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@xxxxxxxxx>
Cc: Ezequiel Garcia <ezequiel@xxxxxxxxxxxxx>
Cc: Paul Kocialkowski <paul.kocialkowski@xxxxxxxxxxx>
---
.../media/common/videobuf2/videobuf2-core.c | 23 ++++++++++++++++++-
1 file changed, 22 insertions(+), 1 deletion(-)
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);
--
2.30.2
