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 <vapier@gentoo.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
diff --git a/lib/checksum.c b/lib/checksum.c
index 12e5a1c..b2e2fd4 100644
--- a/lib/checksum.c
+++ b/lib/checksum.c
@@ -55,7 +55,11 @@
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 @@
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 @@
}
}
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);