genirq/irqdomain: Remove auto-recursive hierarchy support

It did seem like a good idea at the time, but it never really
caught on, and auto-recursive domains remain unused 3 years after
having been introduced.

Oh well, time for a late spring cleanup.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

include/linux/irqdomain.h

@@ -180,8 +180,8 @@ enum {
 	/* Irq domain is hierarchical */
 	IRQ_DOMAIN_FLAG_HIERARCHY	= (1 << 0),
 
-	/* Core calls alloc/free recursive through the domain hierarchy. */
-	IRQ_DOMAIN_FLAG_AUTO_RECURSIVE	= (1 << 1),
+	/* Irq domain name was allocated in __irq_domain_add() */
+	IRQ_DOMAIN_NAME_ALLOCATED	= (1 << 6),
 
 	/* Irq domain is an IPI domain with virq per cpu */
 	IRQ_DOMAIN_FLAG_IPI_PER_CPU	= (1 << 2),
@@ -195,9 +195,6 @@ enum {
 	/* Irq domain implements MSI remapping */
 	IRQ_DOMAIN_FLAG_MSI_REMAP	= (1 << 5),
 
-	/* Irq domain name was allocated in __irq_domain_add() */
-	IRQ_DOMAIN_NAME_ALLOCATED	= (1 << 6),
-
 	/*
 	 * Flags starting from IRQ_DOMAIN_FLAG_NONCORE are reserved
 	 * for implementation specific purposes and ignored by the
@@ -448,7 +445,7 @@ static inline int irq_domain_alloc_irqs(struct irq_domain *domain,
 				       NULL);
 }
 
-extern int irq_domain_alloc_irqs_recursive(struct irq_domain *domain,
+extern int irq_domain_alloc_irqs_hierarchy(struct irq_domain *domain,
 					   unsigned int irq_base,
 					   unsigned int nr_irqs, void *arg);
 extern int irq_domain_set_hwirq_and_chip(struct irq_domain *domain,

kernel/irq/irqdomain.c

@@ -1342,43 +1342,18 @@ void irq_domain_free_irqs_top(struct irq_domain *domain, unsigned int virq,
 	irq_domain_free_irqs_common(domain, virq, nr_irqs);
 }
 
-static bool irq_domain_is_auto_recursive(struct irq_domain *domain)
-{
-	return domain->flags & IRQ_DOMAIN_FLAG_AUTO_RECURSIVE;
-}
-
-static void irq_domain_free_irqs_recursive(struct irq_domain *domain,
+static void irq_domain_free_irqs_hierarchy(struct irq_domain *domain,
 					   unsigned int irq_base,
 					   unsigned int nr_irqs)
 {
 	domain->ops->free(domain, irq_base, nr_irqs);
-	if (irq_domain_is_auto_recursive(domain)) {
-		BUG_ON(!domain->parent);
-		irq_domain_free_irqs_recursive(domain->parent, irq_base,
-					       nr_irqs);
-	}
 }
 
-int irq_domain_alloc_irqs_recursive(struct irq_domain *domain,
+int irq_domain_alloc_irqs_hierarchy(struct irq_domain *domain,
 				    unsigned int irq_base,
 				    unsigned int nr_irqs, void *arg)
 {
-	int ret = 0;
-	struct irq_domain *parent = domain->parent;
-	bool recursive = irq_domain_is_auto_recursive(domain);
-
-	BUG_ON(recursive && !parent);
-	if (recursive)
-		ret = irq_domain_alloc_irqs_recursive(parent, irq_base,
-						      nr_irqs, arg);
-	if (ret < 0)
-		return ret;
-
-	ret = domain->ops->alloc(domain, irq_base, nr_irqs, arg);
-	if (ret < 0 && recursive)
-		irq_domain_free_irqs_recursive(parent, irq_base, nr_irqs);
-
-	return ret;
+	return domain->ops->alloc(domain, irq_base, nr_irqs, arg);
 }
 
 /**
@@ -1439,7 +1414,7 @@ int __irq_domain_alloc_irqs(struct irq_domain *domain, int irq_base,
 	}
 
 	mutex_lock(&irq_domain_mutex);
-	ret = irq_domain_alloc_irqs_recursive(domain, virq, nr_irqs, arg);
+	ret = irq_domain_alloc_irqs_hierarchy(domain, virq, nr_irqs, arg);
 	if (ret < 0) {
 		mutex_unlock(&irq_domain_mutex);
 		goto out_free_irq_data;
@@ -1474,7 +1449,7 @@ void irq_domain_free_irqs(unsigned int virq, unsigned int nr_irqs)
 	mutex_lock(&irq_domain_mutex);
 	for (i = 0; i < nr_irqs; i++)
 		irq_domain_remove_irq(virq + i);
-	irq_domain_free_irqs_recursive(data->domain, virq, nr_irqs);
+	irq_domain_free_irqs_hierarchy(data->domain, virq, nr_irqs);
 	mutex_unlock(&irq_domain_mutex);
 
 	irq_domain_free_irq_data(virq, nr_irqs);
@@ -1494,15 +1469,11 @@ int irq_domain_alloc_irqs_parent(struct irq_domain *domain,
 				 unsigned int irq_base, unsigned int nr_irqs,
 				 void *arg)
 {
-	/* irq_domain_alloc_irqs_recursive() has called parent's alloc() */
-	if (irq_domain_is_auto_recursive(domain))
-		return 0;
+	if (!domain->parent)
+		return -ENOSYS;
 
-	domain = domain->parent;
-	if (domain)
-		return irq_domain_alloc_irqs_recursive(domain, irq_base,
-						       nr_irqs, arg);
-	return -ENOSYS;
+	return irq_domain_alloc_irqs_hierarchy(domain->parent, irq_base,
+					       nr_irqs, arg);
 }
 EXPORT_SYMBOL_GPL(irq_domain_alloc_irqs_parent);
 
@@ -1517,10 +1488,10 @@ EXPORT_SYMBOL_GPL(irq_domain_alloc_irqs_parent);
 void irq_domain_free_irqs_parent(struct irq_domain *domain,
 				 unsigned int irq_base, unsigned int nr_irqs)
 {
-	/* irq_domain_free_irqs_recursive() will call parent's free */
-	if (!irq_domain_is_auto_recursive(domain) && domain->parent)
-		irq_domain_free_irqs_recursive(domain->parent, irq_base,
-					       nr_irqs);
+	if (!domain->parent)
+		return;
+
+	irq_domain_free_irqs_hierarchy(domain->parent, irq_base, nr_irqs);
 }
 EXPORT_SYMBOL_GPL(irq_domain_free_irqs_parent);
 

kernel/irq/msi.c

@@ -315,7 +315,7 @@ int msi_domain_populate_irqs(struct irq_domain *domain, struct device *dev,
 
 		ops->set_desc(arg, desc);
 		/* Assumes the domain mutex is held! */
-		ret = irq_domain_alloc_irqs_recursive(domain, virq, 1, arg);
+		ret = irq_domain_alloc_irqs_hierarchy(domain, virq, 1, arg);
 		if (ret)
 			break;