From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758009AbbCCXXh (ORCPT ); Tue, 3 Mar 2015 18:23:37 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:36800 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932343AbbCCXVg (ORCPT ); Tue, 3 Mar 2015 18:21:36 -0500 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Al Viro" , netdev@vger.kernel.org, "karl beldan" , "Arnd Bergmann" , "Karl Beldan" , "Eric Dumazet" , "Eric Dumazet" , "Mike Frysinger" , "David S. Miller" Date: Tue, 03 Mar 2015 22:11:28 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.2 06/24] lib/checksum.c: fix carry in csum_tcpudp_nofold In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.249 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.2.68-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: karl beldan commit 150ae0e94634714b23919f0c333fee28a5b199d5 upstream. The carry from the 64->32bits folding was dropped, e.g with: saddr=0xFFFFFFFF daddr=0xFF0000FF len=0xFFFF proto=0 sum=1, csum_tcpudp_nofold returned 0 instead of 1. Signed-off-by: Karl Beldan Cc: Al Viro Cc: Eric Dumazet Cc: Arnd Bergmann Cc: Mike Frysinger Cc: netdev@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Ben Hutchings --- lib/checksum.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) --- a/lib/checksum.c +++ b/lib/checksum.c @@ -47,6 +47,15 @@ static inline unsigned short from32to16( return x; } +static inline u32 from64to32(u64 x) +{ + /* add up 32-bit and 32-bit for 32+c bit */ + x = (x & 0xffffffff) + (x >> 32); + /* add up carry.. */ + x = (x & 0xffffffff) + (x >> 32); + return (u32)x; +} + static unsigned int do_csum(const unsigned char *buff, int len) { int odd; @@ -193,8 +202,7 @@ __wsum csum_tcpudp_nofold(__be32 saddr, #else s += (proto + len) << 8; #endif - s += (s >> 32); - return (__force __wsum)s; + return (__force __wsum)from64to32(s); } EXPORT_SYMBOL(csum_tcpudp_nofold); #endif