[dpdk-dev] [PATCH] virtio: fix idx in used ring retrieved only once
Yuanhan Liu
yuanhan.liu at linux.intel.com
Mon Jun 20 08:27:10 CEST 2016
On Thu, Jun 16, 2016 at 02:30:37AM +0800, Huawei Xie wrote:
> - while (vq->vq_used_cons_idx != vq->vq_ring.used->idx) {
> + while (VIRTQUEUE_NUSED(vq)) {
> uint32_t idx, desc_idx, used_idx;
> struct vring_used_elem *uep;
>
> diff --git a/drivers/net/virtio/virtio_ring.h b/drivers/net/virtio/virtio_ring.h
> index 447760a..fcecc16 100644
> --- a/drivers/net/virtio/virtio_ring.h
> +++ b/drivers/net/virtio/virtio_ring.h
> @@ -79,7 +79,7 @@ struct vring_used_elem {
>
> struct vring_used {
> uint16_t flags;
> - uint16_t idx;
> + volatile uint16_t idx;
> struct vring_used_elem ring[0];
> };
>
> diff --git a/drivers/net/virtio/virtio_rxtx_simple.c b/drivers/net/virtio/virtio_rxtx_simple.c
> index 7b50119..a0ef8d2 100644
> --- a/drivers/net/virtio/virtio_rxtx_simple.c
> +++ b/drivers/net/virtio/virtio_rxtx_simple.c
> @@ -184,8 +184,7 @@ virtio_recv_pkts_vec(void *rx_queue, struct rte_mbuf **rx_pkts,
> if (unlikely(nb_pkts < RTE_VIRTIO_DESC_PER_LOOP))
> return 0;
>
> - nb_used = *(volatile uint16_t *)&vq->vq_ring.used->idx -
> - vq->vq_used_cons_idx;
> + nb_used = vq->vq_ring.used->idx - vq->vq_used_cons_idx;
How about replacing it with VIRTQUEUE_NUSED here?
--yliu
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