linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Linus Torvalds <torvalds@linux-foundation.org>
To: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Aaro Koskinen <aaro.koskinen@iki.fi>,
	Andrew Pinski <pinskia@gmail.com>,
	Sasha Levin <sasha.levin@oracle.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] kernel: use the gnu89 standard explicitly
Date: Sun, 19 Oct 2014 16:49:16 -0700	[thread overview]
Message-ID: <CA+55aFxf6_cA5hTtDGqPU4=DkKz_6OUizhiqge+Xf5u34RxeXw@mail.gmail.com> (raw)
In-Reply-To: <20141019231031.GB9319@node.dhcp.inet.fi>

On Sun, Oct 19, 2014 at 4:10 PM, Kirill A. Shutemov
<kirill@shutemov.name> wrote:
>
> IIUC, it's nothing to do with volatile. C11 and above reads
>
>         (rwlock_t) { .raw_lock = { 0 }, }
>
> as compound literal (which is not constant) rather than constant
> initalizer plus a cast.

Ahh. I thought it was the volatile, just because of the "constant"
part and the fact that it looked like the test-case was minimal. But
apparently that was just a red herring.

So it's just the fact that C11 hasn't got the useful GNU extension of
a cast-with-initializer, and then that extension got removed (probably
just an oversight) because people thought that the "standard" C11
initializers were good enough.

And it sounds like this will get fixed (perhaps already is) in gcc anyway.

So maybe we need to do that "--std=gnu89" as a temporary workaround,
but not as long long-term "newer versions are broken".

That doesn't sound too bad. My main objection to the patch was a
"let's try to fix this properly instead", but if the breakage is just
a temporary problem, there's no issue with "properly". Although it
does look like the *placement* of the --std=gnu89 was incorrect in
that original patch, so it needs updating regardless.

AndrewP, mind explaing the other difference you mentioned (ie wrt
"extern inline")? I thought we had already long since ended up
following the gcc semantics (ie use "static inline" if we don't have
an external version somehwre), what exactly changed?

Thanks,

                       Linus

  parent reply	other threads:[~2014-10-19 23:49 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-10-19 16:07 [PATCH] kernel: use the gnu89 standard explicitly Sasha Levin
2014-10-19 20:05 ` Linus Torvalds
2014-10-19 20:23   ` Joe Perches
     [not found]     ` <CA+55aFwbq4TtQXC9PTjOF3UPP7u8XH1mSYjvT7pevKcQBfy25A@mail.gmail.com>
2014-10-19 21:31       ` Joe Perches
2014-10-19 21:03   ` Aaro Koskinen
2014-10-19 23:05     ` Linus Torvalds
2014-10-19 23:10       ` Kirill A. Shutemov
2014-10-19 23:19         ` Al Viro
2014-10-19 23:21         ` Kirill A. Shutemov
2014-10-19 23:26           ` Al Viro
2014-10-19 23:49         ` Linus Torvalds [this message]
2014-10-19 23:59           ` Sasha Levin
2014-10-20  0:23             ` Linus Torvalds
2014-10-20  4:16               ` Al Viro
2014-10-19 23:25       ` pinskia
2014-10-19 23:52   ` Sasha Levin
2014-10-19 22:29 ` Kirill A. Shutemov

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='CA+55aFxf6_cA5hTtDGqPU4=DkKz_6OUizhiqge+Xf5u34RxeXw@mail.gmail.com' \
    --to=torvalds@linux-foundation.org \
    --cc=aaro.koskinen@iki.fi \
    --cc=akpm@linux-foundation.org \
    --cc=kirill@shutemov.name \
    --cc=linux-kernel@vger.kernel.org \
    --cc=pinskia@gmail.com \
    --cc=sasha.levin@oracle.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).