[ Upstream commit 471ba0e686cb13752bc1ff3216c54b69a2d250ea ] The QEMU PowerPC/PSeries machine model was not expecting a self-IPI, and it may be a bit surprising thing to do, so have irq_work_queue_on do local queueing when target is the current CPU.
Suggested-by: Steven Rostedt <rost...@goodmis.org> Reported-by: Sebastian Andrzej Siewior <bige...@linutronix.de> Tested-by: Sebastian Andrzej Siewior <bige...@linutronix.de> Signed-off-by: Nicholas Piggin <npig...@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <pet...@infradead.org> Reviewed-by: Frederic Weisbecker <frede...@kernel.org> Acked-by: Peter Zijlstra (Intel) <pet...@infradead.org> Cc: =?UTF-8?q?C=C3=A9dric=20Le=20Goater?= <c...@kaod.org> Cc: Linus Torvalds <torva...@linux-foundation.org> Cc: Paul Mackerras <pau...@samba.org> Cc: Peter Zijlstra <pet...@infradead.org> Cc: Suraj Jitindar Singh <sjitindarsi...@gmail.com> Cc: Thomas Gleixner <t...@linutronix.de> Link: https://lkml.kernel.org/r/20190409093403.20994-1-npig...@gmail.com [ Simplified the preprocessor comments. Fixed unbalanced curly brackets pointed out by Thomas. ] Signed-off-by: Ingo Molnar <mi...@kernel.org> Signed-off-by: Sasha Levin <sas...@kernel.org> --- kernel/irq_work.c | 75 ++++++++++++++++++++++++++--------------------- 1 file changed, 42 insertions(+), 33 deletions(-) diff --git a/kernel/irq_work.c b/kernel/irq_work.c index 6b7cdf17ccf89..73288914ed5e7 100644 --- a/kernel/irq_work.c +++ b/kernel/irq_work.c @@ -56,61 +56,70 @@ void __weak arch_irq_work_raise(void) */ } -/* - * Enqueue the irq_work @work on @cpu unless it's already pending - * somewhere. - * - * Can be re-enqueued while the callback is still in progress. - */ -bool irq_work_queue_on(struct irq_work *work, int cpu) +/* Enqueue on current CPU, work must already be claimed and preempt disabled */ +static void __irq_work_queue_local(struct irq_work *work) { - /* All work should have been flushed before going offline */ - WARN_ON_ONCE(cpu_is_offline(cpu)); - -#ifdef CONFIG_SMP - - /* Arch remote IPI send/receive backend aren't NMI safe */ - WARN_ON_ONCE(in_nmi()); + /* If the work is "lazy", handle it from next tick if any */ + if (work->flags & IRQ_WORK_LAZY) { + if (llist_add(&work->llnode, this_cpu_ptr(&lazy_list)) && + tick_nohz_tick_stopped()) + arch_irq_work_raise(); + } else { + if (llist_add(&work->llnode, this_cpu_ptr(&raised_list))) + arch_irq_work_raise(); + } +} +/* Enqueue the irq work @work on the current CPU */ +bool irq_work_queue(struct irq_work *work) +{ /* Only queue if not already pending */ if (!irq_work_claim(work)) return false; - if (llist_add(&work->llnode, &per_cpu(raised_list, cpu))) - arch_send_call_function_single_ipi(cpu); - -#else /* #ifdef CONFIG_SMP */ - irq_work_queue(work); -#endif /* #else #ifdef CONFIG_SMP */ + /* Queue the entry and raise the IPI if needed. */ + preempt_disable(); + __irq_work_queue_local(work); + preempt_enable(); return true; } +EXPORT_SYMBOL_GPL(irq_work_queue); -/* Enqueue the irq work @work on the current CPU */ -bool irq_work_queue(struct irq_work *work) +/* + * Enqueue the irq_work @work on @cpu unless it's already pending + * somewhere. + * + * Can be re-enqueued while the callback is still in progress. + */ +bool irq_work_queue_on(struct irq_work *work, int cpu) { +#ifndef CONFIG_SMP + return irq_work_queue(work); + +#else /* CONFIG_SMP: */ + /* All work should have been flushed before going offline */ + WARN_ON_ONCE(cpu_is_offline(cpu)); + /* Only queue if not already pending */ if (!irq_work_claim(work)) return false; - /* Queue the entry and raise the IPI if needed. */ preempt_disable(); - - /* If the work is "lazy", handle it from next tick if any */ - if (work->flags & IRQ_WORK_LAZY) { - if (llist_add(&work->llnode, this_cpu_ptr(&lazy_list)) && - tick_nohz_tick_stopped()) - arch_irq_work_raise(); + if (cpu != smp_processor_id()) { + /* Arch remote IPI send/receive backend aren't NMI safe */ + WARN_ON_ONCE(in_nmi()); + if (llist_add(&work->llnode, &per_cpu(raised_list, cpu))) + arch_send_call_function_single_ipi(cpu); } else { - if (llist_add(&work->llnode, this_cpu_ptr(&raised_list))) - arch_irq_work_raise(); + __irq_work_queue_local(work); } - preempt_enable(); return true; +#endif /* CONFIG_SMP */ } -EXPORT_SYMBOL_GPL(irq_work_queue); + bool irq_work_needs_cpu(void) { -- 2.20.1
