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Date: Wed, 8 Jan 2020 10:07:32 +0100
From: Krzysztof Kozlowski <krzk@kernel.org>
Subject: Re: [RFT 02/13] alpha: Constify ioreadX() iomem argument (as in
 generic implementation)
Message-ID: <20200108090732.GA10145@pi3>
References: <1578415992-24054-1-git-send-email-krzk@kernel.org>
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To: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Richard Henderson <rth@twiddle.net>, Ivan Kokshaysky <ink@jurassic.park.msu.ru>, Matt Turner <mattst88@gmail.com>, Alexey Brodkin <abrodkin@synopsys.com>, Vineet Gupta <vgupta@synopsys.com>, "James E.J. Bottomley" <James.Bottomley@hansenpartnership.com>, Helge Deller <deller@gmx.de>, Benjamin Herrenschmidt <benh@kernel.crashing.org>, Paul Mackerras <paulus@samba.org>, Michael Ellerman <mpe@ellerman.id.au>, Yoshinori Sato <ysato@users.sourceforge.jp>, Rich Felker <dalias@libc.org>, Dave Airlie <airlied@redhat.com>, David Airlie <airlied@linux.ie>, Daniel Vetter <daniel@ffwll.ch>, Ben Skeggs <bskeggs@redhat.com>, Mauro Carvalho Chehab <mchehab@kernel.org>, Jiri Slaby <jirislaby@gmail.com>, Nick Kossifidis <mickflemm@gmail.com>, Luis Chamberlain <mcgrof@kernel.org>, Kalle Valo <kvalo@codeaurora.org>, "David S. Miller" <davem@davemloft.net>, Dave Jiang <dave.jiang@intel.com>, Jon Mason <jdmason@kudzu.us>, Allen Hubbe <allenbh@gmail.com>, "Michael S. Tsirkin" <mst@redhat.com>, Jason Wang <jasowang@redhat.com>, Arnd Bergmann <arnd@arndb.de>, Andrew Morton <akpm@linux-foundation.org>, Thomas Gleixner <tglx@linutronix.de>, alpha <linux-alpha@vger.kernel.org>, Linux Kernel Mailing List <linux-kernel@vger.kernel.org>, arcml <linux-snps-arc@lists.infradead.org>, Parisc List <linux-parisc@vger.kernel.org>, linuxppc-dev <linuxppc-dev@lists.ozlabs.org>, Linux-sh list <linux-sh@vger.kernel.org>, DRI Development <dri-devel@lists.freedesktop.org>, nouveau@lists.freedesktop.org, Linux Media Mailing List <linux-media@vger.kernel.org>, linux-wireless <linux-wireless@vger.kernel.org>, netdev <netdev@vger.kernel.org>, linux-ntb@googlegroups.com, virtualization@lists.linux-foundation.org, Linux-Arch <linux-arch@vger.kernel.org>
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On Wed, Jan 08, 2020 at 09:10:06AM +0100, Geert Uytterhoeven wrote:
> Hi Krzysztof,
> 
> On Tue, Jan 7, 2020 at 5:53 PM Krzysztof Kozlowski <krzk@kernel.org> wrote:
> > The ioreadX() helpers have inconsistent interface.  On some architectures
> > void *__iomem address argument is a pointer to const, on some not.
> >
> > Implementations of ioreadX() do not modify the memory under the address
> > so they can be converted to a "const" version for const-safety and
> > consistency among architectures.
> >
> > Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
> 
> > --- a/arch/alpha/include/asm/io.h
> > +++ b/arch/alpha/include/asm/io.h
> > @@ -151,9 +151,9 @@ static inline void generic_##NAME(TYPE b, QUAL void __iomem *addr)  \
> >         alpha_mv.mv_##NAME(b, addr);                                    \
> >  }
> >
> > -REMAP1(unsigned int, ioread8, /**/)
> > -REMAP1(unsigned int, ioread16, /**/)
> > -REMAP1(unsigned int, ioread32, /**/)
> > +REMAP1(unsigned int, ioread8, const)
> > +REMAP1(unsigned int, ioread16, const)
> > +REMAP1(unsigned int, ioread32, const)
> 
> If these would become "const volatile", there would no longer be a need
> for the last parameter of the REMAP1() macro.
> 
> >  REMAP1(u8, readb, const volatile)
> >  REMAP1(u16, readw, const volatile)
> >  REMAP1(u32, readl, const volatile)
> 
> Same for REMAP2() macro below, for iowrite*().

Good point, thanks!

Best regards,
Krzysztof