From: Maarten Lankhorst <maarten.lankhorst@canonical.com>
To: Ingo Molnar <mingo@kernel.org>,
Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: peterz@infradead.org, imirkin@alum.mit.edu,
linux-kernel@vger.kernel.org, daniel.vetter@ffwll.ch,
robdclark@gmail.com
Subject: Re: [PATCH for 3.12] mutex: Avoid gcc version dependent__builtin_constant_p() usage.
Date: Fri, 18 Oct 2013 17:51:18 +0200 [thread overview]
Message-ID: <526158F6.5010909@canonical.com> (raw)
In-Reply-To: <20131018131326.GA24572@gmail.com>
op 18-10-13 15:13, Ingo Molnar schreef:
> * Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> wrote:
>
>> Peter Zijlstra wrote:
>>> On Thu, Oct 17, 2013 at 12:54:21PM +0200, Maarten Lankhorst wrote:
>>>> op 17-10-13 12:52, Peter Zijlstra schreef:
>>>>> On Thu, Oct 17, 2013 at 07:45:29PM +0900, Tetsuo Handa wrote:
>>>>>> Commit 040a0a37 "mutex: Add support for wound/wait style locks" used
>>>>>> "!__builtin_constant_p(p == NULL)" but gcc 3.x cannot handle such expression
>>>>>> correctly, leading to boot failure when built with CONFIG_DEBUG_MUTEXES=y.
>>>>> So I completely forgot all about this, but wouldn't something like:
>>>>>
>>>>> !(__builtin_constant_p(p) && p == NULL)
>>>>>
>>>>> Not also work and generate the same code?
>>>>>
>>>> See earlier discussion. It was already answered why that was undesirable. ;)
>>> OK; I forgot if we covered that particular option.. I so hate this
>>> patch; but I'm afraid we'll have to take it :-/
>>>
>> I see. Ingo, would you send this patch via your tree?
>> Then, I'll post a patch for 3.11-stable which differs white spaces.
> If it has Maarten's and PeterZ's Acked-by then sure.
>
> Thanks,
>
> Ingo
>
Acked. ;-)
next prev parent reply other threads:[~2013-10-18 15:51 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-10-17 10:45 [PATCH for 3.12] mutex: Avoid gcc version dependent __builtin_constant_p() usage Tetsuo Handa
2013-10-17 10:52 ` Peter Zijlstra
2013-10-17 10:54 ` Maarten Lankhorst
2013-10-17 11:02 ` Peter Zijlstra
2013-10-18 12:51 ` [PATCH for 3.12] mutex: Avoid gcc version dependent__builtin_constant_p() usage Tetsuo Handa
2013-10-18 13:13 ` Ingo Molnar
2013-10-18 15:51 ` Maarten Lankhorst [this message]
2013-10-30 13:14 ` [PATCH 3.11-stable] mutex: Avoid gcc version dependent __builtin_constant_p() usage Tetsuo Handa
2013-10-20 19:31 ` [tip:core/urgent] " tip-bot for Tetsuo Handa
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