[Ksummit-2010-discuss] [v2] Remaining BKL users, what to do

Steven Rostedt rostedt at goodmis.org
Tue Oct 19 06:43:52 PDT 2010

On Tue, 2010-10-19 at 15:36 +0200, Arnd Bergmann wrote:
> [trimming Cc list]
> On Tuesday 19 October 2010, Steven Rostedt wrote:
> > I think we also need to cover the PREEMPT case too. But that could be a
> > compile time check, since you can't boot a preempt kernel and make it
> > non preempt.
> Right. Can we turn the lock_kernel() into preempt_disable() in these
> drivers when we know we never run on SMP?

I'm not sure that will work. A holder of the BKL can call schedule or
even a mutex. The schedule code will drop the BKL and re-enable
preemption. Unless the code is known not to schedule while holding BKL,
we would need to open code the preempt_enable() around the locations
that the code may schedule.

-- Steve

More information about the dri-devel mailing list