linux-kernel - Re: [patch] da9052-battery: don't free IRQ that wasn't requested

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Message-ID: <20120906150758.GL19410@mwanda>
Date:	Thu, 6 Sep 2012 08:07:58 -0700
From:	Dan Carpenter <dan.carpenter@...cle.com>
To:	walter harms <wharms@....de>
Cc:	Ashish Jangam <ashish.jangam@...tcummins.com>,
	Anton Vorontsov <cbou@...l.ru>,
	David Woodhouse <dwmw2@...radead.org>,
	linux-kernel@...r.kernel.org, kernel-janitors@...r.kernel.org
Subject: Re: [patch] da9052-battery: don't free IRQ that wasn't requested

On Wed, Sep 05, 2012 at 04:11:01PM +0200, walter harms wrote:
> 
> 
> Am 05.09.2012 14:34, schrieb Dan Carpenter:
> > We should decrement "i" before doing the free_irq().  If we call this
> > because request_threaded_irq() failed then we don't want to free the
> > thing which failed.  Or in the case where we get here because
> > power_supply_register() failed then the original codes does a read past
> > the end of the array.
> > 
> > Signed-off-by: Dan Carpenter <dan.carpenter@...cle.com>
> > 
> > diff --git a/drivers/power/da9052-battery.c b/drivers/power/da9052-battery.c
> > index 20b86ed..d9d034d 100644
> > --- a/drivers/power/da9052-battery.c
> > +++ b/drivers/power/da9052-battery.c
> > @@ -623,7 +623,7 @@ static s32 __devinit da9052_bat_probe(struct platform_device *pdev)
> >  	return 0;
> >  
> >  err:
> > -	for (; i >= 0; i--) {
> > +	while (--i >= 0) {
> >  		irq = platform_get_irq_byname(pdev, da9052_bat_irqs[i]);
> >  		free_irq(bat->da9052->irq_base + irq, bat);
> >  	}
> 
> hi da,
> (my usual nitpicking ...)

Ha ha.  Your nit picks are welcome even if I don't always agree.

> since a lot of people do make mistakes on count-down-loops, is there any chance to
> make this a common count-up-for()-loop ?
> like:

I like the count down loops...  It feels very natural to unwind that
way.

>    for (j=0; j <= i ;j++ ) {
               ^^^^^^
The count up loops are prone to the exact same off by one bugs.  ;)
You've got one in your sample code.  Plus I'd have to declare
another variable and send a v2 patch and I am very lazy...  So in
this case I think should just take my original patch.

regards,
dan carpenter

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