linux-toradex.git/drivers/s390/block/dasd_devmap.c, branch v5.0

s390/dasd,zfcp: fix gcc 8 stringop-truncation warnings

2018-07-02T09:24:52+00:00

ccw "busid" should always be NUL-terminated, as evident from e.g.
get_ccwdev_by_busid doing "return (strcmp(bus_id, dev_name(dev)) == 0)".

Replace all strncpy initializing busid with strlcpy. This fixes the
following gcc 8 warnings:

drivers/s390/scsi/zfcp_aux.c:104:2: warning: 'strncpy' specified bound 20
equals destination size [-Wstringop-truncation]
  strncpy(busid, token, ZFCP_BUS_ID_SIZE);

drivers/s390/block/dasd_eer.c:316:2: warning: 'strncpy' specified bound 10
equals destination size [-Wstringop-truncation]
  strncpy(header.busid, dev_name(&device->cdev->dev), DASD_EER_BUSID_SIZE);

drivers/s390/block/dasd_eer.c:359:2: warning: 'strncpy' specified bound 10
equals destination size [-Wstringop-truncation]
  strncpy(header.busid, dev_name(&device->cdev->dev), DASD_EER_BUSID_SIZE);

drivers/s390/block/dasd_devmap.c:429:3: warning: 'strncpy' specified bound
20 equals destination size [-Wstringop-truncation]
   strncpy(new->bus_id, bus_id, DASD_BUS_ID_SIZE);

Acked-by: Stefan Haberland 
Acked-by: Steffen Maier 
Reviewed-by: Heiko Carstens 
Signed-off-by: Vasily Gorbik 
Signed-off-by: Martin Schwidefsky

s390/dasd: configurable IFCC handling

2018-02-22T14:31:23+00:00

Make the behavior in case of constant IFCC/CCC errors configurable.
Add a sysfs attribute to switch between path disabled after threshold
exceeded (default) and message only.

Reviewed-by: Jan Hoeppner 
Reviewed-by: Sebastian Ott 
Signed-off-by: Stefan Haberland 
Signed-off-by: Martin Schwidefsky

s390: block: add SPDX identifiers to the remaining files

2017-11-24T13:28:37+00:00

It's good to have SPDX identifiers in all files to make it easier to
audit the kernel tree for correct licenses.

Update the drivers/s390/block/ files with the correct SPDX license
identifier based on the license text in the file itself.  The SPDX
identifier is a legally binding shorthand, which can be used instead of
the full boiler plate text.

This work is based on a script and data from Thomas Gleixner, Philippe
Ombredanne, and Kate Stewart.

Cc: Stefan Haberland 
Cc: Jan Hoeppner 
Cc: Martin Schwidefsky 
Cc: Heiko Carstens 
Cc: Thomas Gleixner 
Cc: Kate Stewart 
Cc: Philippe Ombredanne 
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Heiko Carstens 
Signed-off-by: Martin Schwidefsky

s390/dasd: blk-mq conversion

2017-09-08T13:31:08+00:00

Use new blk-mq interfaces. Use multiple queues and also use the block
layer complete helper that finish the IO on the CPU that initiated it.

Reviewed-by: Jan Hoeppner 
Signed-off-by: Stefan Haberland 
Signed-off-by: Martin Schwidefsky

s390/dasd: Add discard support for FBA devices

2017-08-29T14:31:26+00:00

The z/VM hypervisor provides virtual disks (VDISK) which are backed by
main memory of the hypervisor. Those devices are seen as DASD FBA disks
within the Linux guest.

Whenever data is written to such a device, memory is allocated
on-the-fly by z/VM accordingly. This memory, however, is not being freed
if data on the device is deleted by the guest OS.

In order to make memory usable after deletion again, add discard support
to the FBA discipline.

While at it, update comments regarding the DASD_FEATURE_* flags.

Reviewed-by: Stefan Haberland 
Signed-off-by: Jan Höppner 
Signed-off-by: Martin Schwidefsky

s390/dasd: constify attribute_group structures.

2017-07-26T06:25:17+00:00

attribute_group are not supposed to change at runtime. All functions
working with attribute_group provided by  work
with const attribute_group. So mark the non-const structs as const.

Signed-off-by: Arvind Yadav 
Signed-off-by: Martin Schwidefsky

s390/dasd: remove unneeded code

2017-07-05T05:35:29+00:00

Fix these set but not used warnings:

drivers/s390/block/dasd.c:3933:6: warning: variable 'rc' set but not used [-Wunused-but-set-variable]
drivers/s390/block/dasd_alias.c:757:6: warning: variable 'rc' set but not used [-Wunused-but-set-variable]

In addition to that remove the test if an unsigned is < 0:

drivers/s390/block/dasd_devmap.c:153:11: warning: comparison of unsigned expression < 0 is always false [-Wtype-limits]

Signed-off-by: Sebastian Ott 
Signed-off-by: Martin Schwidefsky

s390/dasd: Fix faulty ENODEV for RO sysfs attribute

2017-06-28T05:32:15+00:00

If a device is offline it can still be set to read-only via the bus id
through sysfs. Only the read-only feature flag for the ccw_device is
then set. If the device is online the corresponding block device needs
to be set to read-only as well (via set_disk_ro()).
The check whether there is a device to do so, however, happens after the
feature flag was set. This leads to an unnecessary "no such device"
error in the offline case.

This bug was introduced by commit 7571cb1c8e3cc ("s390/dasd: Make use of
dasd_set_feature() more often"). Fix this by simply returning count if
no device is available.

Fixes: 7571cb1c8e3cc ("s390/dasd: Make use of dasd_set_feature() more often")
Reviewed-by: Stefan Haberland 
Signed-off-by: Jan Höppner 
Signed-off-by: Martin Schwidefsky

s390/dasd: fix unusable device after safe offline processing

2017-06-12T14:26:01+00:00

The safe offline processing needs, as well as the normal offline
processing, to be locked against multiple parallel executions. But it
should be able to be overtaken by a normal offline processing to make sure
that the device does not wait forever for outstanding I/O if the user
wants to.

Unfortunately the parallel processing of safe offline and normal offline
might lead to a race situation where both threads report successful
execution to the CIO layer which in turn tries to deregister the kobject
of the device twice. This leads to a

refcount_t: underflow; use-after-free.

error and the device is not able to be set online again afterwards without
a reboot.

Correct the locking of the safe offline processing by doing the following:
	- Use the cdev lock to secure all set and test operations to the
	  device flags.
	- Two safe offline processes are locked against each other using
	  the DASD_FLAG_SAFE_OFFLINE and DASD_FLAG_SAFE_OFFLINE_RUNNING
	  device flags.
	  The differentiation between offline triggered and offline running
	  is needed since the normal offline attribute is owned by CIO and
	  we have to pass over control in between.
	- The dasd_generic_set_offline process handles the offline
	  processing. It is locked against parallel execution using the
	  DASD_FLAG_OFFLINE.
	- Only a running safe offline should be able to be overtaken by a
	  single normal offline. This is ensured by clearing the
	  DASD_FLAG_SAFE_OFFLINE_RUNNING flag when a normal offline
	  overtakes. So this can only happen ones.
	- The safe offline just aborts in this case doing nothing and
	  the normal offline processing finishes as usual.

Signed-off-by: Stefan Haberland 
Signed-off-by: Martin Schwidefsky

s390/dasd: Display read-only attribute correctly

2017-06-12T14:26:00+00:00

We have two flags, DASD_FLAG_DEVICE_RO and DASD_FEATURE_READONLY, that
tell us whether a device is read-only. DASD_FLAG_DEVICE_RO is set when a
device is attached as read-only to z/VM and DASD_FEATURE_READONLY is set
when either the corresponding kernel parameter is configured, or the
read-only state is changed via sysfs.
This is valuable information in any case. However, only the feature flag
is being checked at the moment when we display the current state.

Fix this by checking both flags.

Reviewed-by: Stefan Haberland 
Signed-off-by: Jan Höppner 
Signed-off-by: Martin Schwidefsky