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From: | Zhang Chen |
Subject: | Re: [Qemu-devel] [RFC PATCH 2/9] jhash: add linux kernel jhashtable in qemu |
Date: | Thu, 3 Dec 2015 11:40:16 +0800 |
User-agent: | Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.3.0 |
Hi,Dave On 12/01/2015 07:23 PM, Dr. David Alan Gilbert wrote:
* Zhang Chen (address@hidden) wrote:From: zhangchen <address@hidden> This used by colo-proxy to save and lookup connection info Signed-off-by: zhangchen <address@hidden> --- include/qemu/jhash.h | 52 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 52 insertions(+) create mode 100644 include/qemu/jhash.h diff --git a/include/qemu/jhash.h b/include/qemu/jhash.h new file mode 100644 index 0000000..f6cc7b3 --- /dev/null +++ b/include/qemu/jhash.h @@ -0,0 +1,52 @@ +/* + * COarse-grain LOck-stepping Virtual Machines for Non-stop Service (COLO) + * (a.k.a. Fault Tolerance or Continuous Replication) + * + * Copyright (c) 2015 HUAWEI TECHNOLOGIES CO., LTD. + * Copyright (c) 2015 FUJITSU LIMITED + * Copyright (c) 2015 Intel Corporation + * + * Author: Zhang Chen <address@hidden> + * + * This work is licensed under the terms of the GNU GPL, version 2 or + * later. See the COPYING file in the top-level directory. + */Please be careful with the copyright. This code is mostly a copy of the kernel code, so I think it should take the copyright from the kernel code (see kernel's include/linux/jhash.h); and that copyright states it's based on Bob Jenkins' Public Domain code. Normally we have a problem as well QEMU doesn't like taking GPL2 code from the kernel, but my reading of the kernel's header file is that it's still Public domain; but I don't know what the right thing is to be sure. Dave
I will remove it and change it to kernel jhash.h's copyright in next version Thanks for review zhangchen
+ +#ifndef QEMU_JHASH_H__ +#define QEMU_JHASH_H__ + +/* + * hashtable relation copy from linux kernel jhash + */ +static inline uint32_t rol32(uint32_t word, unsigned int shift) +{ + return (word << shift) | (word >> (32 - shift)); +} + +/* __jhash_mix -- mix 3 32-bit values reversibly. */ +#define __jhash_mix(a, b, c) \ +{ \ + a -= c; a ^= rol32(c, 4); c += b; \ + b -= a; b ^= rol32(a, 6); a += c; \ + c -= b; c ^= rol32(b, 8); b += a; \ + a -= c; a ^= rol32(c, 16); c += b; \ + b -= a; b ^= rol32(a, 19); a += c; \ + c -= b; c ^= rol32(b, 4); b += a; \ +} + +/* __jhash_final - final mixing of 3 32-bit values (a,b,c) into c */ +#define __jhash_final(a, b, c) \ +{ \ + c ^= b; c -= rol32(b, 14); \ + a ^= c; a -= rol32(c, 11); \ + b ^= a; b -= rol32(a, 25); \ + c ^= b; c -= rol32(b, 16); \ + a ^= c; a -= rol32(c, 4); \ + b ^= a; b -= rol32(a, 14); \ + c ^= b; c -= rol32(b, 24); \ +} + +/* An arbitrary initial parameter */ +#define JHASH_INITVAL 0xdeadbeef + +#endif /* QEMU_JHASH_H__ */ -- 1.9.1-- Dr. David Alan Gilbert / address@hidden / Manchester, UK .
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