[dpdk-dev] [PATCH v2 3/4] net/virtio: allocate fake mbuf in Rx queue

[David Marchand]

On Mon, Mar 15, 2021 at 4:20 PM Maxime Coquelin
<maxime.coquelin at redhat.com> wrote:
> @@ -550,10 +551,18 @@ virtio_init_queue(struct rte_eth_dev *dev, uint16_t queue_idx)
>                         goto free_hdr_mz;
>                 }
>
> +               fake_mbuf = malloc(sizeof(*fake_mbuf));
> +               if (!fake_mbuf) {
> +                       PMD_INIT_LOG(ERR, "can not allocate fake mbuf");
> +                       ret = -ENOMEM;
> +                       goto free_sw_ring;
> +               }
> +
>                 vq->sw_ring = sw_ring;
>                 rxvq = &vq->rxq;
>                 rxvq->port_id = dev->data->port_id;
>                 rxvq->mz = mz;
> +               rxvq->fake_mbuf = fake_mbuf;

IIRC, vq is allocated as dpdk memory (rte_malloc).
Generally speaking, storing a local pointer inside such an object is
dangerous if other processes start to look at this part.


>         } else if (queue_type == VTNET_TQ) {
>                 txvq = &vq->txq;
>                 txvq->port_id = dev->data->port_id;
> @@ -613,6 +622,9 @@ virtio_init_queue(struct rte_eth_dev *dev, uint16_t queue_idx)
>  clean_vq:
>         hw->cvq = NULL;
>
> +       if (fake_mbuf)
> +               free(fake_mbuf);

No need for if().


-- 
David Marchand