> From: Michael S. Tsirkin <mst@xxxxxxxxxx> > Sent: Tuesday, May 27, 2025 7:57 PM > To: linux-kernel@xxxxxxxxxxxxxxx > Cc: Parav Pandit <parav@xxxxxxxxxx>; Jason Wang <jasowang@xxxxxxxxxx>; > Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx>; Eugenio Pérez > <eperezma@xxxxxxxxxx>; virtualization@xxxxxxxxxxxxxxx > Subject: [PATCH] virtio: document ENOSPC > > 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 Reviewed-by: Parav Pandit <parav@xxxxxxxxxx>
