v4.19.13 snapshot.
diff --git a/arch/s390/include/asm/isc.h b/arch/s390/include/asm/isc.h
new file mode 100644
index 0000000..6cb9e2e
--- /dev/null
+++ b/arch/s390/include/asm/isc.h
@@ -0,0 +1,30 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_S390_ISC_H
+#define _ASM_S390_ISC_H
+
+#include <linux/types.h>
+
+/*
+ * I/O interruption subclasses used by drivers.
+ * Please add all used iscs here so that it is possible to distribute
+ * isc usage between drivers.
+ * Reminder: 0 is highest priority, 7 lowest.
+ */
+#define MAX_ISC 7
+
+/* Regular I/O interrupts. */
+#define IO_SCH_ISC 3 /* regular I/O subchannels */
+#define CONSOLE_ISC 1 /* console I/O subchannel */
+#define EADM_SCH_ISC 4 /* EADM subchannels */
+#define CHSC_SCH_ISC 7 /* CHSC subchannels */
+#define VFIO_CCW_ISC IO_SCH_ISC /* VFIO-CCW I/O subchannels */
+/* Adapter interrupts. */
+#define QDIO_AIRQ_ISC IO_SCH_ISC /* I/O subchannel in qdio mode */
+#define PCI_ISC 2 /* PCI I/O subchannels */
+#define AP_ISC 6 /* adjunct processor (crypto) devices */
+
+/* Functions for registration of I/O interruption subclasses */
+void isc_register(unsigned int isc);
+void isc_unregister(unsigned int isc);
+
+#endif /* _ASM_S390_ISC_H */