From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: "Aguirre, Sergio" <saaguirre@ti.com>
Cc: LKML <linux-kernel@vger.kernel.org>,
Huang Ying <ying.huang@intel.com>,
Martin Schwidefsky <schwidefsky@de.ibm.com>,
Ingo Molnar <mingo@elte.hu>, Kyle McMartin <kyle@mcmartin.ca>
Subject: RE: [RFC][PATCH] irq_work: Don't ignore possible cmpxchg failure
Date: Tue, 16 Nov 2010 18:08:46 +0100 [thread overview]
Message-ID: <1289927326.2109.631.camel@laptop> (raw)
In-Reply-To: <A24693684029E5489D1D202277BE89447382A55A@dlee02.ent.ti.com>
On Tue, 2010-11-16 at 10:57 -0600, Aguirre, Sergio wrote:
> > > @@ -145,7 +145,10 @@ void irq_work_run(void)
> > > * Clear the BUSY bit and return to the free state if
> > > * no-one else claimed it meanwhile.
> > > */
> > > - cmpxchg(&entry->next, next_flags(NULL, IRQ_WORK_BUSY), NULL);
> > > + xchgres = cmpxchg(&entry->next,
> > > + next_flags(NULL, IRQ_WORK_BUSY),
> > > + NULL);
> > > + BUG_ON(unlikely(xchgres != next_flags(NULL, IRQ_WORK_BUSY)));
> >
> > simply adding (void) in front would be much easier.
>
> But isn't that still leaving the remote possibility of a hidden cmpxchg
> Failure open?
No, we don't care if it fails, read the comment. All we want to know is
that if it still matched, we flipped the bit.
next prev parent reply other threads:[~2010-11-16 17:08 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-11-16 16:32 [RFC][PATCH] irq_work: Don't ignore possible cmpxchg failure Sergio Aguirre
2010-11-16 16:45 ` Peter Zijlstra
2010-11-16 16:57 ` Aguirre, Sergio
2010-11-16 17:08 ` Peter Zijlstra [this message]
2010-11-16 17:11 ` Aguirre, Sergio
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