Merge branch 'net-hash-tx'

Tom Herbert says:

====================
net: Improvements and applications of packet flow hash in transmit path

This patch series includes some patches which improve and make use
of skb->hash in the transmit path.

What is included:

- Infrastructure to save a precomputed hash in the sock structure.
  For connected TCP and UDP sockets we only need to compute the
  flow hash once and not once for every packet.
- Call skb_get_hash in get_xps_queue and __skb_tx_hash. This eliminates
  the awkward access to skb->sk->sk_hash in the lower transmit path.
- Move UDP source port generation into a common function in udp.h This
  implementation is mostly based on vxlan_src_port.
- Use non-zero IPv6 flow labels in flow_dissector as port information
  for flow hash calculation.
- Implement automatic flow label generation on transmit (per RFC 6438).
- Don't repeatedly try to compute an L4 hash in skb_get_hash if we've
  already tried to find one in software stack calculation.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 11 insertions, 5 deletions

diff --git a/include/linux/ipv6.h b/include/linux/ipv6.h
index 5dc68c3ebcbd..ff560537dd61 100644
--- a/include/linux/ipv6.h
+++ b/include/linux/ipv6.h
@@ -199,7 +199,8 @@ struct ipv6_pinfo {
 						 * 010: prefer public address
 						 * 100: prefer care-of address
 						 */
-				dontfrag:1;
+				dontfrag:1,
+				autoflowlabel:1;
 	__u8			min_hopcount;
 	__u8			tclass;
 	__be32			rcv_flowinfo;
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 66f9a04ec270..8b43a28ee0bc 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -2486,7 +2486,7 @@ static inline int netif_set_xps_queue(struct net_device *dev,
  * as a distribution range limit for the returned value.
  */
 static inline u16 skb_tx_hash(const struct net_device *dev,
-			      const struct sk_buff *skb)
+			      struct sk_buff *skb)
 {
 	return __skb_tx_hash(dev, skb, dev->real_num_tx_queues);
 }
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index ec89301ada41..890fb3307dd6 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -455,6 +455,7 @@ static inline u32 skb_mstamp_us_delta(const struct skb_mstamp *t1,
  *	@ooo_okay: allow the mapping of a socket to a queue to be changed
  *	@l4_hash: indicate hash is a canonical 4-tuple hash over transport
  *		ports.
+ *	@sw_hash: indicates hash was computed in software stack
  *	@wifi_acked_valid: wifi_acked was set
  *	@wifi_acked: whether frame was acked on wifi or not
  *	@no_fcs:  Request NIC to treat last 4 bytes as Ethernet FCS
@@ -562,6 +563,7 @@ struct sk_buff {
 	__u8			pfmemalloc:1;
 	__u8			ooo_okay:1;
 	__u8			l4_hash:1;
+	__u8			sw_hash:1;
 	__u8			wifi_acked_valid:1;
 	__u8			wifi_acked:1;
 	__u8			no_fcs:1;
@@ -575,7 +577,7 @@ struct sk_buff {
 	__u8			encap_hdr_csum:1;
 	__u8			csum_valid:1;
 	__u8			csum_complete_sw:1;
-	/* 3/5 bit hole (depending on ndisc_nodetype presence) */
+	/* 2/4 bit hole (depending on ndisc_nodetype presence) */
 	kmemcheck_bitfield_end(flags2);
 
 #if defined CONFIG_NET_DMA || defined CONFIG_NET_RX_BUSY_POLL
@@ -830,13 +832,14 @@ static inline void
 skb_set_hash(struct sk_buff *skb, __u32 hash, enum pkt_hash_types type)
 {
 	skb->l4_hash = (type == PKT_HASH_TYPE_L4);
+	skb->sw_hash = 0;
 	skb->hash = hash;
 }
 
 void __skb_get_hash(struct sk_buff *skb);
 static inline __u32 skb_get_hash(struct sk_buff *skb)
 {
-	if (!skb->l4_hash)
+	if (!skb->l4_hash && !skb->sw_hash)
 		__skb_get_hash(skb);
 
 	return skb->hash;
@@ -850,6 +853,7 @@ static inline __u32 skb_get_hash_raw(const struct sk_buff *skb)
 static inline void skb_clear_hash(struct sk_buff *skb)
 {
 	skb->hash = 0;
+	skb->sw_hash = 0;
 	skb->l4_hash = 0;
 }
 
@@ -862,6 +866,7 @@ static inline void skb_clear_hash_if_not_l4(struct sk_buff *skb)
 static inline void skb_copy_hash(struct sk_buff *to, const struct sk_buff *from)
 {
 	to->hash = from->hash;
+	to->sw_hash = from->sw_hash;
 	to->l4_hash = from->l4_hash;
 };
 
@@ -3005,7 +3010,7 @@ static inline bool skb_rx_queue_recorded(const struct sk_buff *skb)
 	return skb->queue_mapping != 0;
 }
 
-u16 __skb_tx_hash(const struct net_device *dev, const struct sk_buff *skb,
+u16 __skb_tx_hash(const struct net_device *dev, struct sk_buff *skb,
 		  unsigned int num_tx_queues);
 
 static inline struct sec_path *skb_sec_path(struct sk_buff *skb)