s390/cio: Initialize the host addresses in pfn_array

Let's initialize the host address to something that is invalid,
rather than letting it default to zero.  This just makes it easier
to notice when a pin operation has failed or been skipped.
Signed-off-by: Eric Farman <farman@linux.ibm.com>
Message-Id: <20190514234248.36203-5-farman@linux.ibm.com>
Reviewed-by: Farhan Ali <alifm@linux.ibm.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>

drivers/s390/cio/vfio_ccw_cp.c

@@ -91,8 +91,11 @@ static int pfn_array_alloc(struct pfn_array *pa, u64 iova, unsigned int len)
 	pa->pa_pfn = pa->pa_iova_pfn + pa->pa_nr;
 
 	pa->pa_iova_pfn[0] = pa->pa_iova >> PAGE_SHIFT;
-	for (i = 1; i < pa->pa_nr; i++)
+	pa->pa_pfn[0] = -1ULL;
+	for (i = 1; i < pa->pa_nr; i++) {
 		pa->pa_iova_pfn[i] = pa->pa_iova_pfn[i - 1] + 1;
+		pa->pa_pfn[i] = -1ULL;
+	}
 
 	return 0;
 }