From: Steve French <smfrench@gmail.com>
To: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: Steve French <sfrench@samba.org>,
CIFS <linux-cifs@vger.kernel.org>,
samba-technical <samba-technical@lists.samba.org>,
LKML <linux-kernel@vger.kernel.org>,
Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Subject: Re: [PATCH 1/2] cifs: remove unused status severity defines
Date: Thu, 14 Mar 2019 03:03:18 -0500 [thread overview]
Message-ID: <CAH2r5msU25CMDfTON2fSTpg5tmt7O_2sguFDL96b=vys5u+ViQ@mail.gmail.com> (raw)
In-Reply-To: <20190314073954.GA5272@jagdpanzerIV>
I am fine with taking a patch to get rid of __constant_cpu_to_XXX
(and converting to the same cpu_to_XXX with the "__constant") in
fs/cifs (assuming that that is still recommended).
On Thu, Mar 14, 2019 at 2:39 AM Sergey Senozhatsky
<sergey.senozhatsky.work@gmail.com> wrote:
>
> On (03/14/19 02:19), Steve French wrote:
> > All of those uses of __constant_cpu_to_le32 apparently (at least
> > according to checkpatch) should be changed (someday) to cpu_to_le32
> > but I didn't research why the change from __constant_cpu_to_le32
> > ---> cpu_to_le32
>
> Probably historic reasons.
>
> Looking at linux 2.4.21
>
> /*
> * Allow constant folding
> */
> #if defined(__GNUC__) && (__GNUC__ >= 2) && defined(__OPTIMIZE__)
> # define __swahw32(x) \
> (__builtin_constant_p((__u32)(x)) ? \
> ___swahw32((x)) : \
> __fswahw32((x)))
>
>
> My assumption would be that __GNUC__ < 2 did no support
> __builtin_constant_p?
>
>
> > If it has benefit - and checkpatch is right (it warned about
> > __constant_cpu_to_le32 being no longer preferred) ... perhaps would be
> > worth a followup patch to clean the rest of them up? If you have any
> > context on why kernel code has moved away from using the older format
> > of __constant_cpu_to_.... would be useful to know if any benefit to
> > the change
>
> Right, that's what I'm going to do - send out patches and update the rest
> of __constant_cpu_to_XX users; so, eventually, __constant_cpu_to_XX
> can be removed.
>
> -ss
--
Thanks,
Steve
next prev parent reply other threads:[~2019-03-14 8:03 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-14 6:17 [PATCH 1/2] cifs: remove unused status severity defines Sergey Senozhatsky
2019-03-14 6:17 ` [PATCH 2/2] cifs: don't use __constant_cpu_to_le32() Sergey Senozhatsky
2019-03-15 12:31 ` David Laight
2019-03-15 14:29 ` Sergey Senozhatsky
2019-03-14 6:54 ` [PATCH 1/2] cifs: remove unused status severity defines Steve French
2019-03-14 7:04 ` Steve French
2019-03-14 7:12 ` Sergey Senozhatsky
2019-03-14 7:19 ` Steve French
2019-03-14 7:39 ` Sergey Senozhatsky
2019-03-14 8:03 ` Steve French [this message]
2019-03-14 7:08 ` Sergey Senozhatsky
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