net: fix sparse error in csum_replace4()

make C=2 CF=-D__CHECK_ENDIAN__ net/ipv4/netfilter/nf_nat_l3proto_ipv4.o
  CHECK   net/ipv4/netfilter/nf_nat_l3proto_ipv4.c
include/net/checksum.h:125:64: warning: incorrect type in argument 2 (different base types)
include/net/checksum.h:125:64:    expected restricted __wsum [usertype] addend
include/net/checksum.h:125:64:    got restricted __be32 [usertype] from
include/net/checksum.h:125:71: warning: incorrect type in argument 2 (different base types)
include/net/checksum.h:125:71:    expected restricted __wsum [usertype] addend
include/net/checksum.h:125:71:    got restricted __be32 [usertype] to
include/net/checksum.h:125:64: warning: incorrect type in argument 2 (different base types)
include/net/checksum.h:125:64:    expected restricted __wsum [usertype] addend
include/net/checksum.h:125:64:    got restricted __be32 [usertype] from
include/net/checksum.h:125:71: warning: incorrect type in argument 2 (different base types)
include/net/checksum.h:125:71:    expected restricted __wsum [usertype] addend
include/net/checksum.h:125:71:    got restricted __be32 [usertype] to

Fixes: 4565af0d406b ("net: optimise csum_replace4()")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/checksum.h b/include/net/checksum.h
index 0a55ac715077d0aad820916f9daf979ae3dfd0fd..2d1d73cb773e9bd160f5c43bb58981ee8597b87c 100644 (file)
--- a/include/net/checksum.h
+++ b/include/net/checksum.h
@@ -122,7 +122,9 @@ static inline __wsum csum_partial_ext(const void *buff, int len, __wsum sum)
 
 static inline void csum_replace4(__sum16 *sum, __be32 from, __be32 to)
 {
-       *sum = csum_fold(csum_add(csum_sub(~csum_unfold(*sum), from), to));
+       __wsum tmp = csum_sub(~csum_unfold(*sum), (__force __wsum)from);
+
+       *sum = csum_fold(csum_add(tmp, (__force __wsum)to));
 }
 
 /* Implements RFC 1624 (Incremental Internet Checksum)