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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>
This commit is contained in:
Yinghai Lu 2009-04-27 17:59:53 -07:00 committed by Ingo Molnar
parent d5dedd4507
commit 57b150cce8
3 changed files with 23 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
kernel/irq/internals.h
View File

@ -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:
*/

17
kernel/irq/manage.c
View File

@ -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
cpumask_copy(desc->affinity, cpumask);
desc->chip->set_affinity(irq, cpumask);
if (!desc->chip->set_affinity(irq, cpumask)) {
cpumask_copy(desc->affinity, cpumask);
irq_set_thread_affinity(desc, cpumask);
}
#endif
irq_set_thread_affinity(desc, cpumask);
desc->status |= IRQ_AFFINITY_SET;
spin_unlock_irqrestore(&desc->lock, flags);
return 0;

14
kernel/irq/migration.c
View File

@ -1,5 +1,8 @@
#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);
}