diff mbox series

[3/3] videobuf2-core: sanity checks for requests and qbuf

Message ID 20210729133627.1592672-4-hverkuil-cisco@xs4all.nl
State Accepted
Commit 9015fcc256d3a74d4fdc3d87877e270968550444
Headers show
Series None | expand

Commit Message

Hans Verkuil July 29, 2021, 1:36 p.m. UTC
The combination of supports_requests == 1 and min_buffers_needed > 0
is not allowed, WARN on that and return an error.

Also check that if vb2_core_qbuf() is called from req_queue, that it
doesn't return an error, unless it is -EIO.

Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Cc: Ezequiel Garcia <ezequiel@collabora.com>
Cc: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
---
 .../media/common/videobuf2/videobuf2-core.c   | 23 ++++++++++++++++++-
 1 file changed, 22 insertions(+), 1 deletion(-)

Comments

Ezequiel Garcia July 29, 2021, 3:08 p.m. UTC | #1
On Thu, 2021-07-29 at 15:36 +0200, Hans Verkuil wrote:
> The combination of supports_requests == 1 and min_buffers_needed > 0
> is not allowed, WARN on that and return an error.
> 
> Also check that if vb2_core_qbuf() is called from req_queue, that it
> doesn't return an error, unless it is -EIO.
> 
> Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
> Cc: Ezequiel Garcia <ezequiel@collabora.com>
> Cc: Paul Kocialkowski <paul.kocialkowski@bootlin.com>

Reviewed-by: Ezequiel Garcia <ezequiel@collabora.com>

Thanks,
Ezequiel
diff mbox series

Patch

diff --git a/drivers/media/common/videobuf2/videobuf2-core.c b/drivers/media/common/videobuf2/videobuf2-core.c
index 02281d13505f..3f0e816472d8 100644
--- a/drivers/media/common/videobuf2/videobuf2-core.c
+++ b/drivers/media/common/videobuf2/videobuf2-core.c
@@ -1421,9 +1421,19 @@  int vb2_core_qbuf(struct vb2_queue *q, unsigned int index, void *pb,
 static void vb2_req_queue(struct media_request_object *obj)
 {
 	struct vb2_buffer *vb = container_of(obj, struct vb2_buffer, req_obj);
+	int err;
 
 	mutex_lock(vb->vb2_queue->lock);
-	vb2_core_qbuf(vb->vb2_queue, vb->index, NULL, NULL);
+	/*
+	 * There is no method to propagate an error from vb2_core_qbuf(),
+	 * so if this returns a non-0 value, then WARN.
+	 *
+	 * The only exception is -EIO which is returned if q->error is
+	 * set. We just ignore that, and expect this will be caught the
+	 * next time vb2_req_prepare() is called.
+	 */
+	err = vb2_core_qbuf(vb->vb2_queue, vb->index, NULL, NULL);
+	WARN_ON_ONCE(err && err != -EIO);
 	mutex_unlock(vb->vb2_queue->lock);
 }
 
@@ -2331,6 +2341,17 @@  int vb2_core_queue_init(struct vb2_queue *q)
 	if (WARN_ON(q->requires_requests && !q->supports_requests))
 		return -EINVAL;
 
+	/*
+	 * This combination is not allowed since a non-zero value of
+	 * q->min_buffers_needed can cause vb2_core_qbuf() to fail if
+	 * it has to call start_streaming(), and the Request API expects
+	 * that queueing a request (and thus queueing a buffer contained
+	 * in that request) will always succeed. There is no method of
+	 * propagating an error back to userspace.
+	 */
+	if (WARN_ON(q->supports_requests && q->min_buffers_needed))
+		return -EINVAL;
+
 	INIT_LIST_HEAD(&q->queued_list);
 	INIT_LIST_HEAD(&q->done_list);
 	spin_lock_init(&q->done_lock);