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Commit 57b150cc authored by Yinghai Lu's avatar Yinghai Lu Committed by Ingo Molnar
Browse files

irq: only update affinity if ->set_affinity() is sucessfull 



irq_set_affinity() and move_masked_irq() try to assign affinity
before calling chip set_affinity(). Some archs are assigning it
in ->set_affinity() again.

We do something like:

 cpumask_cpy(desc->affinity, mask);
 desc->chip->set_affinity(mask);

But in the failure path, affinity should not be touched - otherwise
we'll end up with a different affinity mask despite the failure to
migrate the IRQ.

So try to update the afffinity only if set_affinity returns with 0.
Also call irq_set_thread_affinity accordingly.

v2: update after "irq, x86: Remove IRQ_DISABLED check in process context IRQ move"
v3: according to Ingo, change set_affinity() in irq_chip should return int.
v4: update comments by removing moving irq_desc code.

[ Impact: fix /proc/irq/*/smp_affinity setting corner case bug ]

Signed-off-by: default avatarYinghai Lu <yinghai@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
LKML-Reference: <49F65509.60307@kernel.org>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent d5dedd45

kernel/irq/internals.h

+3 −0
Original line number Diff line number Diff line
@@ -42,6 +42,9 @@ static inline void unregister_handler_proc(unsigned int irq, 


extern int irq_select_affinity_usr(unsigned int irq);



extern void

irq_set_thread_affinity(struct irq_desc *desc, const struct cpumask *cpumask);



/*

 * Debugging printout:

 */

kernel/irq/manage.c

+11 −6
Original line number Diff line number Diff line
@@ -80,7 +80,7 @@ int irq_can_set_affinity(unsigned int irq) 
	return 1;

}



static void

void

irq_set_thread_affinity(struct irq_desc *desc, const struct cpumask *cpumask)

{

	struct irqaction *action = desc->action;
@@ -109,17 +109,22 @@ int irq_set_affinity(unsigned int irq, const struct cpumask *cpumask) 
	spin_lock_irqsave(&desc->lock, flags);



#ifdef CONFIG_GENERIC_PENDING_IRQ

	if (desc->status & IRQ_MOVE_PCNTXT)

		desc->chip->set_affinity(irq, cpumask);

	if (desc->status & IRQ_MOVE_PCNTXT) {

		if (!desc->chip->set_affinity(irq, cpumask)) {

			cpumask_copy(desc->affinity, cpumask);

			irq_set_thread_affinity(desc, cpumask);

		}

	}

	else {

		desc->status |= IRQ_MOVE_PENDING;

		cpumask_copy(desc->pending_mask, cpumask);

	}

#else

	if (!desc->chip->set_affinity(irq, cpumask)) {

		cpumask_copy(desc->affinity, cpumask);

	desc->chip->set_affinity(irq, cpumask);

#endif

		irq_set_thread_affinity(desc, cpumask);

	}

#endif

	desc->status |= IRQ_AFFINITY_SET;

	spin_unlock_irqrestore(&desc->lock, flags);

	return 0;

kernel/irq/migration.c

+9 −5
Original line number Diff line number Diff line 


#include <linux/irq.h>

#include <linux/interrupt.h>



#include "internals.h"



void move_masked_irq(int irq)

{
@@ -39,11 +42,12 @@ void move_masked_irq(int irq) 
	 * masking the irqs.

	 */

	if (likely(cpumask_any_and(desc->pending_mask, cpu_online_mask)

		   < nr_cpu_ids)) {

		cpumask_and(desc->affinity,

			    desc->pending_mask, cpu_online_mask);

		desc->chip->set_affinity(irq, desc->affinity);

		   < nr_cpu_ids))

		if (!desc->chip->set_affinity(irq, desc->pending_mask)) {

			cpumask_copy(desc->affinity, desc->pending_mask);

			irq_set_thread_affinity(desc, desc->pending_mask);

		}



	cpumask_clear(desc->pending_mask);

}