xen: remove irq bindcount

There should be no need for us to maintain our own bind count for
irqs, since the surrounding irq system should keep track of shared
irqs for us.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

drivers/xen/events.c

@@ -54,7 +54,7 @@ static DEFINE_PER_CPU(int, ipi_to_irq[XEN_NR_IPIS]) = {[0 ... XEN_NR_IPIS-1] = -
 
 /* Interrupt types. */
 enum xen_irq_type {
-	IRQT_UNBOUND,
+	IRQT_UNBOUND = 0,
 	IRQT_PIRQ,
 	IRQT_VIRQ,
 	IRQT_IPI,
@@ -102,9 +102,6 @@ static inline unsigned long *cpu_evtchn_mask(int cpu)
 	return cpu_evtchn_mask_p[cpu].bits;
 }
 
-/* Reference counts for bindings to IRQs. */
-static int irq_bindcount[NR_IRQS];
-
 /* Xen will never allocate port zero for any purpose. */
 #define VALID_EVTCHN(chn)	((chn) != 0)
 
@@ -330,9 +327,8 @@ static int find_unbound_irq(void)
 	int irq;
 	struct irq_desc *desc;
 
-	/* Only allocate from dynirq range */
 	for (irq = 0; irq < nr_irqs; irq++)
-		if (irq_bindcount[irq] == 0)
+		if (irq_info[irq].type == IRQT_UNBOUND)
 			break;
 
 	if (irq == nr_irqs)
@@ -365,8 +361,6 @@ int bind_evtchn_to_irq(unsigned int evtchn)
 		irq_info[irq] = mk_evtchn_info(evtchn);
 	}
 
-	irq_bindcount[irq]++;
-
 	spin_unlock(&irq_mapping_update_lock);
 
 	return irq;
@@ -403,8 +397,6 @@ static int bind_ipi_to_irq(unsigned int ipi, unsigned int cpu)
 		bind_evtchn_to_cpu(evtchn, cpu);
 	}
 
-	irq_bindcount[irq]++;
-
  out:
 	spin_unlock(&irq_mapping_update_lock);
 	return irq;
@@ -441,8 +433,6 @@ static int bind_virq_to_irq(unsigned int virq, unsigned int cpu)
 		bind_evtchn_to_cpu(evtchn, cpu);
 	}
 
-	irq_bindcount[irq]++;
-
 	spin_unlock(&irq_mapping_update_lock);
 
 	return irq;
@@ -455,7 +445,7 @@ static void unbind_from_irq(unsigned int irq)
 
 	spin_lock(&irq_mapping_update_lock);
 
-	if ((--irq_bindcount[irq] == 0) && VALID_EVTCHN(evtchn)) {
+	if (VALID_EVTCHN(evtchn)) {
 		close.port = evtchn;
 		if (HYPERVISOR_event_channel_op(EVTCHNOP_close, &close) != 0)
 			BUG();
@@ -681,6 +671,8 @@ void xen_evtchn_do_upcall(struct pt_regs *regs)
 /* Rebind a new event channel to an existing irq. */
 void rebind_evtchn_irq(int evtchn, int irq)
 {
+	struct irq_info *info = info_for_irq(irq);
+
 	/* Make sure the irq is masked, since the new event channel
 	   will also be masked. */
 	disable_irq(irq);
@@ -690,8 +682,8 @@ void rebind_evtchn_irq(int evtchn, int irq)
 	/* After resume the irq<->evtchn mappings are all cleared out */
 	BUG_ON(evtchn_to_irq[evtchn] != -1);
 	/* Expect irq to have been bound before,
-	   so the bindcount should be non-0 */
-	BUG_ON(irq_bindcount[irq] == 0);
+	   so there should be a proper type */
+	BUG_ON(info->type == IRQT_UNBOUND);
 
 	evtchn_to_irq[evtchn] = irq;
 	irq_info[irq] = mk_evtchn_info(evtchn);
@@ -948,9 +940,5 @@ void __init xen_init_IRQ(void)
 	for (i = 0; i < NR_EVENT_CHANNELS; i++)
 		mask_evtchn(i);
 
-	/* Dynamic IRQ space is currently unbound. Zero the refcnts. */
-	for (i = 0; i < nr_irqs; i++)
-		irq_bindcount[i] = 0;
-
 	irq_ctx_init(smp_processor_id());
 }