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* [PATCH v2 2/3] x86/hash: swap arguments passed to crc32_u32()
@ 2014-02-27  8:47 Jan Beulich
  2014-02-27 18:52 ` H. Peter Anvin
                   ` (2 more replies)
  0 siblings, 3 replies; 4+ messages in thread
From: Jan Beulich @ 2014-02-27  8:47 UTC (permalink / raw)
  To: mingo, tglx, Jan Beulich, hpa
  Cc: davem, dborkman, ffusco, tgraf, linux-kernel

... 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@suse.com>
Acked-by: Daniel Borkmann <dborkman@redhat.com>
Cc: Francesco Fusco <ffusco@redhat.com>
Cc: Thomas Graf <tgraf@redhat.com>
Cc: David S. Miller <davem@davemloft.net>
---
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;
 }




^ permalink raw reply	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2014-03-19 23:55 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
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2014-02-27  8:47 [PATCH v2 2/3] x86/hash: swap arguments passed to crc32_u32() Jan Beulich
2014-02-27 18:52 ` H. Peter Anvin
2014-03-19 23:48 ` [tip:x86/hash] x86, hash: Swap " tip-bot for Jan Beulich
2014-03-19 23:54 ` tip-bot for Jan Beulich

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