[PATCH 4.9 076/148] powerpc/64: Fix checksum folding in csum_add()

Greg Kroah-Hartman
2017-12-12T12:59:55Z

From: Shile Zhang <shile.zhang@nokia.com>

[ Upstream commit 6ad966d7303b70165228dba1ee8da1a05c10eefe ]

Paul's patch to fix checksum folding, commit b492f7e4e07a ("powerpc/64:
Fix checksum folding in csum_tcpudp_nofold and ip_fast_csum_nofold")
missed a case in csum_add(). Fix it.

Signed-off-by: Shile Zhang <shile.zhang@nokia.com>
Acked-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/powerpc/include/asm/checksum.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/powerpc/include/asm/checksum.h
+++ b/arch/powerpc/include/asm/checksum.h
@@ -100,7 +100,7 @@ static inline __wsum csum_add(__wsum csu

#ifdef __powerpc64__
res += (__force u64)addend;
- return (__force __wsum)((u32)res + (res >> 32));
+ return (__force __wsum) from64to32(res);
#else
asm("addc %0,%0,%1;"
"addze %0,%0;"