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>

diff --git a/virt/kvm/irq_comm.c b/virt/kvm/irq_comm.c
index f019725..6c94614 100644 (file)
--- 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)