Re: [PATCH 0/2] Provide a driver for the Apple Magic Mouse - opps

Jiri Kosina
2010-02-16T12:55:23Z

On Tue, 16 Feb 2010, Ed Tomlinson wrote:

> > Almost... you need to do hid_hw_stop() first and only then unregister
> > input device, Otherwise if you unload the module while moving the mouse
> > it is likely to still oops.
>
> The exit routing for the module also has a hid_hw_stop. Is it going to cause
> problems when it gets called twice?

The routine wasn't probably meant/designed with re-entrancy in mind, but
looking quickly at all the subsequent callpaths, I don't see why it should
cause any problem, as skb_queue_purge(), usb_kill_urb() and usb_free_urb()
should be safe.

Maybe we should even add test_bit() for HID_STARTED and HID_DISCONNECTED
at the beginning of the low-level drivers' ->stop callbacks, so that we
don't do all the magic when all the work has been already done.

--
Jiri Kosina
SUSE Labs, Novell Inc.