On Tue, Dec 23, 2025 at 10:25:33PM +0700, Bui Quang Minh wrote:
> As we need to move the enable_delayed_refill after napi_enable, it's
> possible that a refill work needs to be scheduled in virtnet_receive but
> it cannot. This can make the receive side stuck because if we don't have
> any receive buffers, there will be nothing trigger the refill logic. So
> in case it happens, in virtnet_receive, set the rx queue's
> refill_pending, then when the refill work is enabled again, a refill
> work will be scheduled.
>
> Signed-off-by: Bui Quang Minh <[email protected]>
Sounds like this fixes a bug previous patch introduces?
The thing to do is to reorder these two patches then.
> ---
> drivers/net/virtio_net.c | 21 ++++++++++++---------
> 1 file changed, 12 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index 8016d2b378cf..ddc62dab2f9a 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -383,6 +383,9 @@ struct receive_queue {
> /* Is delayed refill enabled? */
> bool refill_enabled;
>
> + /* A refill work needs to be scheduled when delayed refill is enabled */
> + bool refill_pending;
> +
> /* The lock to synchronize the access to refill_enabled */
> spinlock_t refill_lock;
>
> @@ -720,10 +723,13 @@ static void virtnet_rq_free_buf(struct virtnet_info *vi,
> put_page(virt_to_head_page(buf));
> }
>
> -static void enable_delayed_refill(struct receive_queue *rq)
> +static void enable_delayed_refill(struct receive_queue *rq,
> + bool schedule_refill)
> {
> spin_lock_bh(&rq->refill_lock);
> rq->refill_enabled = true;
> + if (rq->refill_pending || schedule_refill)
> + schedule_delayed_work(&rq->refill, 0);
> spin_unlock_bh(&rq->refill_lock);
> }
>
> @@ -3032,6 +3038,8 @@ static int virtnet_receive(struct receive_queue *rq,
> int budget,
> spin_lock(&rq->refill_lock);
> if (rq->refill_enabled)
> schedule_delayed_work(&rq->refill, 0);
> + else
> + rq->refill_pending = true;
> spin_unlock(&rq->refill_lock);
> }
> }
> @@ -3228,11 +3236,8 @@ static int virtnet_open(struct net_device *dev)
> if (err < 0)
> goto err_enable_qp;
>
> - if (i < vi->curr_queue_pairs) {
> - enable_delayed_refill(&vi->rq[i]);
> - if (schedule_refill)
> - schedule_delayed_work(&vi->rq[i].refill, 0);
> - }
> + if (i < vi->curr_queue_pairs)
> + enable_delayed_refill(&vi->rq[i], schedule_refill);
> }
>
> if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_STATUS)) {
> @@ -3480,9 +3485,7 @@ static void __virtnet_rx_resume(struct virtnet_info *vi,
> if (running)
> virtnet_napi_enable(rq);
>
> - enable_delayed_refill(rq);
> - if (schedule_refill)
> - schedule_delayed_work(&rq->refill, 0);
> + enable_delayed_refill(rq, schedule_refill);
> }
>
> static void virtnet_rx_resume_all(struct virtnet_info *vi)
> --
> 2.43.0
