linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Masahiro Yamada <yamada.masahiro@socionext.com>
To: Matthias Kaehlcke <mka@chromium.org>
Cc: Michal Marek <mmarek@suse.com>,
	Linux Kbuild mailing list <linux-kbuild@vger.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Grant Grundler <grundler@chromium.org>,
	Greg Hackmann <ghackmann@google.com>,
	Michael Davidson <md@google.com>,
	masahiroy@kernel.org
Subject: Re: [PATCH 2/2] kbuild: clang: Disable the 'duplicate-decl-specifier' warning
Date: Sun, 30 Apr 2017 23:01:11 +0900	[thread overview]
Message-ID: <CAK7LNATD-KbP6GtV_j6NMgcPQYRigz5pA8fdos7hQSzQpL8czw@mail.gmail.com> (raw)
In-Reply-To: <20170421213931.155210-3-mka@chromium.org>

Hi Matthias,


2017-04-22 6:39 GMT+09:00 Matthias Kaehlcke <mka@chromium.org>:
> clang generates plenty of these warnings in different parts of the code.
> They are mostly caused by container_of() and other macros which declare
> a "const <type> *" variable for their internal use which triggers a
> "duplicate 'const' specifier" warning if the <type> is already const
> qualified.
>
> Wording-mostly-from: Michael Davidson <md@google.com>
> Signed-off-by: Matthias Kaehlcke <mka@chromium.org>



I think container_of() can be more simple,
dropping the 'const'.

The following patch worked for me.


diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index 4c26dc3..d53672b 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -846,11 +846,9 @@ static inline void ftrace_dump(enum
ftrace_dump_mode oops_dump_mode) { }
  * @ptr:       the pointer to the member.
  * @type:      the type of the container struct this is embedded in.
  * @member:    the name of the member within the struct.
- *
  */
 #define container_of(ptr, type, member) ({                     \
-       const typeof( ((type *)0)->member ) *__mptr = (ptr);    \
-       (type *)( (char *)__mptr - offsetof(type,member) );})
+       (type *)((void *)(ptr) - offsetof(type, member));})

 /* Rebuild everything on CONFIG_FTRACE_MCOUNT_RECORD */
 #ifdef CONFIG_FTRACE_MCOUNT_RECORD



For also this one,
I'd like to try to fix the code rather than hiding warnings.

(We may end up with applying your patch after all,
but I'd like to think about it for now.)



-- 
Best Regards
Masahiro Yamada

  reply	other threads:[~2017-04-30 14:01 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-04-21 21:39 [PATCH 0/2] kbuild: clang: Disable spurious warnings Matthias Kaehlcke
2017-04-21 21:39 ` [PATCH 1/2] kbuild: clang: Disable 'address-of-packed-member' warning Matthias Kaehlcke
2017-04-30 13:59   ` Masahiro Yamada
2017-05-02  1:23     ` Matthias Kaehlcke
2017-05-06 16:52       ` Masahiro Yamada
2017-05-08 23:18         ` Matthias Kaehlcke
2017-05-16  6:31           ` Masahiro Yamada
2017-05-16 21:32   ` Doug Anderson
2017-06-22  1:19     ` Masahiro Yamada
2017-04-21 21:39 ` [PATCH 2/2] kbuild: clang: Disable the 'duplicate-decl-specifier' warning Matthias Kaehlcke
2017-04-30 14:01   ` Masahiro Yamada [this message]
2017-05-04 19:50     ` Matthias Kaehlcke
2017-05-08  8:29       ` Masahiro Yamada
2017-05-16 21:41   ` Doug Anderson
2017-05-17  7:35     ` Arnd Bergmann
2017-05-17 18:45       ` Matthias Kaehlcke
2017-05-24  0:04         ` Matthias Kaehlcke
2017-05-24  8:21           ` Arnd Bergmann
2017-06-21  9:11             ` Masahiro Yamada
2017-06-21 10:11               ` Arnd Bergmann
2017-06-21 16:58                 ` Matthias Kaehlcke
2017-06-21 17:59                   ` Arnd Bergmann
2017-06-21 21:19                     ` Matthias Kaehlcke
2017-07-31 16:35                     ` Matthias Kaehlcke

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=CAK7LNATD-KbP6GtV_j6NMgcPQYRigz5pA8fdos7hQSzQpL8czw@mail.gmail.com \
    --to=yamada.masahiro@socionext.com \
    --cc=ghackmann@google.com \
    --cc=grundler@chromium.org \
    --cc=linux-kbuild@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=masahiroy@kernel.org \
    --cc=md@google.com \
    --cc=mka@chromium.org \
    --cc=mmarek@suse.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).