From mboxrd@z Thu Jan 1 00:00:00 1970 From: Greg Kroah-Hartman Subject: [PATCH 3.14 10/20] lib/checksum.c: fix carry in csum_tcpudp_nofold Date: Mon, 9 Feb 2015 16:34:02 +0800 Message-ID: <20150209083042.674770509@linuxfoundation.org> References: <20150209083042.033412726@linuxfoundation.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Karl Beldan , Al Viro , Eric Dumazet , Arnd Bergmann , Mike Frysinger , netdev@vger.kernel.org, Eric Dumazet , "David S. Miller" To: linux-kernel@vger.kernel.org Return-path: In-Reply-To: <20150209083042.033412726@linuxfoundation.org> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org 3.14-stable 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: Greg Kroah-Hartman --- 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; @@ -195,8 +204,7 @@ __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