[S390] tape: add support for irq statistics

Add support for ccw based tape I/O interrupt statistics in /proc/interrupts.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/include/asm/irq.h

@@ -20,6 +20,7 @@ enum interruption_class {
 	IOINT_DAS,
 	IOINT_C15,
 	IOINT_C70,
+	IOINT_TAP,
 	NMI_NMI,
 	NR_IRQS,
 };

arch/s390/kernel/irq.c

@@ -37,6 +37,7 @@ static const struct irq_class intrclass_names[] = {
 	{.name = "DAS", .desc = "[I/O] DASD" },
 	{.name = "C15", .desc = "[I/O] 3215" },
 	{.name = "C70", .desc = "[I/O] 3270" },
+	{.name = "TAP", .desc = "[I/O] Tape" },
 	{.name = "NMI", .desc = "[NMI] Machine Check" },
 };
 

drivers/s390/char/tape_core.c

@@ -14,6 +14,7 @@
 #define KMSG_COMPONENT "tape"
 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
 
+#include <linux/kernel_stat.h>
 #include <linux/module.h>
 #include <linux/init.h>	     // for kernel parameters
 #include <linux/kmod.h>	     // for requesting modules
@@ -1114,6 +1115,7 @@ __tape_do_irq (struct ccw_device *cdev, unsigned long intparm, struct irb *irb)
 	struct tape_request *request;
 	int rc;
 
+	kstat_cpu(smp_processor_id()).irqs[IOINT_TAP]++;
 	device = dev_get_drvdata(&cdev->dev);
 	if (device == NULL) {
 		return;