From: LABBE Corentin <clabbe@baylibre•com>
To: Russell King - ARM Linux <linux@armlinux•org.uk>
Cc: Gilles.Muller@lip6•fr, Julia.Lawall@lip6•fr, agust@denx•de,
airlied@linux•ie, alexandre.torgue@st•com, alistair@popple•id.au,
benh@kernel•crashing.org, carlo@caione•org, davem@davemloft•net,
galak@kernel•crashing.org, joabreu@synopsys•com,
khilman@baylibre•com, matthias.bgg@gmail•com,
maxime.ripard@bootlin•com, michal.lkml@markovi•net,
mpe@ellerman•id.au, mporter@kernel•crashing.org,
narmstrong@baylibre•com, nicolas.palix@imag•fr, oss@buserror•net,
paulus@samba•org, peppe.cavallaro@st•com, tj@kernel•org,
vitb@kernel•crashing.org, wens@csie•org, netdev@vger•kernel.org,
linux-kernel@vger•kernel.org, dri-devel@lists•freedesktop.org,
linux-ide@vger•kernel.org, linux-sunxi@googlegroups•com,
linux-mediatek@lists•infradead.org,
linux-amlogic@lists•infradead.org, linuxppc-dev@lists•ozlabs.
Subject: Re: [PATCH v3 0/7] include: add setbits32/clrbits32/clrsetbits32/setbits64/clrbits64/clrsetbits64
Date: Thu, 15 Nov 2018 10:30:34 +0100 [thread overview]
Message-ID: <20181115093034.GB23965@Red> (raw)
In-Reply-To: <20181024085700.GR30658@n2100.armlinux.org.uk>
On Wed, Oct 24, 2018 at 09:57:00AM +0100, Russell King - ARM Linux wrote:
> 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.
>
Hello
I understand your fear, but I think the benefit overhaul thoses.
Furthermore, drivers which I have converted does not need such locking.
If you want I can rename the header to linux/setbits-non-atomic.h for making obvious the lack of locking.
Regards
next prev parent reply other threads:[~2018-11-15 9:30 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-24 7:35 [PATCH v3 0/7] include: add setbits32/clrbits32/clrsetbits32/setbits64/clrbits64/clrsetbits64 Corentin Labbe
2018-10-24 7:35 ` [PATCH v3 1/7] powerpc: rename setbits32/clrbits32 to setbits_be32/clrbits_be32 Corentin Labbe
2018-10-24 7:35 ` [PATCH v3 2/7] include: add setbits_leXX/clrbits_leXX/clrsetbits_leXX in linux/setbits.h Corentin Labbe
2018-10-24 22:46 ` Jakub Kicinski
2018-10-24 7:35 ` [PATCH v3 3/7 DONOTMERGE] coccinelle: add xxxsetbits_leXX converting spatch Corentin Labbe
2018-10-24 7:35 ` [PATCH v3 4/7] ata: ahci_sunxi: use xxxsetbitsi_le32 functions Corentin Labbe
[not found] ` <1540366553-18541-5-git-send-email-clabbe-rdvid1DuHRBWk0Htik3J/w@public.gmane.org>
2018-10-24 7:57 ` Sergei Shtylyov
2018-10-24 7:35 ` [PATCH v3 5/7] net: ethernet: stmmac: dwmac-sun8i: use xxxsetbits_le32 Corentin Labbe
2018-10-24 7:35 ` [PATCH v3 6/7] drm: meson: " Corentin Labbe
2018-10-24 7:35 ` [PATCH v3 7/7] net: stmmac: dwmac-meson8b: " Corentin Labbe
2018-10-24 8:57 ` [PATCH v3 0/7] include: add setbits32/clrbits32/clrsetbits32/setbits64/clrbits64/clrsetbits64 Russell King - ARM Linux
2018-11-15 9:30 ` LABBE Corentin [this message]
2018-11-15 9:33 ` Russell King - ARM Linux
2018-11-15 12:24 ` LABBE Corentin
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