Re: [PATCH] Input: introduce managed input devices (add devres support)

On Wednesday, October 31, 2012 02:05:32 PM Tejun Heo wrote:

Hello, Dmitry.

On Mon, Oct 22, 2012 at 10:35:14PM -0700, Dmitry Torokhov wrote:

quoted

There is a demand from driver's writers to use managed devices framework
for their drivers. Unfortunately up to this moment input devices did not
provide support for managed devices and that lead to mixing two styles
of resource management which usually introduced more bugs, such as
manually unregistering input device but relying in devres to free
interrupt handler which (unless device is properly shut off) can cause
ISR to reference already freed memory.

This change introduces devm_input_allocate_device() that will allocate
managed instance of input device so that driver writers who prefer
using devm_* framework do not have to mix 2 styles.

It generally looks good to me although it's a bit unusual to use
devres on device.  Given the way input_dev is used, it probably makes
sense, I guess.

One thing tho.  If possible and there aren't too many, wouldn't it be
better to convert all to use devres.  Having two different lifetime
fules tends to lead to gotchas.

Not all drivers use devres for rest of their resources so it makes sense
to have unmanaged versions (like we have request_irq/devm_request_irq).
Besides:

[dtor@dtor-ws vmci]$ grep -r input_allocate_device drivers/ | wc -l
298

so I'd rather not ;)

Thanks.

-- 
Dmitry