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-rw-r--r--drivers/net/virtio_net.c173
-rw-r--r--include/linux/virtio_net.h9
2 files changed, 162 insertions, 20 deletions
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 27559c987d47..e6b5d6ef9ea8 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -34,6 +34,7 @@ module_param(gso, bool, 0444);
/* FIXME: MTU in config. */
#define MAX_PACKET_LEN (ETH_HLEN+ETH_DATA_LEN)
+#define GOOD_COPY_LEN 128
struct virtnet_info
{
@@ -58,6 +59,9 @@ struct virtnet_info
/* I like... big packets and I cannot lie! */
bool big_packets;
+ /* Host will merge rx buffers for big packets (shake it! shake it!) */
+ bool mergeable_rx_bufs;
+
/* Receive & send queues. */
struct sk_buff_head recv;
struct sk_buff_head send;
@@ -66,16 +70,11 @@ struct virtnet_info
struct page *pages;
};
-static inline struct virtio_net_hdr *skb_vnet_hdr(struct sk_buff *skb)
+static inline void *skb_vnet_hdr(struct sk_buff *skb)
{
return (struct virtio_net_hdr *)skb->cb;
}
-static inline void vnet_hdr_to_sg(struct scatterlist *sg, struct sk_buff *skb)
-{
- sg_init_one(sg, skb_vnet_hdr(skb), sizeof(struct virtio_net_hdr));
-}
-
static void give_a_page(struct virtnet_info *vi, struct page *page)
{
page->private = (unsigned long)vi->pages;
@@ -121,25 +120,97 @@ static void skb_xmit_done(struct virtqueue *svq)
static void receive_skb(struct net_device *dev, struct sk_buff *skb,
unsigned len)
{
+ struct virtnet_info *vi = netdev_priv(dev);
struct virtio_net_hdr *hdr = skb_vnet_hdr(skb);
int err;
+ int i;
if (unlikely(len < sizeof(struct virtio_net_hdr) + ETH_HLEN)) {
pr_debug("%s: short packet %i\n", dev->name, len);
dev->stats.rx_length_errors++;
goto drop;
}
- len -= sizeof(struct virtio_net_hdr);
- if (len <= MAX_PACKET_LEN)
- trim_pages(netdev_priv(dev), skb);
+ if (vi->mergeable_rx_bufs) {
+ struct virtio_net_hdr_mrg_rxbuf *mhdr = skb_vnet_hdr(skb);
+ unsigned int copy;
+ char *p = page_address(skb_shinfo(skb)->frags[0].page);
- err = pskb_trim(skb, len);
- if (err) {
- pr_debug("%s: pskb_trim failed %i %d\n", dev->name, len, err);
- dev->stats.rx_dropped++;
- goto drop;
+ if (len > PAGE_SIZE)
+ len = PAGE_SIZE;
+ len -= sizeof(struct virtio_net_hdr_mrg_rxbuf);
+
+ memcpy(hdr, p, sizeof(*mhdr));
+ p += sizeof(*mhdr);
+
+ copy = len;
+ if (copy > skb_tailroom(skb))
+ copy = skb_tailroom(skb);
+
+ memcpy(skb_put(skb, copy), p, copy);
+
+ len -= copy;
+
+ if (!len) {
+ give_a_page(vi, skb_shinfo(skb)->frags[0].page);
+ skb_shinfo(skb)->nr_frags--;
+ } else {
+ skb_shinfo(skb)->frags[0].page_offset +=
+ sizeof(*mhdr) + copy;
+ skb_shinfo(skb)->frags[0].size = len;
+ skb->data_len += len;
+ skb->len += len;
+ }
+
+ while (--mhdr->num_buffers) {
+ struct sk_buff *nskb;
+
+ i = skb_shinfo(skb)->nr_frags;
+ if (i >= MAX_SKB_FRAGS) {
+ pr_debug("%s: packet too long %d\n", dev->name,
+ len);
+ dev->stats.rx_length_errors++;
+ goto drop;
+ }
+
+ nskb = vi->rvq->vq_ops->get_buf(vi->rvq, &len);
+ if (!nskb) {
+ pr_debug("%s: rx error: %d buffers missing\n",
+ dev->name, mhdr->num_buffers);
+ dev->stats.rx_length_errors++;
+ goto drop;
+ }
+
+ __skb_unlink(nskb, &vi->recv);
+ vi->num--;
+
+ skb_shinfo(skb)->frags[i] = skb_shinfo(nskb)->frags[0];
+ skb_shinfo(nskb)->nr_frags = 0;
+ kfree_skb(nskb);
+
+ if (len > PAGE_SIZE)
+ len = PAGE_SIZE;
+
+ skb_shinfo(skb)->frags[i].size = len;
+ skb_shinfo(skb)->nr_frags++;
+ skb->data_len += len;
+ skb->len += len;
+ }
+ } else {
+ len -= sizeof(struct virtio_net_hdr);
+
+ if (len <= MAX_PACKET_LEN)
+ trim_pages(vi, skb);
+
+ err = pskb_trim(skb, len);
+ if (err) {
+ pr_debug("%s: pskb_trim failed %i %d\n", dev->name,
+ len, err);
+ dev->stats.rx_dropped++;
+ goto drop;
+ }
}
+
skb->truesize += skb->data_len;
dev->stats.rx_bytes += skb->len;
dev->stats.rx_packets++;
@@ -198,7 +269,7 @@ drop:
dev_kfree_skb(skb);
}
-static void try_fill_recv(struct virtnet_info *vi)
+static void try_fill_recv_maxbufs(struct virtnet_info *vi)
{
struct sk_buff *skb;
struct scatterlist sg[2+MAX_SKB_FRAGS];
@@ -206,12 +277,16 @@ static void try_fill_recv(struct virtnet_info *vi)
sg_init_table(sg, 2+MAX_SKB_FRAGS);
for (;;) {
+ struct virtio_net_hdr *hdr;
+
skb = netdev_alloc_skb(vi->dev, MAX_PACKET_LEN);
if (unlikely(!skb))
break;
skb_put(skb, MAX_PACKET_LEN);
- vnet_hdr_to_sg(sg, skb);
+
+ hdr = skb_vnet_hdr(skb);
+ sg_init_one(sg, hdr, sizeof(*hdr));
if (vi->big_packets) {
for (i = 0; i < MAX_SKB_FRAGS; i++) {
@@ -247,6 +322,54 @@ static void try_fill_recv(struct virtnet_info *vi)
vi->rvq->vq_ops->kick(vi->rvq);
}
+static void try_fill_recv(struct virtnet_info *vi)
+{
+ struct sk_buff *skb;
+ struct scatterlist sg[1];
+ int err;
+
+ if (!vi->mergeable_rx_bufs) {
+ try_fill_recv_maxbufs(vi);
+ return;
+ }
+
+ for (;;) {
+ skb_frag_t *f;
+
+ skb = netdev_alloc_skb(vi->dev, GOOD_COPY_LEN + NET_IP_ALIGN);
+ if (unlikely(!skb))
+ break;
+
+ skb_reserve(skb, NET_IP_ALIGN);
+
+ f = &skb_shinfo(skb)->frags[0];
+ f->page = get_a_page(vi, GFP_ATOMIC);
+ if (!f->page) {
+ kfree_skb(skb);
+ break;
+ }
+
+ f->page_offset = 0;
+ f->size = PAGE_SIZE;
+
+ skb_shinfo(skb)->nr_frags++;
+
+ sg_init_one(sg, page_address(f->page), PAGE_SIZE);
+ skb_queue_head(&vi->recv, skb);
+
+ err = vi->rvq->vq_ops->add_buf(vi->rvq, sg, 0, 1, skb);
+ if (err) {
+ skb_unlink(skb, &vi->recv);
+ kfree_skb(skb);
+ break;
+ }
+ vi->num++;
+ }
+ if (unlikely(vi->num > vi->max))
+ vi->max = vi->num;
+ vi->rvq->vq_ops->kick(vi->rvq);
+}
+
static void skb_recv_done(struct virtqueue *rvq)
{
struct virtnet_info *vi = rvq->vdev->priv;
@@ -325,15 +448,14 @@ static int xmit_skb(struct virtnet_info *vi, struct sk_buff *skb)
{
int num, err;
struct scatterlist sg[2+MAX_SKB_FRAGS];
- struct virtio_net_hdr *hdr;
+ struct virtio_net_hdr_mrg_rxbuf *mhdr = skb_vnet_hdr(skb);
+ struct virtio_net_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);
- /* Encode metadata header at front. */
- hdr = skb_vnet_hdr(skb);
if (skb->ip_summed == CHECKSUM_PARTIAL) {
hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
hdr->csum_start = skb->csum_start - skb_headroom(skb);
@@ -361,7 +483,14 @@ static int xmit_skb(struct virtnet_info *vi, struct sk_buff *skb)
hdr->gso_size = hdr->hdr_len = 0;
}
- vnet_hdr_to_sg(sg, skb);
+ mhdr->num_buffers = 0;
+
+ /* Encode metadata header at front. */
+ if (vi->mergeable_rx_bufs)
+ sg_init_one(sg, mhdr, sizeof(*mhdr));
+ else
+ sg_init_one(sg, hdr, sizeof(*hdr));
+
num = skb_to_sgvec(skb, sg+1, 0, skb->len) + 1;
err = vi->svq->vq_ops->add_buf(vi->svq, sg, num, 0, skb);
@@ -551,6 +680,9 @@ static int virtnet_probe(struct virtio_device *vdev)
|| virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_ECN))
vi->big_packets = true;
+ if (virtio_has_feature(vdev, VIRTIO_NET_F_MRG_RXBUF))
+ vi->mergeable_rx_bufs = true;
+
/* We expect two virtqueues, receive then send. */
vi->rvq = vdev->config->find_vq(vdev, 0, skb_recv_done);
if (IS_ERR(vi->rvq)) {
@@ -643,6 +775,7 @@ static unsigned int features[] = {
VIRTIO_NET_F_HOST_TSO4, VIRTIO_NET_F_HOST_UFO, VIRTIO_NET_F_HOST_TSO6,
VIRTIO_NET_F_HOST_ECN, VIRTIO_NET_F_GUEST_TSO4, VIRTIO_NET_F_GUEST_TSO6,
VIRTIO_NET_F_GUEST_ECN, /* We don't yet handle UFO input. */
+ VIRTIO_NET_F_MRG_RXBUF,
VIRTIO_F_NOTIFY_ON_EMPTY,
};
diff --git a/include/linux/virtio_net.h b/include/linux/virtio_net.h
index 5e33761b9b8a..5cdd0aa8bde9 100644
--- a/include/linux/virtio_net.h
+++ b/include/linux/virtio_net.h
@@ -20,6 +20,7 @@
#define VIRTIO_NET_F_HOST_TSO6 12 /* Host can handle TSOv6 in. */
#define VIRTIO_NET_F_HOST_ECN 13 /* Host can handle TSO[6] w/ ECN in. */
#define VIRTIO_NET_F_HOST_UFO 14 /* Host can handle UFO in. */
+#define VIRTIO_NET_F_MRG_RXBUF 15 /* Host can merge receive buffers. */
struct virtio_net_config
{
@@ -44,4 +45,12 @@ struct virtio_net_hdr
__u16 csum_start; /* Position to start checksumming from */
__u16 csum_offset; /* Offset after that to place checksum */
};
+
+/* This is the version of the header to use when the MRG_RXBUF
+ * feature has been negotiated. */
+struct virtio_net_hdr_mrg_rxbuf {
+ struct virtio_net_hdr hdr;
+ __u16 num_buffers; /* Number of merged rx buffers */
+};
+
#endif /* _LINUX_VIRTIO_NET_H */
generated by cgit v1.2.3 (git 2.25.1) at 2024-12-05 00:27:01 +0000