linux-kernel - Re: [PATCH v4] locking/memory-barriers.txt: Improve documentation for writel() example

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Message-Id: <d5faaf6f-7de5-49b0-92d6-9989ffbdbf2e@app.fastmail.com>
Date:   Mon, 17 Oct 2022 22:55:00 +0200
From:   "Arnd Bergmann" <arnd@...db.de>
To:     "Parav Pandit" <parav@...dia.com>, bagasdotme@...il.com,
        "Alan Stern" <stern@...land.harvard.edu>, parri.andrea@...il.com,
        "Will Deacon" <will@...nel.org>,
        "Peter Zijlstra" <peterz@...radead.org>, boqun.feng@...il.com,
        "Nicholas Piggin" <npiggin@...il.com>, dhowells@...hat.com,
        j.alglave@....ac.uk, luc.maranget@...ia.fr,
        "Paul E. McKenney" <paulmck@...nel.org>,
        "Akira Yokosawa" <akiyks@...il.com>, dlustig@...dia.com,
        "Joel Fernandes" <joel@...lfernandes.org>,
        "Jonathan Corbet" <corbet@....net>, linux-kernel@...r.kernel.org,
        Linux-Arch <linux-arch@...r.kernel.org>,
        linux-doc@...r.kernel.org
Subject: Re: [PATCH v4] locking/memory-barriers.txt: Improve documentation for writel()
 example

On Mon, Oct 10, 2022, at 12:13 PM, Parav Pandit wrote:
> The cited commit describes that when using writel(), explcit wmb()
> is not needed. wmb() is an expensive barrier. writel() uses the needed
> platform specific barrier instead of expensive wmb().
>
> Hence update the example to be more accurate that matches the current
> implementation.
>
> commit 5846581e3563 ("locking/memory-barriers.txt: Fix broken DMA vs. 
> MMIO ordering example")
>
> Signed-off-by: Parav Pandit <parav@...dia.com>

I have no objections, though I still don't see a real need to change
the wording here.

Acked-by: Arnd Bergmann <arnd@...db.de>