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authorJason Wang <jasowang@redhat.com>2015-08-27 14:53:06 +0800
committerDavid S. Miller <davem@davemloft.net>2015-08-27 15:51:45 -0700
commit547c890cfd26010e01b3faf98f29ca9b2252c8d8 (patch)
tree9d4c1428dff69ecf799eeb0e313a72257551a3b1 /drivers/net/virtio_net.c
parent5e0aa59728854837a7256e21644596f21a16ce0f (diff)
virtio-net: avoid unnecessary sg initialzation
Usually an skb does not have up to MAX_SKB_FRAGS frags. So no need to initialize the unuse part of sg. This patch initialize the sg based on the real number it will used: - during xmit, it could be inferred from nr_frags and can_push. - for small receive buffer, it will also be 2. Cc: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Jason Wang <jasowang@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/virtio_net.c')
-rw-r--r--drivers/net/virtio_net.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 9b950f2db836..d8838dedb7a4 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -540,7 +540,7 @@ static int add_recvbuf_small(struct virtnet_info *vi, struct receive_queue *rq,
skb_put(skb, GOOD_PACKET_LEN);
hdr = skb_vnet_hdr(skb);
- sg_init_table(rq->sg, MAX_SKB_FRAGS + 2);
+ sg_init_table(rq->sg, 2);
sg_set_buf(rq->sg, hdr, vi->hdr_len);
skb_to_sgvec(skb, rq->sg + 1, 0, skb->len);
@@ -893,7 +893,7 @@ static int xmit_skb(struct send_queue *sq, struct sk_buff *skb)
if (vi->mergeable_rx_bufs)
hdr->num_buffers = 0;
- sg_init_table(sq->sg, MAX_SKB_FRAGS + 2);
+ sg_init_table(sq->sg, skb_shinfo(skb)->nr_frags + (can_push ? 1 : 2));
if (can_push) {
__skb_push(skb, hdr_len);
num_sg = skb_to_sgvec(skb, sq->sg, 0, skb->len);