KVM: Convert irq notifiers lists to RCU locking

Use RCU locking for mask/ack notifiers lists.

Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 12 insertions, 10 deletions

diff --git a/virt/kvm/irq_comm.c b/virt/kvm/irq_comm.c
index f01972595938..6c946141dbcc 100644
--- a/virt/kvm/irq_comm.c
+++ b/virt/kvm/irq_comm.c
@@ -183,19 +183,19 @@ void kvm_notify_acked_irq(struct kvm *kvm, unsigned irqchip, unsigned pin)
 
         rcu_read_lock();
         gsi = rcu_dereference(kvm->irq_routing)->chip[irqchip][pin];
-        rcu_read_unlock();
-
         if (gsi != -1)
-                hlist_for_each_entry(kian, n, &kvm->irq_ack_notifier_list, link)
+                hlist_for_each_entry_rcu(kian, n, &kvm->irq_ack_notifier_list,
+                                         link)
                         if (kian->gsi == gsi)
                                 kian->irq_acked(kian);
+        rcu_read_unlock();
 }
 
 void kvm_register_irq_ack_notifier(struct kvm *kvm,
                                    struct kvm_irq_ack_notifier *kian)
 {
         mutex_lock(&kvm->irq_lock);
-        hlist_add_head(&kian->link, &kvm->irq_ack_notifier_list);
+        hlist_add_head_rcu(&kian->link, &kvm->irq_ack_notifier_list);
         mutex_unlock(&kvm->irq_lock);
 }
 
@@ -203,8 +203,9 @@ void kvm_unregister_irq_ack_notifier(struct kvm *kvm,
                                     struct kvm_irq_ack_notifier *kian)
 {
         mutex_lock(&kvm->irq_lock);
-        hlist_del_init(&kian->link);
+        hlist_del_init_rcu(&kian->link);
         mutex_unlock(&kvm->irq_lock);
+        synchronize_rcu();
 }
 
 int kvm_request_irq_source_id(struct kvm *kvm)
@@ -257,7 +258,7 @@ void kvm_register_irq_mask_notifier(struct kvm *kvm, int irq,
 {
         mutex_lock(&kvm->irq_lock);
         kimn->irq = irq;
-        hlist_add_head(&kimn->link, &kvm->mask_notifier_list);
+        hlist_add_head_rcu(&kimn->link, &kvm->mask_notifier_list);
         mutex_unlock(&kvm->irq_lock);
 }
 
@@ -265,8 +266,9 @@ void kvm_unregister_irq_mask_notifier(struct kvm *kvm, int irq,
                                       struct kvm_irq_mask_notifier *kimn)
 {
         mutex_lock(&kvm->irq_lock);
-        hlist_del(&kimn->link);
+        hlist_del_rcu(&kimn->link);
         mutex_unlock(&kvm->irq_lock);
+        synchronize_rcu();
 }
 
 void kvm_fire_mask_notifiers(struct kvm *kvm, int irq, bool mask)
@@ -274,11 +276,11 @@ void kvm_fire_mask_notifiers(struct kvm *kvm, int irq, bool mask)
         struct kvm_irq_mask_notifier *kimn;
         struct hlist_node *n;
 
-        WARN_ON(!mutex_is_locked(&kvm->irq_lock));
-
-        hlist_for_each_entry(kimn, n, &kvm->mask_notifier_list, link)
+        rcu_read_lock();
+        hlist_for_each_entry_rcu(kimn, n, &kvm->mask_notifier_list, link)
                 if (kimn->irq == irq)
                         kimn->func(kimn, mask);
+        rcu_read_unlock();
 }
 
 void kvm_free_irq_routing(struct kvm *kvm)