Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Date:   Fri, 25 Jan 2019 11:31:46 +0100
From:   Peter Zijlstra <peterz@infradead.org>
To:     "Reshetova, Elena" <elena.reshetova@intel.com>
Cc:     Kees Cook <keescook@chromium.org>,
        Alan Stern <stern@rowland.harvard.edu>,
        Dmitry Vyukov <dvyukov@google.com>,
        Andrea Parri <andrea.parri@amarulasolutions.com>,
        "Paul E. McKenney" <paulmck@linux.ibm.com>,
        Will Deacon <will.deacon@arm.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Andrey Ryabinin <aryabinin@virtuozzo.com>,
        Anders Roxell <anders.roxell@linaro.org>,
        Mark Rutland <mark.rutland@arm.com>,
        LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] kcov: convert kcov.refcount to refcount_t
Message-ID: <20190125103146.GD4500@hirez.programming.kicks-ass.net>
References: <20190121131816.GC17749@hirez.programming.kicks-ass.net>
 <Pine.LNX.4.44L0.1901211103000.24162-100000@netrider.rowland.org>
 <20190122090456.GE13777@hirez.programming.kicks-ass.net>
 <CAGXu5jKHo4CZWAnn4Wvg=MV=xaf3j4mBvxggBHuZETTkMOxkOA@mail.gmail.com>
 <2236FBA76BA1254E88B949DDB74E612BA4B92711@IRSMSX102.ger.corp.intel.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <2236FBA76BA1254E88B949DDB74E612BA4B92711@IRSMSX102.ger.corp.intel.com>
User-Agent: Mutt/1.10.1 (2018-07-13)
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Fri, Jan 25, 2019 at 09:02:42AM +0000, Reshetova, Elena wrote:
> > > I suppose we can add smp_acquire__after_ctrl_dep() on the true branch.
> > > Then it reall does become rel_acq.
> > >
> > > A wee something like so (I couldn't find an arm64 refcount, even though
> > > I have distinct memories of talk about it).
> > 
> > In the end, arm and arm64 chose to use REFCOUNT_FULL unconditionally,
> > so there's no arch-specific implementation.
> > 
> > > This isn't compiled, and obviously needs comment/documentation updates
> > > to go along with it.
> > 
> > Elena, can you do the doc updates?
> 
> Well, doc updates should go with below patch + and additional testing...
> 
> Peter, should I create a full version from below with doc/comments
> updates, run the whole thing via zero day and send to you if it all looks ok?

If you have to time to do so, yes please!