From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arnd Bergmann Subject: [PATCH] netfilter: xt_hashlimit: avoid 64-bit division Date: Wed, 6 Sep 2017 21:57:30 +0200 Message-ID: <20170906195825.3715290-1-arnd@arndb.de> Cc: Arnd Bergmann , Vishwanath Pai , Josh Hunt , netfilter-devel@vger.kernel.org, coreteam@netfilter.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org To: Pablo Neira Ayuso , Jozsef Kadlecsik , Florian Westphal , "David S. Miller" Return-path: Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org 64-bit division is expensive on 32-bit architectures, and requires a special function call to avoid a link error like: net/netfilter/xt_hashlimit.o: In function `hashlimit_mt_common': xt_hashlimit.c:(.text+0x1328): undefined reference to `__aeabi_uldivmod' In the case of hashlimit_mt_common, we don't actually need a 64-bit operation, we can simply rewrite the function slightly to make that clear to the compiler. Fixes: bea74641e378 ("netfilter: xt_hashlimit: add rate match mode") Signed-off-by: Arnd Bergmann --- net/netfilter/xt_hashlimit.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/net/netfilter/xt_hashlimit.c b/net/netfilter/xt_hashlimit.c index 10d48234f5f4..50b53d86eef5 100644 --- a/net/netfilter/xt_hashlimit.c +++ b/net/netfilter/xt_hashlimit.c @@ -531,7 +531,10 @@ static u64 user2rate_bytes(u64 user) { u64 r; - r = user ? 0xFFFFFFFFULL / user : 0xFFFFFFFFULL; + if (user > 0xFFFFFFFFULL) + return 0; + + r = user ? 0xFFFFFFFFULL / (u32)user : 0xFFFFFFFFULL; r = (r - 1) << 4; return r; } -- 2.9.0