[S390] irqstats: fix counting of pfault, dasd diag and virtio irqs

pfault, dasd diag and virtio all use the same external interrupt number.
The respective interrupt handlers decide by the subcode if they are
meant to handle the interrupt.
Counting is currently done before looking at the subcode which means
each handler counts an interrupt even if it is not handling it.
Fix this by moving the kstat code after the code which looks at the
subcode.

Signed-off-by: Heiko Carstens <[e-mail]>
Signed-off-by: Martin Schwidefsky <[e-mail]>

arch/s390/mm/fault.c

···
 	struct task_struct *tsk;
 	__u16 subcode;
 
-	kstat_cpu(smp_processor_id()).irqs[EXTINT_PFL]++;
 	/*
 	 * Get the external interruption subcode & pfault
 	 * initial/completion signal bit. VM stores this 
···
 	subcode = ext_int_code >> 16;
 	if ((subcode & 0xff00) != __SUBCODE_MASK)
 		return;
+	kstat_cpu(smp_processor_id()).irqs[EXTINT_PFL]++;
 
 	/*
 	 * Get the token (= address of the task structure of the affected task).

drivers/s390/block/dasd_diag.c

···
 	addr_t ip;
 	int rc;
 
-	kstat_cpu(smp_processor_id()).irqs[EXTINT_DSD]++;
 	switch (ext_int_code >> 24) {
 	case DASD_DIAG_CODE_31BIT:
 		ip = (addr_t) param32;
···
 	default:
 		return;
 	}
+	kstat_cpu(smp_processor_id()).irqs[EXTINT_DSD]++;
 	if (!ip) {		/* no intparm: unsolicited interrupt */
 		DBF_EVENT(DBF_NOTICE, "%s", "caught unsolicited "
 			      "interrupt");

drivers/s390/kvm/kvm_virtio.c

···
 	u16 subcode;
 	u32 param;
 
-	kstat_cpu(smp_processor_id()).irqs[EXTINT_VRT]++;
 	subcode = ext_int_code >> 16;
 	if ((subcode & 0xff00) != VIRTIO_SUBCODE_64)
 		return;
+	kstat_cpu(smp_processor_id()).irqs[EXTINT_VRT]++;
 
 	/* The LSB might be overloaded, we have to mask it */
 	vq = (struct virtqueue *)(param64 & ~1UL);