Messages in this thread | | | Date | Sat, 10 Aug 2019 14:12:51 -0400 | From | "Michael S. Tsirkin" <> | Subject | Re: [PATCH v3 2/2] virtio: decrement avail idx with buffer detach for packed ring |
| |
On Fri, Aug 09, 2019 at 12:18:47PM +0530, Pankaj Gupta wrote: > This patch decrements 'next_avail_idx' count when detaching a buffer > from vq for packed ring code. Split ring code already does this in > virtqueue_detach_unused_buf_split function. This updates the > 'next_avail_idx' to the previous correct index after an unused buffer > is detatched from the vq. > > Signed-off-by: Pankaj Gupta <pagupta@redhat.com>
I would make this patch 1, not patch 2, otherwise patch 1 corrupts the ring.
> --- > drivers/virtio/virtio_ring.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c > index c8be1c4f5b55..7c69181113e2 100644 > --- a/drivers/virtio/virtio_ring.c > +++ b/drivers/virtio/virtio_ring.c > @@ -1537,6 +1537,12 @@ static void *virtqueue_detach_unused_buf_packed(struct virtqueue *_vq) > /* detach_buf clears data, so grab it now. */ > buf = vq->packed.desc_state[i].data; > detach_buf_packed(vq, i, NULL); > + vq->packed.next_avail_idx--; > + if (vq->packed.next_avail_idx < 0) { > + vq->packed.next_avail_idx = vq->packed.vring.num - 1; > + vq->packed.avail_wrap_counter ^= 1; > + } > + > END_USE(vq); > return buf; > } > -- > 2.20.1
| |