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    SubjectRe: [PATCH net v3] virtio_net: Fix error unwinding of XDP initialization
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    On Sat, 6 May 2023 08:08:02 -0400, Feng Liu <feliu@nvidia.com> wrote:
    >
    >
    > 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

    This is not the point, the key is whether we should handle with:

    disable_delayed_refill(vi);
    cancel_delayed_work_sync(&vi->refill);

    Thanks.


    >
    > >> +
    > >> + 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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