Re: [Qemu-devel] [RFC PATCH v2 02/10] Jhash: add linux kernel jhashtable in qemu

[Zhang Chen <zhangchen.fnst@cn.fujitsu.com>]

On 01/11/2016 08:50 PM, Dr. David Alan Gilbert wrote:
> * Zhang Chen (zhangchen.fnst@cn.fujitsu.com) wrote:
>>
>> On 01/08/2016 08:08 PM, Dr. David Alan Gilbert wrote:
>>> * Zhang Chen (zhangchen.fnst@cn.fujitsu.com) wrote:
>>>> From: zhangchen <zhangchen.fnst@cn.fujitsu.com>
>>>>
>>>> Jhash used by colo-proxy to save and lookup
>>>> net connection info
>>>>
>>>> Signed-off-by: zhangchen <zhangchen.fnst@cn.fujitsu.com>
>>>> Signed-off-by: zhanghailiang <zhang.zhanghailiang@huawei.com>
>>>> ---
>>>>   include/qemu/jhash.h | 61 ++++++++++++++++++++++++++++++++++++++++++++++++++++
>>>>   1 file changed, 61 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..5b82d02
>>>> --- /dev/null
>>>> +++ b/include/qemu/jhash.h
>>>> @@ -0,0 +1,61 @@
>>>> +/* jhash.h: Jenkins hash support.
>>>> +  *
>>>> +  * Copyright (C) 2006. Bob Jenkins (bob_jenkins@burtleburtle.net)
>>>> +  *
>>>> +  * http://burtleburtle.net/bob/hash/
>>>> +  *
>>>> +  * These are the credits from Bob's sources:
>>>> +  *
>>>> +  * lookup3.c, by Bob Jenkins, May 2006, Public Domain.
>>>> +  *
>>>> +  * These are functions for producing 32-bit hashes for hash table lookup.
>>>> +  * hashword(), hashlittle(), hashlittle2(), hashbig(), mix(), and final()
>>>> +  * are externally useful functions.  Routines to test the hash are
>>>> +included
>>>> +  * if SELF_TEST is defined.  You can use this free for any purpose.
>>>> +It's in
>>>> +  * the public domain.  It has no warranty.
>>>> +  *
>>>> +  * Copyright (C) 2009-2010 Jozsef Kadlecsik (kadlec@blackhole.kfki.hu)
>>>> +  *
>>>> +  * I've modified Bob's hash to be useful in the Linux kernel, and
>>>> +  * any bugs present are my fault.
>>>> +  * Jozsef
>>>> +  */
>>>> +
>>>> +#ifndef QEMU_JHASH_H__
>>>> +#define QEMU_JHASH_H__
>>>> +
>>>> +#include "qemu/bitopt.h"
>>> That does not build, the header in qemu is bitop*s*.h.
>>>
>>> Dave
>> I'm very sorry for it, fix it to
>>
>> #include "qemu/bitopts.h"
> No! It's:
>
> #include "qemu/bitops.h"
>
> Please at least build test this code!
>
> Dave

Fix it to #include "qemu/bitops.h"
I have rebuild this code,but qemu makefile did't check the .h
I don't know whether it is a qemu bug.
you can try change it to #include "qemu/bitops.h" and make.
then change it to #include "qemu/bitopts.h" and make.
repeat it twice, now, you can change it to #include "everything"
in jhash.h. gcc don't check the .h and report error.////


Thanks
zhangchen


>> Thanks
>> zhangchen
>>
>>
>>>> +
>>>> +/*
>>>> + * hashtable relation copy from linux kernel jhash
>>>> + */
>>>> +
>>>> +/* __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 / dgilbert@redhat.com / Manchester, UK
>>>
>>>
>>> .
>>>
>> -- 
>> Thanks
>> zhangchen
>>
>>
>>
> --
> Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
>
>
> .
>

-- 
Thanks
zhangchen