[PATCH 3.19.y-ckt 099/196] s390/dasd: fix refcount for PAV reassignment

From: Kamal Mostafa
Date: Tue Mar 08 2016 - 19:34:55 EST


3.19.8-ckt16 -stable review patch. If anyone has any objections, please let me know.

---8<------------------------------------------------------------

From: Stefan Haberland <stefan.haberland@xxxxxxxxxx>

commit 9d862ababb609439c5d6987f6d3ddd09e703aa0b upstream.

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.

Signed-off-by: Stefan Haberland <stefan.haberland@xxxxxxxxxx>
Signed-off-by: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
Signed-off-by: Kamal Mostafa <kamal@xxxxxxxxxxxxx>
---
drivers/s390/block/dasd_alias.c | 21 ++++++++++++++++-----
1 file changed, 16 insertions(+), 5 deletions(-)

diff --git a/drivers/s390/block/dasd_alias.c b/drivers/s390/block/dasd_alias.c
index d52d7a2..6a64e86 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;
}

@@ -926,6 +934,7 @@ 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);
}

@@ -985,6 +994,8 @@ 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);
};
--
2.7.0