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From:   David Laight <David.Laight@ACULAB.COM>
To:     'Joe Perches' <joe@perches.com>,
        Geert Uytterhoeven <geert@linux-m68k.org>,
        Al Viro <viro@zeniv.linux.org.uk>,
        Andrew Morton <akpm@linux-foundation.org>
CC:     Bernard Metzler <bmt@zurich.ibm.com>,
        Doug Ledford <dledford@redhat.com>,
        Jason Gunthorpe <jgg@ziepe.ca>,
        linux-rdma <linux-rdma@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: RE: [PATCH] RDMA/siw: Fix compiler warnings on 32-bit due to
 u64/pointer abuse
Thread-Topic: [PATCH] RDMA/siw: Fix compiler warnings on 32-bit due to
 u64/pointer abuse
Thread-Index: AQHVXQXl4BhhBlFhpEW57H2RBHAQPacQOptA
Date:   Wed, 28 Aug 2019 08:27:45 +0000
Message-ID: <ab04933a7dea42049d20597cb65d84f1@AcuMS.aculab.com>
References: <20190819100526.13788-1-geert@linux-m68k.org>
         <581e7d79ed75484beb227672b2695ff14e1f1e34.camel@perches.com>
         <CAMuHMdVh8dwd=77mHTqG80_D8DK+EtVGewRUJuaJzK1qRYrB+w@mail.gmail.com>
         <dbc03b4ac1ef4ba2a807409676cf8066@AcuMS.aculab.com>
         <CAMuHMdWHGTMwK+PO_BgsNZMpqRat1SHE-_CP0UqxEALA_OJeNg@mail.gmail.com>
         <20190827174639.GT1131@ZenIV.linux.org.uk>
         <CAMuHMdW0jEpE3YrA5Znq8O9e4eswARwYYerEhRLSLWxeXMbsEQ@mail.gmail.com>
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From: Joe Perches
> Sent: 27 August 2019 19:33
> On Tue, 2019-08-27 at 19:59 +0200, Geert Uytterhoeven wrote:
> > On Tue, Aug 27, 2019 at 7:46 PM Al Viro <viro@zeniv.linux.org.uk> wrote:
> > > On Tue, Aug 27, 2019 at 07:29:52PM +0200, Geert Uytterhoeven wrote:
> > > > On Tue, Aug 27, 2019 at 4:17 PM David Laight <David.Laight@aculab.com> wrote:
> > > > > From: Geert Uytterhoeven
> > > > > > Sent: 19 August 2019 18:15
> > > > > ...
> > > > > > > I think a cast to unsigned long is rather more common.
> > > > > > >
> > > > > > > uintptr_t is used ~1300 times in the kernel.
> > > > > > > I believe a cast to unsigned long is much more common.
> 
> btw: apparently that's not true.
> 
> This grep may be incomplete but it seems there are fewer
> kernel uses of a cast to unsigned long then pointer:
> 
> $ git grep -P '\(\s*\w+(\s+\w+){0,3}(\s*\*)+\s*\)\s*\(\s*unsigned\s+long\s*\)'|wc -l
> 423
> 
> Maybe add a cast_to_ptr macro like
> 
> #define cast_to_ptr(type, val)	((type)(uintptr_t)(val))
> 
> though that may not save any horizontal space

And it is another bit of pointless obfuscation....

	David

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