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Date: Tue, 15 Nov 2011 15:44:29 +0400
From: Pavel Emelyanov <xemul@parallels.com>
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To: Pekka Enberg <penberg@kernel.org>
CC: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Cyrill Gorcunov <gorcunov@openvz.org>,
        Glauber Costa <glommer@parallels.com>,
        Andi Kleen <andi@firstfloor.org>, Tejun Heo <tj@kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Matt Helsley <matthltc@us.ibm.com>
Subject: Re: [PATCH 1/4] Routine for generating an safe ID for kernel pointer
References: <4EC24E9E.8040502@parallels.com>	<4EC24EC1.7060203@parallels.com> <CAOJsxLECV5yr+A_mSooS674CKgGoNxgrbhOs0CCu0Pa0=KPkPw@mail.gmail.com>
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>> +unsigned long gen_object_id(void *ptr)
>> +{
>> +       if (!ptr)
>> +               return 0;
>> +
>> +       if (unlikely(!ptr_poison)) {
>> +               spin_lock(&ptr_poison_lock);
>> +               if (!ptr_poison)
>> +                       get_random_bytes(&ptr_poison, sizeof(ptr_poison));
>> +               spin_unlock(&ptr_poison_lock);
>> +       }
>> +
>> +       return ((unsigned long)ptr) ^ ptr_poison;
>> +}
> 
> You could put this in mm/util.c. Wouldn't it make sense to separate
> the initialization and use late_initcall() to call it?

OK, will put to util.c

About the initialization - I will put the sanity check about poison being not 0 on
get_object_id() anyway, so what's the point in separate initialization?

>                         Pekka
> .
>