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Subject[PATCH 4/9] irq: only update affinity if set_affinity() sucessfully -v4

Impact: don't change smp_affinity if set_affinity fail

irq_set_affinity() and move_masked_irq() try to assign affinity
before calling chip set_affinity(). some archs are assigning again in set_affinity
again.

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

in the failing path, affinity should not be touched.

So try update the afffinity only if set_affinity return wth 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 to return int.
v4: update comments by removing moving irq_desc code.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>

---
kernel/irq/internals.h | 3 +++
kernel/irq/manage.c | 17 +++++++++++------
kernel/irq/migration.c | 14 +++++++++-----
3 files changed, 23 insertions(+), 11 deletions(-)
Index: linux-2.6/kernel/irq/internals.h
===================================================================
--- linux-2.6.orig/kernel/irq/internals.h
+++ linux-2.6/kernel/irq/internals.h
@@ -42,6 +42,9 @@ static inline void unregister_handler_pr

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:
*/
Index: linux-2.6/kernel/irq/manage.c
===================================================================
--- linux-2.6.orig/kernel/irq/manage.c
+++ linux-2.6/kernel/irq/manage.c
@@ -80,7 +80,7 @@ int irq_can_set_affinity(unsigned int ir
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, c
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;
Index: linux-2.6/kernel/irq/migration.c
===================================================================
--- linux-2.6.orig/kernel/irq/migration.c
+++ linux-2.6/kernel/irq/migration.c
@@ -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);
}


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