diff mbox

linux-next: manual merge of the rr tree with the net tree

Message ID 20100428155457.GB7467@redhat.com
State RFC, archived
Delegated to: David Miller
Headers show

Commit Message

Michael S. Tsirkin April 28, 2010, 3:54 p.m. UTC 
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@redhat.com>
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@redhat.com>
    Tested-by: Michael S. Tsirkin <mst@redhat.com>
    Signed-off-by: David S. Miller <davem@davemloft.net>
    
    Conflicts:
    
    	drivers/net/virtio_net.c

Comments

Rusty Russell April 29, 2010, 12:53 p.m. UTC | #1 
On Thu, 29 Apr 2010 01:24:57 am Michael S. Tsirkin wrote:
> 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.

Naah, they hit too many random virtio drivers.  It's pretty simple to keep
them separate, and once the new API is in place I'll send to Dave to merge.
It could take two cycles, but there's no huge rush.

Cheers,
Rusty.
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Michael S. Tsirkin April 29, 2010, 2:06 p.m. UTC | #2 
On Thu, Apr 29, 2010 at 10:23:36PM +0930, Rusty Russell wrote:
> On Thu, 29 Apr 2010 01:24:57 am Michael S. Tsirkin wrote:
> > 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.
> 
> Naah, they hit too many random virtio drivers.  It's pretty simple to keep
> them separate, and once the new API is in place I'll send to Dave to merge.
> It could take two cycles, but there's no huge rush.
> 
> Cheers,
> Rusty.

Well, I'm just thinking of a way to make working on virtio-net less painful.
Maybe you could just put a copy of the two patches above on your tree?
diff mbox

Patch

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) ||