lib/checksum.c: use 32-bit arithmetic consistently
The use of 'unsigned long' variables in the 32-bit part of do_csum()
is confusing at best, and potentially broken for long input on 64-bit
machines.
This changes the code to use 'unsigned int' instead, which makes
the code behave in the same (correct) way on both 32 and 64 bit
machines.
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
diff --git a/lib/checksum.c b/lib/checksum.c
index b2e2fd4..886b48db 100644
--- a/lib/checksum.c
+++ b/lib/checksum.c
@@ -37,7 +37,7 @@
#include <asm/byteorder.h>
-static inline unsigned short from32to16(unsigned long x)
+static inline unsigned short from32to16(unsigned int x)
{
/* add up 16-bit and 16-bit for 16+c bit */
x = (x & 0xffff) + (x >> 16);
@@ -49,7 +49,7 @@
static unsigned int do_csum(const unsigned char *buff, int len)
{
int odd, count;
- unsigned long result = 0;
+ unsigned int result = 0;
if (len <= 0)
goto out;
@@ -73,9 +73,9 @@
}
count >>= 1; /* nr of 32-bit words.. */
if (count) {
- unsigned long carry = 0;
+ unsigned int carry = 0;
do {
- unsigned long w = *(unsigned int *) buff;
+ unsigned int w = *(unsigned int *) buff;
count--;
buff += 4;
result += carry;