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

From: Jassi Brar <jassisinghbrar@gmail.com>
To: linux-kernel@vger.kernel.org
Cc: gregkh@linuxfoundation.org, s-anna@ti.com, tony@atomide.com,
	omar.ramirez@copitl.com, loic.pallardy@st.com,
	lftan.linux@gmail.com, slapdau@yahoo.com.au,
	courtney.cavin@sonymobile.com, rafael.j.wysocki@intel.com,
	robherring2@gmail.com, arnd@arndb.de, joshc@codeaurora.org,
	linus.walleij@linaro.org, galak@codeaurora.org,
	ks.giri@samsung.com, Jassi Brar <jaswinder.singh@linaro.org>
Subject: [PATCHv4 4/5] mailbox: Fix TX completion init
Date: Wed, 19 Mar 2014 00:16:16 +0530	[thread overview]
Message-ID: <1395168376-29200-1-git-send-email-jaswinder.singh@linaro.org> (raw)
In-Reply-To: <1395168169-28978-1-git-send-email-jaswinder.singh@linaro.org>

From: LeyFoon Tan <lftan.linux@gmail.com>

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@gmail.com>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>
---
 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

