6 files changed, 32 insertions, 7 deletions

diff --git a/arch/s390/include/asm/s390_ext.h b/arch/s390/include/asm/s390_ext.h
index 080876d5f196..85b2154b899f 100644
--- a/arch/s390/include/asm/s390_ext.h
+++ b/arch/s390/include/asm/s390_ext.h
@@ -13,5 +13,7 @@ typedef void (*ext_int_handler_t)(unsigned int, 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);
 
 #endif /* _S390_EXTINT_H */
diff --git a/arch/s390/kernel/s390_ext.c b/arch/s390/kernel/s390_ext.c
index 185029919c4d..87b5c532abf1 100644
--- a/arch/s390/kernel/s390_ext.c
+++ b/arch/s390/kernel/s390_ext.c
@@ -106,3 +106,26 @@ void __irq_entry do_extint(struct pt_regs *regs, unsigned int ext_int_code,
         irq_exit();
         set_irq_regs(old_regs);
 }
+
+static DEFINE_SPINLOCK(sc_irq_lock);
+static int sc_irq_refcount;
+
+void service_subclass_irq_register(void)
+{
+        spin_lock(&sc_irq_lock);
+        if (!sc_irq_refcount)
+                ctl_set_bit(0, 9);
+        sc_irq_refcount++;
+        spin_unlock(&sc_irq_lock);
+}
+EXPORT_SYMBOL(service_subclass_irq_register);
+
+void service_subclass_irq_unregister(void)
+{
+        spin_lock(&sc_irq_lock);
+        sc_irq_refcount--;
+        if (!sc_irq_refcount)
+                ctl_clear_bit(0, 9);
+        spin_unlock(&sc_irq_lock);
+}
+EXPORT_SYMBOL(service_subclass_irq_unregister);
diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c
index e46ba2927424..6e922b50efa4 100644
--- a/arch/s390/mm/fault.c
+++ b/arch/s390/mm/fault.c
@@ -613,7 +613,7 @@ static int __init pfault_irq_init(void)
         rc = pfault_init() == 0 ? 0 : -EOPNOTSUPP;
         if (rc)
                 goto out_pfault;
-        ctl_set_bit(0, 9);
+        service_subclass_irq_register();
         hotcpu_notifier(pfault_cpu_notify, 0);
         return 0;
 
diff --git a/drivers/s390/block/dasd_diag.c b/drivers/s390/block/dasd_diag.c
index 85dddb1e4126..5e8e82db1886 100644
--- a/drivers/s390/block/dasd_diag.c
+++ b/drivers/s390/block/dasd_diag.c
@@ -642,7 +642,7 @@ dasd_diag_init(void)
         }
         ASCEBC(dasd_diag_discipline.ebcname, 4);
 
-        ctl_set_bit(0, 9);
+        service_subclass_irq_register();
         register_external_interrupt(0x2603, dasd_ext_handler);
         dasd_diag_discipline_pointer = &dasd_diag_discipline;
         return 0;
@@ -652,7 +652,7 @@ static void __exit
 dasd_diag_cleanup(void)
 {
         unregister_external_interrupt(0x2603, dasd_ext_handler);
-        ctl_clear_bit(0, 9);
+        service_subclass_irq_unregister();
         dasd_diag_discipline_pointer = NULL;
 }
 
diff --git a/drivers/s390/char/sclp.c b/drivers/s390/char/sclp.c
index b76c61f82485..b37b98cbbd00 100644
--- a/drivers/s390/char/sclp.c
+++ b/drivers/s390/char/sclp.c
@@ -885,12 +885,12 @@ sclp_check_interface(void)
                 spin_unlock_irqrestore(&sclp_lock, flags);
                 /* Enable service-signal interruption - needs to happen
                  * with IRQs enabled. */
-                ctl_set_bit(0, 9);
+                service_subclass_irq_register();
                 /* Wait for signal from interrupt or timeout */
                 sclp_sync_wait();
                 /* Disable service-signal interruption - needs to happen
                  * with IRQs enabled. */
-                ctl_clear_bit(0,9);
+                service_subclass_irq_unregister();
                 spin_lock_irqsave(&sclp_lock, flags);
                 del_timer(&sclp_request_timer);
                 if (sclp_init_req.status == SCLP_REQ_DONE &&
@@ -1070,7 +1070,7 @@ sclp_init(void)
         spin_unlock_irqrestore(&sclp_lock, flags);
         /* Enable service-signal external interruption - needs to happen with
          * IRQs enabled. */
-        ctl_set_bit(0, 9);
+        service_subclass_irq_register();
         sclp_init_mask(1);
         return 0;
 
diff --git a/drivers/s390/kvm/kvm_virtio.c b/drivers/s390/kvm/kvm_virtio.c
index 607998f0b7d8..724b5923b6e2 100644
--- a/drivers/s390/kvm/kvm_virtio.c
+++ b/drivers/s390/kvm/kvm_virtio.c
@@ -441,7 +441,7 @@ static int __init kvm_devices_init(void)
 
         INIT_WORK(&hotplug_work, hotplug_devices);
 
-        ctl_set_bit(0, 9);
+        service_subclass_irq_register();
         register_external_interrupt(0x2603, kvm_extint_handler);
 
         scan_devices();