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Linus Torvalds 6f2689a766 SCSI misc on 20220324
This series consists of the usual driver updates (qla2xxx, pm8001,
 libsas, smartpqi, scsi_debug, lpfc, iscsi, mpi3mr) plus minor updates
 and bug fixes.  The high blast radius core update is the removal of
 write same, which affects block and several non-SCSI devices.  The
 other big change, which is more local, is the removal of the SCSI
 pointer.
 
 Signed-off-by: James E.J. Bottomley <jejb@linux.ibm.com>
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Merge tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi

Pull SCSI updates from James Bottomley:
 "This series consists of the usual driver updates (qla2xxx, pm8001,
  libsas, smartpqi, scsi_debug, lpfc, iscsi, mpi3mr) plus minor updates
  and bug fixes.

  The high blast radius core update is the removal of write same, which
  affects block and several non-SCSI devices. The other big change,
  which is more local, is the removal of the SCSI pointer"

* tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi: (281 commits)
  scsi: scsi_ioctl: Drop needless assignment in sg_io()
  scsi: bsg: Drop needless assignment in scsi_bsg_sg_io_fn()
  scsi: lpfc: Copyright updates for 14.2.0.0 patches
  scsi: lpfc: Update lpfc version to 14.2.0.0
  scsi: lpfc: SLI path split: Refactor BSG paths
  scsi: lpfc: SLI path split: Refactor Abort paths
  scsi: lpfc: SLI path split: Refactor SCSI paths
  scsi: lpfc: SLI path split: Refactor CT paths
  scsi: lpfc: SLI path split: Refactor misc ELS paths
  scsi: lpfc: SLI path split: Refactor VMID paths
  scsi: lpfc: SLI path split: Refactor FDISC paths
  scsi: lpfc: SLI path split: Refactor LS_RJT paths
  scsi: lpfc: SLI path split: Refactor LS_ACC paths
  scsi: lpfc: SLI path split: Refactor the RSCN/SCR/RDF/EDC/FARPR paths
  scsi: lpfc: SLI path split: Refactor PLOGI/PRLI/ADISC/LOGO paths
  scsi: lpfc: SLI path split: Refactor base ELS paths and the FLOGI path
  scsi: lpfc: SLI path split: Introduce lpfc_prep_wqe
  scsi: lpfc: SLI path split: Refactor fast and slow paths to native SLI4
  scsi: lpfc: SLI path split: Refactor lpfc_iocbq
  scsi: lpfc: Use kcalloc()
  ...
2022-03-24 19:37:53 -07:00
Christoph Hellwig a773187e37 scsi: dm: Remove WRITE_SAME support
There are no more end-users of REQ_OP_WRITE_SAME left, so we can start
deleting it.

Link: https://lore.kernel.org/r/20220209082828.2629273-7-hch@lst.de
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
2022-02-22 21:11:08 -05:00
Mike Snitzer fa247089de dm: requeue IO if mapping table not yet available
Update both bio-based and request-based DM to requeue IO if the
mapping table not available.

This race of IO being submitted before the DM device ready is so
narrow, yet possible for initial table load given that the DM device's
request_queue is created prior, that it best to requeue IO to handle
this unlikely case.

Reported-by: Zhang Yi <yi.zhang@huawei.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2022-02-22 13:55:52 -05:00
Christoph Hellwig 9f9adea718 dm: remove dm_dispatch_clone_request
Fold dm_dispatch_clone_request into it's only caller, and use a switch
statement to single dispatch for the handling of the different return
values from blk_insert_cloned_request.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Link: https://lore.kernel.org/r/20220215100540.3892965-6-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-02-16 19:39:10 -07:00
Christoph Hellwig 8803c89f36 dm: remove useless code from dm_dispatch_clone_request
Both ->start_time_ns and the RQF_IO_STAT are set when the request is
allocated using blk_mq_alloc_request by dm-mpath in blk_mq_rq_ctx_init.
The block layer also ensures ->start_time_ns is only set when actually
needed.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Link: https://lore.kernel.org/r/20220215100540.3892965-5-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-02-16 19:39:10 -07:00
Christoph Hellwig 28db4711bf blk-mq: remove the request_queue argument to blk_insert_cloned_request
The request must be submitted to the queue it was allocated for, so
remove the extra request_queue argument.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Link: https://lore.kernel.org/r/20220215100540.3892965-4-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-02-16 19:39:10 -07:00
Christoph Hellwig 1d9433cdd0 block: remove the unused rq_end_sector macro
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20210920123328.1399408-9-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-18 06:17:01 -06:00
Ming Lei b4459b11e8 dm rq: don't queue request to blk-mq during DM suspend
DM uses blk-mq's quiesce/unquiesce to stop/start device mapper queue.

But blk-mq's unquiesce may come from outside events, such as elevator
switch, updating nr_requests or others, and request may come during
suspend, so simply ask for blk-mq to requeue it.

Fixes one kernel panic issue when running updating nr_requests and
dm-mpath suspend/resume stress test.

Cc: stable@vger.kernel.org
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2021-10-12 13:54:10 -04:00
Christoph Hellwig 89f871af1b dm: delay registering the gendisk
device mapper is currently the only outlier that tries to call
register_disk after add_disk, leading to fairly inconsistent state
of these block layer data structures.  Instead change device-mapper
to just register the gendisk later now that the holder mechanism
can cope with that.

Note that this introduces a user visible change: the dm kobject is
now only visible after the initial table has been loaded.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Link: https://lore.kernel.org/r/20210804094147.459763-8-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-09 11:50:43 -06:00
Christoph Hellwig 26a9750aa8 blk-mq: improve the blk_mq_init_allocated_queue interface
Don't return the passed in request_queue but a normal error code, and
drop the elevator_init argument in favor of just calling elevator_init_mq
directly from dm-rq.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Link: https://lore.kernel.org/r/20210602065345.355274-3-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-06-11 11:53:02 -06:00
Benjamin Block 8e947c8f4a dm rq: fix double free of blk_mq_tag_set in dev remove after table load fails
When loading a device-mapper table for a request-based mapped device,
and the allocation/initialization of the blk_mq_tag_set for the device
fails, a following device remove will cause a double free.

E.g. (dmesg):
  device-mapper: core: Cannot initialize queue for request-based dm-mq mapped device
  device-mapper: ioctl: unable to set up device queue for new table.
  Unable to handle kernel pointer dereference in virtual kernel address space
  Failing address: 0305e098835de000 TEID: 0305e098835de803
  Fault in home space mode while using kernel ASCE.
  AS:000000025efe0007 R3:0000000000000024
  Oops: 0038 ilc:3 [#1] SMP
  Modules linked in: ... lots of modules ...
  Supported: Yes, External
  CPU: 0 PID: 7348 Comm: multipathd Kdump: loaded Tainted: G        W      X    5.3.18-53-default #1 SLE15-SP3
  Hardware name: IBM 8561 T01 7I2 (LPAR)
  Krnl PSW : 0704e00180000000 000000025e368eca (kfree+0x42/0x330)
             R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:3 CC:2 PM:0 RI:0 EA:3
  Krnl GPRS: 000000000000004a 000000025efe5230 c1773200d779968d 0000000000000000
             000000025e520270 000000025e8d1b40 0000000000000003 00000007aae10000
             000000025e5202a2 0000000000000001 c1773200d779968d 0305e098835de640
             00000007a8170000 000003ff80138650 000000025e5202a2 000003e00396faa8
  Krnl Code: 000000025e368eb8: c4180041e100       lgrl    %r1,25eba50b8
             000000025e368ebe: ecba06b93a55       risbg   %r11,%r10,6,185,58
            #000000025e368ec4: e3b010000008       ag      %r11,0(%r1)
            >000000025e368eca: e310b0080004       lg      %r1,8(%r11)
             000000025e368ed0: a7110001           tmll    %r1,1
             000000025e368ed4: a7740129           brc     7,25e369126
             000000025e368ed8: e320b0080004       lg      %r2,8(%r11)
             000000025e368ede: b904001b           lgr     %r1,%r11
  Call Trace:
   [<000000025e368eca>] kfree+0x42/0x330
   [<000000025e5202a2>] blk_mq_free_tag_set+0x72/0xb8
   [<000003ff801316a8>] dm_mq_cleanup_mapped_device+0x38/0x50 [dm_mod]
   [<000003ff80120082>] free_dev+0x52/0xd0 [dm_mod]
   [<000003ff801233f0>] __dm_destroy+0x150/0x1d0 [dm_mod]
   [<000003ff8012bb9a>] dev_remove+0x162/0x1c0 [dm_mod]
   [<000003ff8012a988>] ctl_ioctl+0x198/0x478 [dm_mod]
   [<000003ff8012ac8a>] dm_ctl_ioctl+0x22/0x38 [dm_mod]
   [<000000025e3b11ee>] ksys_ioctl+0xbe/0xe0
   [<000000025e3b127a>] __s390x_sys_ioctl+0x2a/0x40
   [<000000025e8c15ac>] system_call+0xd8/0x2c8
  Last Breaking-Event-Address:
   [<000000025e52029c>] blk_mq_free_tag_set+0x6c/0xb8
  Kernel panic - not syncing: Fatal exception: panic_on_oops

When allocation/initialization of the blk_mq_tag_set fails in
dm_mq_init_request_queue(), it is uninitialized/freed, but the pointer
is not reset to NULL; so when dev_remove() later gets into
dm_mq_cleanup_mapped_device() it sees the pointer and tries to
uninitialize and free it again.

Fix this by setting the pointer to NULL in dm_mq_init_request_queue()
error-handling. Also set it to NULL in dm_mq_cleanup_mapped_device().

Cc: <stable@vger.kernel.org> # 4.6+
Fixes: 1c357a1e86 ("dm: allocate blk_mq_tag_set rather than embed in mapped_device")
Signed-off-by: Benjamin Block <bblock@linux.ibm.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2021-04-30 14:19:08 -04:00
Christoph Hellwig a54895fa05 block: remove the request_queue to argument request based tracepoints
The request_queue can trivially be derived from the request.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-04 09:42:00 -07:00
Mike Snitzer 33bd6f0693 dm table: make 'struct dm_table' definition accessible to all of DM core
Move 'struct dm_table' definition from dm-table.c to dm-core.h and
update DM core to access its members directly.

Helps optimize max_io_len() and other methods slightly.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2020-09-29 16:33:07 -04:00
Linus Torvalds 2f12d44085 - 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.
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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
2020-08-07 13:08:09 -07:00
Linus Torvalds 382625d0d4 for-5.9/block-20200802
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Merge tag 'for-5.9/block-20200802' of git://git.kernel.dk/linux-block

Pull core block updates from Jens Axboe:
 "Good amount of cleanups and tech debt removals in here, and as a
  result, the diffstat shows a nice net reduction in code.

   - Softirq completion cleanups (Christoph)

   - Stop using ->queuedata (Christoph)

   - Cleanup bd claiming (Christoph)

   - Use check_events, moving away from the legacy media change
     (Christoph)

   - Use inode i_blkbits consistently (Christoph)

   - Remove old unused writeback congestion bits (Christoph)

   - Cleanup/unify submission path (Christoph)

   - Use bio_uninit consistently, instead of bio_disassociate_blkg
     (Christoph)

   - sbitmap cleared bits handling (John)

   - Request merging blktrace event addition (Jan)

   - sysfs add/remove race fixes (Luis)

   - blk-mq tag fixes/optimizations (Ming)

   - Duplicate words in comments (Randy)

   - Flush deferral cleanup (Yufen)

   - IO context locking/retry fixes (John)

   - struct_size() usage (Gustavo)

   - blk-iocost fixes (Chengming)

   - blk-cgroup IO stats fixes (Boris)

   - Various little fixes"

* tag 'for-5.9/block-20200802' of git://git.kernel.dk/linux-block: (135 commits)
  block: blk-timeout: delete duplicated word
  block: blk-mq-sched: delete duplicated word
  block: blk-mq: delete duplicated word
  block: genhd: delete duplicated words
  block: elevator: delete duplicated word and fix typos
  block: bio: delete duplicated words
  block: bfq-iosched: fix duplicated word
  iocost_monitor: start from the oldest usage index
  iocost: Fix check condition of iocg abs_vdebt
  block: Remove callback typedefs for blk_mq_ops
  block: Use non _rcu version of list functions for tag_set_list
  blk-cgroup: show global disk stats in root cgroup io.stat
  blk-cgroup: make iostat functions visible to stat printing
  block: improve discard bio alignment in __blkdev_issue_discard()
  block: change REQ_OP_ZONE_RESET and REQ_OP_ZONE_RESET_ALL to be odd numbers
  block: defer flush request no matter whether we have elevator
  block: make blk_timeout_init() static
  block: remove retry loop in ioc_release_fn()
  block: remove unnecessary ioc nested locking
  block: integrate bd_start_claiming into __blkdev_get
  ...
2020-08-03 11:57:03 -07:00
Ming Lei e766668c6c dm rq: don't call blk_mq_queue_stopped() in dm_stop_queue()
dm_stop_queue() only uses blk_mq_quiesce_queue() so it doesn't
formally stop the blk-mq queue; therefore there is no point making the
blk_mq_queue_stopped() check -- it will never be stopped.

In addition, even though dm_stop_queue() actually tries to quiesce hw
queues via blk_mq_quiesce_queue(), checking with blk_queue_quiesced()
to avoid unnecessary queue quiesce isn't reliable because: the
QUEUE_FLAG_QUIESCED flag is set before synchronize_rcu() and
dm_stop_queue() may be called when synchronize_rcu() from another
blk_mq_quiesce_queue() is in-progress.

Fixes: 7b17c2f729 ("dm: Fix a race condition related to stopping and starting queues")
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2020-07-20 11:17:42 -04:00
Ming Lei 85067747cf dm: do not use waitqueue for request-based DM
Given request-based DM now uses blk-mq's blk_mq_queue_inflight() to
determine if outstanding IO has completed (and DM has no control over
the blk-mq state machine used to track outstanding IO) it is unsafe to
wakeup waiter (dm_wait_for_completion) before blk-mq has cleared a
request's state bits (e.g. MQ_RQ_IN_FLIGHT or MQ_RQ_COMPLETE).  As
such dm_wait_for_completion() could be left to wait indefinitely if no
other requests complete.

Fix this by eliminating request-based DM's use of waitqueue to wait
for blk-mq requests to complete in dm_wait_for_completion.

Signed-off-by: Ming Lei <ming.lei@redhat.com>
Depends-on: 3c94d83cb3 ("blk-mq: change blk_mq_queue_busy() to blk_mq_queue_inflight()")
Cc: stable@vger.kernel.org
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2020-07-07 12:00:01 -04:00
Christoph Hellwig 15f73f5b3e blk-mq: move failure injection out of blk_mq_complete_request
Move the call to blk_should_fake_timeout out of blk_mq_complete_request
and into the drivers, skipping call sites that are obvious error
handlers, and remove the now superflous blk_mq_force_complete_rq helper.
This ensures we don't keep injecting errors into completions that just
terminate the Linux request after the hardware has been reset or the
command has been aborted.

Reviewed-by: Daniel Wagner <dwagner@suse.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-06-24 09:15:57 -06:00
Ming Lei bf0beec060 blk-mq: drain I/O when all CPUs in a hctx are offline
Most of blk-mq drivers depend on managed IRQ's auto-affinity to setup
up queue mapping. Thomas mentioned the following point[1]:

"That was the constraint of managed interrupts from the very beginning:

 The driver/subsystem has to quiesce the interrupt line and the associated
 queue _before_ it gets shutdown in CPU unplug and not fiddle with it
 until it's restarted by the core when the CPU is plugged in again."

However, current blk-mq implementation doesn't quiesce hw queue before
the last CPU in the hctx is shutdown.  Even worse, CPUHP_BLK_MQ_DEAD is a
cpuhp state handled after the CPU is down, so there isn't any chance to
quiesce the hctx before shutting down the CPU.

Add new CPUHP_AP_BLK_MQ_ONLINE state to stop allocating from blk-mq hctxs
where the last CPU goes away, and wait for completion of in-flight
requests.  This guarantees that there is no inflight I/O before shutting
down the managed IRQ.

Add a BLK_MQ_F_STACKING and set it for dm-rq and loop, so we don't need
to wait for completion of in-flight requests from these drivers to avoid
a potential dead-lock. It is safe to do this for stacking drivers as those
do not use interrupts at all and their I/O completions are triggered by
underlying devices I/O completion.

[1] https://lore.kernel.org/linux-block/alpine.DEB.2.21.1904051331270.1802@nanos.tec.linutronix.de/

[hch: different retry mechanism, merged two patches, minor cleanups]

Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Daniel Wagner <dwagner@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-29 10:23:25 -06:00
Damien Le Moal 737eb78e82 block: Delay default elevator initialization
When elevator_init_mq() is called from blk_mq_init_allocated_queue(),
the only information known about the device is the number of hardware
queues as the block device scan by the device driver is not completed
yet for most drivers. The device type and elevator required features
are not set yet, preventing to correctly select the default elevator
most suitable for the device.

This currently affects all multi-queue zoned block devices which default
to the "none" elevator instead of the required "mq-deadline" elevator.
These drives currently include host-managed SMR disks connected to a
smartpqi HBA and null_blk block devices with zoned mode enabled.
Upcoming NVMe Zoned Namespace devices will also be affected.

Fix this by adding the boolean elevator_init argument to
blk_mq_init_allocated_queue() to control the execution of
elevator_init_mq(). Two cases exist:
1) elevator_init = false is used for calls to
   blk_mq_init_allocated_queue() within blk_mq_init_queue(). In this
   case, a call to elevator_init_mq() is added to __device_add_disk(),
   resulting in the delayed initialization of the queue elevator
   after the device driver finished probing the device information. This
   effectively allows elevator_init_mq() access to more information
   about the device.
2) elevator_init = true preserves the current behavior of initializing
   the elevator directly from blk_mq_init_allocated_queue(). This case
   is used for the special request based DM devices where the device
   gendisk is created before the queue initialization and device
   information (e.g. queue limits) is already known when the queue
   initialization is executed.

Additionally, to make sure that the elevator initialization is never
done while requests are in-flight (there should be none when the device
driver calls device_add_disk()), freeze and quiesce the device request
queue before calling blk_mq_init_sched() in elevator_init_mq().

Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-09-05 19:52:34 -06:00
Ming Lei 226b4fc75c blk-mq: add callback of .cleanup_rq
SCSI maintains its own driver private data hooked off of each SCSI
request, and the pridate data won't be freed after scsi_queue_rq()
returns BLK_STS_RESOURCE or BLK_STS_DEV_RESOURCE. An upper layer driver
(e.g. dm-rq) may need to retry these SCSI requests, before SCSI has
fully dispatched them, due to a lower level SCSI driver's resource
limitation identified in scsi_queue_rq(). Currently SCSI's per-request
private data is leaked when the upper layer driver (dm-rq) frees and
then retries these requests in response to BLK_STS_RESOURCE or
BLK_STS_DEV_RESOURCE returns from scsi_queue_rq().

This usecase is so specialized that it doesn't warrant training an
existing blk-mq interface (e.g. blk_mq_free_request) to allow SCSI to
account for freeing its driver private data -- doing so would add an
extra branch for handling a special case that all other consumers of
SCSI (and blk-mq) won't ever need to worry about.

So the most pragmatic way forward is to delegate freeing SCSI driver
private data to the upper layer driver (dm-rq).  Do so by adding
new .cleanup_rq callback and calling a new blk_mq_cleanup_rq() method
from dm-rq.  A following commit will implement the .cleanup_rq() hook
in scsi_mq_ops.

Cc: Ewan D. Milne <emilne@redhat.com>
Cc: Bart Van Assche <bvanassche@acm.org>
Cc: Hannes Reinecke <hare@suse.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: dm-devel@redhat.com
Cc: <stable@vger.kernel.org>
Fixes: 396eaf21ee ("blk-mq: improve DM's blk-mq IO merging via blk_insert_cloned_request feedback")
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-08-04 21:42:06 -06:00
Pavel Begunkov d370ad23a5 dm: update stale comment in end_clone_bio()
Since commit a1ce35fa49 ("block: remove dead elevator
code") blk_end_request() has been replaced with blk_mq_end_request().
So update comment to reference blk_mq_end_request() accordingly.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2019-07-09 14:14:20 -04:00
Yufen Yu 5de719e3d0 dm mpath: fix missing call of path selector type->end_io
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>
2019-04-25 15:38:52 -04:00
Mike Snitzer bcb44433bb dm: disable DISCARD if the underlying storage no longer supports it
Storage devices which report supporting discard commands like
WRITE_SAME_16 with unmap, but reject discard commands sent to the
storage device.  This is a clear storage firmware bug but it doesn't
change the fact that should a program cause discards to be sent to a
multipath device layered on this buggy storage, all paths can end up
failed at the same time from the discards, causing possible I/O loss.

The first discard to a path will fail with Illegal Request, Invalid
field in cdb, e.g.:
 kernel: sd 8:0:8:19: [sdfn] tag#0 FAILED Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE
 kernel: sd 8:0:8:19: [sdfn] tag#0 Sense Key : Illegal Request [current]
 kernel: sd 8:0:8:19: [sdfn] tag#0 Add. Sense: Invalid field in cdb
 kernel: sd 8:0:8:19: [sdfn] tag#0 CDB: Write same(16) 93 08 00 00 00 00 00 a0 08 00 00 00 80 00 00 00
 kernel: blk_update_request: critical target error, dev sdfn, sector 10487808

The SCSI layer converts this to the BLK_STS_TARGET error number, the sd
device disables its support for discard on this path, and because of the
BLK_STS_TARGET error multipath fails the discard without failing any
path or retrying down a different path.  But subsequent discards can
cause path failures.  Any discards sent to the path which already failed
a discard ends up failing with EIO from blk_cloned_rq_check_limits with
an "over max size limit" error since the discard limit was set to 0 by
the sd driver for the path.  As the error is EIO, this now fails the
path and multipath tries to send the discard down the next path.  This
cycle continues as discards are sent until all paths fail.

Fix this by training DM core to disable DISCARD if the underlying
storage already did so.

Also, fix branching in dm_done() and clone_endio() to reflect the
mutually exclussive nature of the IO operations in question.

Cc: stable@vger.kernel.org
Reported-by: David Jeffery <djeffery@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2019-04-04 15:33:59 -04:00
Linus Torvalds 6cdc577a18 - Update bio-based DM core to always call blk_queue_split() and update
DM targets to properly advertise discard limits that blk_queue_split()
   looks at when dtermining to split discard.  Whereby allowing DM core's
   own 'split_discard_bios' to be removed.
 
 - Improve DM cache target to provide support for discard passdown to the
   origin device.
 
 - Introduce support to directly boot to a DM mapped device from init by
   using dm-mod.create= module param.  This eliminates the need for an
   elaborate initramfs that is otherwise needed to create DM devices.
   This feature's implementation has been worked on for quite some time
   (got up to v12) and is of particular interest to Android and other
   more embedded platforms (e.g. ARM).
 
 - Rate limit errors from the DM integrity target that were identified as
   the cause for recent NMI hangs due to console limitations.
 
 - Add sanity checks for user input to thin-pool and external snapshot
   creation.
 
 - Remove some unused leftover kmem caches from when old .request_fn
   request-based support was removed.
 
 - Various small cleanups and fixes to targets (e.g. typos, needless
   unlikely() annotations, use struct_size(), remove needless
   .direct_access method from dm-snapshot)
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Merge tag 'for-5.1/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull device mapper updates from Mike Snitzer:

 - Update bio-based DM core to always call blk_queue_split() and update
   DM targets to properly advertise discard limits that
   blk_queue_split() looks at when dtermining to split discard. Whereby
   allowing DM core's own 'split_discard_bios' to be removed.

 - Improve DM cache target to provide support for discard passdown to
   the origin device.

 - Introduce support to directly boot to a DM mapped device from init by
   using dm-mod.create= module param. This eliminates the need for an
   elaborate initramfs that is otherwise needed to create DM devices.

   This feature's implementation has been worked on for quite some time
   (got up to v12) and is of particular interest to Android and other
   more embedded platforms (e.g. ARM).

 - Rate limit errors from the DM integrity target that were identified
   as the cause for recent NMI hangs due to console limitations.

 - Add sanity checks for user input to thin-pool and external snapshot
   creation.

 - Remove some unused leftover kmem caches from when old .request_fn
   request-based support was removed.

 - Various small cleanups and fixes to targets (e.g. typos, needless
   unlikely() annotations, use struct_size(), remove needless
   .direct_access method from dm-snapshot)

* tag 'for-5.1/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
  dm integrity: limit the rate of error messages
  dm snapshot: don't define direct_access if we don't support it
  dm cache: add support for discard passdown to the origin device
  dm writecache: fix typo in name for writeback_wq
  dm: add support to directly boot to a mapped device
  dm thin: add sanity checks to thin-pool and external snapshot creation
  dm block manager: remove redundant unlikely annotation
  dm verity fec: remove redundant unlikely annotation
  dm integrity: remove redundant unlikely annotation
  dm: always call blk_queue_split() in dm_process_bio()
  dm: fix to_sector() for 32bit
  dm switch: use struct_size() in kzalloc()
  dm: remove unused _rq_tio_cache and _rq_cache
  dm: eliminate 'split_discard_bios' flag from DM target interface
  dm: update dm_process_bio() to split bio if in ->make_request_fn()
2019-03-09 17:40:27 -08:00
Mike Snitzer e689fbab3d dm: remove unused _rq_tio_cache and _rq_cache
Also move dm_rq_target_io structure definition from dm-rq.h to dm-rq.c

Fixes: 6a23e05c2f ("dm: remove legacy request-based IO path")
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2019-03-05 14:48:50 -05:00
Jens Axboe 6fb845f0e7 Linux 5.0-rc6
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Merge tag 'v5.0-rc6' into for-5.1/block

Pull in 5.0-rc6 to avoid a dumb merge conflict with fs/iomap.c.
This is needed since io_uring is now based on the block branch,
to avoid a conflict between the multi-page bvecs and the bits
of io_uring that touch the core block parts.

* tag 'v5.0-rc6': (525 commits)
  Linux 5.0-rc6
  x86/mm: Make set_pmd_at() paravirt aware
  MAINTAINERS: Update the ocores i2c bus driver maintainer, etc
  blk-mq: remove duplicated definition of blk_mq_freeze_queue
  Blk-iolatency: warn on negative inflight IO counter
  blk-iolatency: fix IO hang due to negative inflight counter
  MAINTAINERS: unify reference to xen-devel list
  x86/mm/cpa: Fix set_mce_nospec()
  futex: Handle early deadlock return correctly
  futex: Fix barrier comment
  net: dsa: b53: Fix for failure when irq is not defined in dt
  blktrace: Show requests without sector
  mips: cm: reprime error cause
  mips: loongson64: remove unreachable(), fix loongson_poweroff().
  sit: check if IPv6 enabled before calling ip6_err_gen_icmpv6_unreach()
  geneve: should not call rt6_lookup() when ipv6 was disabled
  KVM: nVMX: unconditionally cancel preemption timer in free_nested (CVE-2019-7221)
  KVM: x86: work around leak of uninitialized stack contents (CVE-2019-7222)
  kvm: fix kvm_ioctl_create_device() reference counting (CVE-2019-6974)
  signal: Better detection of synchronous signals
  ...
2019-02-15 08:43:59 -07:00
Ming Lei 56d18f62f5 block: kill BLK_MQ_F_SG_MERGE
QUEUE_FLAG_NO_SG_MERGE has been killed, so kill BLK_MQ_F_SG_MERGE too.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-02-15 08:40:12 -07:00
Mikulas Patocka 645efa84f6 dm: add memory barrier before waitqueue_active
Block core changes to switch bio-based IO accounting to be percpu had a
side-effect of altering DM core to now rely on calling waitqueue_active
(in both bio-based and request-based) to check if another task is in
dm_wait_for_completion().

A memory barrier is needed before calling waitqueue_active().  DM core
doesn't piggyback on a preceding memory barrier so it must explicitly
use its own.

For more details on why using waitqueue_active() without a preceding
barrier is unsafe, please see the comment before the waitqueue_active()
definition in include/linux/wait.h.

Add the missing memory barrier by switching to using wq_has_sleeper().

Fixes: 6f75723190 ("dm: remove the pending IO accounting")
Fixes: c4576aed8d ("dm: fix request-based dm's use of dm_wait_for_completion")
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2019-02-06 17:24:37 -05:00
Mike Snitzer 34743bfdde dm rq: cleanup leftover code from recently removed q->mq_ops branching
When commit 6a23e05c2f ("dm: remove legacy request-based IO path")
removed some q->mq_ops branching from map_request() it left in place a
goto that was only needed if that branching (and conditional 'r'
assignment) existed.  Now that the branching is gone map_request()'s
goto can be removed too.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2018-12-18 09:02:27 -05:00
Mike Snitzer 2adc5c559a dm rq: remove unused arguments from rq_completed()
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2018-12-18 09:02:25 -05:00
Mike Snitzer c4576aed8d dm: fix request-based dm's use of dm_wait_for_completion
The md->wait waitqueue is used by both bio-based and request-based DM.
Commit dbd3bbd291 ("dm rq: leverage blk_mq_queue_busy() to check for
outstanding IO") lost sight of the requirement that
dm_wait_for_completion() must work with all types of DM devices.

Fix md_in_flight() to call the blk-mq or bio-based method accordingly.

Fixes: dbd3bbd291 ("dm rq: leverage blk_mq_queue_busy() to check for outstanding IO")
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-12-11 07:40:02 -07:00
Mike Snitzer dbd3bbd291 dm rq: leverage blk_mq_queue_busy() to check for outstanding IO
Now that request-based dm-multipath only supports blk-mq, make use of
the newly introduced blk_mq_queue_busy() to check for outstanding IO --
rather than (ab)using the block core's in_flight counters.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-12-10 08:30:37 -07:00
Jens Axboe 344e9ffcbd block: add queue_is_mq() helper
Various spots check for q->mq_ops being non-NULL, but provide
a helper to do this instead.

Where the ->mq_ops != NULL check is redundant, remove it.

Since mq == rq-based now that legacy is gone, get rid of the
queue_is_rq_based() and just use queue_is_mq() everywhere.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-11-16 08:34:06 -07:00
Jens Axboe 6a23e05c2f dm: remove legacy request-based IO path
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>
2018-10-11 11:36:09 -04:00
Kent Overstreet 6f1c819c21 dm: convert to bioset_init()/mempool_init()
Convert dm to embedded bio sets.

Acked-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-05-30 15:33:32 -06:00
Omar Sandoval 522a777566 block: consolidate struct request timestamp fields
Currently, struct request has four timestamp fields:

- A start time, set at get_request time, in jiffies, used for iostats
- An I/O start time, set at start_request time, in ktime nanoseconds,
  used for blk-stats (i.e., wbt, kyber, hybrid polling)
- Another start time and another I/O start time, used for cfq and bfq

These can all be consolidated into one start time and one I/O start
time, both in ktime nanoseconds, shaving off up to 16 bytes from struct
request depending on the kernel config.

Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-05-09 08:33:09 -06:00
Linus Torvalds 64b28683de for-linus-20180204
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Merge tag 'for-linus-20180204' of git://git.kernel.dk/linux-block

Pull more block updates from Jens Axboe:
 "Most of this is fixes and not new code/features:

   - skd fix from Arnd, fixing a build error dependent on sla allocator
     type.

   - blk-mq scheduler discard merging fixes, one from me and one from
     Keith. This fixes a segment miscalculation for blk-mq-sched, where
     we mistakenly think two segments are physically contigious even
     though the request isn't carrying real data. Also fixes a bio-to-rq
     merge case.

   - Don't re-set a bit on the buffer_head flags, if it's already set.
     This can cause scalability concerns on bigger machines and
     workloads. From Kemi Wang.

   - Add BLK_STS_DEV_RESOURCE return value to blk-mq, allowing us to
     distuingish between a local (device related) resource starvation
     and a global one. The latter might happen without IO being in
     flight, so it has to be handled a bit differently. From Ming"

* tag 'for-linus-20180204' of git://git.kernel.dk/linux-block:
  block: skd: fix incorrect linux/slab_def.h inclusion
  buffer: Avoid setting buffer bits that are already set
  blk-mq-sched: Enable merging discard bio into request
  blk-mq: fix discard merge with scheduler attached
  blk-mq: introduce BLK_STS_DEV_RESOURCE
2018-02-04 11:16:35 -08:00
Linus Torvalds 0be600a5ad - 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).
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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
  ...
2018-01-31 11:05:47 -08:00
Ming Lei 86ff7c2a80 blk-mq: introduce BLK_STS_DEV_RESOURCE
This status is returned from driver to block layer if device related
resource is unavailable, but driver can guarantee that IO dispatch
will be triggered in future when the resource is available.

Convert some drivers to return BLK_STS_DEV_RESOURCE.  Also, if driver
returns BLK_STS_RESOURCE and SCHED_RESTART is set, rerun queue after
a delay (BLK_MQ_DELAY_QUEUE) to avoid IO stalls.  BLK_MQ_DELAY_QUEUE is
3 ms because both scsi-mq and nvmefc are using that magic value.

If a driver can make sure there is in-flight IO, it is safe to return
BLK_STS_DEV_RESOURCE because:

1) If all in-flight IOs complete before examining SCHED_RESTART in
blk_mq_dispatch_rq_list(), SCHED_RESTART must be cleared, so queue
is run immediately in this case by blk_mq_dispatch_rq_list();

2) if there is any in-flight IO after/when examining SCHED_RESTART
in blk_mq_dispatch_rq_list():
- if SCHED_RESTART isn't set, queue is run immediately as handled in 1)
- otherwise, this request will be dispatched after any in-flight IO is
  completed via blk_mq_sched_restart()

3) if SCHED_RESTART is set concurently in context because of
BLK_STS_RESOURCE, blk_mq_delay_run_hw_queue() will cover the above two
cases and make sure IO hang can be avoided.

One invariant is that queue will be rerun if SCHED_RESTART is set.

Suggested-by: Jens Axboe <axboe@kernel.dk>
Tested-by: Laurence Oberman <loberman@redhat.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-01-30 20:18:28 -07:00
Mike Snitzer c12c9a3c38 dm: various cleanups to md->queue initialization code
Also, add dm_sysfs_init() error handling to dm_create().

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2018-01-29 13:44:55 -05:00
Mike Snitzer ac514ffc96 dm mpath: delay the retry of a request if the target responded as busy
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."]
2018-01-29 13:44:54 -05:00
Ming Lei 396eaf21ee blk-mq: improve DM's blk-mq IO merging via blk_insert_cloned_request feedback
blk_insert_cloned_request() is called in the fast path of a dm-rq driver
(e.g. blk-mq request-based DM mpath).  blk_insert_cloned_request() uses
blk_mq_request_bypass_insert() to directly append the request to the
blk-mq hctx->dispatch_list of the underlying queue.

1) This way isn't efficient enough because the hctx spinlock is always
used.

2) With blk_insert_cloned_request(), we completely bypass underlying
queue's elevator and depend on the upper-level dm-rq driver's elevator
to schedule IO.  But dm-rq currently can't get the underlying queue's
dispatch feedback at all.  Without knowing whether a request was issued
or not (e.g. due to underlying queue being busy) the dm-rq elevator will
not be able to provide effective IO merging (as a side-effect of dm-rq
currently blindly destaging a request from its elevator only to requeue
it after a delay, which kills any opportunity for merging).  This
obviously causes very bad sequential IO performance.

Fix this by updating blk_insert_cloned_request() to use
blk_mq_request_direct_issue().  blk_mq_request_direct_issue() allows a
request to be issued directly to the underlying queue and returns the
dispatch feedback (blk_status_t).  If blk_mq_request_direct_issue()
returns BLK_SYS_RESOURCE the dm-rq driver will now use DM_MAPIO_REQUEUE
to _not_ destage the request.  Whereby preserving the opportunity to
merge IO.

With this, request-based DM's blk-mq sequential IO performance is vastly
improved (as much as 3X in mpath/virtio-scsi testing).

Signed-off-by: Ming Lei <ming.lei@redhat.com>
[blk-mq.c changes heavily influenced by Ming Lei's initial solution, but
they were refactored to make them less fragile and easier to read/review]
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-01-17 09:46:54 -07:00
Mike Snitzer c100ec49fd dm: fix incomplete request_queue initialization
DM is no longer prone to having its request_queue be improperly
initialized.

Summary of changes:

- defer DM's blk_register_queue() from add_disk()-time until
  dm_setup_md_queue() by using add_disk_no_queue_reg() in alloc_dev().

- dm_setup_md_queue() is updated to fully initialize DM's request_queue
  (_after_ all table loads have occurred and the request_queue's type,
  features and limits are known).

A very welcome side-effect of these changes is DM no longer needs to:
1) backfill the "mq" sysfs entry (because historically DM didn't
initialize the request_queue to use blk-mq until _after_
blk_register_queue() was called via add_disk()).
2) call elv_register_queue() to get .request_fn request-based DM
device's "iosched" exposed in syfs.

In addition, blk-mq debugfs support is now made available because
request-based DM's blk-mq request_queue is now properly initialized
before dm_setup_md_queue() calls blk_register_queue().

These changes also stave off the need to introduce new DM-specific
workarounds in block core, e.g. this proposal:
https://patchwork.kernel.org/patch/10067961/

In the end DM devices should be less unicorn in nature (relative to
initialization and availability of block core infrastructure provided by
the request_queue).

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Tested-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-01-15 08:54:32 -07:00
Christoph Hellwig 5fdee2127f block: remove QUEUE_FLAG_STACKABLE
We already have a queue_is_rq_based helper to check if a request_queue
is request based, so we can remove the flag for it.

Acked-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-10-05 15:22:59 -06:00
Ming Lei dc6364b517 dm rq: do not update rq partially in each ending bio
We don't need to update the original dm request partially when ending
each cloned bio: just update original dm request once when the whole
cloned request is finished.  This still allows full support for partial
completion because a new 'completed' counter accounts for incremental
progress as the clone bios complete.

Partial request update can be a bit expensive, so we should try to avoid
it, especially because it is run in softirq context.

Avoiding all the partial request updates fixes both hard lockup and
soft lockups that were easily reproduced while running Laurence's
test[1] on IB/SRP.

BTW, after d4acf3650c ("block: Make blk_mq_delay_kick_requeue_list()
rerun the queue at a quiet time"), we need to make the test more
aggressive for reproducing the lockup:

	1) run hammer_write.sh 32 or 64 concurrently.
	2) write 8M each time

[1] https://marc.info/?l=linux-block&m=150220185510245&w=2

Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2017-08-28 10:23:28 -04:00
Bart Van Assche d5c27f3ffb dm rq: make dm-sq requeuing behavior consistent with dm-mq behavior
DM_MAPIO_DELAY_REQUEUE causes dm-mq to requeue after a delay but
causes dm-sq to requeue immediately.  Make the behavior of dm-sq
consistent with that of dm-mq.

Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2017-08-28 10:01:33 -04:00
Ming Lei f660174e8b blk-mq: use the introduced blk_mq_unquiesce_queue()
blk_mq_unquiesce_queue() is used for unquiescing the
queue explicitly, so replace blk_mq_start_stopped_hw_queues()
with it.

For the scsi part, this patch takes Bart's suggestion to
switch to block quiesce/unquiesce API completely.

Cc: linux-nvme@lists.infradead.org
Cc: linux-scsi@vger.kernel.org
Cc: dm-devel@redhat.com
Reviewed-by: Bart Van Assche <Bart.VanAssche@sandisk.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-06-18 14:20:04 -06:00
Christoph Hellwig 4e4cbee93d block: switch bios to blk_status_t
Replace bi_error with a new bi_status to allow for a clear conversion.
Note that device mapper overloaded bi_error with a private value, which
we'll have to keep arround at least for now and thus propagate to a
proper blk_status_t value.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2017-06-09 09:27:32 -06:00
Christoph Hellwig fc17b6534e blk-mq: switch ->queue_rq return value to blk_status_t
Use the same values for use for request completion errors as the return
value from ->queue_rq.  BLK_STS_RESOURCE is special cased to cause
a requeue, and all the others are completed as-is.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2017-06-09 09:27:32 -06:00