From 32a9ff9cc55b42543a84bca90b070df92af72671 Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Fri, 19 Jun 2009 10:41:19 +0200 Subject: [PATCH] lib/checksum.c: fix endianess bug The new generic checksum code has a small dependency on endianess and worked only on big-endian systems. I could not find a nice efficient way to express this, so I added an #ifdef. Using 'result += le16_to_cpu(*buff);' would have worked as well, but would be slightly less efficient on big-endian systems and IMHO would not be clearer. Also fix a bug that prevents this from working on 64-bit machines. If you have a 64-bit CPU and want to use the generic checksum code, you should probably do some more optimizations anyway, but at least the code should not break. Reported-by: Mike Frysinger Signed-off-by: Arnd Bergmann --- lib/checksum.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/lib/checksum.c b/lib/checksum.c index 12e5a1c91cda..b2e2fd468461 100644 --- a/lib/checksum.c +++ b/lib/checksum.c @@ -55,7 +55,11 @@ static unsigned int do_csum(const unsigned char *buff, int len) goto out; odd = 1 & (unsigned long) buff; if (odd) { +#ifdef __LITTLE_ENDIAN result = *buff; +#else + result += (*buff << 8); +#endif len--; buff++; } @@ -71,7 +75,7 @@ static unsigned int do_csum(const unsigned char *buff, int len) if (count) { unsigned long carry = 0; do { - unsigned long w = *(unsigned long *) buff; + unsigned long w = *(unsigned int *) buff; count--; buff += 4; result += carry; @@ -87,7 +91,11 @@ static unsigned int do_csum(const unsigned char *buff, int len) } } if (len & 1) +#ifdef __LITTLE_ENDIAN + result += *buff; +#else result += (*buff << 8); +#endif result = from32to16(result); if (odd) result = ((result >> 8) & 0xff) | ((result & 0xff) << 8); -- GitLab