KVM: improve comment on rcu use in irqfd_deassign (c8ce057e) · Commits · 戴 / test

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 <mst@redhat.com> Signed-off-by:

Avi Kivity <avi@redhat.com>

virt/kvm/eventfd.c

+3 −2

Original line number	Diff line number	Diff line
		@@ -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.
		*/

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