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Date:   Wed, 29 Jul 2020 12:30:22 -0700
From:   Kees Cook <keescook@chromium.org>
To:     peterz@infradead.org
Cc:     David Howells <dhowells@redhat.com>, Will Deacon <will@kernel.org>,
        Xiaoming Ni <nixiaoming@huawei.com>,
        David Windsor <dwindsor@gmail.com>,
        Hans Liljestrand <ishkamiel@gmail.com>,
        Elena Reshetova <elena.reshetova@intel.com>,
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        paulmck@kernel.org, shakeelb@google.com,
        James Morris <jamorris@linux.microsoft.com>,
        alex.huangjianhui@huawei.com, dylix.dailei@huawei.com,
        chenzefeng2@huawei.com, linux-kernel@vger.kernel.org
Subject: Re: [RFC][PATCH] locking/refcount: Provide __refcount API to obtain
 the old value
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On Wed, Jul 29, 2020 at 01:11:20PM +0200, peterz@infradead.org wrote:
> Subject: locking/refcount: Provide __refcount API to obtain the old value
> From: Peter Zijlstra <peterz@infradead.org>
> Date: Wed Jul 29 13:00:57 CEST 2020
> 
> David requested means to obtain the old/previous value from the
> refcount API for tracing purposes.
> 
> Duplicate (most of) the API as __refcount*() with an additional
> 'int *' argument into which, if !NULL, the old value will be stored.
> 
> Requested-by: David Howells <dhowells@redhat.com>
> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>

This looks good to me. Thanks for poking at it!

Reviewed-by: Kees Cook <keescook@chromium.org>

-- 
Kees Cook