[PATCH 4/7] irqbypass: Explicitly track producer and consumer bindings

[Sean Christopherson <seanjc@google.com>]

Explicitly track IRQ bypass producer:consumer bindings.  This will allow
making removal an O(1) operation; searching through the list to find
information that is trivially tracked (and useful for debug) is wasteful.

Signed-off-by: Sean Christopherson <seanjc@google.com>
---
 include/linux/irqbypass.h | 5 +++++
 virt/lib/irqbypass.c      | 9 +++++++++
 2 files changed, 14 insertions(+)

diff --git a/include/linux/irqbypass.h b/include/linux/irqbypass.h
index 379725b9a003..6d4e4882843c 100644
--- a/include/linux/irqbypass.h
+++ b/include/linux/irqbypass.h
@@ -29,6 +29,8 @@ struct irq_bypass_consumer;
  * 1:N pairings are not supported.
  */
 
+struct irq_bypass_consumer;
+
 /**
  * struct irq_bypass_producer - IRQ bypass producer definition
  * @node: IRQ bypass manager private list management
@@ -46,6 +48,7 @@ struct irq_bypass_consumer;
 struct irq_bypass_producer {
 	struct list_head node;
 	void *token;
+	struct irq_bypass_consumer *consumer;
 	int irq;
 	int (*add_consumer)(struct irq_bypass_producer *,
 			    struct irq_bypass_consumer *);
@@ -72,6 +75,8 @@ struct irq_bypass_producer {
 struct irq_bypass_consumer {
 	struct list_head node;
 	void *token;
+	struct irq_bypass_producer *producer;
+
 	int (*add_producer)(struct irq_bypass_consumer *,
 			    struct irq_bypass_producer *);
 	void (*del_producer)(struct irq_bypass_consumer *,
diff --git a/virt/lib/irqbypass.c b/virt/lib/irqbypass.c
index 98bf76d03078..4c912c30b7e6 100644
--- a/virt/lib/irqbypass.c
+++ b/virt/lib/irqbypass.c
@@ -51,6 +51,10 @@ static int __connect(struct irq_bypass_producer *prod,
 	if (prod->start)
 		prod->start(prod);
 
+	if (!ret) {
+		prod->consumer = cons;
+		cons->producer = prod;
+	}
 	return ret;
 }
 
@@ -72,6 +76,9 @@ static void __disconnect(struct irq_bypass_producer *prod,
 		cons->start(cons);
 	if (prod->start)
 		prod->start(prod);
+
+	prod->consumer = NULL;
+	cons->producer = NULL;
 }
 
 /**
@@ -145,6 +152,7 @@ void irq_bypass_unregister_producer(struct irq_bypass_producer *producer)
 
 		list_for_each_entry(consumer, &consumers, node) {
 			if (consumer->token == producer->token) {
+				WARN_ON_ONCE(producer->consumer != consumer);
 				__disconnect(producer, consumer);
 				break;
 			}
@@ -234,6 +242,7 @@ void irq_bypass_unregister_consumer(struct irq_bypass_consumer *consumer)
 
 		list_for_each_entry(producer, &producers, node) {
 			if (producer->token == consumer->token) {
+				WARN_ON_ONCE(consumer->producer != producer);
 				__disconnect(producer, consumer);
 				break;
 			}
-- 
2.49.0.504.g3bcea36a83-goog