Re: [dpdk-dev] [PATCH] net/vhost: Initialise vid to -1

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

On 05/03/2018 03:18 PM, Loftus, Ciara wrote:
>>
>>>
>>> On 04/27/2018 04:19 PM, Ciara Loftus wrote:
>>>> rte_eth_vhost_get_vid_from_port_id returns a value of 0 if called before
>>>> the first call to the new_device callback. A vid value >=0 suggests the
>>>> device is active which is not the case in this instance. Initialise vid
>>>> to a negative value to prevent this.
>>>>
>>>> Signed-off-by: Ciara Loftus <ciara.loftus@intel.com>
>>>> ---
>>>>    drivers/net/vhost/rte_eth_vhost.c | 1 +
>>>>    1 file changed, 1 insertion(+)
>>>>
>>>> diff --git a/drivers/net/vhost/rte_eth_vhost.c
>>> b/drivers/net/vhost/rte_eth_vhost.c
>>>> index 99a7727..f47950c 100644
>>>> --- a/drivers/net/vhost/rte_eth_vhost.c
>>>> +++ b/drivers/net/vhost/rte_eth_vhost.c
>>>> @@ -1051,6 +1051,7 @@ eth_rx_queue_setup(struct rte_eth_dev *dev,
>>> uint16_t rx_queue_id,
>>>>    		return -ENOMEM;
>>>>    	}
>>>>
>>>> +	vq->vid = -1;
>>>>    	vq->mb_pool = mb_pool;
>>>>    	vq->virtqueue_id = rx_queue_id * VIRTIO_QNUM + VIRTIO_TXQ;
>>>>    	dev->data->rx_queues[rx_queue_id] = vq;
>>>>
>>>
>>> Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>
>>>
>>> Thanks,
>>> Maxime
>>
>> On second thoughts, self-NACK.
>>
>> We need to provision for the case where we want to call
>> eth_rx_queue_setup AFTER new_device. For instance when we want to
>> change the mb_pool. In this case we need to maintain the same vid and not
>> reset it to -1.
>>
>> Without this patch the original problem still exists and need to find an
>> alternative workaround.
> 
> Junjie's patches fix the issue I was observing. Thanks Junjie!
> https://dpdk.org/browse/dpdk/commit/?id=30a701a53737a0b6f7953412cc3b3d36c1d49122
> https://dpdk.org/browse/dpdk/commit/?id=e6722dee533cda3756fbc5c9ea4ddfbf30276f1b
> 
> Along with the v2 of this patch could they be considered for the 17.11 stable branch?

Yes, I think it is a good idea.
It wasn't planned for -stable initially as it fixed a new use-case in
v18.05.

Junjie, can you please generate a backport against v17.11 and post it to
stable@dpdk.org, adding "PATCH v17.11 LTS" as subject prefix, and using
-x option of when cherry-picking so that it references the patches in
master?

Thanks in advance,
Maxime
> Thanks,
> Ciara
> 
>>
>> Thanks,
>> Ciara