From: Hollis Blanchard <hollisb-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org>
To: Rusty Russell <rusty-8n+1lVoiYb80n/F98K4Iww@public.gmane.org>
Cc: Jan Beulich <JBeulich-Et1tbQHTxzrQT0dZR+AlfA@public.gmane.org>,
sfr-3FnU+UHB4dNDw9hX6IcOSA@public.gmane.org,
akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org,
linuxppc-dev-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org,
kvm-ppc-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-next-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: Re: linux-next: tree build failure
Date: Mon, 19 Oct 2009 18:29:53 -0700 [thread overview]
Message-ID: <1256002193.6546.2.camel@slab> (raw)
In-Reply-To: <200910201142.34006.rusty-8n+1lVoiYb80n/F98K4Iww@public.gmane.org>
On Tue, 2009-10-20 at 11:42 +1030, Rusty Russell wrote:
> On Tue, 20 Oct 2009 04:49:29 am Hollis Blanchard wrote:
> > On Thu, 2009-10-15 at 08:27 +0100, Jan Beulich wrote:
> > > My perspective is that it just uncovered already existing brokenness.
> >
> > Sorry, I thought it was clear, but to be more explicit: I propose the
> > following patch, which replaces the current BUILD_BUG_ON implementation
> > with Rusty's version.
>
> OK, I switched my brain back on. Yeah, I agree: we may still want
> BUILD_OR_RUNTIME_BUG_ON one day, but I like this.
>
> It's just missing the giant comment that it needs :)
>
> /**
> * BUILD_BUG_ON - break compile if a condition is true.
> * @cond: the condition which the compiler should know is false.
> *
> * If you have some code which relies on certain constants being equal, or
> * other compile-time-evaluated condition, you should use BUILD_BUG_ON to
> * detect if someone changes it.
> *
> * The implementation uses gcc's reluctance to create a negative array, but
> * gcc (as of 4.4) only emits that error for obvious cases (eg. not arguments
> * to inline functions). So as a fallback we use the optimizer; if it can't
> * prove the condition is false, it will cause a link error on the undefined
> * "__build_bug_on_failed". This error is less neat, and can be harder to
> * track down.
> */
Do you want to put together a signed-off patch Rusty? It's your code, so
I don't feel comfortable doing that.
Once we have that, can we remove the mysterious MAYBE_BUILD_BUG_ON
statements introduced in previous patches? (Does it BUG or doesn't it??)
--
Hollis Blanchard
IBM Linux Technology Center
next prev parent reply other threads:[~2009-10-20 1:29 UTC|newest]
Thread overview: 64+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-09-29 9:28 linux-next: tree build failure Jan Beulich
[not found] ` <4AC1E15502000078000516B5-Qfbpwmsw6RoS3W1tAdPHOtBPR1lH4CV8@public.gmane.org>
2009-09-29 9:51 ` roel kluin
[not found] ` <25e057c00909290251h55c0dc25o4ab1f2e84c920dca-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2009-09-30 6:29 ` Jan Beulich
2009-09-29 23:39 ` Hollis Blanchard
[not found] ` <1254267572.15622.1621.camel-yDUrRDS8jBVhsM67afOH+sxtgHpCUUYS@public.gmane.org>
2009-09-30 6:35 ` Jan Beulich
[not found] ` <4AC318450200007800017355-Qfbpwmsw6RoS3W1tAdPHOtBPR1lH4CV8@public.gmane.org>
2009-10-02 15:48 ` Hollis Blanchard
2009-10-05 6:58 ` Jan Beulich
2009-10-09 19:14 ` Hollis Blanchard
2009-10-14 22:57 ` Hollis Blanchard
2009-10-15 7:27 ` Jan Beulich
2009-10-19 18:19 ` Hollis Blanchard
2009-10-20 1:12 ` Rusty Russell
[not found] ` <200910201142.34006.rusty-8n+1lVoiYb80n/F98K4Iww@public.gmane.org>
2009-10-20 1:29 ` Hollis Blanchard [this message]
2009-10-20 3:45 ` [PATCH] BUILD_BUG_ON: make it handle more cases Rusty Russell
2009-10-20 13:58 ` Américo Wang
2009-10-20 14:43 ` Alan Jenkins
[not found] ` <9b2b86520910200743h4e134cf8jd2860d42b3936597-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2009-10-23 1:50 ` Américo Wang
[not found] ` <200910201415.34361.rusty-8n+1lVoiYb80n/F98K4Iww@public.gmane.org>
2009-10-22 21:04 ` Hollis Blanchard
2009-11-05 0:20 ` Stephen Rothwell
2009-11-05 6:28 ` Rusty Russell
[not found] ` <200911051658.36265.rusty-8n+1lVoiYb80n/F98K4Iww@public.gmane.org>
2009-11-05 6:37 ` Rusty Russell
2009-11-05 6:38 ` Stephen Rothwell
[not found] ` <20091105173842.c94ba501.sfr-3FnU+UHB4dNDw9hX6IcOSA@public.gmane.org>
2009-11-06 6:30 ` Rusty Russell
2009-10-29 21:30 ` Hollis Blanchard
2009-11-05 6:01 ` Benjamin Herrenschmidt
-- strict thread matches above, loose matches on Subject: below --
2009-12-16 7:21 linux-next: tree build failure Stephen Rothwell
2009-12-16 9:02 ` Felipe Balbi
2009-12-16 10:10 ` Liam Girdwood
2009-10-01 3:19 Stephen Rothwell
2009-10-01 7:58 ` Jens Axboe
2009-10-01 10:41 ` Stephen Rothwell
2009-09-24 5:21 Stephen Rothwell
[not found] ` <20090924152102.8d7d40cf.sfr-3FnU+UHB4dNDw9hX6IcOSA@public.gmane.org>
2009-09-29 0:00 ` Hollis Blanchard
2009-08-17 8:39 Stephen Rothwell
2009-08-03 0:35 Stephen Rothwell
2009-08-03 1:01 ` NeilBrown
2009-08-03 1:30 ` Stephen Rothwell
2009-07-27 7:53 Stephen Rothwell
2009-07-27 9:21 ` Karsten Keil
2009-07-27 15:06 ` David Miller
2009-07-28 4:22 ` Stephen Rothwell
2009-04-07 3:41 Stephen Rothwell
2009-04-07 10:00 ` Mark Brown
2009-04-08 1:48 ` Takashi Iwai
2009-03-23 9:38 Stephen Rothwell
2009-03-23 22:27 ` Mauro Carvalho Chehab
2009-03-23 23:25 ` Stephen Rothwell
2009-03-05 7:41 Stephen Rothwell
2009-03-06 5:01 ` Rusty Russell
2009-01-16 5:37 Stephen Rothwell
2009-01-16 7:25 ` Peter Zijlstra
2009-01-16 9:03 ` Ingo Molnar
2009-01-16 10:39 ` Stephen Rothwell
2009-01-16 10:53 ` Ingo Molnar
2009-01-16 11:53 ` Stephen Rothwell
2009-01-16 12:32 ` Ingo Molnar
2008-11-28 10:04 Stephen Rothwell
2008-11-28 10:25 ` Takashi Iwai
2008-11-28 10:43 ` Stephen Rothwell
2008-11-28 17:23 ` Takashi Iwai
2008-10-21 8:30 Stephen Rothwell
2008-08-25 10:33 Stephen Rothwell
2008-08-25 16:36 ` Steven Rostedt
2008-06-30 14:35 Stephen Rothwell
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