From a58354409a00f2d8f7882c6a91fde1df5d0a4bb8 Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Thu, 11 Sep 2014 10:17:36 +0930 Subject: [PATCH] virtio_net: pass well-formed sgs to virtqueue_add_*() This is the only driver which doesn't hand virtqueue_add_inbuf and virtqueue_add_outbuf a well-formed, well-terminated sg. Fix it, so we can make virtio_add_* simpler. pktgen results: modprobe pktgen echo 'add_device eth0' > /proc/net/pktgen/kpktgend_0 echo nowait 1 > /proc/net/pktgen/eth0 echo count 1000000 > /proc/net/pktgen/eth0 echo clone_skb 100000 > /proc/net/pktgen/eth0 echo dst_mac 4e:14:25:a9:30:ac > /proc/net/pktgen/eth0 echo dst 192.168.1.2 > /proc/net/pktgen/eth0 for i in `seq 20`; do echo start > /proc/net/pktgen/pgctrl; tail -n1 /proc/net/pktgen/eth0; done Before: 746547-793084(786421+/-9.6e+03)pps 346-367(364.4+/-4.4)Mb/sec (346397808-367990976(3.649e+08+/-4.5e+06)bps) errors: 0 After: 767390-792966(785159+/-6.5e+03)pps 356-367(363.75+/-2.9)Mb/sec (356068960-367936224(3.64314e+08+/-3e+06)bps) errors: 0 Signed-off-by: Rusty Russell Signed-off-by: David S. Miller --- drivers/net/virtio_net.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 9359a13d285..3d0ce4468ce 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -546,8 +546,8 @@ static int add_recvbuf_small(struct receive_queue *rq, gfp_t gfp) skb_put(skb, GOOD_PACKET_LEN); hdr = skb_vnet_hdr(skb); + sg_init_table(rq->sg, MAX_SKB_FRAGS + 2); sg_set_buf(rq->sg, &hdr->hdr, sizeof hdr->hdr); - skb_to_sgvec(skb, rq->sg + 1, 0, skb->len); err = virtqueue_add_inbuf(rq->vq, rq->sg, 2, skb, gfp); @@ -563,6 +563,8 @@ static int add_recvbuf_big(struct receive_queue *rq, gfp_t gfp) char *p; int i, err, offset; + sg_init_table(rq->sg, MAX_SKB_FRAGS + 2); + /* page in rq->sg[MAX_SKB_FRAGS + 1] is list tail */ for (i = MAX_SKB_FRAGS + 1; i > 1; --i) { first = get_a_page(rq, gfp); @@ -899,6 +901,7 @@ static int xmit_skb(struct send_queue *sq, struct sk_buff *skb) if (vi->mergeable_rx_bufs) hdr->mhdr.num_buffers = 0; + sg_init_table(sq->sg, MAX_SKB_FRAGS + 2); if (can_push) { __skb_push(skb, hdr_len); num_sg = skb_to_sgvec(skb, sq->sg, 0, skb->len); -- 2.41.0