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Message-ID: <20081229122445.GA11161@gondor.apana.org.au>
Date: Mon, 29 Dec 2008 23:24:46 +1100
From: Herbert Xu <herbert@...dor.apana.org.au>
To: netdev@...r.kernel.org
Subject: Re: [UNTESTED] gro: Add page frag support
On Sat, Dec 27, 2008 at 09:51:57AM +1100, Herbert Xu wrote:
>
> This patch is totally untested so please don't apply it. I need
> to hack the e1000e driver to not make skbs before I can test it.
OK I've tested it with a hacked e1000e driver, which indeed revealed
a gaping hole in my design :) The pages interface needs to have some
extra fields for the checksum information.
Here's a patch that actually works.
gro: Use gso_size to store MSS
In order to allow GRO packets without frag_list at all, we need to
store the MSS in the packet itself. The obvious place is gso_size.
The only thing to watch out for is if the packet ends up not being
GRO then we need to clear gso_size before pushing the packet into
the stack.
diff --git a/net/core/dev.c b/net/core/dev.c
index 4464240..67a6ff4 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -2365,6 +2365,7 @@ static int napi_gro_complete(struct sk_buff *skb)
}
out:
+ skb_shinfo(skb)->gso_size = 0;
__skb_push(skb, -skb_network_offset(skb));
return netif_receive_skb(skb);
}
@@ -2446,6 +2447,7 @@ int napi_gro_receive(struct napi_struct *napi, struct sk_buff *skb)
}
NAPI_GRO_CB(skb)->count = 1;
+ skb_shinfo(skb)->gso_size = skb->len;
skb->next = napi->gro_list;
napi->gro_list = skb;
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index b8d0abb..3aafb10 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -2613,6 +2613,7 @@ int skb_gro_receive(struct sk_buff **head, struct sk_buff *skb)
*NAPI_GRO_CB(nskb) = *NAPI_GRO_CB(p);
skb_shinfo(nskb)->frag_list = p;
+ skb_shinfo(nskb)->gso_size = skb_shinfo(p)->gso_size;
skb_header_release(p);
nskb->prev = p;
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 1f3d529..218a6e5 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -2518,9 +2518,7 @@ found:
flush |= memcmp(th + 1, th2 + 1, thlen - sizeof(*th));
total = p->len;
- mss = total;
- if (skb_shinfo(p)->frag_list)
- mss = skb_shinfo(p)->frag_list->len;
+ mss = skb_shinfo(p)->gso_size;
flush |= skb->len > mss || skb->len <= 0;
flush |= ntohl(th2->seq) + total != ntohl(th->seq);
@@ -2556,7 +2554,6 @@ int tcp_gro_complete(struct sk_buff *skb)
skb->csum_offset = offsetof(struct tcphdr, check);
skb->ip_summed = CHECKSUM_PARTIAL;
- skb_shinfo(skb)->gso_size = skb_shinfo(skb)->frag_list->len;
skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count;
if (th->cwr)
And the real thing.
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 41e1224..c28bbba 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -313,10 +313,11 @@ struct napi_struct {
#ifdef CONFIG_NETPOLL
spinlock_t poll_lock;
int poll_owner;
- struct net_device *dev;
#endif
+ struct net_device *dev;
struct list_head dev_list;
struct sk_buff *gro_list;
+ struct sk_buff *skb;
};
enum
@@ -990,6 +991,9 @@ struct napi_gro_cb {
/* Number of segments aggregated. */
int count;
+
+ /* Free the skb? */
+ int free;
};
#define NAPI_GRO_CB(skb) ((struct napi_gro_cb *)(skb)->cb)
@@ -1011,6 +1015,14 @@ struct packet_type {
struct list_head list;
};
+struct napi_gro_fraginfo {
+ skb_frag_t frags[MAX_SKB_FRAGS];
+ unsigned int nr_frags;
+ unsigned int ip_summed;
+ unsigned int len;
+ __wsum csum;
+};
+
#include <linux/interrupt.h>
#include <linux/notifier.h>
@@ -1363,6 +1375,8 @@ extern int netif_receive_skb(struct sk_buff *skb);
extern void napi_gro_flush(struct napi_struct *napi);
extern int napi_gro_receive(struct napi_struct *napi,
struct sk_buff *skb);
+extern int napi_gro_frags(struct napi_struct *napi,
+ struct napi_gro_fraginfo *info);
extern void netif_nit_deliver(struct sk_buff *skb);
extern int dev_valid_name(const char *name);
extern int dev_ioctl(struct net *net, unsigned int cmd, void __user *);
diff --git a/net/core/dev.c b/net/core/dev.c
index 67a6ff4..c392bed 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -132,6 +132,9 @@
/* Instead of increasing this, you should create a hash table. */
#define MAX_GRO_SKBS 8
+/* This should be increased if a protocol with a bigger head is added. */
+#define GRO_MAX_HEAD (MAX_HEADER + 128)
+
/*
* The list of packet types we will receive (as opposed to discard)
* and the routines to invoke.
@@ -2345,7 +2348,7 @@ static int napi_gro_complete(struct sk_buff *skb)
struct list_head *head = &ptype_base[ntohs(type) & PTYPE_HASH_MASK];
int err = -ENOENT;
- if (!skb_shinfo(skb)->frag_list)
+ if (NAPI_GRO_CB(skb)->count == 1)
goto out;
rcu_read_lock();
@@ -2384,7 +2387,7 @@ void napi_gro_flush(struct napi_struct *napi)
}
EXPORT_SYMBOL(napi_gro_flush);
-int napi_gro_receive(struct napi_struct *napi, struct sk_buff *skb)
+static int __napi_gro_receive(struct napi_struct *napi, struct sk_buff *skb)
{
struct sk_buff **pp = NULL;
struct packet_type *ptype;
@@ -2393,6 +2396,7 @@ int napi_gro_receive(struct napi_struct *napi, struct sk_buff *skb)
int count = 0;
int same_flow;
int mac_len;
+ int free;
if (!(skb->dev->features & NETIF_F_GRO))
goto normal;
@@ -2409,6 +2413,7 @@ int napi_gro_receive(struct napi_struct *napi, struct sk_buff *skb)
skb->mac_len = mac_len;
NAPI_GRO_CB(skb)->same_flow = 0;
NAPI_GRO_CB(skb)->flush = 0;
+ NAPI_GRO_CB(skb)->free = 0;
for (p = napi->gro_list; p; p = p->next) {
count++;
@@ -2428,6 +2433,7 @@ int napi_gro_receive(struct napi_struct *napi, struct sk_buff *skb)
goto normal;
same_flow = NAPI_GRO_CB(skb)->same_flow;
+ free = NAPI_GRO_CB(skb)->free;
if (pp) {
struct sk_buff *nskb = *pp;
@@ -2452,13 +2458,86 @@ int napi_gro_receive(struct napi_struct *napi, struct sk_buff *skb)
napi->gro_list = skb;
ok:
- return NET_RX_SUCCESS;
+ return free;
normal:
- return netif_receive_skb(skb);
+ return -1;
+}
+
+int napi_gro_receive(struct napi_struct *napi, struct sk_buff *skb)
+{
+
+ switch (__napi_gro_receive(napi, skb)) {
+ case -1:
+ return netif_receive_skb(skb);
+
+ case 1:
+ kfree_skb(skb);
+ }
+
+ return NET_RX_SUCCESS;
}
EXPORT_SYMBOL(napi_gro_receive);
+int napi_gro_frags(struct napi_struct *napi, struct napi_gro_fraginfo *info)
+{
+ struct net_device *dev = napi->dev;
+ struct sk_buff *skb = napi->skb;
+ int err = NET_RX_DROP;
+
+ napi->skb = NULL;
+
+ if (!skb) {
+ skb = netdev_alloc_skb(dev, GRO_MAX_HEAD + NET_IP_ALIGN);
+ if (!skb)
+ goto out;
+
+ skb_reserve(skb, NET_IP_ALIGN);
+ }
+
+ BUG_ON(info->nr_frags > MAX_SKB_FRAGS);
+ skb_shinfo(skb)->nr_frags = info->nr_frags;
+ memcpy(skb_shinfo(skb)->frags, info->frags, sizeof(info->frags));
+
+ skb->data_len = info->len;
+ skb->len += info->len;
+ skb->truesize += info->len;
+
+ if (!pskb_may_pull(skb, ETH_HLEN))
+ goto reuse;
+
+ err = NET_RX_SUCCESS;
+
+ skb->protocol = eth_type_trans(skb, dev);
+
+ skb->ip_summed = info->ip_summed;
+ skb->csum = info->csum;
+
+ switch (__napi_gro_receive(napi, skb)) {
+ case -1:
+ return netif_receive_skb(skb);
+
+ case 0:
+ goto out;
+ }
+
+reuse:
+ skb_shinfo(skb)->nr_frags = 0;
+
+ skb->len -= skb->data_len;
+ skb->truesize -= skb->data_len;
+ skb->data_len = 0;
+
+ __skb_pull(skb, skb_headlen(skb));
+ skb_reserve(skb, NET_IP_ALIGN - skb_headroom(skb));
+
+ napi->skb = skb;
+
+out:
+ return err;
+}
+EXPORT_SYMBOL(napi_gro_frags);
+
static int process_backlog(struct napi_struct *napi, int quota)
{
int work = 0;
@@ -2537,11 +2616,12 @@ void netif_napi_add(struct net_device *dev, struct napi_struct *napi,
{
INIT_LIST_HEAD(&napi->poll_list);
napi->gro_list = NULL;
+ napi->skb = NULL;
napi->poll = poll;
napi->weight = weight;
list_add(&napi->dev_list, &dev->napi_list);
-#ifdef CONFIG_NETPOLL
napi->dev = dev;
+#ifdef CONFIG_NETPOLL
spin_lock_init(&napi->poll_lock);
napi->poll_owner = -1;
#endif
@@ -2554,6 +2634,7 @@ void netif_napi_del(struct napi_struct *napi)
struct sk_buff *skb, *next;
list_del_init(&napi->dev_list);
+ kfree(napi->skb);
for (skb = napi->gro_list; skb; skb = next) {
next = skb->next;
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 3aafb10..5110b35 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -2594,6 +2594,17 @@ int skb_gro_receive(struct sk_buff **head, struct sk_buff *skb)
if (skb_shinfo(p)->frag_list)
goto merge;
+ else if (!skb_headlen(p) && !skb_headlen(skb) &&
+ skb_shinfo(p)->nr_frags + skb_shinfo(skb)->nr_frags <
+ MAX_SKB_FRAGS) {
+ memcpy(skb_shinfo(p)->frags + skb_shinfo(p)->nr_frags,
+ skb_shinfo(skb)->frags,
+ skb_shinfo(skb)->nr_frags * sizeof(skb_frag_t));
+
+ skb_shinfo(p)->nr_frags += skb_shinfo(skb)->nr_frags;
+ NAPI_GRO_CB(skb)->free = 1;
+ goto done;
+ }
headroom = skb_headroom(p);
nskb = netdev_alloc_skb(p->dev, headroom);
@@ -2628,11 +2639,12 @@ int skb_gro_receive(struct sk_buff **head, struct sk_buff *skb)
p = nskb;
merge:
- NAPI_GRO_CB(p)->count++;
p->prev->next = skb;
p->prev = skb;
skb_header_release(skb);
+done:
+ NAPI_GRO_CB(p)->count++;
p->data_len += skb->len;
p->truesize += skb->len;
p->len += skb->len;
Cheers,
--
Visit Openswan at http://www.openswan.org/
Email: Herbert Xu ~{PmV>HI~} <herbert@...dor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
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