Eric Lee / smarc-ti-linux-kernel

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Commit 1ff733ae2347f93a20376defe1e6af77ede4da52

Authored by karl beldan
Committed by Greg Kroah-Hartman
1 parent 75a94c278e
Exists in smarc-ti-linux-3.14.y and in 1 other branch processor-sdk-linux-01.00.00

lib/checksum.c: fix carry in csum_tcpudp_nofold 

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 <karl.beldan@rivierawaves.com>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Mike Frysinger <vapier@gentoo.org>
Cc: netdev@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Showing 1 changed file with 10 additions and 2 deletions Side-by-side Diff

... ... @@ -47,6 +47,15 @@
47 47 return x;
48 48 }
49 49  
  50 +static inline u32 from64to32(u64 x)
  51 +{
  52 + /* add up 32-bit and 32-bit for 32+c bit */
  53 + x = (x & 0xffffffff) + (x >> 32);
  54 + /* add up carry.. */
  55 + x = (x & 0xffffffff) + (x >> 32);
  56 + return (u32)x;
  57 +}
  58 +
50 59 static unsigned int do_csum(const unsigned char *buff, int len)
51 60 {
52 61 int odd;
... ... @@ -195,8 +204,7 @@
195 204 #else
196 205 s += (proto + len) << 8;
197 206 #endif
198   - s += (s >> 32);
199   - return (__force __wsum)s;
  207 + return (__force __wsum)from64to32(s);
200 208 }
201 209 EXPORT_SYMBOL(csum_tcpudp_nofold);
202 210 #endif