[PATCH 5/7] irqbypass: Use paired consumer/producer to disconnect during unregister

[Sean Christopherson <seanjc@google.com>]

Use the paired consumer/producer information to disconnect IRQ bypass
producers/consumers in O(1) time (ignoring the cost of __disconnect()).

Signed-off-by: Sean Christopherson <seanjc@google.com>
---
 virt/lib/irqbypass.c | 50 +++++++-------------------------------------
 1 file changed, 8 insertions(+), 42 deletions(-)

diff --git a/virt/lib/irqbypass.c b/virt/lib/irqbypass.c
index 4c912c30b7e6..6d68a0f71dd9 100644
--- a/virt/lib/irqbypass.c
+++ b/virt/lib/irqbypass.c
@@ -138,32 +138,16 @@ EXPORT_SYMBOL_GPL(irq_bypass_register_producer);
  */
 void irq_bypass_unregister_producer(struct irq_bypass_producer *producer)
 {
-	struct irq_bypass_producer *tmp;
-	struct irq_bypass_consumer *consumer;
-
 	if (!producer->token)
 		return;
 
 	mutex_lock(&lock);
 
-	list_for_each_entry(tmp, &producers, node) {
-		if (tmp->token != producer->token)
-			continue;
+	if (producer->consumer)
+		__disconnect(producer, producer->consumer);
 
-		list_for_each_entry(consumer, &consumers, node) {
-			if (consumer->token == producer->token) {
-				WARN_ON_ONCE(producer->consumer != consumer);
-				__disconnect(producer, consumer);
-				break;
-			}
-		}
-
-		producer->token = NULL;
-		list_del(&producer->node);
-		break;
-	}
-
-	WARN_ON_ONCE(producer->token);
+	producer->token = NULL;
+	list_del(&producer->node);
 	mutex_unlock(&lock);
 }
 EXPORT_SYMBOL_GPL(irq_bypass_unregister_producer);
@@ -173,8 +157,6 @@ EXPORT_SYMBOL_GPL(irq_bypass_unregister_producer);
  * @consumer: pointer to consumer structure
  * @eventfd: pointer to the eventfd context associated with the consumer
  *
- * Add the provided IRQ consumer to the list of consumers and connect
- * with any matching token found on the IRQ producer list.
  */
 int irq_bypass_register_consumer(struct irq_bypass_consumer *consumer,
 				 struct eventfd_ctx *eventfd)
@@ -228,32 +210,16 @@ EXPORT_SYMBOL_GPL(irq_bypass_register_consumer);
  */
 void irq_bypass_unregister_consumer(struct irq_bypass_consumer *consumer)
 {
-	struct irq_bypass_consumer *tmp;
-	struct irq_bypass_producer *producer;
-
 	if (!consumer->token)
 		return;
 
 	mutex_lock(&lock);
 
-	list_for_each_entry(tmp, &consumers, node) {
-		if (tmp != consumer)
-			continue;
+	if (consumer->producer)
+		__disconnect(consumer->producer, consumer);
 
-		list_for_each_entry(producer, &producers, node) {
-			if (producer->token == consumer->token) {
-				WARN_ON_ONCE(consumer->producer != producer);
-				__disconnect(producer, consumer);
-				break;
-			}
-		}
-
-		consumer->token = NULL;
-		list_del(&consumer->node);
-		break;
-	}
-
-	WARN_ON_ONCE(consumer->token);
+	consumer->token = NULL;
+	list_del(&consumer->node);
 	mutex_unlock(&lock);
 }
 EXPORT_SYMBOL_GPL(irq_bypass_unregister_consumer);
-- 
2.49.0.504.g3bcea36a83-goog