[PATCH 5/6] kvm: Serialize wq active checks in kvm_vcpu_wake_up()

[Davidlohr Bueso]

This is a generic call and can be suceptible to races
in reading the wq task_list while another task is adding
itself to the list. Add a full barrier by using the
swq_has_sleeper() helper.

Signed-off-by: Davidlohr Bueso <dbu...@suse.de>
---
 virt/kvm/kvm_main.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 4d81f6ded88e..4e76e6d15ce0 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -2185,7 +2185,7 @@ bool kvm_vcpu_wake_up(struct kvm_vcpu *vcpu)
        struct swait_queue_head *wqp;
 
        wqp = kvm_arch_vcpu_wq(vcpu);
-       if (swait_active(wqp)) {
+       if (swq_has_sleeper(wqp)) {
                swake_up(wqp);
                ++vcpu->stat.halt_wakeup;
                return true;
-- 
2.12.0