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References: <cover.1496743523.git.dvyukov@google.com> <ca52d3d26fcc5d5d8af430bc269610d3aa7df252.1496743523.git.dvyukov@google.com>
 <7c4a35fe-67eb-6520-b036-bfa2b4267276@virtuozzo.com>
From: Dmitry Vyukov <dvyukov@google.com>
Date: Sat, 17 Jun 2017 11:16:33 +0200
Message-ID: <CACT4Y+aQqwa1bb0Z2OJ3JLE6V6+6cAaoEiGDZdFBa23RkS6q+g@mail.gmail.com>
Subject: Re: [PATCH v3 4/7] x86: switch atomic.h to use atomic-instrumented.h
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Sender: owner-linux-mm@kvack.org
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To: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Mark Rutland <mark.rutland@arm.com>, Peter Zijlstra <peterz@infradead.org>, Ingo Molnar <mingo@redhat.com>, Will Deacon <will.deacon@arm.com>, "H. Peter Anvin" <hpa@zytor.com>, Andrew Morton <akpm@linux-foundation.org>, kasan-dev <kasan-dev@googlegroups.com>, "linux-mm@kvack.org" <linux-mm@kvack.org>, LKML <linux-kernel@vger.kernel.org>, "x86@kernel.org" <x86@kernel.org>

On Fri, Jun 16, 2017 at 5:54 PM, Andrey Ryabinin
<aryabinin@virtuozzo.com> wrote:
> On 06/06/2017 01:11 PM, Dmitry Vyukov wrote:
>> Add arch_ prefix to all atomic operations and include
>> <asm-generic/atomic-instrumented.h>. This will allow
>> to add KASAN instrumentation to all atomic ops.
>>
>> Signed-off-by: Dmitry Vyukov <dvyukov@google.com>
>> Cc: Mark Rutland <mark.rutland@arm.com>
>> Cc: Peter Zijlstra <peterz@infradead.org>
>> Cc: Will Deacon <will.deacon@arm.com>
>> Cc: Andrew Morton <akpm@linux-foundation.org>
>> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
>> Cc: Ingo Molnar <mingo@redhat.com>
>> Cc: kasan-dev@googlegroups.com
>> Cc: linux-mm@kvack.org
>> Cc: linux-kernel@vger.kernel.org
>> Cc: x86@kernel.org
>>
>> ---
>
>
>
>
>> -static __always_inline void atomic_set(atomic_t *v, int i)
>> +static __always_inline void arch_atomic_set(atomic_t *v, int i)
>>  {
>> +     /*
>> +      * We could use WRITE_ONCE_NOCHECK() if it exists, similar to
>> +      * READ_ONCE_NOCHECK() in arch_atomic_read(). But there is no such
>> +      * thing at the moment, and introducing it for this case does not
>> +      * worth it.
>> +      */
>
>
> I'd rather remove this comment. I woudn't say that WRITE_ONCE() here looks confusing
> and needs comment. Also there is no READ_ONCE_NOCHECK() in arch_atomic_read() anymore.

Done.
It also should have gone to the patch that adds comments.


> Otherwise,
>         Reviewed-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
>
>>       WRITE_ONCE(v->counter, i);
>>  }

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