When the connection between host and storage server is lost, the
dasd device driver usually blocks all I/O on affected devices and
waits for them to reappear. In some setups however it would be
better if the I/O is returned as error so that device can be
recovered by some other means, eg. in a raid or multipath setup.
Signed-off-by: NHolger Smolinski <Holger.Smolinski@de.ibm.com>
Signed-off-by: NStefan Weinhuber <wein@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Multipath is best at handling transport errors. If it gets a device
error then there is not much the multipath layer can do. It will just
access the same device but from a different path.

This patch breaks up failfast into device, transport and driver errors.
The multipath layers (md and dm mutlipath) only ask the lower levels to
fast fail transport errors. The user of failfast, read ahead, will ask
to fast fail on all errors.

Note that blk_noretry_request will return true if any failfast bit
is set. This allows drivers that do not support the multipath failfast
bits to continue to fail on any failfast error like before. Drivers
like scsi that are able to fail fast specific errors can check
for the specific fail fast type. In the next patch I will convert
scsi.
Signed-off-by: NMike Christie <michaelc@cs.wisc.edu>
Cc: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

return value -ENOTSUPP is not valid in userspace context, use
-EOPNOTSUPP instead
Signed-off-by: NStefan Haberland <stefan.haberland@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>

Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>

Parallel access volumes (PAV) is a storage server feature, that allows
to start multiple channel programs on the same DASD in parallel. It
defines alias devices which can be used as alternative paths to the
same disk. With the old base PAV support we only needed rudimentary
functionality in the DASD device driver. As the mapping between base
and alias devices was static, we just had to export an identifier
(uid) and could leave the combining of devices to external layers
like a device mapper multipath.
Now hyper PAV removes the requirement to dedicate alias devices to
specific base devices. Instead each alias devices can be combined with
multiple base device on a per request basis. This requires full
support by the DASD device driver as now each channel program itself
has to identify the target base device.
The changes to the dasd device driver and the ECKD discipline are:
- Separate subchannel device representation (dasd_device) from block
  device representation (dasd_block). Only base devices are block
  devices.
- Gather information about base and alias devices and possible
  combinations.
- For each request decide which dasd_device should be used (base or
  alias) and build specific channel program.
- Support summary unit checks, which allow the storage server to
  upgrade / downgrade between base and hyper PAV at runtime (support
  is mandatory).
Signed-off-by: NStefan Weinhuber <wein@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Remove one level of nesting where appropriate.
Signed-off-by: NJens Axboe <jens.axboe@oracle.com>

Every usage of rq_for_each_bio wraps a usage of
bio_for_each_segment, so these can be combined into
rq_for_each_segment.

We define "struct req_iterator" to hold the 'bio' and 'index' that
are needed for the double iteration.
Signed-off-by: NNeil Brown <neilb@suse.de>

Various compile fixes by me...
Signed-off-by: NJens Axboe <jens.axboe@oracle.com>

There are several s390 diagnose calls, which must be executed below the
2GB memory boundary. In order to enforce this, those diagnoses must be
compiled into the kernel. Currently diag 14 can be called within the
vmur kernel module from addresses above 2GB. This leads to specification
exceptions. This patch moves diag10, diag14 and diag210 into the new
diag.c file.
Signed-off-by: NMichael Holzheu <holzheu@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>

The function shouldn't have existed in the first place (not MSS-aware).
Introduce a new function ccw_device_get_id() that extracts the
ccw_dev_id structure of a ccw device and convert all users of
_ccw_device_get_device_number to ccw_device_get_id.
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

gcc incorrectly removes initialization of register 0 in dasd diag
inline assembly. Use different register to work around this compiler
bug.

Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: NPeter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>

Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Right now ->flags is a bit of a mess: some are request types, and
others are just modifiers. Clean this up by splitting it into
->cmd_type and ->cmd_flags. This allows introduction of generic
Linux block message types, useful for sending generic Linux commands
to block devices.
Signed-off-by: NJens Axboe <axboe@suse.de>

Major cleanup of all s390 inline assemblies. They now have a common
coding style. Quite a few have been shortened, mainly by using register
asm variables. Use of the EX_TABLE macro helps  as well. The atomic ops,
bit ops and locking inlines new use the Q-constraint if a newer gcc
is used.  That results in slightly better code.

Thanks to Christian Borntraeger for proof reading the changes.
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Signed-off-by: NJörn Engel <joern@wohnheim.fh-wedel.de>
Signed-off-by: NAdrian Bunk <bunk@stusta.de>

Dasd code cleanup: 1) remove white space, 2) remove the emacs override
sections, and 3) use kzalloc instead of kmalloc.
Signed-off-by: NHorst Hummel <horst.hummel@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

- Remove all CVS generated information like e.g. revision IDs from
  drivers/s390 and include/asm-s390 (none present in arch/s390).

- Add newline at end of arch/s390/lib/Makefile to avoid diff message.
Acked-by: NAndreas Herrmann <aherrman@de.ibm.com>
Acked-by: NFrank Pavlic <pavlic@de.ibm.com>
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Sanitize some s390 Kconfig options.  We have ARCH_S390, ARCH_S390X,
ARCH_S390_31, 64BIT, S390_SUPPORT and COMPAT.  Replace these 6 options by
S390, 64BIT and COMPAT.
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

To properly support multipath-failover handling, the linux block layer has
introduced a special request flag, 'REQ_FAILFAST'.  This flag is now used to
return requests immediately in case the device is not operational.
Signed-off-by: NHorst Hummel <horst.hummel@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Moved definition of CMS volume label to vtoc.h and modify partitions/ibm.c to
use this volume label definition instead of anonymous array.
Signed-off-by: NPeter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Access to FBA disks via DIAG fails for block sizes > 512 byte.  The device
analysis code of the DIAG discipline does not properly initialize the DIAG250
device environment after completion of the analysis.  This results in VM only
serving 512 bytes per block I/O request whereas Linux expects larger block
sizes.  Add proper device environment setup to end of analysis code.
Signed-off-by: NPeter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Future versions of gcc may remove initialization code for control blocks used
by the diag250 inline assembly due to incompletely specified constraints.
This may lead to erratic behavior.  Fix the diag250 inline assembly
constraints.
Signed-off-by: NPeter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Add support for diag 250 access to dasd devices for 64 bit kernels.  In
addition fix detach/attach for diag disks.  The VM control block needs to get
recreated by a call to mdsk_init_io.
Signed-off-by: NHorst Hummel <horst.hummel@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!