diff mbox series

[v4,1/5] genirq/affinity: Add irq_update_affinity_desc()

Message ID 1606757759-6076-2-git-send-email-john.garry@huawei.com
State Accepted
Commit 1d3aec89286254487df7641c30f1b14ad1d127a5
Headers show
Series Support managed interrupts for platform devices | expand

Commit Message

John Garry Nov. 30, 2020, 5:35 p.m. UTC 
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 <tglx@linutronix.de>
Signed-off-by: John Garry <john.garry@huawei.com>
---
 include/linux/interrupt.h |  8 +++++
 kernel/irq/manage.c       | 63 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 71 insertions(+)

Comments

Thomas Gleixner Nov. 30, 2020, 11:19 p.m. UTC | #1 
On Tue, Dec 01 2020 at 01:35, John Garry wrote:

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

Could you please add a paragraph which explains the limitations of that
interface?

> +/**
> + * 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.

Same here.

Thanks,

        tglx
diff mbox series

Patch

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..791691cb9005 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_activate_irq(&desc->irq_data, false);
+
+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);