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

[Maxime Coquelin <maxime.coquelin@redhat.com>]

On 3/15/21 4:50 PM, David Marchand wrote:
> On Mon, Mar 15, 2021 at 4:20 PM Maxime Coquelin
> <maxime.coquelin@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.

Agree, I will change to rte_zmalloc_socket, as vq (which is was part of)
is allocated like that.


Thanks,
Maxime

> 
>>         } 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().
> 
>