2020-11-25 17:27:03

by John Garry

Subject: [PATCH v3 1/5] genirq/affinity: Add irq_update_affinity_desc()

Add a function to allow the affinity of an interrupt be switched to
managed, such that interrupts allocated for platform devices may be
managed.

Suggested-by: Thomas Gleixner <[email protected]>
Signed-off-by: John Garry <[email protected]>
---
include/linux/interrupt.h | 8 +++++
kernel/irq/manage.c | 63 +++++++++++++++++++++++++++++++++++++++
2 files changed, 71 insertions(+)

diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
index ee8299eb1f52..870b3251e174 100644
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -352,6 +352,8 @@ extern int irq_can_set_affinity(unsigned int irq);
extern int irq_select_affinity(unsigned int irq);

extern int irq_set_affinity_hint(unsigned int irq, const struct cpumask *m);
+extern int irq_update_affinity_desc(unsigned int irq,
+ struct irq_affinity_desc *affinity);

extern int
irq_set_affinity_notifier(unsigned int irq, struct irq_affinity_notify *notify);
@@ -387,6 +389,12 @@ static inline int irq_set_affinity_hint(unsigned int irq,
return -EINVAL;
}

+static inline int irq_update_affinity_desc(unsigned int irq,
+ struct irq_affinity_desc *affinity)
+{
+ return -EINVAL;
+}
+
static inline int
irq_set_affinity_notifier(unsigned int irq, struct irq_affinity_notify *notify)
{
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index c460e0496006..8201aff639f7 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -371,6 +371,69 @@ int irq_set_affinity_locked(struct irq_data *data, const struct cpumask *mask,
return ret;
}

+/**
+ * irq_update_affinity_desc - Update affinity management for an interrupt
+ * @irq: The interrupt number to update
+ * @affinity: Pointer to the affinity descriptor
+ *
+ * This interface can be used to configure the affinity management of
+ * interrupts which have been allocated already.
+ */
+int irq_update_affinity_desc(unsigned int irq,
+ struct irq_affinity_desc *affinity)
+{
+ struct irq_desc *desc;
+ unsigned long flags;
+ bool activated;
+ int ret = 0;
+
+ /*
+ * Supporting this with the reservation scheme used by x86 needs
+ * some more thought. Fail it for now.
+ */
+ if (IS_ENABLED(CONFIG_GENERIC_IRQ_RESERVATION_MODE))
+ return -EOPNOTSUPP;
+
+ desc = irq_get_desc_buslock(irq, &flags, 0);
+ if (!desc)
+ return -EINVAL;
+
+ /* Requires the interrupt to be shut down */
+ if (irqd_is_started(&desc->irq_data)) {
+ ret = -EBUSY;
+ goto out_unlock;
+ }
+
+ /* Interrupts which are already managed cannot be modified */
+ if (irqd_affinity_is_managed(&desc->irq_data)) {
+ ret = -EBUSY;
+ goto out_unlock;
+ }
+
+ /*
+ * Deactivate the interrupt. That's required to undo
+ * anything an earlier activation has established.
+ */
+ activated = irqd_is_activated(&desc->irq_data);
+ if (activated)
+ irq_domain_deactivate_irq(&desc->irq_data);
+
+ if (affinity->is_managed) {
+ irqd_set(&desc->irq_data, IRQD_AFFINITY_MANAGED);
+ irqd_set(&desc->irq_data, IRQD_MANAGED_SHUTDOWN);
+ }
+
+ cpumask_copy(desc->irq_common_data.affinity, &affinity->mask);
+
+ /* Restore the activation state */
+ if (activated)
+ irq_domain_deactivate_irq(&desc->irq_data);
+
+out_unlock:
+ irq_put_desc_busunlock(desc, flags);
+ return ret;
+}
+
int __irq_set_affinity(unsigned int irq, const struct cpumask *mask, bool force)
{
struct irq_desc *desc = irq_to_desc(irq);
--
2.26.2

2020-11-26 10:59:30

by Daniel Wagner

Subject: Re: [PATCH v3 1/5] genirq/affinity: Add irq_update_affinity_desc()

Hi John,

On Thu, Nov 26, 2020 at 01:20:37AM +0800, John Garry wrote:
> + activated = irqd_is_activated(&desc->irq_data);
> + if (activated)
> + irq_domain_deactivate_irq(&desc->irq_data);
> +
> + if (affinity->is_managed) {
> + irqd_set(&desc->irq_data, IRQD_AFFINITY_MANAGED);
> + irqd_set(&desc->irq_data, IRQD_MANAGED_SHUTDOWN);
> + }
> +
> + cpumask_copy(desc->irq_common_data.affinity, &affinity->mask);
> +
> + /* Restore the activation state */
> + if (activated)
> + irq_domain_deactivate_irq(&desc->irq_data);

Shouldn't this be irq_domain_activate_irq() ?

Thanks,
Daniel

2020-11-26 11:02:37

by John Garry

Subject: Re: [PATCH v3 1/5] genirq/affinity: Add irq_update_affinity_desc()

Hi Daniel,

>
> On Thu, Nov 26, 2020 at 01:20:37AM +0800, John Garry wrote:
>> + activated = irqd_is_activated(&desc->irq_data);
>> + if (activated)
>> + irq_domain_deactivate_irq(&desc->irq_data);
>> +
>> + if (affinity->is_managed) {
>> + irqd_set(&desc->irq_data, IRQD_AFFINITY_MANAGED);
>> + irqd_set(&desc->irq_data, IRQD_MANAGED_SHUTDOWN);
>> + }
>> +
>> + cpumask_copy(desc->irq_common_data.affinity, &affinity->mask);
>> +
>> + /* Restore the activation state */
>> + if (activated)
>> + irq_domain_deactivate_irq(&desc->irq_data);
> Shouldn't this be irq_domain_activate_irq() ?

Yeah, I think so. Blushes.

Cheers,
John