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From: "Michael S. Tsirkin" <mst@redhat.com>
To: unlisted-recipients:; (no To-header on input)
Cc: Avi Kivity <avi@redhat.com>,
	Marcelo Tosatti <mtosatti@redhat.com>,
	kvm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH] kvm: eventfd comment fixup
Date: Wed, 2 Mar 2011 22:04:18 +0200	[thread overview]
Message-ID: <20110302200418.GA5479@redhat.com> (raw)

Clarify a comment in kvm/eventfd.c: we do
rcu_assign_pointer without explicit synchronize_rcu
afterwards, and the reason this works is because we
use a spinlock to synch against another place
which does call synchronize_rcu.

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

---

diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c
index 2ca4535..e347b53 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.
 			 */

-- 
MST

                 reply	other threads:[~2011-03-02 20:04 UTC|newest]

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