[media] v4l: omap4iss: Signal fatal errors to the vb2 queue

When a fatal error occurs in the pipeline signal it to the vb2 queue
with a call to vb2_queue_error(). The queue will then take care to
return -EIO when preparing buffers, remove the driver-specific code that
now duplicates that check.
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>

drivers/staging/media/omap4iss/iss_video.c

@@ -331,15 +331,6 @@ static int iss_video_buf_prepare(struct vb2_buffer *vb)
 	if (vb2_plane_size(vb, 0) < size)
 		return -ENOBUFS;
 
-	/* Refuse to prepare the buffer is the video node has registered an
-	 * error. We don't need to take any lock here as the operation is
-	 * inherently racy. The authoritative check will be performed in the
-	 * queue handler, which can't return an error, this check is just a best
-	 * effort to notify userspace as early as possible.
-	 */
-	if (unlikely(video->error))
-		return -EIO;
-
 	addr = vb2_dma_contig_plane_dma_addr(vb, 0);
 	if (!IS_ALIGNED(addr, 32)) {
 		dev_dbg(video->iss->dev,
@@ -363,6 +354,11 @@ static void iss_video_buf_queue(struct vb2_buffer *vb)
 
 	spin_lock_irqsave(&video->qlock, flags);
 
+	/* Mark the buffer is faulty and give it back to the queue immediately
+	 * if the video node has registered an error. vb2 will perform the same
+	 * check when preparing the buffer, but that is inherently racy, so we
+	 * need to handle the race condition with an authoritative check here.
+	 */
 	if (unlikely(video->error)) {
 		vb2_buffer_done(vb, VB2_BUF_STATE_ERROR);
 		spin_unlock_irqrestore(&video->qlock, flags);
@@ -513,6 +509,7 @@ void omap4iss_video_cancel_stream(struct iss_video *video)
 		vb2_buffer_done(&buf->vb, VB2_BUF_STATE_ERROR);
 	}
 
+	vb2_queue_error(video->queue);
 	video->error = true;
 
 	spin_unlock_irqrestore(&video->qlock, flags);