From: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Date: Wed, 8 Jan 2014 08:01:33 +0000 (-0300)
Subject: [media] vb2: Check if there are buffers before streamon
X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=249f5a58bc844506fef2e9d5d55a88fbc708c5fa;p=openwrt%2Fstaging%2Fblogic.git

[media] vb2: Check if there are buffers before streamon

This patch adds a test preventing streamon() if there is no buffer
ready.

Without this patch, a user could call streamon() before
preparing any buffer. This leads to a situation where if he calls
close() before calling streamoff() the device is kept streaming.

Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
---

diff --git a/drivers/media/v4l2-core/videobuf2-core.c b/drivers/media/v4l2-core/videobuf2-core.c
index 8e6695c9b0e2..3c07534e9ba5 100644
--- a/drivers/media/v4l2-core/videobuf2-core.c
+++ b/drivers/media/v4l2-core/videobuf2-core.c
@@ -1832,6 +1832,11 @@ static int vb2_internal_streamon(struct vb2_queue *q, enum v4l2_buf_type type)
 		return -EINVAL;
 	}
 
+	if (!q->num_buffers) {
+		dprintk(1, "streamon: no buffers have been allocated\n");
+		return -EINVAL;
+	}
+
 	/*
 	 * If any buffers were queued before streamon,
 	 * we can now pass them to driver for processing.