linux-kernel - Re: [PATCH 07/11] mfd: menelaus: use devm_request_irq() and devm

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Date:	Wed, 20 Feb 2013 00:36:29 -0800
From:	Dmitry Torokhov <dmitry.torokhov@...il.com>
To:	Jingoo Han <jg1.han@...sung.com>
Cc:	'Samuel Ortiz' <sameo@...ux.intel.com>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 07/11] mfd: menelaus: use devm_request_irq() and
 devm_kzalloc()

On Wed, Feb 20, 2013 at 05:17:30PM +0900, Jingoo Han wrote:
> On Wednesday, February 20, 2013 5:10 PM, Dmitry Torokhov wrote:
> > 
> > On Wed, Feb 20, 2013 at 05:05:10PM +0900, Jingoo Han wrote:
> > > On Wednesday, February 20, 2013 4:31 PM, Dmitry Torokhov wrote:
> > > >
> > > > Hi Jongoo,
> > > >
> > > > On Wed, Feb 20, 2013 at 03:12:38PM +0900, Jingoo Han wrote:
> > > > > Use devm_request_irq() and devm_kzalloc() to make cleanup paths
> > > > > more simple.
> > > > >
> > > >
> > > > ...
> > > >
> > > > > @@ -1269,9 +1266,7 @@ static int __exit menelaus_remove(struct i2c_client *client)
> > > > >  {
> > > > >  	struct menelaus_chip	*menelaus = i2c_get_clientdata(client);
> > > > >
> > > > > -	free_irq(client->irq, menelaus);
> > > > >  	flush_work(&menelaus->work);
> > > > > -	kfree(menelaus);
> > > > >  	the_menelaus = NULL;
> > > > >  	return 0;
> > > >
> > > > This conversion is certainly wrong - you really want to disable IRQ and
> > > > then wait for the scheduled work to finish before freeing memory. Here
> > > > you flush work but nothing stops IRQ from firing and scheduling that
> > > > work again.
> > >
> > > Yes, you're right.
> > > I will use devm_free_irq() before flush_work().
> > 
> > Why change it at all if you have to call it manually in both error
> > unwinding and menelaus_remove() cases?
> > 
> > BTW, that __exit markup on menelaus_remove() is surprising... I am
> > pretty sure it can be unbound via sysfs and so there will be a nasty
> > oops.
> 
> I see, I will not modify this menelaus mfd driver.
> Thank you.

Same goes for the other drivers that can't safely use devm_request_irq()
please.

Thanks.

-- 
Dmitry
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