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

[Sean Christopherson]

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 <sea...@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