The DASD device driver prevents I/O from being started on stopped
devices. This also prevented channel paths to be verified and so
the device was unable to be resumed.
Fix by allowing path verification requests on stopped devices.
Signed-off-by: NStefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

The DASD device driver only has a limited amount of memory to build
I/O requests.
This memory was used by blocklayer requests leading to an inability
to build needed internal requests to resume the device.
Fix by preventing the DASD driver to fetch requests for a stopped
device.
Signed-off-by: NStefan Haberland <stefan.haberland@de.ibm.com>
Reference-ID: RQM 2520
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Fix ref counting for DASD devices leading to an inability to set a
DASD device offline.
Before a worker is scheduled the DASD device driver takes a reference
to the device. If the worker was already scheduled this reference was
never freed.
Fix by giving the reference to the DASD device free when
schedule_work() returns false.
Signed-off-by: NStefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Remove the hard coded scheduler for the DASD device driver to enable
change of the scheduler during runtime. Set recommended deadline
scheduler via additional udev rule.
Signed-off-by: NStefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Remove the 31 bit support in order to reduce maintenance cost and
effectively remove dead code. Since a couple of years there is no
distribution left that comes with a 31 bit kernel.

The 31 bit kernel also has been broken since more than a year before
anybody noticed. In addition I added a removal warning to the kernel
shown at ipl for 5 minutes: a960062e ("s390: add 31 bit warning
message") which let everybody know about the plan to remove 31 bit
code. We didn't get any response.

Given that the last 31 bit only machine was introduced in 1999 let's
remove the code.
Anybody with 31 bit user space code can still use the compat mode.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

The dasd driver has a lot of duplicated code to handle
dasd_global_profile. With this patch we use the same code for the
global and the per device profiling data. Note that dasd_stats_write
had to change slightly to maintain some odd differences between
A) per device and global profile and B) proc and sysfs interface
usage.
Signed-off-by: NSebastian Ott <sebott@linux.vnet.ibm.com>
Reviewed-by: NStefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Access to DASDs global statistics is done without locking which
can lead to inconsistent data. Add locking to fix this. Also move
the relevant structs in a global dasd_profile struct.
Signed-off-by: NSebastian Ott <sebott@linux.vnet.ibm.com>
Reviewed-by: NStefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Fix race for sleep_on requests leading to list corruption.
The SLEEP_ON_END_TAG is set during CQR clean up. Remove it from
interrupt handler to avoid the CQR from being cleared when it is
still in the device_queue.
Signed-off-by: NStefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

During device activation all paths could be lost and since the device
is not active it has no indication of this fact - hence the CQR will
time-out. The following cancelation might fail with -EINVAL because
CIO took over control and started path verification. In this case mark
the CQR as being CLEARED since it could not be running any more.
Signed-off-by: NStefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Signed-off-by: NStefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Add support for Control Unit Initiated Reconfiguration (CUIR) to
Linux, a storage server interface to reconcile concurrent hardware
changes between storage and host.
Reviewed-by: NStefan Weinhuber <wein@de.ibm.com>
Signed-off-by: NStefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Error recovery requests may not be cleaned up correctly so that other
needed erp requests can not be build because of insufficient memory.
This would lead to an infinite loop trying to build erp requests.
Signed-off-by: NStefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Kernel panic or a hanging device during format if an alias device is
set offline or I/O errors occur.

Omit the error recovery procedure for alias devices and do retries on
the base device with full erp.
Signed-off-by: NStefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

If I/O errors occur during format a kernel panic with a list_del
corruption may occur.

Stop error recovery procedure after an erp action was taken.
Signed-off-by: NStefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

If path events occur the formatting process stucks because path
events may flush format requests from the queue.

Kick the format process after path events are handled.
Signed-off-by: NStefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Formatting of a previously formatted device is slower than newly
format a device when alias devices are available.
For already formatted devices the alias devices are not used for
formatting.

Fix the alias handling for already formatted devices.
Signed-off-by: NStefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Fix checkpatch warnings:
"WARNING: Prefer seq_puts to seq_printf"
Signed-off-by: NFabian Frederick <fabf@skynet.be>
Signed-off-by: NStefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Fix checkpatch warning:
"WARNING: Prefer pr_warn(... to pr_warning(..."
+ coalesce formats.
Signed-off-by: NFabian Frederick <fabf@skynet.be>
Signed-off-by: NStefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Fix checkpatch warnings:
"WARNING: EXPORT_SYMBOL(foo); should immediately follow its function/variable"
Signed-off-by: NFabian Frederick <fabf@skynet.be>
Signed-off-by: NStefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

This fixes checkpatch warning:
"WARNING: debugfs_remove(NULL) is safe this check is probably not required"
Signed-off-by: NFabian Frederick <fabf@skynet.be>
Signed-off-by: NStefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Signed-off-by: NHendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

"elevator: Fix a race in elevator switching and md device initialization"
changed the semantics of elevator_init() in a way that now enforces to hold
the corresponding request queue's sysfs_lock when calling elevator_init()
to fix a race.
The patch did not convert the s390 dasd device driver which is the only
device driver which also calls elevator_init(). So add the missing locking.

Cc: Tomoki Sekiyama <tomoki.sekiyama@hds.com>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

We check for the existence of block->profile.data before we write to
it, but the dependent code block misses braces.
Signed-off-by: NStefan Weinhuber <wein@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

The processing of the dasd_block tasklet may have been interrupted
by a path event.
Restart the dasd tasklets in sleep_on_immediately function.
Signed-off-by: NStefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Whenever a DASD request encounters a timeout we might
need to abort all outstanding requests on this or
even other devices.

This is especially useful if one wants to fail all
devices on one side of a RAID10 configuration, even
though only one device exhibited an error.

To handle this I've introduced a new device flag
DASD_FLAG_ABORTIO.
This flag is evaluated in __dasd_process_request_queue()
and will invoke blk_abort_request() for all
outstanding requests with DASD_CQR_FLAGS_FAILFAST set.
This will cause any of these requests to be aborted
immediately if the blk_timeout function is activated.

The DASD_FLAG_ABORTIO is also evaluated in
__dasd_process_request_queue to abort all
new request which would have the
DASD_CQR_FLAGS_FAILFAST bit set.

The flag can be set with the new ioctls 'BIODASDABORTIO'
and removed with 'BIODASDALLOWIO'.
Signed-off-by: NHannes Reinecke <hare@suse.de>
Signed-off-by: NStefan Weinhuber <wein@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

This patch adds a 'timeout' attibute to the DASD driver.
When set to non-zero, the blk_timeout function will
be enabled with the timeout specified in the attribute.
Setting 'timeout' to '0' will disable block timeouts.
Signed-off-by: NHannes Reinecke <hare@suse.de>
Signed-off-by: NStefan Weinhuber <wein@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

The DASD driver is using FASTFAIL as an equivalent to the
transport errors in SCSI. And the 'steal lock' function maps
roughly to a reservation error. So we should be returning the
appropriate error codes when completing a request.
Acked-by: NJens Axboe <axboe@kernel.dk>
Signed-off-by: NHannes Reinecke <hare@suse.de>
Signed-off-by: NStefan Weinhuber <wein@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

This patch implements generic block layer timeout handling
callbacks for DASDs. When the timeout expires the respective
cqr is aborted.

With this timeout handler time-critical request abort
is guaranteed as the abort does not depend on the internal
state of the various DASD driver queues.
Signed-off-by: NHannes Reinecke <hare@suse.de>
Acked-by: NStefan Weinhuber <wein@de.ibm.com>
Signed-off-by: NStefan Weinhuber <wein@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Originally the DASD device tasklet would process the entries on
the ccw_queue until the first non-final request was found.
Which was okay as long as all requests have the same retries and
expires parameter.
However, as we're now allowing to modify both it is possible to
have requests _after_ the first request which already have expired.
So we need to check all requests in the device tasklet.
Signed-off-by: NHannes Reinecke <hare@suse.de>
Signed-off-by: NStefan Weinhuber <wein@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

dasd_cancel_req will never return 1, only 0.
Signed-off-by: NHannes Reinecke <hare@suse.de>
Signed-off-by: NStefan Weinhuber <wein@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

When a path is gone and dasd_generic_path_event is called with a
PE_PATH_GONE event, we must assume that any I/O request on that
subchannel is still running. This is unlike the dasd_generic_notify
handler and the CIO_NO_PATH event, which implies that the subchannel
has been cleared.
If dasd_generic_path_event finds that the path has been the last
usable path, it must not call dasd_generic_last_path_gone (which would
reset the state of running requests), but just set the
DASD_STOPPED_DC_WAIT bit.
Signed-off-by: NStefan Weinhuber <wein@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

The value passed is 0 in all but "it can never happen" cases (and those
only in a couple of drivers) *and* it would've been lost on the way
out anyway, even if something tried to pass something meaningful.
Just don't bother.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

If too many ccw requests are pre-build before a suspend/resume cycle
the device might not get enough memory to do path verification
during resume.
Requeue requests to the block device request queue on suspend and free
pre-build ccw requests.
Signed-off-by: NStefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Reorganize format IO requests and enable usage of PAV.
Signed-off-by: NStefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

When the DASD devices are detached from the driver, then the
dasd_generic_remove function is called. One of the things this
function should do is to remove the DASD specific sysfs attributes,
but this is not done in all cases. This is likely to cause an oops
when at a later point sysfs stumbles over the stale pointers. In
particular this happens when when the modules are unloaded and loaded
again.
Signed-off-by: NStefan Weinhuber <wein@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Fix name clash with some common code device drivers and add "tod"
to all tod clock access function names.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

The regular behavior of the DASD device driver when setting a device
offline is to return all outstanding I/O as failed. This behavior is
different from that of other System z operating systems and may lead
to unexpected data loss. Adding an explicit 'safe' offline function
will allow customers to use DASDs in the way they expect them to work.
Signed-off-by: NStefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

If a new path is available we need to verify the path data. If it is the
first path for a device the stop bits are removed after path verification.
If a pathgroup is established we need to set system characteristics for
the lcu. Therefore I/O has to be started.
If the device is stopped the set system characteristics worker may block
the path verification worker and the device is blocked.

Turn on failfast for set system characteristics CQR to prevent a deadlock
with the path verification worker.

If a pathgroup is established on a device that is not in use trigger path
verification. Maybe we were not informed about a working path.
Signed-off-by: NStefan Haberland <stefan.haberland@de.ibm.com>
Reviewed-by: NStefan Weinhuber <wein@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Ensure that all work is done when the process waiting for a
dasd state change is woken up. With this change it is save
to assume that after a userspace triggered state change and
a udev settle invocation there are no unexpected users of a
dasd device.
Acked-by: NStefan Weinhuber <wein@de.ibm.com>
Signed-off-by: NSebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Remove the file name from the comment at top of many files. In most
cases the file name was wrong anyway, so it's rather pointless.

Also unify the IBM copyright statement. We did have a lot of sightly
different statements and wanted to change them one after another
whenever a file gets touched. However that never happened. Instead
people start to take the old/"wrong" statements to use as a template
for new files.
So unify all of them in one go.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>