1 files changed, 25 insertions, 40 deletions

diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c
index c0e638ba9c2a..170724a07a2c 100644
--- a/kernel/irq/irqdomain.c
+++ b/kernel/irq/irqdomain.c
@@ -686,16 +686,11 @@ EXPORT_SYMBOL_GPL(irq_dispose_mapping);
  * irq_find_mapping() - Find a linux irq from an hw irq number.
  * @domain: domain owning this hardware interrupt
  * @hwirq: hardware irq number in that domain space
- *
- * This is a slow path, for use by generic code. It's expected that an
- * irq controller implementation directly calls the appropriate low level
- * mapping function.
  */
 unsigned int irq_find_mapping(struct irq_domain *domain,
                               irq_hw_number_t hwirq)
 {
-        unsigned int i;
-        unsigned int hint = hwirq % nr_irqs;
+        struct irq_data *data;
 
         /* Look for default domain if nececssary */
         if (domain == NULL)
@@ -703,22 +698,25 @@ unsigned int irq_find_mapping(struct irq_domain *domain,
         if (domain == NULL)
                 return 0;
 
-        /* legacy -> bail early */
-        if (domain->revmap_type == IRQ_DOMAIN_MAP_LEGACY)
+        switch (domain->revmap_type) {
+        case IRQ_DOMAIN_MAP_LEGACY:
                 return irq_domain_legacy_revmap(domain, hwirq);
-
-        /* Slow path does a linear search of the map */
-        if (hint == 0)
-                hint = 1;
-        i = hint;
-        do {
-                struct irq_data *data = irq_get_irq_data(i);
+        case IRQ_DOMAIN_MAP_LINEAR:
+                return irq_linear_revmap(domain, hwirq);
+        case IRQ_DOMAIN_MAP_TREE:
+                rcu_read_lock();
+                data = radix_tree_lookup(&domain->revmap_data.tree, hwirq);
+                rcu_read_unlock();
+                if (data)
+                        return data->irq;
+                break;
+        case IRQ_DOMAIN_MAP_NOMAP:
+                data = irq_get_irq_data(hwirq);
                 if (data && (data->domain == domain) && (data->hwirq == hwirq))
-                        return i;
-                i++;
-                if (i >= nr_irqs)
-                        i = 1;
-        } while(i != hint);
+                        return hwirq;
+                break;
+        }
+
         return 0;
 }
 EXPORT_SYMBOL_GPL(irq_find_mapping);
@@ -728,32 +726,19 @@ EXPORT_SYMBOL_GPL(irq_find_mapping);
  * @domain: domain owning this hardware interrupt
  * @hwirq: hardware irq number in that domain space
  *
- * This is a fast path, for use by irq controller code that uses linear
- * revmaps. It does fallback to the slow path if the revmap doesn't exist
- * yet and will create the revmap entry with appropriate locking
+ * This is a fast path that can be called directly by irq controller code to
+ * save a handful of instructions.
  */
 unsigned int irq_linear_revmap(struct irq_domain *domain,
                                irq_hw_number_t hwirq)
 {
-        unsigned int *revmap;
+        BUG_ON(domain->revmap_type != IRQ_DOMAIN_MAP_LINEAR);
 
-        if (WARN_ON_ONCE(domain->revmap_type != IRQ_DOMAIN_MAP_LINEAR))
-                return irq_find_mapping(domain, hwirq);
-
-        /* Check revmap bounds */
-        if (unlikely(hwirq >= domain->revmap_data.linear.size))
-                return irq_find_mapping(domain, hwirq);
-
-        /* Check if revmap was allocated */
-        revmap = domain->revmap_data.linear.revmap;
-        if (unlikely(revmap == NULL))
-                return irq_find_mapping(domain, hwirq);
-
-        /* Fill up revmap with slow path if no mapping found */
-        if (unlikely(!revmap[hwirq]))
-                revmap[hwirq] = irq_find_mapping(domain, hwirq);
+        /* Check revmap bounds; complain if exceeded */
+        if (WARN_ON(hwirq >= domain->revmap_data.linear.size))
+                return 0;
 
-        return revmap[hwirq];
+        return domain->revmap_data.linear.revmap[hwirq];
 }
 EXPORT_SYMBOL_GPL(irq_linear_revmap);