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@xxxxxxxxxxxxx> 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@xxxxxxxxxxxxx>
> > ---
> > 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
>
