[PATCH v2 2/3] x86/hash: swap arguments passed to crc32_u32()

From: Jan Beulich
Date: Thu Feb 27 2014 - 03:47:31 EST


... to match the function's parameters. While reportedly commutative,
using the proper order allows for leveraging the instruction permitting
the source operand to be in memory.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
Acked-by: Daniel Borkmann <dborkman@xxxxxxxxxx>
Cc: Francesco Fusco <ffusco@xxxxxxxxxx>
Cc: Thomas Graf <tgraf@xxxxxxxxxx>
Cc: David S. Miller <davem@xxxxxxxxxxxxx>
---
v2: now swapping arguments rather than parameters, as requested by hpa
---
arch/x86/lib/hash.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

--- 3.14-rc4-x86-hash-crc32.orig/arch/x86/lib/hash.c
+++ 3.14-rc4-x86-hash-crc32/arch/x86/lib/hash.c
@@ -53,7 +53,7 @@ static u32 intel_crc4_2_hash(const void
u32 i, tmp = 0;

for (i = 0; i < len / 4; i++)
- seed = crc32_u32(*p32++, seed);
+ seed = crc32_u32(seed, *p32++);

switch (3 - (len & 0x03)) {
case 0:
@@ -64,7 +64,7 @@ static u32 intel_crc4_2_hash(const void
/* fallthrough */
case 2:
tmp |= *((const u8 *) p32);
- seed = crc32_u32(tmp, seed);
+ seed = crc32_u32(seed, tmp);
default:
break;
}
@@ -78,7 +78,7 @@ static u32 intel_crc4_2_hash2(const u32
u32 i;

for (i = 0; i < len; i++)
- seed = crc32_u32(*p32++, seed);
+ seed = crc32_u32(seed, *p32++);

return seed;
}



--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/