diff options
| -rw-r--r-- | drivers/net/virtio_net.c | 42 | ||||
| -rw-r--r-- | include/uapi/linux/virtio_net.h | 4 |
2 files changed, 37 insertions, 9 deletions
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 3d2a90a62649..f21600277583 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -106,6 +106,9 @@ struct virtnet_info { /* Has control virtqueue */ bool has_cvq; + /* Host can handle any s/g split between our header and packet data */ + bool any_header_sg; + /* enable config space updates */ bool config_enable; @@ -669,12 +672,28 @@ static void free_old_xmit_skbs(struct send_queue *sq) static int xmit_skb(struct send_queue *sq, struct sk_buff *skb) { - struct skb_vnet_hdr *hdr = skb_vnet_hdr(skb); + struct skb_vnet_hdr *hdr; const unsigned char *dest = ((struct ethhdr *)skb->data)->h_dest; struct virtnet_info *vi = sq->vq->vdev->priv; unsigned num_sg; + unsigned hdr_len; + bool can_push; pr_debug("%s: xmit %p %pM\n", vi->dev->name, skb, dest); + if (vi->mergeable_rx_bufs) + hdr_len = sizeof hdr->mhdr; + else + hdr_len = sizeof hdr->hdr; + + can_push = vi->any_header_sg && + !((unsigned long)skb->data & (__alignof__(*hdr) - 1)) && + !skb_header_cloned(skb) && skb_headroom(skb) >= hdr_len; + /* Even if we can, don't push here yet as this would skew + * csum_start offset below. */ + if (can_push) + hdr = (struct skb_vnet_hdr *)(skb->data - hdr_len); + else + hdr = skb_vnet_hdr(skb); if (skb->ip_summed == CHECKSUM_PARTIAL) { hdr->hdr.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM; @@ -703,15 +722,18 @@ static int xmit_skb(struct send_queue *sq, struct sk_buff *skb) hdr->hdr.gso_size = hdr->hdr.hdr_len = 0; } - hdr->mhdr.num_buffers = 0; - - /* Encode metadata header at front. */ if (vi->mergeable_rx_bufs) - sg_set_buf(sq->sg, &hdr->mhdr, sizeof hdr->mhdr); - else - sg_set_buf(sq->sg, &hdr->hdr, sizeof hdr->hdr); + hdr->mhdr.num_buffers = 0; - num_sg = skb_to_sgvec(skb, sq->sg + 1, 0, skb->len) + 1; + if (can_push) { + __skb_push(skb, hdr_len); + num_sg = skb_to_sgvec(skb, sq->sg, 0, skb->len); + /* Pull header back to avoid skew in tx bytes calculations. */ + __skb_pull(skb, hdr_len); + } else { + sg_set_buf(sq->sg, hdr, hdr_len); + num_sg = skb_to_sgvec(skb, sq->sg + 1, 0, skb->len) + 1; + } return virtqueue_add_outbuf(sq->vq, sq->sg, num_sg, skb, GFP_ATOMIC); } @@ -1552,6 +1574,9 @@ static int virtnet_probe(struct virtio_device *vdev) if (virtio_has_feature(vdev, VIRTIO_NET_F_MRG_RXBUF)) vi->mergeable_rx_bufs = true; + if (virtio_has_feature(vdev, VIRTIO_F_ANY_LAYOUT)) + vi->any_header_sg = true; + if (virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_VQ)) vi->has_cvq = true; @@ -1727,6 +1752,7 @@ static unsigned int features[] = { VIRTIO_NET_F_CTRL_RX, VIRTIO_NET_F_CTRL_VLAN, VIRTIO_NET_F_GUEST_ANNOUNCE, VIRTIO_NET_F_MQ, VIRTIO_NET_F_CTRL_MAC_ADDR, + VIRTIO_F_ANY_LAYOUT, }; static struct virtio_driver virtio_net_driver = { diff --git a/include/uapi/linux/virtio_net.h b/include/uapi/linux/virtio_net.h index c520203fac2f..227d4ce84e79 100644 --- a/include/uapi/linux/virtio_net.h +++ b/include/uapi/linux/virtio_net.h @@ -70,7 +70,9 @@ struct virtio_net_config { __u16 max_virtqueue_pairs; } __attribute__((packed)); -/* This is the first element of the scatter-gather list. If you don't +/* This header comes first in the scatter-gather list. + * If VIRTIO_F_ANY_LAYOUT is not negotiated, it must + * be the first element of the scatter-gather list. If you don't * specify GSO or CSUM features, you can simply ignore the header. */ struct virtio_net_hdr { #define VIRTIO_NET_HDR_F_NEEDS_CSUM 1 // Use csum_start, csum_offset |