Commit a77353e5 authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
Browse files

irq_work: Remove BUG_ON in irq_work_run() 



Because of a collision with 8d056c48 ("CPU hotplug, smp: flush any
pending IPI callbacks before CPU offline"), which ends up calling
hotplug_cfd()->flush_smp_call_function_queue()->irq_work_run(), which
is not from IRQ context.

And since that already calls irq_work_run() from the hotplug path,
remove our entire hotplug handling.

Reported-by: default avatarStephen Warren <swarren@wwwdotorg.org>
Tested-by: default avatarStephen Warren <swarren@wwwdotorg.org>
Reviewed-by: default avatarSrivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: default avatarPeter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/n/tip-busatzs2gvz4v62258agipuf@git.kernel.org


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 51da9830

kernel/irq_work.c

+4 −42
Original line number Diff line number Diff line
@@ -160,20 +160,14 @@ static void irq_work_run_list(struct llist_head *list) 
	}

}



static void __irq_work_run(void)

{

	irq_work_run_list(&__get_cpu_var(raised_list));

	irq_work_run_list(&__get_cpu_var(lazy_list));

}



/*

 * Run the irq_work entries on this cpu. Requires to be ran from hardirq

 * context with local IRQs disabled.

 * hotplug calls this through:

 *  hotplug_cfd() -> flush_smp_call_function_queue()

 */

void irq_work_run(void)

{

	BUG_ON(!in_irq());

	__irq_work_run();

	irq_work_run_list(&__get_cpu_var(raised_list));

	irq_work_run_list(&__get_cpu_var(lazy_list));

}

EXPORT_SYMBOL_GPL(irq_work_run);
@@ -189,35 +183,3 @@ void irq_work_sync(struct irq_work *work) 
		cpu_relax();

}

EXPORT_SYMBOL_GPL(irq_work_sync);
 


#ifdef CONFIG_HOTPLUG_CPU

static int irq_work_cpu_notify(struct notifier_block *self,

			       unsigned long action, void *hcpu)

{

	long cpu = (long)hcpu;



	switch (action) {

	case CPU_DYING:

		/* Called from stop_machine */

		if (WARN_ON_ONCE(cpu != smp_processor_id()))

			break;

		__irq_work_run();

		break;

	default:

		break;

	}

	return NOTIFY_OK;

}



static struct notifier_block cpu_notify;



static __init int irq_work_init_cpu_notifier(void)

{

	cpu_notify.notifier_call = irq_work_cpu_notify;

	cpu_notify.priority = 0;

	register_cpu_notifier(&cpu_notify);

	return 0;

}

device_initcall(irq_work_init_cpu_notifier);



#endif /* CONFIG_HOTPLUG_CPU */

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