For now, XDP_RING_NEED_WAKEUP is not supported properly by the virtio-net in the tx path for example: we set xsk_set_tx_need_wakeup() in virtnet_xsk_xmit(), but we didn't call xsk_clear_tx_need_wakeup() anywhere, which means the user will call send() for every packet. We call xsk_set_tx_need_wakeup() after virtnet_xsk_xmit_batch() if sq->vq is empty, as we can't be wakeup by the skb_xmit_done() in this case. Otherwise, we will clear the wakeup flag. Race condition is considered for tx path. Fixes: 89f86675cb03 ("virtio_net: xsk: tx: support xmit xsk buffer") Signed-off-by: Menglong Dong --- v3: - remove the confusing comment v2: - add the Fixes tag --- drivers/net/virtio_net.c | 23 +++++++++++++++++++---- 1 file changed, 19 insertions(+), 4 deletions(-) diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index f4adcfee7a80..6e099edef6e9 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -1440,8 +1440,9 @@ static bool virtnet_xsk_xmit(struct send_queue *sq, struct xsk_buff_pool *pool, struct virtnet_info *vi = sq->vq->vdev->priv; struct virtnet_sq_free_stats stats = {}; struct net_device *dev = vi->dev; + int sent, vring_size; + bool need_wakeup; u64 kicks = 0; - int sent; /* Avoid to wakeup napi meanless, so call __free_old_xmit instead of * free_old_xmit(). @@ -1451,8 +1452,25 @@ static bool virtnet_xsk_xmit(struct send_queue *sq, struct xsk_buff_pool *pool, if (stats.xsk) xsk_tx_completed(sq->xsk_pool, stats.xsk); + vring_size = virtqueue_get_vring_size(sq->vq); + need_wakeup = xsk_uses_need_wakeup(pool); + + if (need_wakeup && vring_size == sq->vq->num_free) + xsk_set_tx_need_wakeup(pool); + sent = virtnet_xsk_xmit_batch(sq, pool, budget, &kicks); + if (need_wakeup) { + if (vring_size == sq->vq->num_free) + /* we can't wake up by ourself, and it should be done + * by the user. + */ + xsk_set_tx_need_wakeup(pool); + else + /* we can wake up from skb_xmit_done() */ + xsk_clear_tx_need_wakeup(pool); + } + if (!is_xdp_raw_buffer_queue(vi, sq - vi->sq)) check_sq_full_and_disable(vi, vi->dev, sq); @@ -1470,9 +1488,6 @@ static bool virtnet_xsk_xmit(struct send_queue *sq, struct xsk_buff_pool *pool, u64_stats_add(&sq->stats.xdp_tx, sent); u64_stats_update_end(&sq->stats.syncp); - if (xsk_uses_need_wakeup(pool)) - xsk_set_tx_need_wakeup(pool); - return sent; } -- 2.54.0