From: Jan Kiszka <jan.kiszka@siemens.com>
Date: Tue, 9 Jun 2009 13:37:03 +0000 (+0200)
Subject: KVM: Drop useless atomic test from timer function
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=681405bfc73a2717ae9b03b2bad465b009106f31;p=linux-beck.git

KVM: Drop useless atomic test from timer function

The current code tries to optimize the setting of
KVM_REQ_PENDING_TIMER but used atomic_inc_and_test - which always
returns true unless pending had the invalid value of -1 on entry. This
patch drops the test part preserving the original semantic but
expressing it less confusingly.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
---

diff --git a/arch/x86/kvm/timer.c b/arch/x86/kvm/timer.c
index 1baed414b57a..eea40439066c 100644
--- a/arch/x86/kvm/timer.c
+++ b/arch/x86/kvm/timer.c
@@ -15,9 +15,9 @@ static int __kvm_timer_fn(struct kvm_vcpu *vcpu, struct kvm_timer *ktimer)
 	 * case anyway.
 	 */
 	if (ktimer->reinject || !atomic_read(&ktimer->pending)) {
+		atomic_inc(&ktimer->pending);
 		/* FIXME: this code should not know anything about vcpus */
-		if (!atomic_inc_and_test(&ktimer->pending))
-			set_bit(KVM_REQ_PENDING_TIMER, &vcpu->requests);
+		set_bit(KVM_REQ_PENDING_TIMER, &vcpu->requests);
 	}
 
 	if (waitqueue_active(q))