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virtio-net: move sg off stack

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Move sg structure off stack and into virtnet_info structure.
This helps remove extra sg_init_table calls as well as reduce
stack usage.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Tested-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Michael S. Tsirkin 2010-04-07 21:01:41 -07:00 committed by David S. Miller
parent b681ee77f8
commit 5e01d2f91d
1 changed files with 25 additions and 27 deletions
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52
drivers/net/virtio_net.c
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@ -39,8 +39,7 @@ module_param(gso, bool, 0444);
#define VIRTNET_SEND_COMMAND_SG_MAX 2
struct virtnet_info
{
struct virtnet_info {
struct virtio_device *vdev;
struct virtqueue *rvq, *svq, *cvq;
struct net_device *dev;
@ -61,6 +60,10 @@ struct virtnet_info
/* Chain pages by the private ptr. */
struct page *pages;
/* fragments + linear part + virtio header */
struct scatterlist rx_sg[MAX_SKB_FRAGS + 2];
struct scatterlist tx_sg[MAX_SKB_FRAGS + 2];
};
struct skb_vnet_hdr {
@ -323,10 +326,8 @@ static int add_recvbuf_small(struct virtnet_info *vi, gfp_t gfp)
{
struct sk_buff *skb;
struct skb_vnet_hdr *hdr;
struct scatterlist sg[2];
int err;
sg_init_table(sg, 2);
skb = netdev_alloc_skb_ip_align(vi->dev, MAX_PACKET_LEN);
if (unlikely(!skb))
return -ENOMEM;
@ -334,11 +335,11 @@ static int add_recvbuf_small(struct virtnet_info *vi, gfp_t gfp)
skb_put(skb, MAX_PACKET_LEN);
hdr = skb_vnet_hdr(skb);
sg_set_buf(sg, &hdr->hdr, sizeof hdr->hdr);
sg_set_buf(vi->rx_sg, &hdr->hdr, sizeof hdr->hdr);
skb_to_sgvec(skb, sg + 1, 0, skb->len);
skb_to_sgvec(skb, vi->rx_sg + 1, 0, skb->len);
err = vi->rvq->vq_ops->add_buf(vi->rvq, sg, 0, 2, skb);
err = vi->rvq->vq_ops->add_buf(vi->rvq, vi->rx_sg, 0, 2, skb);
if (err < 0)
dev_kfree_skb(skb);
@ -347,13 +348,11 @@ static int add_recvbuf_small(struct virtnet_info *vi, gfp_t gfp)
static int add_recvbuf_big(struct virtnet_info *vi, gfp_t gfp)
{
struct scatterlist sg[MAX_SKB_FRAGS + 2];
struct page *first, *list = NULL;
char *p;
int i, err, offset;
sg_init_table(sg, MAX_SKB_FRAGS + 2);
/* page in sg[MAX_SKB_FRAGS + 1] is list tail */
/* page in vi->rx_sg[MAX_SKB_FRAGS + 1] is list tail */
for (i = MAX_SKB_FRAGS + 1; i > 1; --i) {
first = get_a_page(vi, gfp);
if (!first) {
@ -361,7 +360,7 @@ static int add_recvbuf_big(struct virtnet_info *vi, gfp_t gfp)
give_pages(vi, list);
return -ENOMEM;
}
sg_set_buf(&sg[i], page_address(first), PAGE_SIZE);
sg_set_buf(&vi->rx_sg[i], page_address(first), PAGE_SIZE);
/* chain new page in list head to match sg */
first->private = (unsigned long)list;
@ -375,17 +374,17 @@ static int add_recvbuf_big(struct virtnet_info *vi, gfp_t gfp)
}
p = page_address(first);
/* sg[0], sg[1] share the same page */
/* a separated sg[0] for virtio_net_hdr only during to QEMU bug*/
sg_set_buf(&sg[0], p, sizeof(struct virtio_net_hdr));
/* vi->rx_sg[0], vi->rx_sg[1] share the same page */
/* a separated vi->rx_sg[0] for virtio_net_hdr only due to QEMU bug */
sg_set_buf(&vi->rx_sg[0], p, sizeof(struct virtio_net_hdr));
/* sg[1] for data packet, from offset */
/* vi->rx_sg[1] for data packet, from offset */
offset = sizeof(struct padded_vnet_hdr);
sg_set_buf(&sg[1], p + offset, PAGE_SIZE - offset);
sg_set_buf(&vi->rx_sg[1], p + offset, PAGE_SIZE - offset);
/* chain first in list head */
first->private = (unsigned long)list;
err = vi->rvq->vq_ops->add_buf(vi->rvq, sg, 0, MAX_SKB_FRAGS + 2,
err = vi->rvq->vq_ops->add_buf(vi->rvq, vi->rx_sg, 0, MAX_SKB_FRAGS + 2,
first);
if (err < 0)
give_pages(vi, first);
@ -396,16 +395,15 @@ static int add_recvbuf_big(struct virtnet_info *vi, gfp_t gfp)
static int add_recvbuf_mergeable(struct virtnet_info *vi, gfp_t gfp)
{
struct page *page;
struct scatterlist sg;
int err;
page = get_a_page(vi, gfp);
if (!page)
return -ENOMEM;
sg_init_one(&sg, page_address(page), PAGE_SIZE);
sg_init_one(vi->rx_sg, page_address(page), PAGE_SIZE);
err = vi->rvq->vq_ops->add_buf(vi->rvq, &sg, 0, 1, page);
err = vi->rvq->vq_ops->add_buf(vi->rvq, vi->rx_sg, 0, 1, page);
if (err < 0)
give_pages(vi, page);
@ -514,12 +512,9 @@ static unsigned int free_old_xmit_skbs(struct virtnet_info *vi)
static int xmit_skb(struct virtnet_info *vi, struct sk_buff *skb)
{
struct scatterlist sg[2+MAX_SKB_FRAGS];
struct skb_vnet_hdr *hdr = skb_vnet_hdr(skb);
const unsigned char *dest = ((struct ethhdr *)skb->data)->h_dest;
sg_init_table(sg, 2+MAX_SKB_FRAGS);
pr_debug("%s: xmit %p %pM\n", vi->dev->name, skb, dest);
if (skb->ip_summed == CHECKSUM_PARTIAL) {
@ -553,12 +548,13 @@ static int xmit_skb(struct virtnet_info *vi, struct sk_buff *skb)
/* Encode metadata header at front. */
if (vi->mergeable_rx_bufs)
sg_set_buf(sg, &hdr->mhdr, sizeof hdr->mhdr);
sg_set_buf(vi->tx_sg, &hdr->mhdr, sizeof hdr->mhdr);
else
sg_set_buf(sg, &hdr->hdr, sizeof hdr->hdr);
sg_set_buf(vi->tx_sg, &hdr->hdr, sizeof hdr->hdr);
hdr->num_sg = skb_to_sgvec(skb, sg+1, 0, skb->len) + 1;
return vi->svq->vq_ops->add_buf(vi->svq, sg, hdr->num_sg, 0, skb);
hdr->num_sg = skb_to_sgvec(skb, vi->tx_sg + 1, 0, skb->len) + 1;
return vi->svq->vq_ops->add_buf(vi->svq, vi->tx_sg, hdr->num_sg,
0, skb);
}
static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev)
@ -940,6 +936,8 @@ static int virtnet_probe(struct virtio_device *vdev)
vdev->priv = vi;
vi->pages = NULL;
INIT_DELAYED_WORK(&vi->refill, refill_work);
sg_init_table(vi->rx_sg, ARRAY_SIZE(vi->rx_sg));
sg_init_table(vi->tx_sg, ARRAY_SIZE(vi->tx_sg));
/* If we can receive ANY GSO packets, we must allocate large ones. */
if (virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO4) ||