On Tue, Apr 27, 2010 at 07:09:13AM +0300, Michael S. Tsirkin wrote:
> On Tue, Apr 27, 2010 at 11:58:52AM +1000, Stephen Rothwell wrote:
> > Hi Rusty,
> >
> > Today's linux-next merge of the rr tree got a conflict in
> > drivers/net/virtio_net.c between commit
> > 5e01d2f91df62be4d6f282149bc2a8858992ceca ("virtio-net: move sg off
> > stack") from the net tree and commit
> > 7f62a724a65f864d84f50857bbfd36c240155c8f ("virtio_net: use virtqueue_xxx
> > wrappers") from the rr tree.
> >
> > I fixed it up (see below) and can carry the fix as necessary.
>
> Hmm, Rusty, do you intend for the patches to go through netdev this
> time? If you do, it might be simplest to just ask Dave to merge
> them in net-next-2.6 now. I can prepare and send them if you like.
For whoever develops on top of -rr, the following backports
virtio_net change from net-next. Hope this helps
commit 77416b2a007b67f92d2f7b3b1edac7405c5890f7
Author: Michael S. Tsirkin <mst@xxxxxxxxxx>
Date: Wed Apr 28 18:48:27 2010 +0300
virtio-net: move sg off stack
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@xxxxxxxxxx>
Tested-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Conflicts:
drivers/net/virtio_net.c
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index fca44b2..dc872ba 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -40,8 +40,7 @@ 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;
@@ -62,6 +61,10 @@ 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 {
@@ -324,10 +327,8 @@ 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;
@@ -335,11 +336,11 @@ 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 = virtqueue_add_buf_gfp(vi->rvq, sg, 0, 2, skb, gfp);
+ err = virtqueue_add_buf_gfp(vi->rvq, vi->rx_sg, 0, 2, skb, gfp);
if (err < 0)
dev_kfree_skb(skb);
@@ -348,13 +349,11 @@ 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) {
@@ -362,7 +361,7 @@ 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;
@@ -376,17 +375,17 @@ 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 = virtqueue_add_buf_gfp(vi->rvq, sg, 0, MAX_SKB_FRAGS + 2,
+ err = virtqueue_add_buf_gfp(vi->rvq, vi->rx_sg, 0, MAX_SKB_FRAGS + 2,
first, gfp);
if (err < 0)
give_pages(vi, first);
@@ -397,16 +396,15 @@ 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 = virtqueue_add_buf_gfp(vi->rvq, &sg, 0, 1, page);
+ err = virtqueue_add_buf_gfp(vi->rvq, &vi->rx_sg, 0, 1, page);
if (err < 0)
give_pages(vi, page);
@@ -515,12 +513,9 @@ 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) {
@@ -554,12 +549,12 @@ 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 virtqueue_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 virtqueue_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)
@@ -942,6 +937,8 @@ 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) ||
--
MST
--
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