From: Davidlohr Bueso <dave@stgolabs.net>
Date: Wed, 13 Sep 2017 20:08:23 +0000 (-0700)
Subject: kvm,powerpc: Serialize wq active checks in ops->vcpu_kick
X-Git-Tag: v4.14-rc1~10^2~4
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=267ad7bc2d3f69af536035b6a3e4a9a2b6ae11dc;p=platform%2Fkernel%2Flinux-rpi.git

kvm,powerpc: Serialize wq active checks in ops->vcpu_kick

Particularly because kvmppc_fast_vcpu_kick_hv() is a callback,
ensure that we properly serialize wq active checks in order to
avoid potentially missing a wakeup due to racing with the waiter
side.

Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---

diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index a7177c2..73bf1eb 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -181,7 +181,7 @@ static void kvmppc_fast_vcpu_kick_hv(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;
 	}