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SubjectRe: [PATCH net v3] virtio_net: Fix error unwinding of XDP initialization
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On 2023-05-05 p.m.10:33, Xuan Zhuo wrote:
> External email: Use caution opening links or attachments
>
>
> On Tue, 2 May 2023 20:35:25 -0400, Feng Liu <feliu@nvidia.com> wrote:
>> When initializing XDP in virtnet_open(), some rq xdp initialization
>> may hit an error causing net device open failed. However, previous
>> rqs have already initialized XDP and enabled NAPI, which is not the
>> expected behavior. Need to roll back the previous rq initialization
>> to avoid leaks in error unwinding of init code.
>>
>> Also extract a helper function of disable queue pairs, and use newly
>> introduced helper function in error unwinding and virtnet_close;
>>
>> Issue: 3383038
>> Fixes: 754b8a21a96d ("virtio_net: setup xdp_rxq_info")
>> Signed-off-by: Feng Liu <feliu@nvidia.com>
>> Reviewed-by: William Tu <witu@nvidia.com>
>> Reviewed-by: Parav Pandit <parav@nvidia.com>
>> Reviewed-by: Simon Horman <simon.horman@corigine.com>
>> Acked-by: Michael S. Tsirkin <mst@redhat.com>
>> Change-Id: Ib4c6a97cb7b837cfa484c593dd43a435c47ea68f
>> ---
>> drivers/net/virtio_net.c | 30 ++++++++++++++++++++----------
>> 1 file changed, 20 insertions(+), 10 deletions(-)
>>
>> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
>> index 8d8038538fc4..3737cf120cb7 100644
>> --- a/drivers/net/virtio_net.c
>> +++ b/drivers/net/virtio_net.c
>> @@ -1868,6 +1868,13 @@ static int virtnet_poll(struct napi_struct *napi, int budget)
>> return received;
>> }
>>
>> +static void virtnet_disable_qp(struct virtnet_info *vi, int qp_index)
>> +{
>> + virtnet_napi_tx_disable(&vi->sq[qp_index].napi);
>> + napi_disable(&vi->rq[qp_index].napi);
>> + xdp_rxq_info_unreg(&vi->rq[qp_index].xdp_rxq);
>> +}
>> +
>> static int virtnet_open(struct net_device *dev)
>> {
>> struct virtnet_info *vi = netdev_priv(dev);
>> @@ -1883,20 +1890,26 @@ static int virtnet_open(struct net_device *dev)
>>
>> err = xdp_rxq_info_reg(&vi->rq[i].xdp_rxq, dev, i, vi->rq[i].napi.napi_id);
>> if (err < 0)
>> - return err;
>> + goto err_xdp_info_reg;
>>
>> err = xdp_rxq_info_reg_mem_model(&vi->rq[i].xdp_rxq,
>> MEM_TYPE_PAGE_SHARED, NULL);
>> - if (err < 0) {
>> - xdp_rxq_info_unreg(&vi->rq[i].xdp_rxq);
>> - return err;
>> - }
>> + if (err < 0)
>> + goto err_xdp_reg_mem_model;
>>
>> virtnet_napi_enable(vi->rq[i].vq, &vi->rq[i].napi);
>> virtnet_napi_tx_enable(vi, vi->sq[i].vq, &vi->sq[i].napi);
>> }
>>
>> return 0;
>> +
>> +err_xdp_reg_mem_model:
>> + xdp_rxq_info_unreg(&vi->rq[i].xdp_rxq);
>> +err_xdp_info_reg:
>> + for (i = i - 1; i >= 0; i--)
>> + virtnet_disable_qp(vi, i);
>
>
> I would to know should we handle for these:
>
> disable_delayed_refill(vi);
> cancel_delayed_work_sync(&vi->refill);
>
>
> Maybe we should call virtnet_close() with "i" directly.
>
> Thanks.
>
>
Can’t use i directly here, because if xdp_rxq_info_reg fails, napi has
not been enabled for current qp yet, I should roll back from the queue
pairs where napi was enabled before(i--), otherwise it will hang at napi
disable api

>> +
>> + return err;
>> }
>>
>> static int virtnet_poll_tx(struct napi_struct *napi, int budget)
>> @@ -2305,11 +2318,8 @@ static int virtnet_close(struct net_device *dev)
>> /* Make sure refill_work doesn't re-enable napi! */
>> cancel_delayed_work_sync(&vi->refill);
>>
>> - for (i = 0; i < vi->max_queue_pairs; i++) {
>> - virtnet_napi_tx_disable(&vi->sq[i].napi);
>> - napi_disable(&vi->rq[i].napi);
>> - xdp_rxq_info_unreg(&vi->rq[i].xdp_rxq);
>> - }
>> + for (i = 0; i < vi->max_queue_pairs; i++)
>> + virtnet_disable_qp(vi, i);
>>
>> return 0;
>> }
>> --
>> 2.37.1 (Apple Git-137.1)
>>

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