irqdomain: Move revmap_trees_mutex to struct irq_domain

The revmap_trees_mutex protects domain->revmap_tree.  There is no
need to make it global because it is allowed to modify revmap_tree
of two different domains concurrently.  Having said that, this would
not be a actual bottleneck because the interrupt map/unmap does not
occur quite often.  Rather, the motivation is to tidy up the code
from a data structure point of view.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

include/linux/irqdomain.h

@@ -32,6 +32,7 @@
 #include <linux/types.h>
 #include <linux/irqhandler.h>
 #include <linux/of.h>
+#include <linux/mutex.h>
 #include <linux/radix-tree.h>
 
 struct device_node;
@@ -176,6 +177,7 @@ struct irq_domain {
 	unsigned int revmap_direct_max_irq;
 	unsigned int revmap_size;
 	struct radix_tree_root revmap_tree;
+	struct mutex revmap_tree_mutex;
 	unsigned int linear_revmap[];
 };
 

kernel/irq/irqdomain.c

@@ -21,7 +21,6 @@
 static LIST_HEAD(irq_domain_list);
 static DEFINE_MUTEX(irq_domain_mutex);
 
-static DEFINE_MUTEX(revmap_trees_mutex);
 static struct irq_domain *irq_default_domain;
 
 static void irq_domain_check_hierarchy(struct irq_domain *domain);
@@ -211,6 +210,7 @@ struct irq_domain *__irq_domain_add(struct fwnode_handle *fwnode, int size,
 
 	/* Fill structure */
 	INIT_RADIX_TREE(&domain->revmap_tree, GFP_KERNEL);
+	mutex_init(&domain->revmap_tree_mutex);
 	domain->ops = ops;
 	domain->host_data = host_data;
 	domain->hwirq_max = hwirq_max;
@@ -462,9 +462,9 @@ static void irq_domain_clear_mapping(struct irq_domain *domain,
 	if (hwirq < domain->revmap_size) {
 		domain->linear_revmap[hwirq] = 0;
 	} else {
-		mutex_lock(&revmap_trees_mutex);
+		mutex_lock(&domain->revmap_tree_mutex);
 		radix_tree_delete(&domain->revmap_tree, hwirq);
-		mutex_unlock(&revmap_trees_mutex);
+		mutex_unlock(&domain->revmap_tree_mutex);
 	}
 }
 
@@ -475,9 +475,9 @@ static void irq_domain_set_mapping(struct irq_domain *domain,
 	if (hwirq < domain->revmap_size) {
 		domain->linear_revmap[hwirq] = irq_data->irq;
 	} else {
-		mutex_lock(&revmap_trees_mutex);
+		mutex_lock(&domain->revmap_tree_mutex);
 		radix_tree_insert(&domain->revmap_tree, hwirq, irq_data);
-		mutex_unlock(&revmap_trees_mutex);
+		mutex_unlock(&domain->revmap_tree_mutex);
 	}
 }
 
@@ -1459,11 +1459,11 @@ static void irq_domain_fix_revmap(struct irq_data *d)
 		return; /* Not using radix tree. */
 
 	/* Fix up the revmap. */
-	mutex_lock(&revmap_trees_mutex);
+	mutex_lock(&d->domain->revmap_tree_mutex);
 	slot = radix_tree_lookup_slot(&d->domain->revmap_tree, d->hwirq);
 	if (slot)
 		radix_tree_replace_slot(&d->domain->revmap_tree, slot, d);
-	mutex_unlock(&revmap_trees_mutex);
+	mutex_unlock(&d->domain->revmap_tree_mutex);
 }
 
 /**