V4L/DVB (12002): uvc: Fix for no return value check of uvc_ctrl_set() which calls mutex_lock_interruptible()

Fix for no return value check of uvc_ctrl_set() which calls
mutex_lock_interruptible().

Signed-off-by: Robert Krakora <rob.krakora@messagenetsystems.com>
Acked-by: Laurent Pinchart <laurent.pinchart@skynet.be>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/video/uvc/uvc_v4l2.c

@@ -530,7 +530,10 @@ static long uvc_v4l2_do_ioctl(struct file *file, unsigned int cmd, void *arg)
 		memset(&xctrl, 0, sizeof xctrl);
 		xctrl.id = ctrl->id;
 
-		uvc_ctrl_begin(video);
+	       ret = uvc_ctrl_begin(video);
+	       if (ret < 0)
+			return ret;
+
 		ret = uvc_ctrl_get(video, &xctrl);
 		uvc_ctrl_rollback(video);
 		if (ret >= 0)
@@ -547,7 +550,10 @@ static long uvc_v4l2_do_ioctl(struct file *file, unsigned int cmd, void *arg)
 		xctrl.id = ctrl->id;
 		xctrl.value = ctrl->value;
 
-		uvc_ctrl_begin(video);
+	       ret = uvc_ctrl_begin(video);
+	       if (ret < 0)
+			return ret;
+
 		ret = uvc_ctrl_set(video, &xctrl);
 		if (ret < 0) {
 			uvc_ctrl_rollback(video);
@@ -566,7 +572,10 @@ static long uvc_v4l2_do_ioctl(struct file *file, unsigned int cmd, void *arg)
 		struct v4l2_ext_control *ctrl = ctrls->controls;
 		unsigned int i;
 
-		uvc_ctrl_begin(video);
+	       ret = uvc_ctrl_begin(video);
+	       if (ret < 0)
+			return ret;
+
 		for (i = 0; i < ctrls->count; ++ctrl, ++i) {
 			ret = uvc_ctrl_get(video, ctrl);
 			if (ret < 0) {