s390/perf,oprofile: Share sampling facility

Introduce reserve/release functions to share the sampling facility
between perf and oprofile.
Also improve error handling for the sampling facility support in perf.

Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/arch/s390/oprofile/hwsampler.c b/arch/s390/oprofile/hwsampler.c
index bbca76a..eb09587 100644
--- a/arch/s390/oprofile/hwsampler.c
+++ b/arch/s390/oprofile/hwsampler.c
@@ -41,6 +41,7 @@
 
 static unsigned char hws_flush_all;
 static unsigned int hws_oom;
+static unsigned int hws_alert;
 static struct workqueue_struct *hws_wq;
 
 static unsigned int hws_state;
@@ -182,6 +183,9 @@
 	if (!(param32 & CPU_MF_INT_SF_MASK))
 		return;
 
+	if (!hws_alert)
+		return;
+
 	inc_irq_stat(IRQEXT_CMS);
 	atomic_xchg(&cb->ext_params, atomic_read(&cb->ext_params) | param32);
 
@@ -941,6 +945,7 @@
 		goto deallocate_exit;
 
 	irq_subclass_unregister(IRQ_SUBCLASS_MEASUREMENT_ALERT);
+	hws_alert = 0;
 	deallocate_sdbt();
 
 	hws_state = HWS_DEALLOCATED;
@@ -1055,6 +1060,7 @@
 
 		if (hws_state == HWS_STOPPED) {
 			irq_subclass_unregister(IRQ_SUBCLASS_MEASUREMENT_ALERT);
+			hws_alert = 0;
 			deallocate_sdbt();
 		}
 		if (hws_wq) {
@@ -1129,6 +1135,7 @@
 	hws_oom = 1;
 	hws_flush_all = 0;
 	/* now let them in, 1407 CPUMF external interrupts */
+	hws_alert = 1;
 	irq_subclass_register(IRQ_SUBCLASS_MEASUREMENT_ALERT);
 
 	return 0;