netdev - Re: [PATCH net-next v2 4/5] virtio_ring: add 'flushed' as an argument to virtqueue

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] [day] [month] [year] [list]

Message-ID: <ub7pbfodhjpubwixxsbxlkiclthp3adbxin7etff5seoxqs5i7@aj3c7tpeirwq>
Date: Wed, 4 Dec 2024 13:14:51 +0900
From: Koichiro Den <koichiro.den@...onical.com>
To: Jason Wang <jasowang@...hat.com>
Cc: virtualization@...ts.linux.dev, mst@...hat.com, 
	xuanzhuo@...ux.alibaba.com, eperezma@...hat.com, andrew+netdev@...n.ch, davem@...emloft.net, 
	edumazet@...gle.com, kuba@...nel.org, pabeni@...hat.com, jiri@...nulli.us, 
	netdev@...r.kernel.org, linux-kernel@...r.kernel.org, stable@...r.kernel.org
Subject: Re: [PATCH net-next v2 4/5] virtio_ring: add 'flushed' as an
 argument to virtqueue_reset()

On Wed, Dec 04, 2024 at 10:49:02AM +0800, Jason Wang wrote:
> On Tue, Dec 3, 2024 at 3:31 PM Koichiro Den <koichiro.den@...onical.com> wrote:
> >
> > When virtqueue_reset() has actually recycled all unused buffers,
> > additional work may be required in some cases. Relying solely on its
> > return status is fragile, so introduce a new argument 'flushed' to
> > explicitly indicate whether it has really occurred.
> >
> > Signed-off-by: Koichiro Den <koichiro.den@...onical.com>
> > ---
> >  drivers/net/virtio_net.c     | 6 ++++--
> >  drivers/virtio/virtio_ring.c | 6 +++++-
> >  include/linux/virtio.h       | 3 ++-
> >  3 files changed, 11 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> > index 0103d7990e44..d5240a03b7d6 100644
> > --- a/drivers/net/virtio_net.c
> > +++ b/drivers/net/virtio_net.c
> > @@ -5695,6 +5695,7 @@ static int virtnet_rq_bind_xsk_pool(struct virtnet_info *vi, struct receive_queu
> >                                     struct xsk_buff_pool *pool)
> >  {
> >         int err, qindex;
> > +       bool flushed;
> >
> >         qindex = rq - vi->rq;
> >
> > @@ -5713,7 +5714,7 @@ static int virtnet_rq_bind_xsk_pool(struct virtnet_info *vi, struct receive_queu
> >
> >         virtnet_rx_pause(vi, rq);
> >
> > -       err = virtqueue_reset(rq->vq, virtnet_rq_unmap_free_buf);
> > +       err = virtqueue_reset(rq->vq, virtnet_rq_unmap_free_buf, &flushed);
> >         if (err) {
> >                 netdev_err(vi->dev, "reset rx fail: rx queue index: %d err: %d\n", qindex, err);
> >
> > @@ -5737,12 +5738,13 @@ static int virtnet_sq_bind_xsk_pool(struct virtnet_info *vi,
> >                                     struct xsk_buff_pool *pool)
> >  {
> >         int err, qindex;
> > +       bool flushed;
> >
> >         qindex = sq - vi->sq;
> >
> >         virtnet_tx_pause(vi, sq);
> >
> > -       err = virtqueue_reset(sq->vq, virtnet_sq_free_unused_buf);
> > +       err = virtqueue_reset(sq->vq, virtnet_sq_free_unused_buf, &flushed);
> >         if (err) {
> >                 netdev_err(vi->dev, "reset tx fail: tx queue index: %d err: %d\n", qindex, err);
> >                 pool = NULL;
> > diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
> > index 34a068d401ec..b522ef798946 100644
> > --- a/drivers/virtio/virtio_ring.c
> > +++ b/drivers/virtio/virtio_ring.c
> > @@ -2828,6 +2828,7 @@ EXPORT_SYMBOL_GPL(virtqueue_resize);
> >   * virtqueue_reset - detach and recycle all unused buffers
> >   * @_vq: the struct virtqueue we're talking about.
> >   * @recycle: callback to recycle unused buffers
> > + * @flushed: whether or not unused buffers are all flushed
> >   *
> >   * Caller must ensure we don't call this with other virtqueue operations
> >   * at the same time (except where noted).
> > @@ -2839,14 +2840,17 @@ EXPORT_SYMBOL_GPL(virtqueue_resize);
> >   * -EPERM: Operation not permitted
> >   */
> >  int virtqueue_reset(struct virtqueue *_vq,
> > -                   void (*recycle)(struct virtqueue *vq, void *buf))
> > +                   void (*recycle)(struct virtqueue *vq, void *buf),
> > +                   bool *flushed)
> >  {
> >         struct vring_virtqueue *vq = to_vvq(_vq);
> >         int err;
> >
> > +       *flushed = false;
> >         err = virtqueue_disable_and_recycle(_vq, recycle);
> >         if (err)
> >                 return err;
> > +       *flushed = true;
> >
> 
> This makes me think if it would be easier if we just find a way to
> reset the tx queue inside virtqueue_disable_and_recycle().
> 
> For example, introducing a recycle_done callback?

It sounds reasonable and much cleaner. I'll prepare and send v3 shortly.
Thanks for the review.

-Koichiro Den

> 
> Thanks
>