2 files changed, 62 insertions, 3 deletions

diff --git a/include/linux/irqdomain.h b/include/linux/irqdomain.h
index c65740d76e66..a796dbf80b67 100644
--- a/include/linux/irqdomain.h
+++ b/include/linux/irqdomain.h
@@ -141,10 +141,12 @@ static inline struct irq_domain *irq_domain_add_legacy_isa(
         return irq_domain_add_legacy(of_node, NUM_ISA_INTERRUPTS, 0, 0, ops,
                                      host_data);
 }
+
+extern void irq_domain_remove(struct irq_domain *host);
+
 extern struct irq_domain *irq_find_host(struct device_node *node);
 extern void irq_set_default_host(struct irq_domain *host);
 
-
 extern unsigned int irq_create_mapping(struct irq_domain *host,
                                        irq_hw_number_t hwirq);
 extern void irq_dispose_mapping(unsigned int virq);
diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c
index 0e0ba5f840b2..9cae0b2f509f 100644
--- a/kernel/irq/irqdomain.c
+++ b/kernel/irq/irqdomain.c
@@ -56,6 +56,12 @@ static struct irq_domain *irq_domain_alloc(struct device_node *of_node,
         return domain;
 }
 
+static void irq_domain_free(struct irq_domain *domain)
+{
+        of_node_put(domain->of_node);
+        kfree(domain);
+}
+
 static void irq_domain_add(struct irq_domain *domain)
 {
         mutex_lock(&irq_domain_mutex);
@@ -65,6 +71,58 @@ static void irq_domain_add(struct irq_domain *domain)
                  domain->revmap_type, domain);
 }
 
+/**
+ * irq_domain_remove() - Remove an irq domain.
+ * @domain: domain to remove
+ *
+ * This routine is used to remove an irq domain. The caller must ensure
+ * that all mappings within the domain have been disposed of prior to
+ * use, depending on the revmap type.
+ */
+void irq_domain_remove(struct irq_domain *domain)
+{
+        mutex_lock(&irq_domain_mutex);
+
+        switch (domain->revmap_type) {
+        case IRQ_DOMAIN_MAP_LEGACY:
+                /*
+                 * Legacy domains don't manage their own irq_desc
+                 * allocations, we expect the caller to handle irq_desc
+                 * freeing on their own.
+                 */
+                break;
+        case IRQ_DOMAIN_MAP_TREE:
+                /*
+                 * radix_tree_delete() takes care of destroying the root
+                 * node when all entries are removed. Shout if there are
+                 * any mappings left.
+                 */
+                WARN_ON(domain->revmap_data.tree.height);
+                break;
+        case IRQ_DOMAIN_MAP_LINEAR:
+                kfree(domain->revmap_data.linear.revmap);
+                domain->revmap_data.linear.size = 0;
+                break;
+        case IRQ_DOMAIN_MAP_NOMAP:
+                break;
+        }
+
+        list_del(&domain->link);
+
+        /*
+         * If the going away domain is the default one, reset it.
+         */
+        if (unlikely(irq_default_domain == domain))
+                irq_set_default_host(NULL);
+
+        mutex_unlock(&irq_domain_mutex);
+
+        pr_debug("irq: Removed domain of type %d @0x%p\n",
+                 domain->revmap_type, domain);
+
+        irq_domain_free(domain);
+}
+
 static unsigned int irq_domain_legacy_revmap(struct irq_domain *domain,
                                              irq_hw_number_t hwirq)
 {
@@ -117,8 +175,7 @@ struct irq_domain *irq_domain_add_legacy(struct device_node *of_node,
 
                 if (WARN_ON(!irq_data || irq_data->domain)) {
                         mutex_unlock(&irq_domain_mutex);
-                        of_node_put(domain->of_node);
-                        kfree(domain);
+                        irq_domain_free(domain);
                         return NULL;
                 }
         }