[PATCH 14/42] KVM: Convert irq notifiers lists to RCU locking

Avi Kivity
2009-11-16T12:29:14Z

From: Gleb Natapov <gleb@redhat.com>

Use RCU locking for mask/ack notifiers lists.

Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
---
virt/kvm/irq_comm.c | 22 ++++++++++++----------
1 files changed, 12 insertions(+), 10 deletions(-)

diff --git a/virt/kvm/irq_comm.c b/virt/kvm/irq_comm.c
index f019725..6c94614 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)
--
1.6.5.2