On Thu, 2015-04-23 at 09:12 +0200, Jan Kiszka wrote:
> On 2015-04-23 09:01, Mike Galbraith wrote:
> > On Thu, 2015-04-23 at 08:50 +0200, Jan Kiszka wrote:
> > > On 2015-04-23 08:11, Mike Galbraith wrote:
> > > > @@ -103,6 +98,9 @@ EXPORT_SYMBOL_GPL(irq_work_queue_on);
> > > > /* Enqueue the irq work @work on the current CPU */
> > > > bool irq_work_queue(struct irq_work *work)
> > > > {
> > > > + bool realtime = IS_ENABLED(CONFIG_PREEMPT_RT_FULL);
> > > > + bool raise = false;
> > > > +
> > > > /* Only queue if not already pending */
> > > > if (!irq_work_claim(work))
> > > > return false;
> > > > @@ -110,25 +108,22 @@ bool irq_work_queue(struct irq_work *wor
> > > > /* Queue the entry and raise the IPI if needed. */
> > > > preempt_disable();
> > > >
> > > > -#ifdef CONFIG_PREEMPT_RT_FULL
> > > > - if (work->flags & IRQ_WORK_HARD_IRQ) {
> > > > + if (realtime && (work->flags & IRQ_WORK_HARD_IRQ)) {
> > > > if (llist_add(&work->llnode,
> > > > this_cpu_ptr(&hirq_work_list)))
> > >
> > > This boils down to
> > >
> > > #ifdef CONFIG_X
> > > some_type x;
> > > #endif
> > > ...
> > >
> > > if (IS_ENABLED(CONFIG_X) && ...)
> > > use(x);
> > >
> > > And here we even have an indirection for IS_ENABLED via that
> > > local
> > > bool
> > > variable. Is that pattern OK for Linux? Does it compile in all
> > > supported
> > > optimization levels of all supported compilers?
> >
> > I hope it all goes away, that being what IS_ENABLED() is there for.
>
> Hope is good - but not enough here: it breaks the build under
> !CONFIG_X, even the case without the bool var.
>
> CC kernel/irq_work.o
> In file included from ../include/asm-generic/percpu.h:6:0,
> from ../arch/x86/include/asm/percpu.h:522,
> from ../arch/x86/include/asm/current.h:5,
> from ../arch/x86/include/asm/processor.h:15,
> from ../arch/x86/include/asm/irq_work.h:4,
> from ../include/linux/irq_work.h:47,
> from ../kernel/irq_work.c:11:
> ../kernel/irq_work.c: In function ‘irq_work_queue_on’:
> ../kernel/irq_work.c:85:17: error: ‘hirq_work_list’ undeclared
> (first use in this function)
> &per_cpu(hirq_work_list, cpu));
Aw poo, so that's just what I _thought_ it was for.
-Mike
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