Date: Fri, 3 Jun 2011 18:25:01 +0200 (CEST)
From: Thomas Gleixner <tglx@linutronix.de>
To: Milton Miller <miltonm@bga.com>
cc: Mark Brown <broonie@opensource.wolfsonmicro.com>,
        linux-kernel@vger.kernel.org
Subject: Re: genirq: Ensure we locate the passed IRQ in irq_alloc_descs()
In-Reply-To: <locate-from-more@mdm.bga.com>
Message-ID: <alpine.LFD.2.02.1106031823310.3078@ionos>
References: <1307037313-15733-1-git-send-email-broonie@opensource.wolfsonmicro.com> <nack-locate@mdm.bga.com> <20110603104217.GA4777@opensource.wolfsonmicro.com> <locate-from-more@mdm.bga.com>
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On Fri, 3 Jun 2011, Milton Miller wrote:

> On Fri, 3 Jun 2011 about 11:42:17 +0100, Mark Brown wrote:
> > On Fri, Jun 03, 2011 at 04:24:02AM -0500, Milton Miller wrote:
> > > On Thu, 02 Jun 2011 17:55:13 -0000, Mark Brown wrote:
> > 
> > > >  	start = bitmap_find_next_zero_area(allocated_irqs, IRQ_BITMAP_BITS,
> > 
> > > and then right after this the code continues:
> > 
> > >         ret = -EEXIST;
> > >         if (irq >=0 && start != irq)
> > >                 goto err;
> > 
> > > This patch enables exactly the calls I want to forbid !  Why do
> > 
> > Which you wish to forbid because...?  You've not articulated any
> > motivation for doing this which makes it rather hard to engage here.
> 
> In 2.6.39 all calls to irq_alloc_descs were from the helpers.  Either
> from  irq_alloc_descriptor_at , which says "I need this exact irq",
> or from irq_alloc_desc, which says "give me any irq".

That does not prevent a caller with uses irq_alloc_descs() directly
with the wrong arguments. So we want to sanity check this.
 
Thanks,

	tglx
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