4.17-stable review patch. If anyone has any objections, please let me know.
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From: Jesper Dangaard Brouer brouer@redhat.com
[ Upstream commit 2471c75efed32529698c26da499954f0253cb401 ]
The driver was combining XDP_TX virtqueue_kick and XDP_REDIRECT map flushing (xdp_do_flush_map). This is suboptimal, these two flush operations should be kept separate.
The suboptimal behavior was introduced in commit 9267c430c6b6 ("virtio-net: add missing virtqueue kick when flushing packets").
Fixes: 9267c430c6b6 ("virtio-net: add missing virtqueue kick when flushing packets") Signed-off-by: Jesper Dangaard Brouer brouer@redhat.com Acked-by: Jason Wang jasowang@redhat.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/net/virtio_net.c | 30 +++++++++++++++++++----------- 1 file changed, 19 insertions(+), 11 deletions(-)
--- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -50,6 +50,10 @@ module_param(napi_tx, bool, 0644); /* Amount of XDP headroom to prepend to packets for use by xdp_adjust_head */ #define VIRTIO_XDP_HEADROOM 256
+/* Separating two types of XDP xmit */ +#define VIRTIO_XDP_TX BIT(0) +#define VIRTIO_XDP_REDIR BIT(1) + /* RX packet size EWMA. The average packet size is used to determine the packet * buffer size when refilling RX rings. As the entire RX ring may be refilled * at once, the weight is chosen so that the EWMA will be insensitive to short- @@ -547,7 +551,7 @@ static struct sk_buff *receive_small(str struct receive_queue *rq, void *buf, void *ctx, unsigned int len, - bool *xdp_xmit) + unsigned int *xdp_xmit) { struct sk_buff *skb; struct bpf_prog *xdp_prog; @@ -615,14 +619,14 @@ static struct sk_buff *receive_small(str trace_xdp_exception(vi->dev, xdp_prog, act); goto err_xdp; } - *xdp_xmit = true; + *xdp_xmit |= VIRTIO_XDP_TX; rcu_read_unlock(); goto xdp_xmit; case XDP_REDIRECT: err = xdp_do_redirect(dev, &xdp, xdp_prog); if (err) goto err_xdp; - *xdp_xmit = true; + *xdp_xmit |= VIRTIO_XDP_REDIR; rcu_read_unlock(); goto xdp_xmit; default: @@ -684,7 +688,7 @@ static struct sk_buff *receive_mergeable void *buf, void *ctx, unsigned int len, - bool *xdp_xmit) + unsigned int *xdp_xmit) { struct virtio_net_hdr_mrg_rxbuf *hdr = buf; u16 num_buf = virtio16_to_cpu(vi->vdev, hdr->num_buffers); @@ -772,7 +776,7 @@ static struct sk_buff *receive_mergeable put_page(xdp_page); goto err_xdp; } - *xdp_xmit = true; + *xdp_xmit |= VIRTIO_XDP_REDIR; if (unlikely(xdp_page != page)) put_page(page); rcu_read_unlock(); @@ -784,7 +788,7 @@ static struct sk_buff *receive_mergeable put_page(xdp_page); goto err_xdp; } - *xdp_xmit = true; + *xdp_xmit |= VIRTIO_XDP_TX; if (unlikely(xdp_page != page)) put_page(page); rcu_read_unlock(); @@ -893,7 +897,8 @@ xdp_xmit: }
static int receive_buf(struct virtnet_info *vi, struct receive_queue *rq, - void *buf, unsigned int len, void **ctx, bool *xdp_xmit) + void *buf, unsigned int len, void **ctx, + unsigned int *xdp_xmit) { struct net_device *dev = vi->dev; struct sk_buff *skb; @@ -1186,7 +1191,8 @@ static void refill_work(struct work_stru } }
-static int virtnet_receive(struct receive_queue *rq, int budget, bool *xdp_xmit) +static int virtnet_receive(struct receive_queue *rq, int budget, + unsigned int *xdp_xmit) { struct virtnet_info *vi = rq->vq->vdev->priv; unsigned int len, received = 0, bytes = 0; @@ -1275,7 +1281,7 @@ static int virtnet_poll(struct napi_stru struct virtnet_info *vi = rq->vq->vdev->priv; struct send_queue *sq; unsigned int received, qp; - bool xdp_xmit = false; + unsigned int xdp_xmit = 0;
virtnet_poll_cleantx(rq);
@@ -1285,12 +1291,14 @@ static int virtnet_poll(struct napi_stru if (received < budget) virtqueue_napi_complete(napi, rq->vq, received);
- if (xdp_xmit) { + if (xdp_xmit & VIRTIO_XDP_REDIR) + xdp_do_flush_map(); + + if (xdp_xmit & VIRTIO_XDP_TX) { qp = vi->curr_queue_pairs - vi->xdp_queue_pairs + smp_processor_id(); sq = &vi->sq[qp]; virtqueue_kick(sq->vq); - xdp_do_flush_map(); }
return received;