s390/dasd: Fix locking issue when changing EER attribute
The reference to a device in question may get lost when the extended
error reporting (EER) attribute is being enabled/disabled while the
device is set offline at the same time. This is due to missing
refcounting and incorrect locking. Fix this by the following:
- In dasd_eer_store() get the device directly and handle the refcount
accordingly.
- Move the lock in dasd_eer_enable() up so we can ensure safe
processing.
- Check if the device is being set offline and return with -EBUSY if so.
- While at it, change the return code from -EPERM to -EMEDIUMTYPE as
suggested by a FIXME, since that is what we're actually checking.
Reviewed-by: Stefan Haberland <sth@linux.vnet.ibm.com>
Signed-off-by: Jan Höppner <hoeppner@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2 files changed
