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linux-next/kernel/irq/migration.c
Yinghai Lu 57b150cce8 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: Yinghai 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: Ingo Molnar <mingo@elte.hu>
2009-04-28 12:21:16 +02:00

69 lines
1.5 KiB
C

#include <linux/irq.h>
#include <linux/interrupt.h>
#include "internals.h"
void move_masked_irq(int irq)
{
struct irq_desc *desc = irq_to_desc(irq);
if (likely(!(desc->status & IRQ_MOVE_PENDING)))
return;
/*
* Paranoia: cpu-local interrupts shouldn't be calling in here anyway.
*/
if (CHECK_IRQ_PER_CPU(desc->status)) {
WARN_ON(1);
return;
}
desc->status &= ~IRQ_MOVE_PENDING;
if (unlikely(cpumask_empty(desc->pending_mask)))
return;
if (!desc->chip->set_affinity)
return;
assert_spin_locked(&desc->lock);
/*
* If there was a valid mask to work with, please
* do the disable, re-program, enable sequence.
* This is *not* particularly important for level triggered
* but in a edge trigger case, we might be setting rte
* when an active trigger is comming in. This could
* cause some ioapics to mal-function.
* Being paranoid i guess!
*
* For correct operation this depends on the caller
* masking the irqs.
*/
if (likely(cpumask_any_and(desc->pending_mask, cpu_online_mask)
< 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);
}
void move_native_irq(int irq)
{
struct irq_desc *desc = irq_to_desc(irq);
if (likely(!(desc->status & IRQ_MOVE_PENDING)))
return;
if (unlikely(desc->status & IRQ_DISABLED))
return;
desc->chip->mask(irq);
move_masked_irq(irq);
desc->chip->unmask(irq);
}