Re: [PATCH 2/3] Input: wm831x-ts - Convert to devm_kzalloc()

[Dmitry Torokhov <dmitry.torokhov@gmail.com>]

On Thu, Oct 11, 2012 at 05:33:24PM +0900, Mark Brown wrote:
> On Thu, Oct 11, 2012 at 01:27:49AM -0700, Dmitry Torokhov wrote:
> > On Thu, Oct 11, 2012 at 05:07:24PM +0900, Mark Brown wrote:
> 
> > > 
> > > What's the error pattern you're seeing?  I've not noticed much of an
> > > issue here, but if there is one perhaps we can do something to make the
> > > error more obvious or harder to introduce.
> 
> > 	devm_request_irq();
> 
> > The problem is that input device is freed but interrupts are still fully
> > functional.
> 
> Ah, yes - that one I do spot all the time.  I agree that devm_request_irq()
> is a menace, that error is far too easy to introduce and it always seems
> more work to work out if it's safe than the benefit in the cases where
> it can be used.

Right. Another one (the IRQ again): have IRQ schedule [delayed] work and
then use cancel_delayed_work() in ->remove() but rely on devres to free
IRQ which is the wrong order.

> 
> The other devm APIs are less problematic, though.

I agree, they are indeed safer. I guess if I add devm_input* the some of
the devm_request_*irq() will be safe as well, but we are not there yet.

-- 
Dmitry