Re: [tip: locking/core] lockdep: Annotate irq_work

From: Frederic Weisbecker
Date: Sat Mar 21 2020 - 22:40:01 EST


On Sun, Mar 22, 2020 at 03:33:30AM +0100, Frederic Weisbecker wrote:
> On Sat, Mar 21, 2020 at 07:12:49PM +0100, Sebastian Andrzej Siewior wrote:
> > On 2020-03-21 17:40:58 [+0100], Frederic Weisbecker wrote:
> > > > diff --git a/include/linux/irqflags.h b/include/linux/irqflags.h
> > > > index 9c17f9c..f23f540 100644
> > > > --- a/include/linux/irqflags.h
> > > > +++ b/include/linux/irqflags.h
> > > > @@ -69,6 +69,17 @@ do { \
> > > > current->irq_config = 0; \
> > > > } while (0)
> > > >
> > > > +# define lockdep_irq_work_enter(__work) \
> > > > + do { \
> > > > + if (!(atomic_read(&__work->flags) & IRQ_WORK_HARD_IRQ))\
> > > > + current->irq_config = 1; \
> > >
> > > So, irq_config == 1 means we are in a softirq? Are there other values for
> > > irq_config? In which case there should be enums or something?
> > > I can't find the patch that describes this.
> >
> > 0 means as-is, 1 means threaded / sleeping locks are okay.
>
> So that's the kind of comment we need :-)
>
> Also how about current->irq_locking instead?
>
> And something like:
>
> enum {
> IRQ_LOCKING_NO_SLEEP,
> IRQ_LOCKING_CAN_SLEEP
> }

Or current->irq_preemptible

enum {
IRQ_NEVER_PREEMPTIBLE,
IRQ_MAYBE_PREEMPTIBLE
}