drivers handle ENOSPC specially since it's an error one can get from a working VQ. Document the semantics. Reported-by: Parav Pandit <parav@xxxxxxxxxx> Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx> --- drivers/virtio/virtio_ring.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c index b784aab66867..97ab0cce527d 100644 --- a/drivers/virtio/virtio_ring.c +++ b/drivers/virtio/virtio_ring.c @@ -2296,6 +2296,10 @@ static inline int virtqueue_add(struct virtqueue *_vq, * at the same time (except where noted). * * Returns zero or a negative error (ie. ENOSPC, ENOMEM, EIO). + * + * NB: ENOSPC is a special code that is only returned on an attempt to add a + * buffer to a full VQ. It indicates that some buffers are outstanding and that + * the operation can be retried after some buffers have been used. */ int virtqueue_add_sgs(struct virtqueue *_vq, struct scatterlist *sgs[], -- MST
