Re: [PATCH RFC] apm-emulation: apm_mutex breaks ACK; remove it

["Rafael J. Wysocki" <rjw@sisk.pl>]

On Tuesday, May 17, 2011, Jiri Kosina wrote:
> On Tue, 17 May 2011, Jiri Kosina wrote:
> 
> > On Fri, 13 May 2011, Paul Parsons wrote:
> > 
> > > apm_mutex is locked by a process (e.g. apm -s) at the start of 
> > > apm_ioctl() and remains locked while pm_suspend() is called. Any 
> > > subsequent process trying to ACK the suspend (e.g. apmd) is then blocked 
> > > at the start of apm_ioctl(), causing the suspend to be delayed for 5 
> > > seconds in apm_suspend_notifier() while the ACK times out. In short, 
> > > ACKs don't work.
> > > 
> > > The driver's data structures are sufficiently protected by assorted 
> > > locks. And pm_suspend() has its own mutex to prevent reentrancy. 
> > > Consequently there is no obvious requirement for apm_mutex, which 
> > > evolved from earlier BKL calls. So let's remove it.
> > >
> > > 
> > > Signed-off-by: Paul Parsons <lost.distance@yahoo.com>
> > > ---
> > > This patch supersedes my previous "apm-emulation: Fix mutex race condition" patch; this patch fixes that earlier bug too.
> > 
> > Looks good to me (and sorry for the delay). Thanks Paul, will apply.
> 
> (unless Rafael sees any potential issue there of course ... but I myself 
> don't).

No, I don't.

Thanks,
Rafael