Commit a3b18ddb authored by Tom Herbert's avatar Tom Herbert Committed by David S. Miller
Browse files

net: Only do flow_dissector hash computation once per packet 



Add sw_hash flag to skbuff to indicate that skb->hash was computed
from flow_dissector. This flag is checked in skb_get_hash to avoid
repeatedly trying to compute the hash (ie. in the case that no L4 hash
can be computed).

Signed-off-by: default avatarTom Herbert <therbert@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent cb1ce2ef

include/linux/skbuff.h

+7 −2
Original line number Diff line number Diff line
@@ -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;

};

net/core/flow_dissector.c

+2 −0
Original line number Diff line number Diff line
@@ -256,6 +256,8 @@ void __skb_get_hash(struct sk_buff *skb) 
	if (keys.ports)

		skb->l4_hash = 1;



	skb->sw_hash = 1;



	skb->hash = __flow_hash_from_keys(&keys);

}

EXPORT_SYMBOL(__skb_get_hash);

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