kernel.git/drivers/s390/block/dasd_alias.c, branch linux-4.8.y

s390/dasd: reorder lcu and device lock

2016-03-17T12:18:25Z

Reorder lcu and device lock to get rid of the error-prone trylock mechanism. The locking order is lcu lock -> device lock. This protects against changes to the lcu device lists and enables us to iterate over the devices, take the cdev lock and make changes to the device structures. The complicated part is the summary unit check handler that gets an interrupt on one device of the lcu that leads to structural changes of the whole lcu itself. This work needs to be done even if devices on the lcu disappear. So a device independent worker is used. The old approach tried to update some lcu structures and set up the lcu worker in the interrupt context with the device lock held. But this forced the lock order "cdev lock -> lcu lock" that made it hard to have the lcu lock held and iterate over all devices and change them. The new approach is to schedule a device specific worker that gets out of the interrupt context and rid of the device lock for summary unit checks. This worker is able to take the lcu lock and schedule the lcu worker that updates all devices. The time between interrupt and worker execution is no problem because the devices in the lcu reject all I/O in this time with an appropriate error. The dasd driver can deal with this situation and re-drive the I/O later on. Signed-off-by: Stefan Haberland Signed-off-by: Martin Schwidefsky

s390/dasd: remove casts to dasd_*_private

2016-03-07T12:12:02Z

Convert dasd_device.private to be a void pointer to get rid of a lot of explicit casts. Signed-off-by: Sebastian Ott Reviewed-by: Stefan Haberland Acked-by: Heiko Carstens Signed-off-by: Martin Schwidefsky

s390/dasd: fix incorrect locking order for LCU device add/remove

2016-02-23T07:56:19Z

The correct lock order for LCU lock and cdev lock is to take the cdev lock first and afterwards the LCU lock. This is caused by the fact that LCU functions are called in an interrupt context with the cdev lock implicitly hold by CIO. To assure the right locking order but also be able to iterate over devices in a LCU introduce a trylock block that can be called with the device lock for one device hold and then takes the LCU lock and try to lock all devices accounted to this LCU. Afterwards all devices and the LCU itself are locked. Signed-off-by: Stefan Haberland Signed-off-by: Martin Schwidefsky

s390/dasd: fix refcount for PAV reassignment

2016-02-11T12:05:55Z

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 Signed-off-by: Martin Schwidefsky

s390/dasd: prevent incorrect length error under z/VM after PAV changes

2016-02-11T12:05:53Z

The channel checks the specified length and the provided amount of data for CCWs and provides an incorrect length error if the size does not match. Under z/VM with simulation activated the length may get changed. Having the suppress length indication bit set is stated as good CCW coding practice and avoids errors under z/VM. Cc: stable@vger.kernel.org Signed-off-by: Stefan Haberland Signed-off-by: Martin Schwidefsky

s390/dasd: fix list_del corruption after lcu changes

2015-10-15T07:28:15Z

A summary unit check occurs when the lcu updates the PAV configuration e.g. base PAV assignment or PAV mode at all. This requires the reset of the drivers internal pavgroups. Therefore the alias devices are flushed and moved via a temporary list to the active_devices list where they are not associated with a pavgroup. In conjunction with updates to the base device the pavgroup may be removed since both base_list and alias_list are empty. Unfortunately during alias flush and move to the active_device list from alias_list the pavgroup pointer is not deleted in the device private structure. This leads to a list del_corruption if another lcu_update tries to move the device in the non existent pavgroup. Fix by removing the pavgroup pointer after the alias device was moved to the active_devices list. Signed-off-by: Stefan Haberland Signed-off-by: Martin Schwidefsky

s390: remove unneeded semicolon

2015-08-07T07:57:00Z

Remove unneeded semicolon. The semantic patch that detects this change is available at scripts/coccinelle/misc/semicolon.cocci. Signed-off-by: Peter Senna Tschudin Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky

s390/dasd: fix kernel panic when alias is set offline

2015-07-13T09:02:14Z

The dasd device driver selects which (alias or base) device is used for a given requests when the request is build. If the chosen alias device is set offline before the request gets queued to the device queue the starting function may use device structures that are already freed. This might lead to a hanging offline process or a kernel panic. Add a check to the starting function that returns the request to the upper layer if the device is already in offline processing. In addition to that prevent that an alias device that's already in offline processing gets chosen as start device. Reviewed-by: Sebastian Ott Reviewed-by: Peter Oberparleiter Signed-off-by: Stefan Haberland Signed-off-by: Martin Schwidefsky

s390/time: rename tod clock access functions

2013-02-14T14:55:10Z

Fix name clash with some common code device drivers and add "tod" to all tod clock access function names. Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky

s390/dasd: fix read unit address configuration loop

2012-09-17T07:58:21Z

Read unit address is done for all devices during online processing to read out LCU features. This is also done after disconnect/connect a LCU. Some older storage hardware does not provide the capability to read unit address configuration. This leads to a loop trying to read unit address configuration every 30 seconds. The device is still operational but logs are flooded with error messages. Fix the loop by recognizing a command reject saying that the suborder for ruac is not supported. Signed-off-by: Stefan Haberland Signed-off-by: Martin Schwidefsky