genirq: Add affinity to percpu_devid interrupt requests

Add an affinity field to both the irqaction structure and the interrupt
request primitives. Nothing is making use of it yet, and the only value
used it NULL, which is used as a shorthand for cpu_possible_mask.

This will shortly get used with actual affinities.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Will Deacon <will@kernel.org>
Link: https://patch.msgid.link/20251020122944.3074811-15-maz@kernel.org

Author: Marc Zyngier

include/linux/interrupt.h

@@ -125,6 +125,7 @@ struct irqaction {
 		void		*dev_id;
 		void __percpu	*percpu_dev_id;
 	};
+	const struct cpumask	*affinity;
 	struct irqaction	*next;
 	irq_handler_t		thread_fn;
 	struct task_struct	*thread;
@@ -181,7 +182,7 @@ request_any_context_irq(unsigned int irq, irq_handler_t handler,
 extern int __must_check
 __request_percpu_irq(unsigned int irq, irq_handler_t handler,
 		     unsigned long flags, const char *devname,
-		     void __percpu *percpu_dev_id);
+		     const cpumask_t *affinity, void __percpu *percpu_dev_id);
 
 extern int __must_check
 request_nmi(unsigned int irq, irq_handler_t handler, unsigned long flags,
@@ -192,7 +193,7 @@ request_percpu_irq(unsigned int irq, irq_handler_t handler,
 		   const char *devname, void __percpu *percpu_dev_id)
 {
 	return __request_percpu_irq(irq, handler, 0,
-				    devname, percpu_dev_id);
+				    devname, NULL, percpu_dev_id);
 }
 
 extern int __must_check

kernel/irq/manage.c

@@ -2444,10 +2444,14 @@ int setup_percpu_irq(unsigned int irq, struct irqaction *act)
 
 static
 struct irqaction *create_percpu_irqaction(irq_handler_t handler, unsigned long flags,
-					  const char *devname, void __percpu *dev_id)
+					  const char *devname, const cpumask_t *affinity,
+					  void __percpu *dev_id)
 {
 	struct irqaction *action;
 
+	if (!affinity)
+		affinity = cpu_possible_mask;
+
 	action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
 	if (!action)
 		return NULL;
@@ -2456,6 +2460,7 @@ struct irqaction *create_percpu_irqaction(irq_handler_t handler, unsigned long f
 	action->flags = flags | IRQF_PERCPU | IRQF_NO_SUSPEND;
 	action->name = devname;
 	action->percpu_dev_id = dev_id;
+	action->affinity = affinity;
 
 	return action;
 }
@@ -2466,6 +2471,7 @@ struct irqaction *create_percpu_irqaction(irq_handler_t handler, unsigned long f
  * @handler:	Function to be called when the IRQ occurs.
  * @flags:	Interrupt type flags (IRQF_TIMER only)
  * @devname:	An ascii name for the claiming device
+ * @affinity:	A cpumask describing the target CPUs for this interrupt
  * @dev_id:	A percpu cookie passed back to the handler function
  *
  * This call allocates interrupt resources, but doesn't enable the interrupt
@@ -2478,7 +2484,7 @@ struct irqaction *create_percpu_irqaction(irq_handler_t handler, unsigned long f
  */
 int __request_percpu_irq(unsigned int irq, irq_handler_t handler,
 			 unsigned long flags, const char *devname,
-			 void __percpu *dev_id)
+			 const cpumask_t *affinity, void __percpu *dev_id)
 {
 	struct irqaction *action;
 	struct irq_desc *desc;
@@ -2495,7 +2501,7 @@ int __request_percpu_irq(unsigned int irq, irq_handler_t handler,
 	if (flags && flags != IRQF_TIMER)
 		return -EINVAL;
 
-	action = create_percpu_irqaction(handler, flags, devname, dev_id);
+	action = create_percpu_irqaction(handler, flags, devname, affinity, dev_id);
 	if (!action)
 		return -ENOMEM;
 
@@ -2560,7 +2566,7 @@ int request_percpu_nmi(unsigned int irq, irq_handler_t handler,
 		return -EINVAL;
 
 	action = create_percpu_irqaction(handler, IRQF_NO_THREAD | IRQF_NOBALANCING,
-					 name, dev_id);
+					 name, NULL, dev_id);
 	if (!action)
 		return -ENOMEM;