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Message-ID: <20111122144334.GA22824@p183.telecom.by>
Date: Tue, 22 Nov 2011 17:43:34 +0300
From: Alexey Dobriyan <adobriyan@...il.com>
To: davem@...emloft.net
Cc: netdev@...r.kernel.org
Subject: [PATCH] xfrm: optimize ipv4 selector matching
Current addr_match() is errh, under-optimized.
Compiler doesn't know that memcmp() branch doesn't trigger for IPv4.
Pass addresses by value.
Signed-off-by: Alexey Dobriyan <adobriyan@...il.com>
---
include/net/xfrm.h | 10 ++++++++++
net/xfrm/xfrm_policy.c | 4 ++--
2 files changed, 12 insertions(+), 2 deletions(-)
--- a/include/net/xfrm.h
+++ b/include/net/xfrm.h
@@ -827,6 +827,16 @@ static inline bool addr_match(const void *token1, const void *token2,
return true;
}
+static inline int addr4_match(const __be32 a1, const __be32 a2, const u8 prefixlen)
+{
+ /* C99 6.5.7 (3): u32 << 32 is undefined behaviour */
+ if (prefixlen == 0) {
+ /* Matching constants result in smaller assembly. */
+ return 0xFFFFFFFFu;
+ }
+ return !((a1 ^ a2) & htonl(0xFFFFFFFFu << (32 - prefixlen)));
+}
+
static __inline__
__be16 xfrm_flowi_sport(const struct flowi *fl, const union flowi_uli *uli)
{
--- a/net/xfrm/xfrm_policy.c
+++ b/net/xfrm/xfrm_policy.c
@@ -61,8 +61,8 @@ __xfrm4_selector_match(const struct xfrm_selector *sel, const struct flowi *fl)
{
const struct flowi4 *fl4 = &fl->u.ip4;
- return addr_match(&fl4->daddr, &sel->daddr, sel->prefixlen_d) &&
- addr_match(&fl4->saddr, &sel->saddr, sel->prefixlen_s) &&
+ return addr4_match(fl4->daddr, sel->daddr.a4, sel->prefixlen_d) &&
+ addr4_match(fl4->saddr, sel->saddr.a4, sel->prefixlen_s) &&
!((xfrm_flowi_dport(fl, &fl4->uli) ^ sel->dport) & sel->dport_mask) &&
!((xfrm_flowi_sport(fl, &fl4->uli) ^ sel->sport) & sel->sport_mask) &&
(fl4->flowi4_proto == sel->proto || !sel->proto) &&
--
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