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From: Tom Herbert <therbert@google.com>
To: davem@davemloft.net, netdev@vger.kernel.org
Subject: [PATCH 2/4] rps: Add flag to skb to indicate rxhash is on L4 tuple
Date: Thu, 19 May 2011 08:39:11 -0700 (PDT)	[thread overview]
Message-ID: <alpine.DEB.2.00.1105190827240.12799@pokey.mtv.corp.google.com> (raw)

The l4_rxhash flag was added to the skb structure to indicate
that the rxhash value was computed over the 4 tuple for the
packet which includes the port information in the encapsulated
transport packet.  This is used by the stack to preserve the
rxhash value in __skb_rx_tunnel.

Signed-off-by: Tom Herbert <therbert@google.com>
---
 include/linux/skbuff.h |    5 +++--
 include/net/dst.h      |    9 ++++++++-
 include/net/sock.h     |   14 +++++++++++---
 net/core/dev.c         |   17 +++++++++++------
 net/core/skbuff.c      |    1 +
 net/ipv4/tcp_ipv4.c    |    4 ++--
 net/ipv4/udp.c         |    4 ++--
 7 files changed, 38 insertions(+), 16 deletions(-)

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 79aafbb..4fab336 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -397,6 +397,7 @@ struct sk_buff {
 	__u8			ndisc_nodetype:2;
 #endif
 	__u8			ooo_okay:1;
+	__u8			l4_rxhash:1;
 	kmemcheck_bitfield_end(flags2);
 
 	/* 0/13 bit hole */
@@ -555,11 +556,11 @@ extern unsigned int   skb_find_text(struct sk_buff *skb, unsigned int from,
 				    unsigned int to, struct ts_config *config,
 				    struct ts_state *state);
 
-extern __u32 __skb_get_rxhash(struct sk_buff *skb);
+extern void __skb_get_rxhash(struct sk_buff *skb);
 static inline __u32 skb_get_rxhash(struct sk_buff *skb)
 {
 	if (!skb->rxhash)
-		skb->rxhash = __skb_get_rxhash(skb);
+		__skb_get_rxhash(skb);
 
 	return skb->rxhash;
 }
diff --git a/include/net/dst.h b/include/net/dst.h
index 07a0402..17ff602 100644
--- a/include/net/dst.h
+++ b/include/net/dst.h
@@ -307,7 +307,14 @@ static inline void skb_dst_force(struct sk_buff *skb)
 static inline void __skb_tunnel_rx(struct sk_buff *skb, struct net_device *dev)
 {
 	skb->dev = dev;
-	skb->rxhash = 0;
+
+	/*
+	 * Clear rxhash so that we can reculate the hash for the
+	 * encapsulated packet, unless we have already determine the hash
+	 * over the L4 4-tuple.
+	 */
+	if (!skb->l4_rxhash)
+		skb->rxhash = 0;
 	skb_set_queue_mapping(skb, 0);
 	skb_dst_drop(skb);
 	nf_reset(skb);
diff --git a/include/net/sock.h b/include/net/sock.h
index f2046e4..e670c41 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -685,16 +685,24 @@ static inline void sock_rps_reset_flow(const struct sock *sk)
 #endif
 }
 
-static inline void sock_rps_save_rxhash(struct sock *sk, u32 rxhash)
+static inline void sock_rps_save_rxhash(struct sock *sk, struct sk_buff *skb)
 {
 #ifdef CONFIG_RPS
-	if (unlikely(sk->sk_rxhash != rxhash)) {
+	if (unlikely(sk->sk_rxhash != skb->rxhash)) {
 		sock_rps_reset_flow(sk);
-		sk->sk_rxhash = rxhash;
+		sk->sk_rxhash = skb->rxhash;
 	}
 #endif
 }
 
+static inline void sock_rps_reset_rxhash(struct sock *sk)
+{
+#ifdef CONFIG_RPS
+	sock_rps_reset_flow(sk);
+	sk->sk_rxhash = 0;
+#endif
+}
+
 #define sk_wait_event(__sk, __timeo, __condition)			\
 	({	int __rc;						\
 		release_sock(__sk);					\
diff --git a/net/core/dev.c b/net/core/dev.c
index a40eea9..37ddece 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -2014,8 +2014,10 @@ static inline void skb_orphan_try(struct sk_buff *skb)
 		/* skb_tx_hash() wont be able to get sk.
 		 * We copy sk_hash into skb->rxhash
 		 */
-		if (!skb->rxhash)
+		if (!skb->rxhash) {
 			skb->rxhash = sk->sk_hash;
+			skb->l4_rxhash = 1;
+		}
 		skb_orphan(skb);
 	}
 }
@@ -2499,12 +2501,13 @@ static inline void ____napi_schedule(struct softnet_data *sd,
 
 /*
  * __skb_get_rxhash: calculate a flow hash based on src/dst addresses
- * and src/dst port numbers. Returns a non-zero hash number on success
- * and 0 on failure.
+ * and src/dst port numbers.  Sets rxhash in skb to non-zero hash value
+ * on success, zero indicates no valid hash.  Also, sets l4_rxhash in skb
+ * if hash is a canonical 4-tuple hash over transport ports.
  */
-__u32 __skb_get_rxhash(struct sk_buff *skb)
+void __skb_get_rxhash(struct sk_buff *skb)
 {
-	int nhoff, hash = 0, poff;
+	int nhoff, hash = 0, l4hash = 0, poff;
 	const struct ipv6hdr *ip6;
 	const struct iphdr *ip;
 	u8 ip_proto;
@@ -2554,6 +2557,7 @@ __u32 __skb_get_rxhash(struct sk_buff *skb)
 			ports.v32 = * (__force u32 *) (skb->data + nhoff);
 			if (ports.v16[1] < ports.v16[0])
 				swap(ports.v16[0], ports.v16[1]);
+			l4hash = 1;
 		}
 	}
 
@@ -2566,7 +2570,8 @@ __u32 __skb_get_rxhash(struct sk_buff *skb)
 		hash = 1;
 
 done:
-	return hash;
+	skb->rxhash = hash;
+	skb->l4_rxhash = l4hash;
 }
 EXPORT_SYMBOL(__skb_get_rxhash);
 
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 7ebeed0..cb5c67d 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -513,6 +513,7 @@ static void __copy_skb_header(struct sk_buff *new, const struct sk_buff *old)
 	new->mac_header		= old->mac_header;
 	skb_dst_copy(new, old);
 	new->rxhash		= old->rxhash;
+	new->l4_rxhash		= old->l4_rxhash;
 #ifdef CONFIG_XFRM
 	new->sp			= secpath_get(old->sp);
 #endif
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 3c8d9b6..a4b156dc 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -1572,7 +1572,7 @@ int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
 #endif
 
 	if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
-		sock_rps_save_rxhash(sk, skb->rxhash);
+		sock_rps_save_rxhash(sk, skb);
 		if (tcp_rcv_established(sk, skb, tcp_hdr(skb), skb->len)) {
 			rsk = sk;
 			goto reset;
@@ -1596,7 +1596,7 @@ int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
 			return 0;
 		}
 	} else
-		sock_rps_save_rxhash(sk, skb->rxhash);
+		sock_rps_save_rxhash(sk, skb);
 
 	if (tcp_rcv_state_process(sk, skb, tcp_hdr(skb), skb->len)) {
 		rsk = sk;
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 599374f..d2277cf 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -1263,7 +1263,7 @@ int udp_disconnect(struct sock *sk, int flags)
 	sk->sk_state = TCP_CLOSE;
 	inet->inet_daddr = 0;
 	inet->inet_dport = 0;
-	sock_rps_save_rxhash(sk, 0);
+	sock_rps_reset_rxhash(sk);
 	sk->sk_bound_dev_if = 0;
 	if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK))
 		inet_reset_saddr(sk);
@@ -1351,7 +1351,7 @@ static int __udp_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
 	int rc;
 
 	if (inet_sk(sk)->inet_daddr)
-		sock_rps_save_rxhash(sk, skb->rxhash);
+		sock_rps_save_rxhash(sk, skb);
 
 	rc = ip_queue_rcv_skb(sk, skb);
 	if (rc < 0) {
-- 
1.7.3.1



             reply	other threads:[~2011-05-19 15:39 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-05-19 15:39 Tom Herbert [this message]
2011-05-19 20:26 ` [PATCH 2/4] rps: Add flag to skb to indicate rxhash is on L4 tuple Eric Dumazet

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