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

[Sean Christopherson]

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 <sea...@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