irq_domain: constify irq_domain_ops

Make irq_domain_ops pointer a constant to make it safer for multiple
instances to share the same ops pointer and change the irq_domain code
so that it does not modify the ops.

v4: Fix mismatched type reference in powerpc code

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Milton Miller <miltonm@bga.com>
Tested-by: Olof Johansson <olof@lixom.net>

1 files changed, 15 insertions, 16 deletions

diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c
index 456e3fc8387f..25a498eb98a3 100644
--- a/kernel/irq/irqdomain.c
+++ b/kernel/irq/irqdomain.c
@@ -26,11 +26,6 @@ static DEFINE_MUTEX(revmap_trees_mutex);
 static unsigned int irq_virq_count = NR_IRQS;
 static struct irq_domain *irq_default_domain;
 
-static int default_irq_domain_match(struct irq_domain *d, struct device_node *np)
-{
-        return d->of_node != NULL && d->of_node == np;
-}
-
 /**
  * irq_domain_alloc() - Allocate a new irq_domain data structure
  * @of_node: optional device-tree node of the interrupt controller
@@ -44,7 +39,7 @@ static int default_irq_domain_match(struct irq_domain *d, struct device_node *np
  */
 static struct irq_domain *irq_domain_alloc(struct device_node *of_node,
                                            unsigned int revmap_type,
-                                           struct irq_domain_ops *ops,
+                                           const struct irq_domain_ops *ops,
                                            void *host_data)
 {
         struct irq_domain *domain;
@@ -59,9 +54,6 @@ static struct irq_domain *irq_domain_alloc(struct device_node *of_node,
         domain->host_data = host_data;
         domain->of_node = of_node_get(of_node);
 
-        if (domain->ops->match == NULL)
-                domain->ops->match = default_irq_domain_match;
-
         return domain;
 }
 
@@ -104,7 +96,7 @@ struct irq_domain *irq_domain_add_legacy(struct device_node *of_node,
                                          unsigned int size,
                                          unsigned int first_irq,
                                          irq_hw_number_t first_hwirq,
-                                         struct irq_domain_ops *ops,
+                                         const struct irq_domain_ops *ops,
                                          void *host_data)
 {
         struct irq_domain *domain;
@@ -170,7 +162,7 @@ struct irq_domain *irq_domain_add_legacy(struct device_node *of_node,
  */
 struct irq_domain *irq_domain_add_linear(struct device_node *of_node,
                                          unsigned int size,
-                                         struct irq_domain_ops *ops,
+                                         const struct irq_domain_ops *ops,
                                          void *host_data)
 {
         struct irq_domain *domain;
@@ -192,7 +184,7 @@ struct irq_domain *irq_domain_add_linear(struct device_node *of_node,
 }
 
 struct irq_domain *irq_domain_add_nomap(struct device_node *of_node,
-                                         struct irq_domain_ops *ops,
+                                         const struct irq_domain_ops *ops,
                                          void *host_data)
 {
         struct irq_domain *domain = irq_domain_alloc(of_node,
@@ -211,7 +203,7 @@ struct irq_domain *irq_domain_add_nomap(struct device_node *of_node,
  * (the reverse mapping will use the slow path until that happens).
  */
 struct irq_domain *irq_domain_add_tree(struct device_node *of_node,
-                                         struct irq_domain_ops *ops,
+                                         const struct irq_domain_ops *ops,
                                          void *host_data)
 {
         struct irq_domain *domain = irq_domain_alloc(of_node,
@@ -230,6 +222,7 @@ struct irq_domain *irq_domain_add_tree(struct device_node *of_node,
 struct irq_domain *irq_find_host(struct device_node *node)
 {
         struct irq_domain *h, *found = NULL;
+        int rc;
 
         /* We might want to match the legacy controller last since
          * it might potentially be set to match all interrupts in
@@ -237,11 +230,17 @@ struct irq_domain *irq_find_host(struct device_node *node)
          * yet though...
          */
         mutex_lock(&irq_domain_mutex);
-        list_for_each_entry(h, &irq_domain_list, link)
-                if (h->ops->match(h, node)) {
+        list_for_each_entry(h, &irq_domain_list, link) {
+                if (h->ops->match)
+                        rc = h->ops->match(h, node);
+                else
+                        rc = (h->of_node != NULL) && (h->of_node == node);
+
+                if (rc) {
                         found = h;
                         break;
                 }
+        }
         mutex_unlock(&irq_domain_mutex);
         return found;
 }
@@ -760,7 +759,7 @@ int irq_domain_xlate_onetwocell(struct irq_domain *d,
 }
 EXPORT_SYMBOL_GPL(irq_domain_xlate_onetwocell);
 
-struct irq_domain_ops irq_domain_simple_ops = {
+const struct irq_domain_ops irq_domain_simple_ops = {
         .map = irq_domain_simple_map,
         .xlate = irq_domain_xlate_onetwocell,
 };