Re: [PATCH 2/3] x86/hash: swap parameters of crc32_u32()

From: Daniel Borkmann
Date: Sat Feb 22 2014 - 07:10:26 EST


On 02/21/2014 11:33 AM, Jan Beulich wrote:
... to match its two callers (i.e. the alternative would have been to
swap the arguments at the call sites).

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
Cc: Francesco Fusco <ffusco@xxxxxxxxxx>
Cc: Daniel Borkmann <dborkman@xxxxxxxxxx>
Cc: Thomas Graf <tgraf@xxxxxxxxxx>
Cc: David S. Miller <davem@xxxxxxxxxxxxx>
---
arch/x86/lib/hash.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- 3.14-rc3-x86-hash-crc32.orig/arch/x86/lib/hash.c
+++ 3.14-rc3-x86-hash-crc32/arch/x86/lib/hash.c
@@ -37,7 +37,7 @@
#include <asm/cpufeature.h>
#include <asm/hash.h>

-static inline u32 crc32_u32(u32 crc, u32 val)
+static inline u32 crc32_u32(u32 val, u32 crc)
{
#ifdef CONFIG_AS_CRC32
asm ("crc32l %1,%0\n" : "+r" (crc) : "rm" (val));

Can you elaborate?

Sorry, I need to ask here (even if it's a stupid question ;)) if this
change is safe to do; are referring to a cleanup or fixing a concrete
bug? The code is a modified version of the DPDK hash which you can find
in [1]. Arguments of the caller are in the correct order, afaik.

[1] http://dpdk.org/browse/dpdk/tree/lib/librte_hash/rte_hash_crc.h
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