[PATCH] staging/easycap: fix mismatch in easycap_poll() mutex lock-unlock

[Alexey Khoroshilov]

In case if condition (kd != isdongle(peasycap)) becomes true,
easycap_poll() returns without releasing easycapdc60_dongle[kd].mutex_video.
The patch adds mutex_unlock() before that return.

Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Alexey Khoroshilov <khoroshilov at ispras.ru>
---
 drivers/staging/easycap/easycap_main.c |    4 +++-
 1 files changed, 3 insertions(+), 1 deletions(-)

diff --git a/drivers/staging/easycap/easycap_main.c b/drivers/staging/easycap/easycap_main.c
index bea2816..3ea51c3 100644
--- a/drivers/staging/easycap/easycap_main.c
+++ b/drivers/staging/easycap/easycap_main.c
@@ -953,8 +953,10 @@ static unsigned int easycap_poll(struct file *file, poll_table *wait)
 	 *  peasycap, IN WHICH CASE A REPEAT CALL TO isdongle() WILL FAIL.
 	 *  IF NECESSARY, BAIL OUT.
 	 */
-		if (kd != isdongle(peasycap))
+		if (kd != isdongle(peasycap)) {
+			mutex_unlock(&easycapdc60_dongle[kd].mutex_video);
 			return -ERESTARTSYS;
+		}
 		if (!file) {
 			SAY("ERROR:  file is NULL\n");
 			mutex_unlock(&easycapdc60_dongle[kd].mutex_video);
-- 
1.7.4.1