Fixes a crash in dm_table_find_target() due to a NULL struct dm_table
being passed from dm_old_request_fn() that races with DM device
destruction.
Reported-by: artem@flashgrid.io
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
. some locking improvements in DM bufio
. add Kconfig option to disable the DM block manager's extra locking
which mainly serves as a developer tool
. a few bug fixes to DM's persistent-data
. a couple changes to prepare for multipage biovec support in the block
layer
. various improvements and cleanups in the DM core, DM cache, DM raid
and DM crypt
. add ability to have DM crypt use keys from the kernel key retention
service
. add a new "error_writes" feature to the DM flakey target, reads are
left unchanged in this mode
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Merge tag 'dm-4.10-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm
Pull device mapper updates from Mike Snitzer:
- various fixes and improvements to request-based DM and DM multipath
- some locking improvements in DM bufio
- add Kconfig option to disable the DM block manager's extra locking
which mainly serves as a developer tool
- a few bug fixes to DM's persistent-data
- a couple changes to prepare for multipage biovec support in the block
layer
- various improvements and cleanups in the DM core, DM cache, DM raid
and DM crypt
- add ability to have DM crypt use keys from the kernel key retention
service
- add a new "error_writes" feature to the DM flakey target, reads are
left unchanged in this mode
* tag 'dm-4.10-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm: (40 commits)
dm flakey: introduce "error_writes" feature
dm cache policy smq: use hash_32() instead of hash_32_generic()
dm crypt: reject key strings containing whitespace chars
dm space map: always set ev if sm_ll_mutate() succeeds
dm space map metadata: skip useless memcpy in metadata_ll_init_index()
dm space map metadata: fix 'struct sm_metadata' leak on failed create
Documentation: dm raid: define data_offset status field
dm raid: fix discard support regression
dm raid: don't allow "write behind" with raid4/5/6
dm mpath: use hw_handler_params if attached hw_handler is same as requested
dm crypt: add ability to use keys from the kernel key retention service
dm array: remove a dead assignment in populate_ablock_with_values()
dm ioctl: use offsetof() instead of open-coding it
dm rq: simplify use_blk_mq initialization
dm: use blk_set_queue_dying() in __dm_destroy()
dm bufio: drop the lock when doing GFP_NOIO allocation
dm bufio: don't take the lock in dm_bufio_shrink_count
dm bufio: avoid sleeping while holding the dm_bufio lock
dm table: simplify dm_table_determine_type()
dm table: an 'all_blk_mq' table must be loaded for a blk-mq DM device
...
Pull block layer updates from Jens Axboe:
"This is the main block pull request this series. Contrary to previous
release, I've kept the core and driver changes in the same branch. We
always ended up having dependencies between the two for obvious
reasons, so makes more sense to keep them together. That said, I'll
probably try and keep more topical branches going forward, especially
for cycles that end up being as busy as this one.
The major parts of this pull request is:
- Improved support for O_DIRECT on block devices, with a small
private implementation instead of using the pig that is
fs/direct-io.c. From Christoph.
- Request completion tracking in a scalable fashion. This is utilized
by two components in this pull, the new hybrid polling and the
writeback queue throttling code.
- Improved support for polling with O_DIRECT, adding a hybrid mode
that combines pure polling with an initial sleep. From me.
- Support for automatic throttling of writeback queues on the block
side. This uses feedback from the device completion latencies to
scale the queue on the block side up or down. From me.
- Support from SMR drives in the block layer and for SD. From Hannes
and Shaun.
- Multi-connection support for nbd. From Josef.
- Cleanup of request and bio flags, so we have a clear split between
which are bio (or rq) private, and which ones are shared. From
Christoph.
- A set of patches from Bart, that improve how we handle queue
stopping and starting in blk-mq.
- Support for WRITE_ZEROES from Chaitanya.
- Lightnvm updates from Javier/Matias.
- Supoort for FC for the nvme-over-fabrics code. From James Smart.
- A bunch of fixes from a whole slew of people, too many to name
here"
* 'for-4.10/block' of git://git.kernel.dk/linux-block: (182 commits)
blk-stat: fix a few cases of missing batch flushing
blk-flush: run the queue when inserting blk-mq flush
elevator: make the rqhash helpers exported
blk-mq: abstract out blk_mq_dispatch_rq_list() helper
blk-mq: add blk_mq_start_stopped_hw_queue()
block: improve handling of the magic discard payload
blk-wbt: don't throttle discard or write zeroes
nbd: use dev_err_ratelimited in io path
nbd: reset the setup task for NBD_CLEAR_SOCK
nvme-fabrics: Add FC LLDD loopback driver to test FC-NVME
nvme-fabrics: Add target support for FC transport
nvme-fabrics: Add host support for FC transport
nvme-fabrics: Add FC transport LLDD api definitions
nvme-fabrics: Add FC transport FC-NVME definitions
nvme-fabrics: Add FC transport error codes to nvme.h
Add type 0x28 NVME type code to scsi fc headers
nvme-fabrics: patch target code in prep for FC transport support
nvme-fabrics: set sqe.command_id in core not transports
parser: add u64 number parser
nvme-rdma: align to generic ib_event logging helper
...
Use a single statement to declare and initialize 'use_blk_mq' instead
of two statements.
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Avoid accessing .bi_vcnt directly, because the bio can be split from
block layer and .bi_vcnt should never have been used here.
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
It is required to hold the queue lock when calling blk_run_queue_async()
to avoid that a race between blk_run_queue_async() and
blk_cleanup_queue() is triggered.
Cc: stable@vger.kernel.org
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Ensure that all ongoing dm_mq_queue_rq() and dm_mq_requeue_request()
calls have stopped before setting the "queue stopped" flag. This
allows to remove the "queue stopped" test from dm_mq_queue_rq() and
dm_mq_requeue_request(). This patch fixes a race condition because
dm_mq_queue_rq() is called without holding the queue lock and hence
BLK_MQ_S_STOPPED can be set at any time while dm_mq_queue_rq() is
in progress. This patch prevents that the following hang occurs
sporadically when using dm-mq:
INFO: task systemd-udevd:10111 blocked for more than 480 seconds.
Call Trace:
[<ffffffff8161f397>] schedule+0x37/0x90
[<ffffffff816239ef>] schedule_timeout+0x27f/0x470
[<ffffffff8161e76f>] io_schedule_timeout+0x9f/0x110
[<ffffffff8161fb36>] bit_wait_io+0x16/0x60
[<ffffffff8161f929>] __wait_on_bit_lock+0x49/0xa0
[<ffffffff8114fe69>] __lock_page+0xb9/0xc0
[<ffffffff81165d90>] truncate_inode_pages_range+0x3e0/0x760
[<ffffffff81166120>] truncate_inode_pages+0x10/0x20
[<ffffffff81212a20>] kill_bdev+0x30/0x40
[<ffffffff81213d41>] __blkdev_put+0x71/0x360
[<ffffffff81214079>] blkdev_put+0x49/0x170
[<ffffffff812141c0>] blkdev_close+0x20/0x30
[<ffffffff811d48e8>] __fput+0xe8/0x1f0
[<ffffffff811d4a29>] ____fput+0x9/0x10
[<ffffffff810842d3>] task_work_run+0x83/0xb0
[<ffffffff8106606e>] do_exit+0x3ee/0xc40
[<ffffffff8106694b>] do_group_exit+0x4b/0xc0
[<ffffffff81073d9a>] get_signal+0x2ca/0x940
[<ffffffff8101bf43>] do_signal+0x23/0x660
[<ffffffff810022b3>] exit_to_usermode_loop+0x73/0xb0
[<ffffffff81002cb0>] syscall_return_slowpath+0xb0/0xc0
[<ffffffff81624e33>] entry_SYSCALL_64_fastpath+0xa6/0xa8
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Acked-by: Mike Snitzer <snitzer@redhat.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
Instead of manipulating both QUEUE_FLAG_STOPPED and BLK_MQ_S_STOPPED
in the dm start and stop queue functions, only manipulate the latter
flag. Change blk_queue_stopped() tests into blk_mq_queue_stopped().
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Acked-by: Mike Snitzer <snitzer@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
Most blk_mq_requeue_request() and blk_mq_add_to_requeue_list() calls
are followed by kicking the requeue list. Hence add an argument to
these two functions that allows to kick the requeue list. This was
proposed by Christoph Hellwig.
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Jens Axboe <axboe@fb.com>
Since blk_mq_requeue_work() no longer restarts stopped queues
canceling requeue work is no longer needed to prevent that a
stopped queue would be restarted. Hence remove this function.
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Hannes Reinecke <hare@suse.com>
Cc: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
Since blk_mq_requeue_work() starts stopped queues and since
execution of this function can be scheduled after a queue has
been stopped it is not possible to stop queues without using
an additional state variable to track whether or not the queue
has been stopped. Hence modify blk_mq_requeue_work() such that it
does not start stopped queues. My conclusion after a review of
the blk_mq_stop_hw_queues() and blk_mq_{delay_,}kick_requeue_list()
callers is as follows:
* In the dm driver starting and stopping queues should only happen
if __dm_suspend() or __dm_resume() is called and not if the
requeue list is processed.
* In the SCSI core queue stopping and starting should only be
performed by the scsi_internal_device_block() and
scsi_internal_device_unblock() functions but not by any other
function. Although the blk_mq_stop_hw_queue() call in
scsi_queue_rq() may help to reduce CPU load if a LLD queue is
full, figuring out whether or not a queue should be restarted
when requeueing a command would require to introduce additional
locking in scsi_mq_requeue_cmd() to avoid a race with
scsi_internal_device_block(). Avoid this complexity by removing
the blk_mq_stop_hw_queue() call from scsi_queue_rq().
* In the NVMe core only the functions that call
blk_mq_start_stopped_hw_queues() explicitly should start stopped
queues.
* A blk_mq_start_stopped_hwqueues() call must be added in the
xen-blkfront driver in its blkif_recover() function.
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Roger Pau Monné <roger.pau@citrix.com>
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: James Bottomley <jejb@linux.vnet.ibm.com>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
- A couple .request_fn request-based DM NULL pointer fixes
- A fix for a DM target reference count leak, on target load error, that
prevented associated DM target kernel module(s) from being removed
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Merge tag 'dm-4.9-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm
Pull device mapper fixes from Mike Snitzer:
- a couple DM raid and DM mirror fixes
- a couple .request_fn request-based DM NULL pointer fixes
- a fix for a DM target reference count leak, on target load error,
that prevented associated DM target kernel module(s) from being
removed
* tag 'dm-4.9-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
dm table: fix missing dm_put_target_type() in dm_table_add_target()
dm rq: clear kworker_task if kthread_run() returned an error
dm: free io_barrier after blk_cleanup_queue call
dm raid: fix activation of existing raid4/10 devices
dm mirror: use all available legs on multiple failures
dm mirror: fix read error on recovery after default leg failure
dm raid: fix compat_features validation
A lot of the REQ_* flags are only used on struct requests, and only of
use to the block layer and a few drivers that dig into struct request
internals.
This patch adds a new req_flags_t rq_flags field to struct request for
them, and thus dramatically shrinks the number of common requests. It
also removes the unfortunate situation where we have to fit the fields
from the same enum into 32 bits for struct bio and 64 bits for
struct request.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Shaun Tancheff <shaun.tancheff@seagate.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
cleanup_mapped_device() calls kthread_stop() if kworker_task is
non-NULL. Currently the assigned value could be a valid task struct or
an error code (e.g -ENOMEM). Reset md->kworker_task to NULL if
kthread_run() returned an erorr.
Fixes: 7193a9defc ("dm rq: check kthread_run return for .request_fn request-based DM")
Cc: stable@vger.kernel.org # 4.8
Reported-by: Tahsin Erdogan <tahsin@google.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
A good practice is to prefix the names of functions by the name
of the subsystem.
The kthread worker API is a mix of classic kthreads and workqueues. Each
worker has a dedicated kthread. It runs a generic function that process
queued works. It is implemented as part of the kthread subsystem.
This patch renames the existing kthread worker API to use
the corresponding name from the workqueues API prefixed by
kthread_:
__init_kthread_worker() -> __kthread_init_worker()
init_kthread_worker() -> kthread_init_worker()
init_kthread_work() -> kthread_init_work()
insert_kthread_work() -> kthread_insert_work()
queue_kthread_work() -> kthread_queue_work()
flush_kthread_work() -> kthread_flush_work()
flush_kthread_worker() -> kthread_flush_worker()
Note that the names of DEFINE_KTHREAD_WORK*() macros stay
as they are. It is common that the "DEFINE_" prefix has
precedence over the subsystem names.
Note that INIT() macros and init() functions use different
naming scheme. There is no good solution. There are several
reasons for this solution:
+ "init" in the function names stands for the verb "initialize"
aka "initialize worker". While "INIT" in the macro names
stands for the noun "INITIALIZER" aka "worker initializer".
+ INIT() macros are used only in DEFINE() macros
+ init() functions are used close to the other kthread()
functions. It looks much better if all the functions
use the same scheme.
+ There will be also kthread_destroy_worker() that will
be used close to kthread_cancel_work(). It is related
to the init() function. Again it looks better if all
functions use the same naming scheme.
+ there are several precedents for such init() function
names, e.g. amd_iommu_init_device(), free_area_init_node(),
jump_label_init_type(), regmap_init_mmio_clk(),
+ It is not an argument but it was inconsistent even before.
[arnd@arndb.de: fix linux-next merge conflict]
Link: http://lkml.kernel.org/r/20160908135724.1311726-1-arnd@arndb.de
Link: http://lkml.kernel.org/r/1470754545-17632-3-git-send-email-pmladek@suse.com
Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Borislav Petkov <bp@suse.de>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull blk-mq irq/cpu mapping updates from Jens Axboe:
"This is the block-irq topic branch for 4.9-rc. It's mostly from
Christoph, and it allows drivers to specify their own mappings, and
more importantly, to share the blk-mq mappings with the IRQ affinity
mappings. It's a good step towards making this work better out of the
box"
* 'for-4.9/block-irq' of git://git.kernel.dk/linux-block:
blk_mq: linux/blk-mq.h does not include all the headers it depends on
blk-mq: kill unused blk_mq_create_mq_map()
blk-mq: get rid of the cpumask in struct blk_mq_tags
nvme: remove the post_scan callout
nvme: switch to use pci_alloc_irq_vectors
blk-mq: provide a default queue mapping for PCI device
blk-mq: allow the driver to pass in a queue mapping
blk-mq: remove ->map_queue
blk-mq: only allocate a single mq_map per tag_set
blk-mq: don't redistribute hardware queues on a CPU hotplug event
. add support for delaying the requeue of requests; used by DM multipath
when all paths have failed and 'queue_if_no_path' is enabled
. DM cache improvements to speedup the loading metadata and the writing
of the hint array
. fix potential for a dm-crypt crash on device teardown
. remove dm_bufio_cond_resched() and just using cond_resched()
. change DM multipath to return a reservation conflict error
immediately; rather than failing the path and retrying (potentially
indefinitely)
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Merge tag 'dm-4.9-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm
Pull device mapper updates from Mike Snitzer:
- various fixes and cleanups for request-based DM core
- add support for delaying the requeue of requests; used by DM
multipath when all paths have failed and 'queue_if_no_path' is
enabled
- DM cache improvements to speedup the loading metadata and the writing
of the hint array
- fix potential for a dm-crypt crash on device teardown
- remove dm_bufio_cond_resched() and just using cond_resched()
- change DM multipath to return a reservation conflict error
immediately; rather than failing the path and retrying (potentially
indefinitely)
* tag 'dm-4.9-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm: (24 commits)
dm mpath: always return reservation conflict without failing over
dm bufio: remove dm_bufio_cond_resched()
dm crypt: fix crash on exit
dm cache metadata: switch to using the new cursor api for loading metadata
dm array: introduce cursor api
dm btree: introduce cursor api
dm cache policy smq: distribute entries to random levels when switching to smq
dm cache: speed up writing of the hint array
dm array: add dm_array_new()
dm mpath: delay the requeue of blk-mq requests while all paths down
dm mpath: use dm_mq_kick_requeue_list()
dm rq: introduce dm_mq_kick_requeue_list()
dm rq: reduce arguments passed to map_request() and dm_requeue_original_request()
dm rq: add DM_MAPIO_DELAY_REQUEUE to delay requeue of blk-mq requests
dm: convert wait loops to use autoremove_wake_function()
dm: use signal_pending_state() in dm_wait_for_completion()
dm: rename task state function arguments
dm: add two lockdep_assert_held() statements
dm rq: simplify dm_old_stop_queue()
dm mpath: check if path's request_queue is dying in activate_path()
...
Enable devices without a gendisk instance to register itself with blk-mq
and expose the associated multi-queue sysfs entries.
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@fb.com>
Make it possible for a request-based target to kick the DM device's
blk-mq request_queue's requeue_list.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
All drivers use the default, so provide an inline version of it. If we
ever need other queue mapping we can add an optional method back,
although supporting will also require major changes to the queue setup
code.
This provides better code generation, and better debugability as well.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Otherwise blk-mq will immediately dispatch requests that are requeued
via a BLK_MQ_RQ_QUEUE_BUSY return from blk_mq_ops .queue_rq.
Delayed requeue is implemented using blk_mq_delay_kick_requeue_list()
with a delay of 5 secs. In the context of DM multipath (all paths down)
it doesn't make any sense to requeue more quickly.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
This patch does not change any functionality.
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Every call of queue_flag_clear_unlocked() after block device
initialization has finished is wrong if blk_cleanup_queue() can be
called concurrently. Convert queue_flag_clear_unlocked() into
queue_flag_clear() and protect it by the block layer queue lock.
Also, factor out dm_mq_start_queue().
Reported-by: Bart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
Also, check that the blk-mq request_queue isn't already stopped.
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Improve dm_stop_queue() to cancel any requeue_work. Also, have
dm_start_queue() and dm_stop_queue() clear/set the QUEUE_FLAG_STOPPED
for the blk-mq request_queue.
On suspend dm_stop_queue() handles stopping the blk-mq request_queue
BUT: even though the hw_queues are marked BLK_MQ_S_STOPPED at that point
there is still a race that is allowing block/blk-mq.c to call ->queue_rq
against a hctx that it really shouldn't. Add a check to
dm_mq_queue_rq() that guards against this rarity (albeit _not_
race-free).
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org # must patch dm.c on < 4.8 kernels
Commit d548b34b06 ("dm: reduce the queue delay used in dm_request_fn
from 100ms to 10ms") always intended the value to be 10 msecs -- it
just expressed it in jiffies because earlier commit 7eaceaccab ("block:
remove per-queue plugging") did.
Signed-off-by: Tahsin Erdogan <tahsin@google.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Fixes: d548b34b06 ("dm: reduce the queue delay used in dm_request_fn from 100ms to 10ms")
Cc: stable@vger.kernel.org # 4.1+ -- stable@ backports must be applied to drivers/md/dm.c
Check return value of kthread_run() in dm_old_init_request_queue().
Reported-by: Minfei Huang <mnghuan@gmail.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Allow a user to specify an optional feature 'queue_mode <mode>' where
<mode> may be "bio", "rq" or "mq" -- which corresponds to bio-based,
request_fn rq-based, and blk-mq rq-based respectively.
If the queue_mode feature isn't specified the default for the
"multipath" target is still "rq" but if dm_mod.use_blk_mq is set to Y
it'll default to mode "mq".
This new queue_mode feature introduces the ability for each multipath
device to have its own queue_mode (whereas before this feature all
multipath devices effectively had to have the same queue_mode).
This commit also goes a long way to eliminate the awkward (ab)use of
DM_TYPE_*, the associated filter_md_type() and other relatively fragile
and difficult to maintain code.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Add some seperation between bio-based and request-based DM core code.
'struct mapped_device' and other DM core only structures and functions
have been moved to dm-core.h and all relevant DM core .c files have been
updated to include dm-core.h rather than dm.h
DM targets should _never_ include dm-core.h!
[block core merge conflict resolution from Stephen Rothwell]
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Mike Snitzer