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Message-Id: <1337209604-3412-4-git-send-email-pablo@netfilter.org>
Date: Thu, 17 May 2012 01:06:40 +0200
From: pablo@...filter.org
To: netfilter-devel@...r.kernel.org
Cc: davem@...emloft.net, netdev@...r.kernel.org
Subject: [PATCH 3/7] netfilter: xt_HMARK: modulus is expensive for hash calculation
From: Pablo Neira Ayuso <pablo@...filter.org>
Use:
((u64)(HASH_VAL * HASH_SIZE)) >> 32
as suggested by David S. Miller.
Signed-off-by: Pablo Neira Ayuso <pablo@...filter.org>
---
net/netfilter/xt_HMARK.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/netfilter/xt_HMARK.c b/net/netfilter/xt_HMARK.c
index 5817d03..0a96a43 100644
--- a/net/netfilter/xt_HMARK.c
+++ b/net/netfilter/xt_HMARK.c
@@ -109,7 +109,7 @@ hmark_hash(struct hmark_tuple *t, const struct xt_hmark_info *info)
hash = jhash_3words(t->src, t->dst, t->uports.v32, info->hashrnd);
hash = hash ^ (t->proto & info->proto_mask);
- return (hash % info->hmodulus) + info->hoffset;
+ return (((u64)hash * info->hmodulus) >> 32) + info->hoffset;
}
static void
--
1.7.10
--
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