diff --git a/arch/s390/include/asm/irq.h b/arch/s390/include/asm/irq.h
index 1eaa3625803c..5f8bcc5fe423 100644
--- a/arch/s390/include/asm/irq.h
+++ b/arch/s390/include/asm/irq.h
@@ -78,10 +78,14 @@ typedef void (*ext_int_handler_t)(struct ext_code, unsigned int, unsigned long);
 
 int register_external_interrupt(u16 code, ext_int_handler_t handler);
 int unregister_external_interrupt(u16 code, ext_int_handler_t handler);
-void service_subclass_irq_register(void);
-void service_subclass_irq_unregister(void);
-void measurement_alert_subclass_register(void);
-void measurement_alert_subclass_unregister(void);
+
+enum irq_subclass {
+	IRQ_SUBCLASS_MEASUREMENT_ALERT = 5,
+	IRQ_SUBCLASS_SERVICE_SIGNAL = 9,
+};
+
+void irq_subclass_register(enum irq_subclass subclass);
+void irq_subclass_unregister(enum irq_subclass subclass);
 
 #define irq_canonicalize(irq)  (irq)
 
diff --git a/arch/s390/kernel/irq.c b/arch/s390/kernel/irq.c
index 4ecf017f697c..6834277124c9 100644
--- a/arch/s390/kernel/irq.c
+++ b/arch/s390/kernel/irq.c
@@ -290,48 +290,25 @@ void __init init_ext_interrupts(void)
 	setup_irq(EXT_INTERRUPT, &external_interrupt);
 }
 
-static DEFINE_SPINLOCK(sc_irq_lock);
-static int sc_irq_refcount;
+static DEFINE_SPINLOCK(irq_subclass_lock);
+static unsigned char irq_subclass_refcount[64];
 
-void service_subclass_irq_register(void)
+void irq_subclass_register(enum irq_subclass subclass)
 {
-	spin_lock(&sc_irq_lock);
-	if (!sc_irq_refcount)
-		ctl_set_bit(0, 9);
-	sc_irq_refcount++;
-	spin_unlock(&sc_irq_lock);
+	spin_lock(&irq_subclass_lock);
+	if (!irq_subclass_refcount[subclass])
+		ctl_set_bit(0, subclass);
+	irq_subclass_refcount[subclass]++;
+	spin_unlock(&irq_subclass_lock);
 }
-EXPORT_SYMBOL(service_subclass_irq_register);
+EXPORT_SYMBOL(irq_subclass_register);
 
-void service_subclass_irq_unregister(void)
+void irq_subclass_unregister(enum irq_subclass subclass)
 {
-	spin_lock(&sc_irq_lock);
-	sc_irq_refcount--;
-	if (!sc_irq_refcount)
-		ctl_clear_bit(0, 9);
-	spin_unlock(&sc_irq_lock);
+	spin_lock(&irq_subclass_lock);
+	irq_subclass_refcount[subclass]--;
+	if (!irq_subclass_refcount[subclass])
+		ctl_clear_bit(0, subclass);
+	spin_unlock(&irq_subclass_lock);
 }
-EXPORT_SYMBOL(service_subclass_irq_unregister);
-
-static DEFINE_SPINLOCK(ma_subclass_lock);
-static int ma_subclass_refcount;
-
-void measurement_alert_subclass_register(void)
-{
-	spin_lock(&ma_subclass_lock);
-	if (!ma_subclass_refcount)
-		ctl_set_bit(0, 5);
-	ma_subclass_refcount++;
-	spin_unlock(&ma_subclass_lock);
-}
-EXPORT_SYMBOL(measurement_alert_subclass_register);
-
-void measurement_alert_subclass_unregister(void)
-{
-	spin_lock(&ma_subclass_lock);
-	ma_subclass_refcount--;
-	if (!ma_subclass_refcount)
-		ctl_clear_bit(0, 5);
-	spin_unlock(&ma_subclass_lock);
-}
-EXPORT_SYMBOL(measurement_alert_subclass_unregister);
+EXPORT_SYMBOL(irq_subclass_unregister);
diff --git a/arch/s390/kernel/perf_cpum_cf.c b/arch/s390/kernel/perf_cpum_cf.c
index fb99c2057b85..1105502bf6e9 100644
--- a/arch/s390/kernel/perf_cpum_cf.c
+++ b/arch/s390/kernel/perf_cpum_cf.c
@@ -274,7 +274,7 @@ static int reserve_pmc_hardware(void)
 	int flags = PMC_INIT;
 
 	on_each_cpu(setup_pmc_cpu, &flags, 1);
-	measurement_alert_subclass_register();
+	irq_subclass_register(IRQ_SUBCLASS_MEASUREMENT_ALERT);
 
 	return 0;
 }
@@ -285,7 +285,7 @@ static void release_pmc_hardware(void)
 	int flags = PMC_RELEASE;
 
 	on_each_cpu(setup_pmc_cpu, &flags, 1);
-	measurement_alert_subclass_unregister();
+	irq_subclass_unregister(IRQ_SUBCLASS_MEASUREMENT_ALERT);
 }
 
 /* Release the PMU if event is the last perf event */
diff --git a/arch/s390/kernel/runtime_instr.c b/arch/s390/kernel/runtime_instr.c
index 077a99389b07..e1c9d1c292fa 100644
--- a/arch/s390/kernel/runtime_instr.c
+++ b/arch/s390/kernel/runtime_instr.c
@@ -139,10 +139,10 @@ static int __init runtime_instr_init(void)
 	if (!runtime_instr_avail())
 		return 0;
 
-	measurement_alert_subclass_register();
+	irq_subclass_register(IRQ_SUBCLASS_MEASUREMENT_ALERT);
 	rc = register_external_interrupt(0x1407, runtime_instr_int_handler);
 	if (rc)
-		measurement_alert_subclass_unregister();
+		irq_subclass_unregister(IRQ_SUBCLASS_MEASUREMENT_ALERT);
 	else
 		pr_info("Runtime instrumentation facility initialized\n");
 	return rc;
diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c
index f00aefb66a4e..7de4469915f0 100644
--- a/arch/s390/mm/fault.c
+++ b/arch/s390/mm/fault.c
@@ -673,7 +673,7 @@ static int __init pfault_irq_init(void)
 	rc = pfault_init() == 0 ? 0 : -EOPNOTSUPP;
 	if (rc)
 		goto out_pfault;
-	service_subclass_irq_register();
+	irq_subclass_register(IRQ_SUBCLASS_SERVICE_SIGNAL);
 	hotcpu_notifier(pfault_cpu_notify, 0);
 	return 0;
 
diff --git a/arch/s390/oprofile/hwsampler.c b/arch/s390/oprofile/hwsampler.c
index b5b2916895e0..231cecafc2f1 100644
--- a/arch/s390/oprofile/hwsampler.c
+++ b/arch/s390/oprofile/hwsampler.c
@@ -1001,7 +1001,7 @@ int hwsampler_deallocate(void)
 	if (hws_state != HWS_STOPPED)
 		goto deallocate_exit;
 
-	measurement_alert_subclass_unregister();
+	irq_subclass_unregister(IRQ_SUBCLASS_MEASUREMENT_ALERT);
 	deallocate_sdbt();
 
 	hws_state = HWS_DEALLOCATED;
@@ -1115,7 +1115,7 @@ int hwsampler_shutdown(void)
 		mutex_lock(&hws_sem);
 
 		if (hws_state == HWS_STOPPED) {
-			measurement_alert_subclass_unregister();
+			irq_subclass_unregister(IRQ_SUBCLASS_MEASUREMENT_ALERT);
 			deallocate_sdbt();
 		}
 		if (hws_wq) {
@@ -1190,7 +1190,7 @@ start_all_exit:
 	hws_oom = 1;
 	hws_flush_all = 0;
 	/* now let them in, 1407 CPUMF external interrupts */
-	measurement_alert_subclass_register();
+	irq_subclass_register(IRQ_SUBCLASS_MEASUREMENT_ALERT);
 
 	return 0;
 }
diff --git a/drivers/s390/block/dasd_diag.c b/drivers/s390/block/dasd_diag.c
index feca317b33de..92bd22ce6760 100644
--- a/drivers/s390/block/dasd_diag.c
+++ b/drivers/s390/block/dasd_diag.c
@@ -645,7 +645,7 @@ dasd_diag_init(void)
 	}
 	ASCEBC(dasd_diag_discipline.ebcname, 4);
 
-	service_subclass_irq_register();
+	irq_subclass_register(IRQ_SUBCLASS_SERVICE_SIGNAL);
 	register_external_interrupt(0x2603, dasd_ext_handler);
 	dasd_diag_discipline_pointer = &dasd_diag_discipline;
 	return 0;
@@ -655,7 +655,7 @@ static void __exit
 dasd_diag_cleanup(void)
 {
 	unregister_external_interrupt(0x2603, dasd_ext_handler);
-	service_subclass_irq_unregister();
+	irq_subclass_unregister(IRQ_SUBCLASS_SERVICE_SIGNAL);
 	dasd_diag_discipline_pointer = NULL;
 }
 
diff --git a/drivers/s390/char/sclp.c b/drivers/s390/char/sclp.c
index 3e4fb4e858da..a3aa374799dc 100644
--- a/drivers/s390/char/sclp.c
+++ b/drivers/s390/char/sclp.c
@@ -910,12 +910,12 @@ sclp_check_interface(void)
 		spin_unlock_irqrestore(&sclp_lock, flags);
 		/* Enable service-signal interruption - needs to happen
 		 * with IRQs enabled. */
-		service_subclass_irq_register();
+		irq_subclass_register(IRQ_SUBCLASS_SERVICE_SIGNAL);
 		/* Wait for signal from interrupt or timeout */
 		sclp_sync_wait();
 		/* Disable service-signal interruption - needs to happen
 		 * with IRQs enabled. */
-		service_subclass_irq_unregister();
+		irq_subclass_unregister(IRQ_SUBCLASS_SERVICE_SIGNAL);
 		spin_lock_irqsave(&sclp_lock, flags);
 		del_timer(&sclp_request_timer);
 		if (sclp_init_req.status == SCLP_REQ_DONE &&
@@ -1131,7 +1131,7 @@ sclp_init(void)
 	spin_unlock_irqrestore(&sclp_lock, flags);
 	/* Enable service-signal external interruption - needs to happen with
 	 * IRQs enabled. */
-	service_subclass_irq_register();
+	irq_subclass_register(IRQ_SUBCLASS_SERVICE_SIGNAL);
 	sclp_init_mask(1);
 	return 0;
 
diff --git a/drivers/s390/kvm/kvm_virtio.c b/drivers/s390/kvm/kvm_virtio.c
index 2ea6165366b6..af2166fa5159 100644
--- a/drivers/s390/kvm/kvm_virtio.c
+++ b/drivers/s390/kvm/kvm_virtio.c
@@ -472,7 +472,7 @@ static int __init kvm_devices_init(void)
 
 	INIT_WORK(&hotplug_work, hotplug_devices);
 
-	service_subclass_irq_register();
+	irq_subclass_register(IRQ_SUBCLASS_SERVICE_SIGNAL);
 	register_external_interrupt(0x2603, kvm_extint_handler);
 
 	scan_devices();