Pull block driver updates from Jens Axboe:
"This is the block driver pull request for 3.13. As with the core pull
request just sent out, this was rebased on top of the core branch
again after the immutable series was pulled. This also means that
bcache gets to sit the initial pull over. I will send a second driver
pull request in the merge window to get those fixes in, once they have
been rebased and tested on top of the non-immutable stack.
This pull request contains:
- Add support for the sTec Kronos pci-e flash card from sTec. Also
has various cleanups for this driver, from myself, Bart, Mike
Snizter, and Wei Yongjun.
- Add surprise removal support for the micron mtip32xx driver from
Micron.
- Floppy documentation fix from Ben Harris.
- debugfs bug fix for pktcdvd from Dan Carpenter.
- Fix for the mtip32xx driver stack usage in the debugfs path,
dynamically allocating those buffers instead. From David Milburn.
- Disable cpqarray in Kconfig. The plan is to remove it on request
of HP, but lets disable it for a few revisions just to see if
anyone yells.
- drbd fixes from Lars Ellenberg and Philipp Reisner.
- Elevator switch fix for the s390 block driver from Heiko Carstens.
- loop crash fix on IO to unassigned device from Mikulas Patocka.
- A series of bug fixes for the IBM rsxx pci-e flash driver from
Philip J Kelleher.
- cciss probe fix from Stephen Cameron.
- Xen block front/back fixes from Roger Pau Monne and Vegard Nossum"
* 'for-3.13/drivers' of git://git.kernel.dk/linux-block: (41 commits)
floppy: Correct documentation of driver options when used as a module.
pktcdvd: debugfs functions return NULL on error
xen-blkfront: restore the non-persistent data path
skd: fix formatting in skd_s1120.h
skd: reorder construct/destruct code
skd: cleanup skd_do_inq_page_da()
skd: remove SKD_OMIT_FROM_SRC_DIST ifdefs
skd: remove redundant skdev->pdev assignment from skd_pci_probe()
skd: use <asm/unaligned.h>
skd: remove SCSI subsystem specific includes
skd: register block device only if some devices are present
skd: fix error messages in skd_init()
skd: fix error paths in skd_init()
skd: fix unregister_blkdev() placement
skd: more removal of bio-based code
skd: cleanup the skd_*() function block wrapping
skd: rip out bio path
skd: fix error return code in skd_pci_probe()
s390/dasd: hold request queue sysfs lock when calling elevator_init()
cciss: return 0 from driver probe function on success, not 1
...
"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: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Jens 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: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Martin 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: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin 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: Hannes Reinecke <hare@suse.de>
Signed-off-by: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Martin 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: Hannes Reinecke <hare@suse.de>
Signed-off-by: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Martin 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: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Martin 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: Hannes Reinecke <hare@suse.de>
Acked-by: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Martin 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: Hannes Reinecke <hare@suse.de>
Signed-off-by: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
dasd_cancel_req will never return 1, only 0.
Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Martin 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: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Martin 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: Al 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: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Reorganize format IO requests and enable usage of PAV.
Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin 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: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Martin 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: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin 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: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin 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: Stefan Haberland <stefan.haberland@de.ibm.com>
Reviewed-by: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Martin 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: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin 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: Heiko Carstens <heiko.carstens@de.ibm.com>
Add a mechanism to wait for outstanding IO during shutdown.
Schedule the block_bh and device_bh and wait until our request queues
are empty.
Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Calling validate server on devices in offline processing may cause
an OOPS in the dasd_sleep_on function.
Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Reviewed-by: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
If a pathgroup is established we get an event and have to revalidate
the server to propagate supported features like PAV and enable them.
Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Move invalidate_bdev, block_sync_page into fs/block_dev.c. Export
kill_bdev as well, so brd doesn't have to open code it. Reduce
buffer_head.h requirement accordingly.
Removed a rather large comment from invalidate_bdev, as it looked a bit
obsolete to bother moving. The small comment replacing it says enough.
Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Mark the device as suspended and delay execution of the path
verification worker to prevent mix-up.
Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
The buffer for read configuration data has to be initialized with an
EBCDIC string to show support for extended UIDs to z/VM.
If this read configuration data CQR needs to be retried, the buffer
may have changed in between. So re-initialize the buffer to get a
correct extended UID under z/VM.
Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
After terminating a request in the dasd_sleep_on_immediatly function,
wait for the clear interrupt to be received before starting the
new request. This prevents the requests from getting mixed up.
Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Current IRQ statistics support does not show detail counts for I/O
interrupts which are processed internally only. The result is a
summation count which is way off such as this one:
CPU0 CPU1 CPU2
I/O: 1331 710 442
[...]
QAI: 15 16 16 [I/O] QDIO Adapter Interrupt
QDI: 1 0 0 [I/O] QDIO Interrupt
DAS: 706 645 381 [I/O] DASD
C15: 26 10 0 [I/O] 3215
C70: 0 0 0 [I/O] 3270
TAP: 0 0 0 [I/O] Tape
VMR: 0 0 0 [I/O] Unit Record Devices
LCS: 0 0 0 [I/O] LCS
CLW: 0 0 0 [I/O] CLAW
CTC: 0 0 0 [I/O] CTC
APB: 0 0 0 [I/O] AP Bus
Fix this by moving I/O interrupt accounting into the common I/O layer.
Signed-off-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
The size of the buffer that is used to store DASD statistics input
strings depends on the user input. If the input string is to large,
the write operation could fail with -ENOMEM. To avoid this, use
vmalloc instead of kmalloc.
Signed-off-by: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
This patch extends the DASD statistics to allow for a more detailed
analysis of DASD I/O operations. In particular we want the statistics
to provide answers to the following questions:
- How many requests used a PAV alias?
- How many requests used High Performance FICON?
- How do read request perform versus write requests?
The existing DASD statistics interface has several shortcomings
- The interface for global data is a formatted text table in procfs
(/proc/dasd/statistics). The layout is meant for human readers and
is not to easy to parse. If values get to large for the table
layout, they get scaled down.
- The statistics which are collected per block device can be
accessed via an ioctl interface, which can only be extended by
defining a new ioctl.
- There is no statistics interface for individual PAV base and alias
devices.
To overcome theses shortcomings we create a new DASD statistics
interface in debugfs. This interface will contain one entry for global
data, one per DASD block device, and one per DASD base and alias
device. Each file contains the statistic data in easy to parse
name/value and name/array pairs. The existing interfaces will remain
functional, but they will not be extended.
Signed-off-by: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
The termination of running CQR caused by reserve/release operations
may lead to an IO error if reserve/release is done in a tight loop.
Prevent this by increasing the retry counter after termination.
Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
The dasd_open function uses the private_data pointer of the gendisk to
find the dasd_block structure that matches the gendisk. When a DASD
device is set offline, we set the private_data pointer of the gendisk
to NULL and later remove the dasd_block structure, but there is still
a small race window, in which dasd_open could first read a pointer
from the private_data field and then try to use it, after the structure
has already been freed.
To close this race window, we will store a pointer to the dasd_devmap
structure of the base device in the private_data field. The devmap
entries are not deleted, and we already have proper locking and
reference counting in place, so that we can safely get from a devmap
pointer to the dasd_device and dasd_block structures of the device.
Signed-off-by: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Code has been converted over to the new explicit on-stack plugging,
and delay users have been converted to use the new API for that.
So lets kill off the old plugging along with aops->sync_page().
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
In case the DASD driver needs to term a running I/O the retry counter
is decreased twice.
Remove the unnecessary retry counter decrease in das_term_IO.
Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Normal I/O operations through the DASD device driver give only access
to the data fields of an ECKD device even for track based I/O.
This patch extends the DASD device driver to give access to whole
ECKD tracks including count, key and data fields.
Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
The freeze callback may set a stop bit so that a worker thread could
not start I/O. The discipline specific freeze function waits for the
worker to be completed.
Set the stop_bit after the discipline specific freeze function has
returned and no worker is running.
Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
If a DASD device has been reserved by a Linux system, and later
this reservation is ‘stolen’ by a second system by means of an
unconditional reserve, then the first system receives a
notification about this fact. With this patch such an event can
be either ignored, as before, or it can be used to let the device
fail all I/O request, so that the device will not block anymore.
Signed-off-by: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
When a new path is added at runtime, the CIO layer will call the drivers
path_event callback. The DASD device driver uses this callback to trigger
a path verification for the new path. The driver will use only those
paths for I/O, which have been successfully verified.
Signed-off-by: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Some storage systems support multitrack High Performance FICON
requests, which read or write data to more than one track.
This patch enables the DASD device driver to generate multitrack
High Performance FICON requests.
Signed-off-by: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Add support for DASD I/O interrupt statistics in /proc/interrupts.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
For the DASD DIAG discipline IO is started through special diagnose
calls. Unsolicited interrupts may contain information about the device
itself. But this information is not needed because the device is not
used directly.
Fix the case that an unimplemented dicipline function may be called
by ignoring unsolicited interrupts for the DIAG disciplin.
Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
The dasd interrupt handler needs to distinguish solicited from
unsolicited interrupts, as unsolicited interrupts may require special
handling (e.g. summary unit checks) and solicited interrupts require
proper error recovery for the failed I/O request.
The interrupt handler needs to check several bit fields in the
interrupt response block (irb) to make this distinction.
So far our check of the status control bits has not been specific
enough, which may lead to a failed request getting just retried
instead of the necessary error recovery.
Signed-off-by: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* 'for-2.6.37/barrier' of git://git.kernel.dk/linux-2.6-block: (46 commits)
xen-blkfront: disable barrier/flush write support
Added blk-lib.c and blk-barrier.c was renamed to blk-flush.c
block: remove BLKDEV_IFL_WAIT
aic7xxx_old: removed unused 'req' variable
block: remove the BH_Eopnotsupp flag
block: remove the BLKDEV_IFL_BARRIER flag
block: remove the WRITE_BARRIER flag
swap: do not send discards as barriers
fat: do not send discards as barriers
ext4: do not send discards as barriers
jbd2: replace barriers with explicit flush / FUA usage
jbd2: Modify ASYNC_COMMIT code to not rely on queue draining on barrier
jbd: replace barriers with explicit flush / FUA usage
nilfs2: replace barriers with explicit flush / FUA usage
reiserfs: replace barriers with explicit flush / FUA usage
gfs2: replace barriers with explicit flush / FUA usage
btrfs: replace barriers with explicit flush / FUA usage
xfs: replace barriers with explicit flush / FUA usage
block: pass gfp_mask and flags to sb_issue_discard
dm: convey that all flushes are processed as empty
...
The dasd and dcssblk drivers gained the big
kernel lock in the recent pushdown from the
block layer, but they don't really need it,
so remove the calls without a replacement.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: linux-s390@vger.kernel.org
Barrier is deemed too heavy and will soon be replaced by FLUSH/FUA
requests. Deprecate barrier. All REQ_HARDBARRIERs are failed with
-EOPNOTSUPP and blk_queue_ordered() is replaced with simpler
blk_queue_flush().
blk_queue_flush() takes combinations of REQ_FLUSH and FUA. If a
device has write cache and can flush it, it should set REQ_FLUSH. If
the device can handle FUA writes, it should also set REQ_FUA.
All blk_queue_ordered() users are converted.
* ORDERED_DRAIN is mapped to 0 which is the default value.
* ORDERED_DRAIN_FLUSH is mapped to REQ_FLUSH.
* ORDERED_DRAIN_FLUSH_FUA is mapped to REQ_FLUSH | REQ_FUA.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Boaz Harrosh <bharrosh@panasas.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Jeremy Fitzhardinge <jeremy@xensource.com>
Cc: Chris Wright <chrisw@sous-sol.org>
Cc: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Geert Uytterhoeven <Geert.Uytterhoeven@sonycom.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Alasdair G Kergon <agk@redhat.com>
Cc: Pierre Ossman <drzeus@drzeus.cx>
Cc: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Get rid of these warnings:
drivers/s390/block/dasd.c: In function '__dasd_device_check_expire':
drivers/s390/block/dasd.c:1330: warning: format '%i' expects type 'int', but argument 4 has type 'long unsigned int'
drivers/s390/block/dasd.c:1337: warning: format '%i' expects type 'int', but argument 4 has type 'long unsigned int'
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
The open and release block_device_operations are currently
called with the BKL held. In order to change that, we must
first make sure that all drivers that currently rely
on this have no regressions.
This blindly pushes the BKL into all .open and .release
operations for all block drivers to prepare for the
next step. The drivers can subsequently replace the BKL
with their own locks or remove it completely when it can
be shown that it is not needed.
The functions blkdev_get and blkdev_put are the only
remaining users of the big kernel lock in the block
layer, besides a few uses in the ioctl code, none
of which need to serialize with blkdev_{get,put}.
Most of these two functions is also under the protection
of bdev->bd_mutex, including the actual calls to
->open and ->release, and the common code does not
access any global data structures that need the BKL.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Linus Torvalds