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Date: Mon, 23 Feb 2009 13:28:32 +0100
From: Ingo Molnar <mingo@elte.hu>
To: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Johannes Berg <johannes@sipsolutions.net>,
       Linus Torvalds <torvalds@linux-foundation.org>,
       LKML <linux-kernel@vger.kernel.org>,
       "Eric W. Biederman" <ebiederm@xmission.com>,
       Benjamin Herrenschmidt <benh@kernel.crashing.org>,
       Jeremy Fitzhardinge <jeremy@goop.org>,
       pm list <linux-pm@lists.linux-foundation.org>,
       Len Brown <lenb@kernel.org>, Jesse Barnes <jbarnes@virtuousgeek.org>,
       Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [RFC][PATCH 2/2] PM: Rework handling of interrupts during
	suspend-resume
Message-ID: <20090223122832.GB31427@elte.hu>
References: <200902221837.49396.rjw@sisk.pl> <200902230048.33635.rjw@sisk.pl> <20090223083645.GA9582@elte.hu> <200902231229.58743.rjw@sisk.pl>
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* Rafael J. Wysocki <rjw@sisk.pl> wrote:

> > > Index: linux-2.6/arch/x86/kernel/apm_32.c
> > > ===================================================================
> > > --- linux-2.6.orig/arch/x86/kernel/apm_32.c
> > > +++ linux-2.6/arch/x86/kernel/apm_32.c
> > 
> > > +
> > > +	suspend_device_irqs();
> > >  	device_power_down(PMSG_SUSPEND);
> > > +
> > > +	local_irq_disable();
> > 
> > hm, this is a very repetitive pattern, all around the various 
> > suspend/resume variants. Might make sense to make:
> > 
> >   	device_power_down(PMSG_SUSPEND);
> > 
> > do the irq line disabling plus the local irq disabling 
> > automatically. That also means it cannot be forgotten. The 
> > symmetric action should happen for PMSG_RESUME.
> > 
> > Is there ever a case where we want a different pattern?
> 
> Even if there's no such case, I prefer to call 
> local_irq_disable() explicitly in here, so that it's clearly 
> known where it happens to anyone reading this code.

That property can be implied in the function name:

   	device_power_down_irq_disable(PMSG_SUSPEND);

Open-coding it, if it looks the same in all the cases just 
increases the chances that someone somewhere copies them 
incorrectly.

	Ingo