netdev - Re: [PATCH v3 0/7] include: add setbits32/clrbits32/clrsetbits32/setbits64/clrbits64/clrsetbits64

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Date:   Wed, 24 Oct 2018 09:57:00 +0100
From:   Russell King - ARM Linux <linux@...linux.org.uk>
To:     Corentin Labbe <clabbe@...libre.com>
Cc:     Gilles.Muller@...6.fr, Julia.Lawall@...6.fr, agust@...x.de,
        airlied@...ux.ie, alexandre.torgue@...com, alistair@...ple.id.au,
        benh@...nel.crashing.org, carlo@...one.org, davem@...emloft.net,
        galak@...nel.crashing.org, joabreu@...opsys.com,
        khilman@...libre.com, matthias.bgg@...il.com,
        maxime.ripard@...tlin.com, michal.lkml@...kovi.net,
        mpe@...erman.id.au, mporter@...nel.crashing.org,
        narmstrong@...libre.com, nicolas.palix@...g.fr, oss@...error.net,
        paulus@...ba.org, peppe.cavallaro@...com, tj@...nel.org,
        vitb@...nel.crashing.org, wens@...e.org, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org, dri-devel@...ts.freedesktop.org,
        linux-ide@...r.kernel.org, linux-sunxi@...glegroups.com,
        linux-mediatek@...ts.infradead.org,
        linux-amlogic@...ts.infradead.org, linuxppc-dev@...ts.ozlabs.org,
        cocci@...teme.lip6.fr, linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH v3 0/7] include: add
 setbits32/clrbits32/clrsetbits32/setbits64/clrbits64/clrsetbits64

On Wed, Oct 24, 2018 at 07:35:46AM +0000, Corentin Labbe wrote:
> This patchset adds a new set of functions which are open-coded in lot of
> place.
> Basicly the pattern is always the same, "read, modify a bit, write"
> some driver and the powerpc arch already have thoses pattern them as functions. (like ahci_sunxi.c or dwmac-meson8b)

The advantage of them being open-coded is that it's _obvious_ to the
reviewer that there is a read-modify-write going on which, in a multi-
threaded environment, may need some locking (so it should trigger a
review of the locking around that code.)

With it hidden inside a helper which has no locking itself, it becomes
much easier to pass over in review, which means that races are much
more likely to go unspotted - and that is bad news.

-- 
RMK's Patch system: http://www.armlinux.org.uk/developer/patches/
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