From c8ce057eafd49da6a7afe7791bd84163f65f6132 Mon Sep 17 00:00:00 2001 From: "Michael S. Tsirkin" Date: Sun, 6 Mar 2011 13:03:26 +0200 Subject: [PATCH] KVM: improve comment on rcu use in irqfd_deassign The RCU use in kvm_irqfd_deassign is tricky: we have rcu_assign_pointer but no synchronize_rcu: synchronize_rcu is done by kvm_irq_routing_update which we share a spinlock with. Fix up a comment in an attempt to make this clearer. Signed-off-by: Michael S. Tsirkin Signed-off-by: Avi Kivity --- virt/kvm/eventfd.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c index 2ca4535f4fb7..3656849f78a0 100644 --- a/virt/kvm/eventfd.c +++ b/virt/kvm/eventfd.c @@ -313,8 +313,9 @@ kvm_irqfd_deassign(struct kvm *kvm, int fd, int gsi) if (irqfd->eventfd == eventfd && irqfd->gsi == gsi) { /* * This rcu_assign_pointer is needed for when - * another thread calls kvm_irqfd_update before - * we flush workqueue below. + * another thread calls kvm_irq_routing_update before + * we flush workqueue below (we synchronize with + * kvm_irq_routing_update using irqfds.lock). * It is paired with synchronize_rcu done by caller * of that function. */ -- 2.34.1