From mboxrd@z Thu Jan 1 00:00:00 1970 From: pablo@netfilter.org Subject: [PATCH 3/7] netfilter: xt_HMARK: modulus is expensive for hash calculation Date: Thu, 17 May 2012 01:06:40 +0200 Message-ID: <1337209604-3412-4-git-send-email-pablo@netfilter.org> References: <1337209604-3412-1-git-send-email-pablo@netfilter.org> Cc: davem@davemloft.net, netdev@vger.kernel.org To: netfilter-devel@vger.kernel.org Return-path: In-Reply-To: <1337209604-3412-1-git-send-email-pablo@netfilter.org> Sender: netfilter-devel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org From: Pablo Neira Ayuso Use: ((u64)(HASH_VAL * HASH_SIZE)) >> 32 as suggested by David S. Miller. Signed-off-by: Pablo Neira Ayuso --- 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