bio-based code so that it follows patterns established by
request-based code.
- Request-based DM core improvement to eliminate unnecessary call to
blk_mq_queue_stopped().
- Add "panic_on_corruption" error handling mode to DM verity target.
- DM bufio fix to to perform buffer cleanup from a workqueue rather
than wait for IO in reclaim context from shrinker.
- DM crypt improvement to optionally avoid async processing via
workqueues for reads and/or writes -- via "no_read_workqueue" and
"no_write_workqueue" features. This more direct IO processing
improves latency and throughput with faster storage. Avoiding
workqueue IO submission for writes (DM_CRYPT_NO_WRITE_WORKQUEUE) is
a requirement for adding zoned block device support to DM crypt.
- Add zoned block device support to DM crypt. Makes use of
DM_CRYPT_NO_WRITE_WORKQUEUE and a new optional feature
(DM_CRYPT_WRITE_INLINE) that allows write completion to wait for
encryption to complete. This allows write ordering to be preserved,
which is needed for zoned block devices.
- Fix DM ebs target's check for REQ_OP_FLUSH.
- Fix DM core's report zones support to not report more zones than
were requested.
- A few small compiler warning fixes.
- DM dust improvements to return output directly to the user rather
than require they scrape the system log for output.
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Merge tag 'for-5.9/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm
Pull device mapper updates from Mike Snitzer:
- DM multipath locking fixes around m->flags tests and improvements to
bio-based code so that it follows patterns established by
request-based code.
- Request-based DM core improvement to eliminate unnecessary call to
blk_mq_queue_stopped().
- Add "panic_on_corruption" error handling mode to DM verity target.
- DM bufio fix to to perform buffer cleanup from a workqueue rather
than wait for IO in reclaim context from shrinker.
- DM crypt improvement to optionally avoid async processing via
workqueues for reads and/or writes -- via "no_read_workqueue" and
"no_write_workqueue" features. This more direct IO processing
improves latency and throughput with faster storage. Avoiding
workqueue IO submission for writes (DM_CRYPT_NO_WRITE_WORKQUEUE) is a
requirement for adding zoned block device support to DM crypt.
- Add zoned block device support to DM crypt. Makes use of
DM_CRYPT_NO_WRITE_WORKQUEUE and a new optional feature
(DM_CRYPT_WRITE_INLINE) that allows write completion to wait for
encryption to complete. This allows write ordering to be preserved,
which is needed for zoned block devices.
- Fix DM ebs target's check for REQ_OP_FLUSH.
- Fix DM core's report zones support to not report more zones than were
requested.
- A few small compiler warning fixes.
- DM dust improvements to return output directly to the user rather
than require they scrape the system log for output.
* tag 'for-5.9/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
dm: don't call report zones for more than the user requested
dm ebs: Fix incorrect checking for REQ_OP_FLUSH
dm init: Set file local variable static
dm ioctl: Fix compilation warning
dm raid: Remove empty if statement
dm verity: Fix compilation warning
dm crypt: Enable zoned block device support
dm crypt: add flags to optionally bypass kcryptd workqueues
dm bufio: do buffer cleanup from a workqueue
dm rq: don't call blk_mq_queue_stopped() in dm_stop_queue()
dm dust: add interface to list all badblocks
dm dust: report some message results directly back to user
dm verity: add "panic_on_corruption" error handling mode
dm mpath: use double checked locking in fast path
dm mpath: rename current_pgpath to pgpath in multipath_prepare_ioctl
dm mpath: rework __map_bio()
dm mpath: factor out multipath_queue_bio
dm mpath: push locking down to must_push_back_rq()
dm mpath: take m->lock spinlock when testing QUEUE_IF_NO_PATH
dm mpath: changes from initial m->flags locking audit
Fast-path code biased toward lazy acknowledgement of bit being set
(primarily only for initialization). Multipath code is very retry
oriented so even if state is missed it'll recover.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Fix multipath_end_io, multipath_end_io_bio and multipath_busy to take
m->lock while testing if MPATHF_QUEUE_IF_NO_PATH bit is set. These are
all slow-path cases when no paths are available so extra locking isn't a
performance hit. Correctness matters most.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
generic_make_request has always been very confusingly misnamed, so rename
it to submit_bio_noacct to make it clear that it is submit_bio minus
accounting and a few checks.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
When there are many DM multipath devices it really helps to have
additional context for which DM device a failed or reinstated path is
part of.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Add more DMDEBUG that shows arguments passed and caller, and another
that shows state of related flags at end of queue_if_no_path().
Also add queue_if_no_path DMDEBUG to multipath_resume().
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Do not allow saving disabled queue_if_no_path if already saved as
enabled; implies multiple suspends (which shouldn't ever happen). Log
if this unlikely scenario is ever triggered.
Also, only write MPATHF_SAVED_QUEUE_IF_NO_PATH during presuspend or if
"fail_if_no_path" message. MPATHF_SAVED_QUEUE_IF_NO_PATH is no longer
always modified, e.g.: even if queue_if_no_path()'s save_old_value
argument wasn't set. This just implies a bit tighter control over
the management of MPATHF_SAVED_QUEUE_IF_NO_PATH. Side-effect is
multipath_resume() doesn't reset MPATHF_QUEUE_IF_NO_PATH unless
MPATHF_SAVED_QUEUE_IF_NO_PATH was set (during presuspend); and at that
time the MPATHF_SAVED_QUEUE_IF_NO_PATH bit gets cleared. So
MPATHF_SAVED_QUEUE_IF_NO_PATH's use is much more narrow in scope.
Last, but not least, do _not_ disable queue_if_no_path during noflush
suspend. There is no need/benefit to saving off queue_if_no_path via
MPATHF_SAVED_QUEUE_IF_NO_PATH and clearing MPATHF_QUEUE_IF_NO_PATH for
noflush suspend -- by avoiding this needless queue_if_no_path flag
churn there is less potential for MPATHF_QUEUE_IF_NO_PATH to get lost.
Which avoids potential for IOs to be errored back up to userspace
during DM multipath's handling of path failures.
That said, this last change papers over a reported issue concerning
request-based dm-multipath's interaction with blk-mq, relative to
suspend and resume: multipath_endio is being called _before_
multipath_resume. This should never happen if DM suspend's
blk_mq_quiesce_queue() + dm_wait_for_completion() is genuinely waiting
for all inflight blk-mq requests to complete. Similarly:
drivers/md/dm.c:__dm_resume() clearly calls dm_table_resume_targets()
_before_ dm_start_queue()'s blk_mq_unquiesce_queue() is called. If
the queue isn't even restarted until after multipath_resume(); the BIG
question that still needs answering is: how can multipath_end_io beat
multipath_resume in a race!?
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Remove micro-optimization that infers device is between presuspend and
resume (was done purely to avoid call to dm_noflush_suspending, which
isn't expensive anyway).
Remove flags argument since they are no longer checked.
And remove must_push_back_bio() since it was simply a call to
__must_push_back().
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Now that DMDEBUG uses pr_debug and DMDEBUG_LIMIT uses
pr_debug_ratelimited cleanup DM's 2 direct pr_debug callers to use
them to get the benefit of consistent DM_FMT formatting of debugging
messages.
While doing so, dm-mpath.c:dm_report_EIO() was switched over to using
DMDEBUG_LIMIT due to the potential for error handling floods in the IO
completion path.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
The HST path selector needs this information to perform path
prediction. For request-based mpath, struct request's io_start_time_ns
is used, while for bio-based, use the start_time stored in dm_io.
Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
SCSI LUN passthrough code such as qemu's "scsi-block" device model
pass every IO to the host via SG_IO ioctls. Currently, dm-multipath
calls choose_pgpath() only in the block IO code path, not in the ioctl
code path (unless current_pgpath is NULL). This has the effect that no
path switching and thus no load balancing is done for SCSI-passthrough
IO, unless the active path fails.
Fix this by using the same logic in multipath_prepare_ioctl() as in
multipath_clone_and_map().
Note: The allegedly best path selection algorithm, service-time,
still wouldn't work perfectly, because the io size of the current
request is always set to 0. Changing that for the IO passthrough
case would require the ioctl cmd and arg to be passed to dm's
prepare_ioctl() method.
Signed-off-by: Martin Wilck <mwilck@suse.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Changes made during the 5.6 cycle warrant bumping the version number
for DM core and the targets modified by this commit.
It should be noted that dm-thin, dm-crypt and dm-raid already had
their target version bumped during the 5.6 merge window.
Signed-off-by; Mike Snitzer <snitzer@redhat.com>
Add a configurable timeout mechanism to disable queue_if_no_path without
assistance from userspace multipathd. This reimplements multipathd's
no_path_retry mechanism in kernel space. This is motivated by the
desire to prevent processes from hanging indefinitely waiting for IO
in cases where multipathd might be unable to respond (after a failure
or for whatever reason).
Despite replicating userspace multipathd's policy configuration in
kernel space, it is important to prevent IOs from hanging forever,
waiting for userspace that may be incapable of behaving correctly.
Use of the provided "queue_if_no_path_timeout_secs" dm-multipath
module parameter is optional. This timeout mechanism is disabled by
default (by being set to 0).
Signed-off-by: Anatol Pomazau <anatol@google.com>
Co-developed-by: Gabriel Krisman Bertazi <krisman@collabora.com>
Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Removes the branching for edge-case where no SCSI device handler
exists. The __map_bio_fast() method was far too limited, by only
selecting a new pathgroup or path IFF there was a path failure, fix this
be eliminating it in favor of __map_bio(). __map_bio()'s extra SCSI
device handler specific MPATHF_PG_INIT_REQUIRED test is not in the fast
path anyway.
This change restores full path selector functionality for bio-based
configurations that don't haave a SCSI device handler. But it should be
noted that the path selectors do have an impact on performance for
certain networks that are extremely fast (and don't require frequent
switching).
Fixes: 8d47e65948 ("dm mpath: remove unnecessary NVMe branching in favor of scsi_dh checks")
Cc: stable@vger.kernel.org
Reported-by: Drew Hastings <dhastings@crucialwebhost.com>
Suggested-by: Martin Wilck <mwilck@suse.de>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Commit b592211c33 ("dm mpath: fix attached_handler_name leak and
dangling hw_handler_name pointer") fixed a memory leak for the case
where setup_scsi_dh() returns failure. But setup_scsi_dh may return
success and not "use" attached_handler_name if the
retain_attached_hwhandler flag is not set on the map. As setup_scsi_sh
properly "steals" the pointer by nullifying it, freeing it
unconditionally in parse_path() is safe.
Fixes: b592211c33 ("dm mpath: fix attached_handler_name leak and dangling hw_handler_name pointer")
Cc: stable@vger.kernel.org
Reported-by: Yufen Yu <yuyufen@huawei.com>
Signed-off-by: Martin Wilck <mwilck@suse.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
After commit 396eaf21ee ("blk-mq: improve DM's blk-mq IO merging via
blk_insert_cloned_request feedback"), map_request() will requeue the tio
when issued clone request return BLK_STS_RESOURCE or BLK_STS_DEV_RESOURCE.
Thus, if device driver status is error, a tio may be requeued multiple
times until the return value is not DM_MAPIO_REQUEUE. That means
type->start_io may be called multiple times, while type->end_io is only
called when IO complete.
In fact, even without commit 396eaf21ee, setup_clone() failure can
also cause tio requeue and associated missed call to type->end_io.
The service-time path selector selects path based on in_flight_size,
which is increased by st_start_io() and decreased by st_end_io().
Missed calls to st_end_io() can lead to in_flight_size count error and
will cause the selector to make the wrong choice. In addition,
queue-length path selector will also be affected.
To fix the problem, call type->end_io in ->release_clone_rq before tio
requeue. map_info is passed to ->release_clone_rq() for map_request()
error path that result in requeue.
Fixes: 396eaf21ee ("blk-mq: improve DM's blk-mq IO merging via blk_insert_cloned_request feedback")
Cc: stable@vger.kernl.org
Signed-off-by: Yufen Yu <yuyufen@huawei.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
The workqueues are shared by many multipath devices, only flush whole
workqueue when necessary. Otherwise, we just flush works as needed.
Signed-off-by: wuzhouhui <wuzhouhui14@mails.ucas.ac.cn>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Now that request-based DM is only using blk-mq, there is no need to
differentiate between legacy "rq" and new "mq". We're back to a single
request-based DM -- and there was much rejoicing!
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
dm supports both, and since we're killing off the legacy path in
general, get rid of it in dm.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Commit e8f74a0f00 ("dm mpath: eliminate need to use
scsi_device_from_queue") introduced 2 regressions:
1) memory leak occurs if attached_handler_name is not assigned to
m->hw_handler_name
2) m->hw_handler_name can become a dangling pointer if the
RETAIN_ATTACHED_HW_HANDLER flag is set and scsi_dh_attach() returns
-EBUSY.
Fix both of these by clearing 'attached_handler_name' pointer passed to
setup_scsi_dh() after it is assigned to m->hw_handler_name. And if
setup_scsi_dh() doesn't consume 'attached_handler_name' parse_path()
will kfree() it.
Fixes: e8f74a0f00 ("dm mpath: eliminate need to use scsi_device_from_queue")
Cc: stable@vger.kernel.org # 4.16+
Reported-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Switch everyone to blk_get_request_flags, and then rename
blk_get_request_flags to blk_get_request.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Use the fmode_t that is passed to dm_blk_ioctl() rather than
inconsistently (varies across targets) drop it on the floor by
overriding it with the fmode_t stored in 'struct dm_dev'.
All the persistent reservation functions weren't using the fmode_t they
got back from .prepare_ioctl so remove them.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Could be useful for a target to return stats or other information.
If a target does DMEMIT() anything to @result from its .message method
then it must return 1 to the caller.
Signed-off-By: Mike Snitzer <snitzer@redhat.com>
The ability to have multipath dynamically attach a scsi_dh, that the user
specified in the multipath table, was broken by commit e8f74a0f00 ("dm
mpath: eliminate need to use scsi_device_from_queue").
Restore the ability to load, and attach, a particular scsi_dh module if
one is specified (as noticed by checking m->hw_handler_name).
Fixes: e8f74a0f00 ("dm mpath: eliminate need to use scsi_device_from_queue")
Reported-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
After v4.12 commit e2460f2a4b ("dm: mark targets that pass integrity
data"), dm-multipath, e.g. on DIF+DIX SCSI disk paths, does not support
block integrity any more. So add it to the whitelist.
This is also a pre-requisite to use block integrity with other dm layer(s)
on top of multipath, such as kpartx partitions (dm-linear) or LVM.
Also, bump target version to reflect this fix.
Fixes: e2460f2a4b ("dm: mark targets that pass integrity data")
Cc: <stable@vger.kernel.org> #4.12+
Bisected-by: Fedor Loshakov <loshakov@linux.vnet.ibm.com>
Signed-off-by: Steffen Maier <maier@linux.vnet.ibm.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Initialize all the scsi_dh related 'struct multipath' members regardless
of whether a scsi_dh is in use or not.
The subtle (and fragile) SCSI-assuming legacy code clearly needs further
decoupling from non-SCSI (and/or developer understanding).
Fixes: 8d47e65948 ("dm mpath: remove unnecessary NVMe branching in favor of scsi_dh checks")
Reported-by: Bart Van Assche <bart.vanassche@wdc.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
This eliminates the "queue_mode" configuration's "nvme" mode. There
wasn't anything NVMe-specific about that mode. It was named "nvme"
because it was a short name for the mode. But the entire point of the
mode was to optimize the multipath target for underlying devices that
are _not_ SCSI-based. Devices that aren't SCSI have no need for the
various SCSI device handler (scsi_dh) specific code in DM multipath.
But rather than narrowly define this scsi_dh vs not branching in terms
of "nvme": invert the logic so that we're just checking whether a
multipath device is layered on SCSI devices with scsi_dh attached.
This allows any future storage technology to avoid scsi_dh specific code
in the multipath target too.
Fixes: 848b8aefd4 ("dm mpath: optimize NVMe bio-based support")
Suggested-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
walk; this is critical to allow forward progress without the need to
use the bioset's BIOSET_NEED_RESCUER.
- Remove DM core's BIOSET_NEED_RESCUER based dm_offload infrastructure.
- DM core cleanups and improvements to make bio-based DM more efficient
(e.g. reduced memory footprint as well leveraging per-bio-data more).
- Introduce new bio-based mode (DM_TYPE_NVME_BIO_BASED) that leverages
the more direct IO submission path in the block layer; this mode is
used by DM multipath and also optimizes targets like DM thin-pool that
stack directly on NVMe data device.
- DM multipath improvements to factor out legacy SCSI-only
(e.g. scsi_dh) code paths to allow for more optimized support for NVMe
multipath.
- A fix for DM multipath path selectors (service-time and queue-length)
to select paths in a more balanced way; largely academic but doesn't
hurt.
- Numerous DM raid target fixes and improvements.
- Add a new DM "unstriped" target that enables Intel to workaround
firmware limitations in some NVMe drives that are striped internally
(this target also works when stacked above the DM "striped" target).
- Various Documentation fixes and improvements.
- Misc. cleanups and fixes across various DM infrastructure and targets
(e.g. bufio, flakey, log-writes, snapshot).
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Merge tag 'for-4.16/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm
Pull device mapper updates from Mike Snitzer:
- DM core fixes to ensure that bio submission follows a depth-first
tree walk; this is critical to allow forward progress without the
need to use the bioset's BIOSET_NEED_RESCUER.
- Remove DM core's BIOSET_NEED_RESCUER based dm_offload infrastructure.
- DM core cleanups and improvements to make bio-based DM more efficient
(e.g. reduced memory footprint as well leveraging per-bio-data more).
- Introduce new bio-based mode (DM_TYPE_NVME_BIO_BASED) that leverages
the more direct IO submission path in the block layer; this mode is
used by DM multipath and also optimizes targets like DM thin-pool
that stack directly on NVMe data device.
- DM multipath improvements to factor out legacy SCSI-only (e.g.
scsi_dh) code paths to allow for more optimized support for NVMe
multipath.
- A fix for DM multipath path selectors (service-time and queue-length)
to select paths in a more balanced way; largely academic but doesn't
hurt.
- Numerous DM raid target fixes and improvements.
- Add a new DM "unstriped" target that enables Intel to workaround
firmware limitations in some NVMe drives that are striped internally
(this target also works when stacked above the DM "striped" target).
- Various Documentation fixes and improvements.
- Misc cleanups and fixes across various DM infrastructure and targets
(e.g. bufio, flakey, log-writes, snapshot).
* tag 'for-4.16/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm: (69 commits)
dm cache: Documentation: update default migration_throttling value
dm mpath selector: more evenly distribute ties
dm unstripe: fix target length versus number of stripes size check
dm thin: fix trailing semicolon in __remap_and_issue_shared_cell
dm table: fix NVMe bio-based dm_table_determine_type() validation
dm: various cleanups to md->queue initialization code
dm mpath: delay the retry of a request if the target responded as busy
dm mpath: return DM_MAPIO_DELAY_REQUEUE if QUEUE_IO or PG_INIT_REQUIRED
dm mpath: return DM_MAPIO_REQUEUE on blk-mq rq allocation failure
dm log writes: fix max length used for kstrndup
dm: backfill missing calls to mutex_destroy()
dm snapshot: use mutex instead of rw_semaphore
dm flakey: check for null arg_name in parse_features()
dm thin: extend thinpool status format string with omitted fields
dm thin: fixes in thin-provisioning.txt
dm thin: document representation of <highest mapped sector> when there is none
dm thin: fix documentation relative to low water mark threshold
dm cache: be consistent in specifying sectors and SI units in cache.txt
dm cache: delete obsoleted paragraph in cache.txt
dm cache: fix grammar in cache-policies.txt
...
Add DM_ENDIO_DELAY_REQUEUE to allow request-based multipath's
multipath_end_io() to instruct dm-rq.c:dm_done() to delay a requeue.
This is beneficial to do if BLK_STS_RESOURCE is returned from the target
(because target is busy).
Relative to blk-mq: kick the hw queues via blk_mq_requeue_work(),
indirectly from dm-rq.c:__dm_mq_kick_requeue_list(), after a delay.
For old .request_fn: use blk_delay_queue().
bio-based multipath doesn't have feature parity with request-based for
retryable error requeues; that is something that'll need fixing in the
future.
Suggested-by: Bart Van Assche <bart.vanassche@wdc.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Acked-by: Bart Van Assche <bart.vanassche@wdc.com>
[as interpreted from Bart's "... patch looks fine to me."]
Avoid using DM_MAPIO_REQUEUE unless absolutely necessary because it
results in dm-rq.c:dm_mq_queue_rq() returning BLK_STS_RESOURCE to
blk-mq -- doing so should only ever be done if the underlying queue is
out of resources. So switch to returning DM_MAPIO_DELAY_REQUEUE from
multipath_clone_and_map() if either MPATHF_QUEUE_IO or
MPATHF_PG_INIT_REQUIRED are set.
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
blk-mq will rerun queue via RESTART or dispatch wake after one request
is completed, so not necessary to wait random time for requeuing, we
should trust blk-mq to do it.
More importantly, we need to return BLK_STS_RESOURCE to blk-mq so that
dequeuing from the I/O scheduler can be stopped, this results in
improved I/O merging.
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Uses common code for determining if an error should be retried on
alternate path.
Acked-by: Mike Snitzer <snitzer@redhat.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Keith Busch <keith.busch@intel.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Trying to do both SCSI and NVMe bio-based handling with branching in the
same common code has proven too tedious on a code maintenance level. In
addition it slightly hurts IO performance.
Fix this by factoring out __map_bio() and __map_bio_nvme().
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
All code that deals with pg_init is not used with bio-based NVMe mode.
This includes skipping initialization of pg_init related variables.
Also, pg_init related members on 'struct multipath' have been grouped
together.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
This DM multipath NVMe bio-based support requires CONFIG_NVME_MULTIPATH
to not be set. In the future hopefully NVMe multipath and DM multipath
can co-exist more seemlessly. But as is, if CONFIG_NVME_MULTIPATH=Y
then all the individal NVMe paths will remain hidden to upper layers and
as such DM multipath will not be able to manage them.
Though NVMe's native multipathing doesn't multipath namespaces across
subsystems; so technically a user _could_ use CONFIG_NVME_MULTIPATH=Y
and also use DM multipath to multipath across subsystems.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Moving the dm_bio_restore() to process_queued_bios() avoids doing that
work in multipath_end_io_bio().
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
All underlying members are initialized directly so the memset() calls
are not needed. Also, initialize mpio->nr_bytes from the start since it
never changes.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Commit ca5beb76 ("dm mpath: micro-optimize the hot path relative to
MPATHF_QUEUE_IF_NO_PATH") caused bio-based DM-multipath to fail mptest's
"test_02_sdev_delete".
Restoring the logic that existed prior to commit ca5beb76 fixes this
bio-based DM-multipath regression. Also verified all mptest tests pass
with request-based DM-multipath.
This commit effectively reverts commit ca5beb76 -- but it does so
without reintroducing the need to take the m->lock spinlock in
must_push_back_{rq,bio}.
Fixes: ca5beb76 ("dm mpath: micro-optimize the hot path relative to MPATHF_QUEUE_IF_NO_PATH")
Cc: stable@vger.kernel.org # 4.12+
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Linus Torvalds