[S390] dasd: ignore unsolicited interrupts for DIAG

For the DASD DIAG discipline IO is started through special diagnose
calls. Unsolicited interrupts may contain information about the device
itself. But this information is not needed because the device is not
used directly.
Fix the case that an unimplemented dicipline function may be called
by ignoring unsolicited interrupts for the DIAG disciplin.

Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 14 insertions, 9 deletions

diff --git a/drivers/s390/block/dasd.c b/drivers/s390/block/dasd.c
index 80e45de096a9..fb613d70c2cb 100644
--- a/drivers/s390/block/dasd.c
+++ b/drivers/s390/block/dasd.c
@@ -1107,17 +1107,22 @@ void dasd_int_handler(struct ccw_device *cdev, unsigned long intparm,
                 if (cqr)
                         memcpy(&cqr->irb, irb, sizeof(*irb));
                 device = dasd_device_from_cdev_locked(cdev);
-                if (!IS_ERR(device)) {
-                        device->discipline->dump_sense_dbf(device, irb,
-                                                           "unsolicited");
-                        if ((device->features & DASD_FEATURE_ERPLOG))
-                                device->discipline->dump_sense(device, cqr,
-                                                               irb);
-                        dasd_device_clear_timer(device);
-                        device->discipline->handle_unsolicited_interrupt(device,
-                                                                         irb);
+                if (IS_ERR(device))
+                        return;
+                /* ignore unsolicited interrupts for DIAG discipline */
+                if (device->discipline == dasd_diag_discipline_pointer) {
                         dasd_put_device(device);
+                        return;
                 }
+                device->discipline->dump_sense_dbf(device, irb,
+                                                   "unsolicited");
+                if ((device->features & DASD_FEATURE_ERPLOG))
+                        device->discipline->dump_sense(device, cqr,
+                                                       irb);
+                dasd_device_clear_timer(device);
+                device->discipline->handle_unsolicited_interrupt(device,
+                                                                 irb);
+                dasd_put_device(device);
                 return;
         }