Re: [PATCH 7/7] driver-core : convert semaphore to mutex in struct class

[Jarek Poplawski <jarkao2@gmail.com>]

On Fri, Jan 18, 2008 at 09:00:34AM +0100, Jarek Poplawski wrote:
> On Fri, Jan 18, 2008 at 09:42:25AM +0800, Dave Young wrote:
> ...
> > After digging the class usage code again, I found that the only
> > possible double lock place is the class_interface_register/unregister
> > in which the class_device api could be called.
> 
> OK, but currently after using mostly:
> mutex_lock(&parent_class)
> 
> and once:
> mutex_lock_nested(&parent_class, SINGLE_DEPTH_NESTING)
> 
> lockdep mostly thinks these parent classes are 2 different objects,
> with only 2 possible levels of nesting, so this parent_class has
> to have wrong name (2 parents can't be locked from the same thread,
> so maybe it's class_grandparent sometimes?).

...Hmm... I was probably wrong: this could be right if there are only
two levels of nesting used and class locks it's parent only!

Jarek P.