netdev - Re: [PATCH v11 38/40] virtio_net: support rx queue resize

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CACGkMEu80KP-ULz_CBvauRk_3XsCubMkkWv0uLnbt-wib5KOnA@mail.gmail.com>
Date:   Fri, 8 Jul 2022 14:20:52 +0800
From:   Jason Wang <jasowang@...hat.com>
To:     Xuan Zhuo <xuanzhuo@...ux.alibaba.com>
Cc:     Richard Weinberger <richard@....at>,
        Anton Ivanov <anton.ivanov@...bridgegreys.com>,
        Johannes Berg <johannes@...solutions.net>,
        "Michael S. Tsirkin" <mst@...hat.com>,
        "David S. Miller" <davem@...emloft.net>,
        Eric Dumazet <edumazet@...gle.com>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>,
        Hans de Goede <hdegoede@...hat.com>,
        Mark Gross <markgross@...nel.org>,
        Vadim Pasternak <vadimp@...dia.com>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        Mathieu Poirier <mathieu.poirier@...aro.org>,
        Cornelia Huck <cohuck@...hat.com>,
        Halil Pasic <pasic@...ux.ibm.com>,
        Eric Farman <farman@...ux.ibm.com>,
        Heiko Carstens <hca@...ux.ibm.com>,
        Vasily Gorbik <gor@...ux.ibm.com>,
        Alexander Gordeev <agordeev@...ux.ibm.com>,
        Christian Borntraeger <borntraeger@...ux.ibm.com>,
        Sven Schnelle <svens@...ux.ibm.com>,
        Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        Jesper Dangaard Brouer <hawk@...nel.org>,
        John Fastabend <john.fastabend@...il.com>,
        Vincent Whitchurch <vincent.whitchurch@...s.com>,
        linux-um@...ts.infradead.org, netdev <netdev@...r.kernel.org>,
        platform-driver-x86@...r.kernel.org,
        linux-remoteproc@...r.kernel.org, linux-s390@...r.kernel.org,
        kvm <kvm@...r.kernel.org>,
        "open list:XDP (eXpress Data Path)" <bpf@...r.kernel.org>,
        kangjie.xu@...ux.alibaba.com,
        virtualization <virtualization@...ts.linux-foundation.org>
Subject: Re: [PATCH v11 38/40] virtio_net: support rx queue resize

On Tue, Jul 5, 2022 at 10:00 AM Xuan Zhuo <xuanzhuo@...ux.alibaba.com> wrote:
>
> On Mon, 4 Jul 2022 11:44:12 +0800, Jason Wang <jasowang@...hat.com> wrote:
> >
> > 在 2022/6/29 14:56, Xuan Zhuo 写道:
> > > This patch implements the resize function of the rx queues.
> > > Based on this function, it is possible to modify the ring num of the
> > > queue.
> > >
> > > Signed-off-by: Xuan Zhuo <xuanzhuo@...ux.alibaba.com>
> > > ---
> > >   drivers/net/virtio_net.c | 22 ++++++++++++++++++++++
> > >   1 file changed, 22 insertions(+)
> > >
> > > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> > > index 9fe222a3663a..6ab16fd193e5 100644
> > > --- a/drivers/net/virtio_net.c
> > > +++ b/drivers/net/virtio_net.c
> > > @@ -278,6 +278,8 @@ struct padded_vnet_hdr {
> > >     char padding[12];
> > >   };
> > >
> > > +static void virtnet_rq_free_unused_buf(struct virtqueue *vq, void *buf);
> > > +
> > >   static bool is_xdp_frame(void *ptr)
> > >   {
> > >     return (unsigned long)ptr & VIRTIO_XDP_FLAG;
> > > @@ -1846,6 +1848,26 @@ static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev)
> > >     return NETDEV_TX_OK;
> > >   }
> > >
> > > +static int virtnet_rx_resize(struct virtnet_info *vi,
> > > +                        struct receive_queue *rq, u32 ring_num)
> > > +{
> > > +   int err, qindex;
> > > +
> > > +   qindex = rq - vi->rq;
> > > +
> > > +   napi_disable(&rq->napi);
> >
> >
> > Do we need to cancel the refill work here?
>
>
> I think no, napi_disable is mutually exclusive, which ensures that there will be
> no conflicts between them.

So this sounds similar to what I've fixed recently.

1) NAPI schedule delayed work.
2) we disable NAPI here
3) delayed work get schedule and call NAPI again

?

Thanks

>
> Thanks.
>
> >
> > Thanks
> >
> >
> > > +
> > > +   err = virtqueue_resize(rq->vq, ring_num, virtnet_rq_free_unused_buf);
> > > +   if (err)
> > > +           netdev_err(vi->dev, "resize rx fail: rx queue index: %d err: %d\n", qindex, err);
> > > +
> > > +   if (!try_fill_recv(vi, rq, GFP_KERNEL))
> > > +           schedule_delayed_work(&vi->refill, 0);
> > > +
> > > +   virtnet_napi_enable(rq->vq, &rq->napi);
> > > +   return err;
> > > +}
> > > +
> > >   /*
> > >    * Send command via the control virtqueue and check status.  Commands
> > >    * supported by the hypervisor, as indicated by feature bits, should
> >
>