> On Thu, May 07, 2015 at 12:50:53PM +0200, David Hildenbrand wrote: > > Just to make sure we have a common understanding (as written in my cover > > letter): > > > > Your suggestion won't work with !CONFIG_PREEMPT (!CONFIG_PREEMPT_COUNT). If > > there is no preempt counter, in_atomic() won't work. > > But there is, we _always_ have a preempt_count, and irq_enter() et al. > _always_ increment the relevant bits. > > The thread_info::preempt_count field it never under PREEMPT_COUNT > include/asm-generic/preempt.h provides stuff regardless of > PREEMPT_COUNT. > > See how __irq_enter() -> preempt_count_add(HARDIRQ_OFFSET) -> > __preempt_count_add() _always_ just works. > > Its only things like preempt_disable() / preempt_enable() that get > munged depending on PREEMPT_COUNT/PREEMPT. > Sorry for the confusion. Sure, there is always the count. My point is that preempt_disable() won't result in an in_atomic() == true with !PREEMPT_COUNT, so I don't see any point in adding in to the pagefault handlers. It is not reliable. David -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
