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  1. 19 Dec, 2018 1 commit
  3. 31 Oct, 2018 1 commit
  5. 25 Oct, 2018 2 commits
    • Damien Le Moal's avatar
      block: Introduce blk_revalidate_disk_zones() · bf505456
      Damien Le Moal authored 
      
Drivers exposing zoned block devices have to initialize and maintain
correctness (i.e. revalidate) of the device zone bitmaps attached to
the device request queue (seq_zones_bitmap and seq_zones_wlock).

To simplify coding this, introduce a generic helper function
blk_revalidate_disk_zones() suitable for most (and likely all) cases.
This new function always update the seq_zones_bitmap and seq_zones_wlock
bitmaps as well as the queue nr_zones field when called for a disk
using a request based queue. For a disk using a BIO based queue, only
the number of zones is updated since these queues do not have
schedulers and so do not need the zone bitmaps.

With this change, the zone bitmap initialization code in sd_zbc.c can be
replaced with a call to this function in sd_zbc_read_zones(), which is
called from the disk revalidate block operation method.

A call to blk_revalidate_disk_zones() is also added to the null_blk
driver for devices created with the zoned mode enabled.

Finally, to ensure that zoned devices created with dm-linear or
dm-flakey expose the correct number of zones through sysfs, a call to
blk_revalidate_disk_zones() is added to dm_table_set_restrictions().

The zone bitmaps allocated and initialized with
blk_revalidate_disk_zones() are freed automatically from
__blk_release_queue() using the block internal function
blk_queue_free_zone_bitmaps().
Reviewed-by: default avatarHannes Reinecke <hare@suse.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: default avatarMike Snitzer <snitzer@redhat.com>
Signed-off-by: default avatarDamien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
      bf505456
    • Damien Le Moal's avatar
      block: Expose queue nr_zones in sysfs · 965b652e
      Damien Le Moal authored 
      
Expose through sysfs the nr_zones field of struct request_queue.
Exposing this value helps in debugging disk issues as well as
facilitating scripts based use of the disk (e.g. blktests).

For zoned block devices, the nr_zones field indicates the total number
of zones of the device calculated using the known disk capacity and
zone size. This number of zones is always 0 for regular block devices.

Since nr_zones is defined conditionally with CONFIG_BLK_DEV_ZONED,
introduce the blk_queue_nr_zones() function to return the correct value
for any device, regardless if CONFIG_BLK_DEV_ZONED is set.
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarHannes Reinecke <hare@suse.com>
Signed-off-by: default avatarDamien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
      965b652e
  7. 23 Aug, 2018 1 commit
    • Jens Axboe's avatar
      blk-wbt: don't maintain inflight counts if disabled · c125311d
      Jens Axboe authored 
      A previous commit removed the ability to have per-rq flags. We used
those flags to maintain inflight counts. Since we don't have those
anymore, we have to always maintain inflight counts, even if wbt is
disabled. This is clearly suboptimal.

Add a queue quiesce around changing the wbt latency settings from sysfs
to work around this. With that, we can reliably put the enabled check in
our bio_to_wbt_flags(), since we know the WBT_TRACKED flag will be
consistent for the lifetime of the request.

Fixes: c1c80384

 ("block: remove external dependency on wbt_flags")
Reviewed-by: default avatarJosef Bacik <josef@toxicpanda.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
      c125311d
  9. 11 Aug, 2018 1 commit
  11. 09 Aug, 2018 1 commit
    • Bart Van Assche's avatar
      block: Ensure that a request queue is dissociated from the cgroup controller · 24ecc358
      Bart Van Assche authored 
      
Several block drivers call alloc_disk() followed by put_disk() if
something fails before device_add_disk() is called without calling
blk_cleanup_queue(). Make sure that also for this scenario a request
queue is dissociated from the cgroup controller. This patch avoids
that loading the parport_pc, paride and pf drivers triggers the
following kernel crash:

BUG: KASAN: null-ptr-deref in pi_init+0x42e/0x580 [paride]
Read of size 4 at addr 0000000000000008 by task modprobe/744
Call Trace:
dump_stack+0x9a/0xeb
kasan_report+0x139/0x350
pi_init+0x42e/0x580 [paride]
pf_init+0x2bb/0x1000 [pf]
do_one_initcall+0x8e/0x405
do_init_module+0xd9/0x2f2
load_module+0x3ab4/0x4700
SYSC_finit_module+0x176/0x1a0
do_syscall_64+0xee/0x2b0
entry_SYSCALL_64_after_hwframe+0x42/0xb7
Reported-by: default avatarAlexandru Moise <00moses.alexander00@gmail.com>
Fixes: a063057d

 ("block: Fix a race between request queue removal and the block cgroup controller") # v4.17
Signed-off-by: default avatarBart Van Assche <bart.vanassche@wdc.com>
Tested-by: default avatarAlexandru Moise <00moses.alexander00@gmail.com>
Reviewed-by: default avatarJohannes Thumshirn <jthumshirn@suse.de>
Cc: Tejun Heo <tj@kernel.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: Alexandru Moise <00moses.alexander00@gmail.com>
Cc: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
      24ecc358
  13. 09 Jul, 2018 1 commit
  15. 30 May, 2018 1 commit
  17. 24 May, 2018 1 commit
  19. 14 May, 2018 1 commit
  21. 08 Mar, 2018 1 commit
  23. 28 Feb, 2018 1 commit
  25. 18 Jan, 2018 1 commit
  27. 15 Jan, 2018 2 commits
    • Mike Snitzer's avatar
      block: allow gendisk's request_queue registration to be deferred · fa70d2e2
      Mike Snitzer authored 
      
Since I can remember DM has forced the block layer to allow the
allocation and initialization of the request_queue to be distinct
operations.  Reason for this is block/genhd.c:add_disk() has requires
that the request_queue (and associated bdi) be tied to the gendisk
before add_disk() is called -- because add_disk() also deals with
exposing the request_queue via blk_register_queue().

DM's dynamic creation of arbitrary device types (and associated
request_queue types) requires the DM device's gendisk be available so
that DM table loads can establish a master/slave relationship with
subordinate devices that are referenced by loaded DM tables -- using
bd_link_disk_holder().  But until these DM tables, and their associated
subordinate devices, are known DM cannot know what type of request_queue
it needs -- nor what its queue_limits should be.

This chicken and egg scenario has created all manner of problems for DM
and, at times, the block layer.

Summary of changes:

- Add device_add_disk_no_queue_reg() and add_disk_no_queue_reg() variant
  that drivers may use to add a disk without also calling
  blk_register_queue().  Driver must call blk_register_queue() once its
  request_queue is fully initialized.

- Return early from blk_unregister_queue() if QUEUE_FLAG_REGISTERED
  is not set.  It won't be set if driver used add_disk_no_queue_reg()
  but driver encounters an error and must del_gendisk() before calling
  blk_register_queue().

- Export blk_register_queue().

These changes allow DM to use add_disk_no_queue_reg() to anchor its
gendisk as the "master" for master/slave relationships DM must establish
with subordinate devices referenced in DM tables that get loaded.  Once
all "slave" devices for a DM device are known its request_queue can be
properly initialized and then advertised via sysfs -- important
improvement being that no request_queue resource initialization
performed by blk_register_queue() is missed for DM devices anymore.
Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
Reviewed-by: default avatarMing Lei <ming.lei@redhat.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
      fa70d2e2
    • Mike Snitzer's avatar
      block: properly protect the 'queue' kobj in blk_unregister_queue · 667257e8
      Mike Snitzer authored 
      The original commit e9a823fb (block: fix warning when I/O elevator
is changed as request_queue is being removed) is pretty conflated.
"conflated" because the resource being protected by q->sysfs_lock isn't
the queue_flags (it is the 'queue' kobj).

q->sysfs_lock serializes __elevator_change() (via elv_iosched_store)
from racing with blk_unregister_queue():
1) By holding q->sysfs_lock first, __elevator_change() can complete
before a racing blk_unregister_queue().
2) Conversely, __elevator_change() is testing for QUEUE_FLAG_REGISTERED
in case elv_iosched_store() loses the race with blk_unregister_queue(),
it needs a way to know the 'queue' kobj isn't there.

Expand the scope of blk_unregister_queue()'s q->sysfs_lock use so it is
held until after the 'queue' kobj is removed.

To do so blk_mq_unregister_dev() must not also take q->sysfs_lock.  So
rename __blk_mq_unregister_dev() to blk_mq_unregister_dev().

Also, blk_unregister_queue() shou...
      667257e8
  29. 24 Nov, 2017 1 commit
  31. 02 Nov, 2017 1 commit
    • Greg Kroah-Hartman's avatar
      License cleanup: add SPDX GPL-2.0 license identifier to files with no license · b2441318
      Greg Kroah-Hartman authored 
      Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier.  The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
 - file had no licensing information it it.
 - file was a */uapi/* one with no licensing information in it,
 - file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard...
      b2441318
  33. 28 Aug, 2017 1 commit
    • David Jeffery's avatar
      block: fix warning when I/O elevator is changed as request_queue is being removed · e9a823fb
      David Jeffery authored 
      
There is a race between changing I/O elevator and request_queue removal
which can trigger the warning in kobject_add_internal.  A program can
use sysfs to request a change of elevator at the same time another task
is unregistering the request_queue the elevator would be attached to.
The elevator's kobject will then attempt to be connected to the
request_queue in the object tree when the request_queue has just been
removed from sysfs.  This triggers the warning in kobject_add_internal
as the request_queue no longer has a sysfs directory:

kobject_add_internal failed for iosched (error: -2 parent: queue)
------------[ cut here ]------------
WARNING: CPU: 3 PID: 14075 at lib/kobject.c:244 kobject_add_internal+0x103/0x2d0

To fix this warning, we can check the QUEUE_FLAG_REGISTERED flag when
changing the elevator and use the request_queue's sysfs_lock to
serialize between clearing the flag and the elevator testing the flag.
Signed-off-by: default avatarDavid Jeffery <djeffery@redhat.com>
Tested-by: default avatarMing Lei <ming.lei@redhat.com>
Reviewed-by: default avatarMing Lei <ming.lei@redhat.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
      e9a823fb
  35. 14 Jun, 2017 1 commit
    • Bart Van Assche's avatar
      block: Fix a blk_exit_rl() regression · dc9edc44
      Bart Van Assche authored 
      
Avoid that the following complaint is reported:

 BUG: sleeping function called from invalid context at kernel/workqueue.c:2790
 in_atomic(): 1, irqs_disabled(): 0, pid: 41, name: rcuop/3
 1 lock held by rcuop/3/41:
  #0:  (rcu_callback){......}, at: [<ffffffff8111f9a2>] rcu_nocb_kthread+0x282/0x500
 Call Trace:
  dump_stack+0x86/0xcf
  ___might_sleep+0x174/0x260
  __might_sleep+0x4a/0x80
  flush_work+0x7e/0x2e0
  __cancel_work_timer+0x143/0x1c0
  cancel_work_sync+0x10/0x20
  blk_throtl_exit+0x25/0x60
  blkcg_exit_queue+0x35/0x40
  blk_release_queue+0x42/0x130
  kobject_put+0xa9/0x190

This happens since we invoke callbacks that need to block from the
queue release handler. Fix this by pushing the final release to
a workqueue.
Reported-by: default avatarRoss Zwisler <zwisler@gmail.com>
Fixes: commit b425e504

 ("block: Avoid that blk_exit_rl() triggers a use-after-free")
Signed-off-by: default avatarBart Van Assche <bart.vanassche@sandisk.com>
Tested-by: default avatarRoss Zwisler <ross.zwisler@linux.intel.com>

Updated changelog
Signed-off-by: default avatarJens Axboe <axboe@fb.com>
      dc9edc44
  37. 01 Jun, 2017 1 commit
    • Bart Van Assche's avatar
      block: Avoid that blk_exit_rl() triggers a use-after-free · b425e504
      Bart Van Assche authored 
      Since the introduction of .init_rq_fn() and .exit_rq_fn() it is
essential that the memory allocated for struct request_queue
stays around until all blk_exit_rl() calls have finished. Hence
make blk_init_rl() take a reference on struct request_queue.

This patch fixes the following crash:

general protection fault: 0000 [#2] SMP
CPU: 3 PID: 28 Comm: ksoftirqd/3 Tainted: G      D         4.12.0-rc2-dbg+ #2
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.0.0-prebuilt.qemu-project.org 04/01/2014
task: ffff88013a108040 task.stack: ffffc9000071c000
RIP: 0010:free_request_size+0x1a/0x30
RSP: 0018:ffffc9000071fd38 EFLAGS: 00010202
RAX: 6b6b6b6b6b6b6b6b RBX: ffff880067362a88 RCX: 0000000000000003
RDX: ffff880067464178 RSI: ffff880067362a88 RDI: ffff880135ea4418
RBP: ffffc9000071fd40 R08: 0000000000000000 R09: 0000000100180009
R10: ffffc9000071fd38 R11: ffffffff81110800 R12: ffff88006752d3d8
R13: ffff88006752d3d8 R14: ffff88013a108040 R15: 000000000000000a
FS:  0000000000000000(0000) GS:ffff88013fd80000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fa8ec1edb00 CR3: 0000000138ee8000 CR4: 00000000001406e0
Call Trace:
 mempool_destroy.part.10+0x21/0x40
 mempool_destroy+0xe/0x10
 blk_exit_rl+0x12/0x20
 blkg_free+0x4d/0xa0
 __blkg_release_rcu+0x59/0x170
 rcu_process_callbacks+0x260/0x4e0
 __do_softirq+0x116/0x250
 smpboot_thread_fn+0x123/0x1e0
 kthread+0x109/0x140
 ret_from_fork+0x31/0x40

Fixes: commit e9c787e6

 ("scsi: allocate scsi_cmnd structures as part of struct request")
Signed-off-by: default avatarBart Van Assche <bart.vanassche@sandisk.com>
Acked-by: default avatarTejun Heo <tj@kernel.org>
Reviewed-by: default avatarHannes Reinecke <hare@suse.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Cc: Jan Kara <jack@suse.cz>
Cc: <stable@vger.kernel.org> # v4.11+
Signed-off-by: default avatarJens Axboe <axboe@fb.com>
      b425e504
  39. 26 May, 2017 1 commit
  41. 04 May, 2017 2 commits
  43. 26 Apr, 2017 1 commit
  45. 19 Apr, 2017 1 commit
  47. 08 Apr, 2017 1 commit
  49. 07 Apr, 2017 1 commit
  51. 29 Mar, 2017 2 commits
  53. 28 Mar, 2017 2 commits
    • Shaohua Li's avatar
      blk-throttle: choose a small throtl_slice for SSD · d61fcfa4
      Shaohua Li authored 
      
The throtl_slice is 100ms by default. This is a long time for SSD, a lot
of IO can run. To make cgroups have smoother throughput, we choose a
small value (20ms) for SSD.
Signed-off-by: default avatarShaohua Li <shli@fb.com>
Signed-off-by: default avatarJens Axboe <axboe@fb.com>
      d61fcfa4
    • Shaohua Li's avatar
      blk-throttle: make throtl_slice tunable · 297e3d85
      Shaohua Li authored 
      
throtl_slice is important for blk-throttling. It's called slice
internally but it really is a time window blk-throttling samples data.
blk-throttling will make decision based on the samplings. An example is
bandwidth measurement. A cgroup's bandwidth is measured in the time
interval of throtl_slice.

A small throtl_slice meanse cgroups have smoother throughput but burn
more CPUs. It has 100ms default value, which is not appropriate for all
disks. A fast SSD can dispatch a lot of IOs in 100ms. This patch makes
it tunable.

Since throtl_slice isn't a time slice, the sysfs name
'throttle_sample_time' reflects its character better.
Signed-off-by: default avatarShaohua Li <shli@fb.com>
Signed-off-by: default avatarJens Axboe <axboe@fb.com>
      297e3d85
  55. 21 Mar, 2017 2 commits
    • Omar Sandoval's avatar
      blk-stat: convert to callback-based statistics reporting · 34dbad5d
      Omar Sandoval authored 
      
Currently, statistics are gathered in ~0.13s windows, and users grab the
statistics whenever they need them. This is not ideal for both in-tree
users:

1. Writeback throttling wants its own dynamically sized window of
   statistics. Since the blk-stats statistics are reset after every
   window and the wbt windows don't line up with the blk-stats windows,
   wbt doesn't see every I/O.
2. Polling currently grabs the statistics on every I/O. Again, depending
   on how the window lines up, we may miss some I/Os. It's also
   unnecessary overhead to get the statistics on every I/O; the hybrid
   polling heuristic would be just as happy with the statistics from the
   previous full window.

This reworks the blk-stats infrastructure to be callback-based: users
register a callback that they want called at a given time with all of
the statistics from the window during which the callback was active.
Users can dynamically bucketize the statistics. wbt and polling both
currently use read vs. write, but polling can be extended to further
subdivide based on request size.

The callbacks are kept on an RCU list, and each callback has percpu
stats buffers. There will only be a few users, so the overhead on the
I/O completion side is low. The stats flushing is also simplified
considerably: since the timer function is responsible for clearing the
statistics, we don't have to worry about stale statistics.

wbt is a trivial conversion. After the conversion, the windowing problem
mentioned above is fixed.

For polling, we register an extra callback that caches the previous
window's statistics in the struct request_queue for the hybrid polling
heuristic to use.

Since we no longer have a single stats buffer for the request queue,
this also removes the sysfs and debugfs stats entries. To replace those,
we add a debugfs entry for the poll statistics.
Signed-off-by: default avatarOmar Sandoval <osandov@fb.com>
Signed-off-by: default avatarJens Axboe <axboe@fb.com>
      34dbad5d
    • Omar Sandoval's avatar
      blk-stat: use READ and WRITE instead of BLK_STAT_{READ,WRITE} · fa2e39cb
      Omar Sandoval authored 
      
The stats buckets will become generic soon, so make the existing users
use the common READ and WRITE definitions instead of one internal to
blk-stat.
Signed-off-by: default avatarOmar Sandoval <osandov@fb.com>
Signed-off-by: default avatarJens Axboe <axboe@fb.com>
      fa2e39cb
  57. 02 Mar, 2017 1 commit
  59. 15 Feb, 2017 1 commit
    • Tahsin Erdogan's avatar
      block: do not allow updates through sysfs until registration completes · b410aff2
      Tahsin Erdogan authored 
      
When a new disk shows up, sysfs queue directory is created before elevator
is registered. This allows a user to attempt a scheduler switch even though
the initial registration hasn't completed yet.

In one scenario, blk_register_queue() calls elv_register_queue() and
right before cfq_registered_queue() is called, another process executes
elevator_switch() and replaces q->elevator with deadline scheduler. When
cfq_registered_queue() executes it interprets e->elevator_data as struct
cfq_data even though it is actually struct deadline_data.

Grab q->sysfs_lock in blk_register_queue() to synchronize with sysfs
callers.
Signed-off-by: default avatarTahsin Erdogan <tahsin@google.com>
Signed-off-by: default avatarJens Axboe <axboe@fb.com>
      b410aff2
  61. 08 Feb, 2017 1 commit
  63. 06 Feb, 2017 1 commit
  65. 02 Feb, 2017 2 commits