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-rw-r--r--lib/checksum.c12
1 files changed, 10 insertions, 2 deletions
diff --git a/lib/checksum.c b/lib/checksum.c
index 129775eb6de6..fcf38943132c 100644
--- a/lib/checksum.c
+++ b/lib/checksum.c
@@ -47,6 +47,15 @@ static inline unsigned short from32to16(unsigned int x)
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, __be32 daddr,
#else
s += (proto + len) << 8;
#endif
- s += (s >> 32);
- return (__force __wsum)s;
+ return (__force __wsum)from64to32(s);
}
EXPORT_SYMBOL(csum_tcpudp_nofold);
#endif