[Devel,2/4] KVM: i8254: simplify atomics in kvm_pit_ack_irq

Submitted by Evgeny Yakovlev on Dec. 8, 2016, 1:10 p.m.

Details

Message ID 1481202644-98659-3-git-send-email-eyakovlev@virtuozzo.com
State New
Series "KVM-PIT discard mode fixes"
Headers show

Commit Message

Evgeny Yakovlev Dec. 8, 2016, 1:10 p.m.
From: Radim Krčmář <rkrcmar@redhat.com>

We already have a helper that does the same thing.

Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

ms commit f6e0a0c113f78a0e13c69762b2ab342d6c69220d
("KVM: i8254: simplify atomics in kvm_pit_ack_irq")
Fixes https://jira.sw.ru/browse/PSBM-56972
Signed-off-by: Evgeny Yakovlev <eyakovlev@virtuozzo.com>
---
 arch/x86/kvm/i8254.c | 12 +-----------
 1 file changed, 1 insertion(+), 11 deletions(-)

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diff --git a/arch/x86/kvm/i8254.c b/arch/x86/kvm/i8254.c
index b0a706d..b1bdc4f 100644
--- a/arch/x86/kvm/i8254.c
+++ b/arch/x86/kvm/i8254.c
@@ -235,19 +235,9 @@  static void kvm_pit_ack_irq(struct kvm_irq_ack_notifier *kian)
 {
 	struct kvm_kpit_state *ps = container_of(kian, struct kvm_kpit_state,
 						 irq_ack_notifier);
-	int value;
 
 	spin_lock(&ps->inject_lock);
-	value = atomic_dec_return(&ps->pending);
-	if (value < 0)
-		/* spurious acks can be generated if, for example, the
-		 * PIC is being reset.  Handle it gracefully here
-		 */
-		atomic_inc(&ps->pending);
-	else if (value > 0 && ps->reinject)
-		/* in this case, we had multiple outstanding pit interrupts
-		 * that we needed to inject.  Reinject
-		 */
+	if (atomic_dec_if_positive(&ps->pending) > 0 && ps->reinject)
 		queue_kthread_work(&ps->pit->worker, &ps->pit->expired);
 	ps->irq_ack = 1;
 	spin_unlock(&ps->inject_lock);