s390/dasd: fix refcount for PAV reassignment

Add refcount to the DASD device when a summary unit check worker is
scheduled. This prevents that the device is set offline with worker
in place.

Cc: stable@vger.kernel.org
Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 16 insertions, 5 deletions

diff --git a/drivers/s390/block/dasd_alias.c b/drivers/s390/block/dasd_alias.c
index 4ff914c0f13c..286782c60da4 100644
--- a/drivers/s390/block/dasd_alias.c
+++ b/drivers/s390/block/dasd_alias.c
@@ -264,8 +264,10 @@ void dasd_alias_disconnect_device_from_lcu(struct dasd_device *device)
                 spin_unlock_irqrestore(&lcu->lock, flags);
                 cancel_work_sync(&lcu->suc_data.worker);
                 spin_lock_irqsave(&lcu->lock, flags);
-                if (device == lcu->suc_data.device)
+                if (device == lcu->suc_data.device) {
+                        dasd_put_device(device);
                         lcu->suc_data.device = NULL;
+                }
         }
         was_pending = 0;
         if (device == lcu->ruac_data.device) {
@@ -273,8 +275,10 @@ void dasd_alias_disconnect_device_from_lcu(struct dasd_device *device)
                 was_pending = 1;
                 cancel_delayed_work_sync(&lcu->ruac_data.dwork);
                 spin_lock_irqsave(&lcu->lock, flags);
-                if (device == lcu->ruac_data.device)
+                if (device == lcu->ruac_data.device) {
+                        dasd_put_device(device);
                         lcu->ruac_data.device = NULL;
+                }
         }
         private->lcu = NULL;
         spin_unlock_irqrestore(&lcu->lock, flags);
@@ -549,8 +553,10 @@ static void lcu_update_work(struct work_struct *work)
         if ((rc && (rc != -EOPNOTSUPP)) || (lcu->flags & NEED_UAC_UPDATE)) {
                 DBF_DEV_EVENT(DBF_WARNING, device, "could not update"
                             " alias data in lcu (rc = %d), retry later", rc);
-                schedule_delayed_work(&lcu->ruac_data.dwork, 30*HZ);
+                if (!schedule_delayed_work(&lcu->ruac_data.dwork, 30*HZ))
+                        dasd_put_device(device);
         } else {
+                dasd_put_device(device);
                 lcu->ruac_data.device = NULL;
                 lcu->flags &= ~UPDATE_PENDING;
         }
@@ -593,8 +599,10 @@ static int _schedule_lcu_update(struct alias_lcu *lcu,
          */
         if (!usedev)
                 return -EINVAL;
+        dasd_get_device(usedev);
         lcu->ruac_data.device = usedev;
-        schedule_delayed_work(&lcu->ruac_data.dwork, 0);
+        if (!schedule_delayed_work(&lcu->ruac_data.dwork, 0))
+                dasd_put_device(usedev);
         return 0;
 }
 
@@ -930,6 +938,7 @@ static void summary_unit_check_handling_work(struct work_struct *work)
         /* 3. read new alias configuration */
         _schedule_lcu_update(lcu, device);
         lcu->suc_data.device = NULL;
+        dasd_put_device(device);
         spin_unlock_irqrestore(&lcu->lock, flags);
 }
 
@@ -989,6 +998,8 @@ void dasd_alias_handle_summary_unit_check(struct dasd_device *device,
         }
         lcu->suc_data.reason = reason;
         lcu->suc_data.device = device;
+        dasd_get_device(device);
         spin_unlock(&lcu->lock);
-        schedule_work(&lcu->suc_data.worker);
+        if (!schedule_work(&lcu->suc_data.worker))
+                dasd_put_device(device);
 };