll_txdone --> tx_tick --> complete(&chan->tx_complete)

Init the completion early enough to fix the race.

Signed-off-by: LeyFoon Tan <lftan.linux@xxxxxxxxx>
Signed-off-by: Jassi Brar <jaswinder.singh@xxxxxxxxxx>
---
 drivers/mailbox/mailbox.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/mailbox/mailbox.c b/drivers/mailbox/mailbox.c
index 79d576e..cdf7d45 100644
--- a/drivers/mailbox/mailbox.c
+++ b/drivers/mailbox/mailbox.c
@@ -278,6 +278,9 @@ int mbox_send_message(struct mbox_chan *chan, void *mssg)
 	if (!chan || !chan->cl)
 		return -EINVAL;
 
+	if (chan->cl->tx_block)
+		init_completion(&chan->tx_complete);
+
 	t = _add_to_rbuf(chan, mssg);
 	if (t < 0) {
 		pr_err("Try increasing MBOX_TX_QUEUE_LEN\n");
@@ -291,7 +294,6 @@ int mbox_send_message(struct mbox_chan *chan, void *mssg)
 
 	if (chan->cl->tx_block && chan->active_req) {
 		int ret;
-		init_completion(&chan->tx_complete);
 		ret = wait_for_completion_timeout(&chan->tx_complete,
 			chan->cl->tx_tout);
 		if (ret == 0) {
-- 
1.8.1.2

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