[S390] dasd deadlock after state change pending interrupt.

The dasd_device_from_cdev function is called from interrupt context
to get the struct dasd_device associated with a ccw device. The
driver_data of the ccw device points to the dasd_devmap structure
which contains the pointer to the dasd_device structure. The lock
that protects the dasd_devmap structure is acquire with out irqsave.
To prevent the deadlock in dasd_device_from_cdev if it is called
from interrupt context the dependency to the dasd_devmap structure
needs to be removed. Let the driver_data of the ccw device point
to the dasd_device structure directly and use the ccw device lock
to protect the access.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/drivers/s390/block/dasd.c b/drivers/s390/block/dasd.c
index 25c1ef6dfd44..3cd87f85f702 100644
--- a/drivers/s390/block/dasd.c
+++ b/drivers/s390/block/dasd.c
@@ -893,7 +893,7 @@ dasd_handle_killed_request(struct ccw_device *cdev, unsigned long intparm)
 
         device = (struct dasd_device *) cqr->device;
         if (device == NULL ||
-            device != dasd_device_from_cdev(cdev) ||
+            device != dasd_device_from_cdev_locked(cdev) ||
             strncmp(device->discipline->ebcname, (char *) &cqr->magic, 4)) {
                 MESSAGE(KERN_DEBUG, "invalid device in request: bus_id %s",
                         cdev->dev.bus_id);
@@ -970,7 +970,7 @@ dasd_int_handler(struct ccw_device *cdev, unsigned long intparm,
         /* first of all check for state change pending interrupt */
         mask = DEV_STAT_ATTENTION | DEV_STAT_DEV_END | DEV_STAT_UNIT_EXCEP;
         if ((irb->scsw.dstat & mask) == mask) {
-                device = dasd_device_from_cdev(cdev);
+                device = dasd_device_from_cdev_locked(cdev);
                 if (!IS_ERR(device)) {
                         dasd_handle_state_change_pending(device);
                         dasd_put_device(device);