15 Oct, 2019
1 commit
-
A BIO based request queue does not have a tag_set, which prevent testing
for the flag BLK_MQ_F_NO_SCHED indicating that the queue does not
require an elevator. This leads to an incorrect initialization of a
default elevator in some cases such as BIO based null_blk
(queue_mode == BIO) with zoned mode enabled as the default elevator in
this case is mq-deadline instead of "none".Fix this by testing for a NULL queue mq_ops field which indicates that
the queue is BIO based and should not have an elevator.Reported-by: Shinichiro Kawasaki
Reviewed-by: Bob Liu
Signed-off-by: Damien Le Moal
Signed-off-by: Jens Axboe
26 Sep, 2019
1 commit
-
cecf5d87ff20 ("block: split .sysfs_lock into two locks") starts to
release & acquire sysfs_lock before registering/un-registering elevator
queue during switching elevator for avoiding potential deadlock from
showing & storing 'queue/iosched' attributes and removing elevator's
kobject.Turns out there isn't such deadlock because 'q->sysfs_lock' isn't
required in .show & .store of queue/iosched's attributes, and just
elevator's sysfs lock is acquired in elv_iosched_store() and
elv_iosched_show(). So it is safe to hold queue's sysfs lock when
registering/un-registering elevator queue.The biggest issue is that commit cecf5d87ff20 assumes that concurrent
write on 'queue/scheduler' can't happen. However, this assumption isn't
true, because kernfs_fop_write() only guarantees that concurrent write
aren't called on the same open file, but the write could be from
different open on the file. So we can't release & re-acquire queue's
sysfs lock during switching elevator, otherwise use-after-free on
elevator could be triggered.Fixes the issue by not releasing queue's sysfs lock during switching
elevator.Fixes: cecf5d87ff20 ("block: split .sysfs_lock into two locks")
Cc: Christoph Hellwig
Cc: Hannes Reinecke
Cc: Greg KH
Cc: Mike Snitzer
Reviewed-by: Bart Van Assche
Signed-off-by: Ming Lei
Signed-off-by: Jens Axboe
06 Sep, 2019
6 commits
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The lookup logic is broken - 'e' will never be NULL, even if the
list is empty. Maintain lookup hit in a separate variable instead.Fixes: a0958ba7fcdc ("block: Improve default elevator selection")
Reported-by: Julia Lawall
Signed-off-by: Jens Axboe -
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
Signed-off-by: Damien Le Moal
Signed-off-by: Jens Axboe -
For block devices that do not specify required features, preserve the
current default elevator selection (mq-deadline for single queue
devices, none for multi-queue devices). However, for devices specifying
required features (e.g. zoned block devices ELEVATOR_F_ZBD_SEQ_WRITE
feature), select the first available elevator providing the required
features.In all cases, default to "none" if no elevator is available or if the
initialization of the default elevator fails.Reviewed-by: Johannes Thumshirn
Reviewed-by: Ming Lei
Signed-off-by: Damien Le Moal
Signed-off-by: Jens Axboe -
Introduce the definition of elevator features through the
elevator_features flags in the elevator_type structure. Each flag can
represent a feature supported by an elevator. The first feature defined
by this patch is support for zoned block device sequential write
constraint with the flag ELEVATOR_F_ZBD_SEQ_WRITE, which is implemented
by the mq-deadline elevator using zone write locking.Other possible features are IO priorities, write hints, latency targets
or single-LUN dual-actuator disks (for which the elevator could maintain
one LBA ordered list per actuator).The required_elevator_features field is also added to the request_queue
structure to allow a device driver to specify elevator feature flags
that an elevator must support for the correct operation of the device
(e.g. device drivers for zoned block devices can have the
ELEVATOR_F_ZBD_SEQ_WRITE flag as a required feature).
The helper function blk_queue_required_elevator_features() is
defined for setting this new field.With these two new fields in place, the elevator functions
elevator_match() and elevator_find() are modified to allow a user to set
only an elevator with a set of features that satisfies the device
required features. Elevators not matching the device requirements are
not shown in the device sysfs queue/scheduler file to prevent their use.The "none" elevator can always be selected as before.
Reviewed-by: Johannes Thumshirn
Reviewed-by: Christoph Hellwig
Reviewed-by: Ming Lei
Signed-off-by: Damien Le Moal
Signed-off-by: Jens Axboe -
If the default elevator chosen is mq-deadline, elevator_init_mq() may
return an error if mq-deadline initialization fails, leading to
blk_mq_init_allocated_queue() returning an error, which in turn will
cause the block device initialization to fail and the device not being
exposed.Instead of taking such extreme measure, handle mq-deadline
initialization failures in the same manner as when mq-deadline is not
available (no module to load), that is, default to the "none" scheduler.
With this change, elevator_init_mq() return type can be changed to void.Reviewed-by: Johannes Thumshirn
Reviewed-by: Christoph Hellwig
Reviewed-by: Ming Lei
Signed-off-by: Damien Le Moal
Signed-off-by: Jens Axboe -
Instead of checking a queue tag_set BLK_MQ_F_NO_SCHED flag before
calling elevator_init_mq() to make sure that the queue supports IO
scheduling, use the elevator.c function elv_support_iosched() in
elevator_init_mq(). This does not introduce any functional change but
ensure that elevator_init_mq() does the right thing based on the queue
settings.Reviewed-by: Ming Lei
Reviewed-by: Johannes Thumshirn
Reviewed-by: Christoph Hellwig
Signed-off-by: Damien Le Moal
Signed-off-by: Jens Axboe
03 Sep, 2019
1 commit
-
Since the inclusion of blk-mq, elevator argument was not being
considered anymore, and it's utility died long with the legacy IO path,
now removed too.Reviewed-by: Hannes Reinecke
Reviewed-by: Bob Liu
Reviewed-by: Christoph Hellwig
Signed-off-by: Marcos Paulo de SouzaFold with doc removal patch.
Signed-off-by: Jens Axboe
28 Aug, 2019
3 commits
-
The kernfs built-in lock of 'kn->count' is held in sysfs .show/.store
path. Meantime, inside block's .show/.store callback, q->sysfs_lock is
required.However, when mq & iosched kobjects are removed via
blk_mq_unregister_dev() & elv_unregister_queue(), q->sysfs_lock is held
too. This way causes AB-BA lock because the kernfs built-in lock of
'kn-count' is required inside kobject_del() too, see the lockdep warning[1].On the other hand, it isn't necessary to acquire q->sysfs_lock for
both blk_mq_unregister_dev() & elv_unregister_queue() because
clearing REGISTERED flag prevents storing to 'queue/scheduler'
from being happened. Also sysfs write(store) is exclusive, so no
necessary to hold the lock for elv_unregister_queue() when it is
called in switching elevator path.So split .sysfs_lock into two: one is still named as .sysfs_lock for
covering sync .store, the other one is named as .sysfs_dir_lock
for covering kobjects and related status change.sysfs itself can handle the race between add/remove kobjects and
showing/storing attributes under kobjects. For switching scheduler
via storing to 'queue/scheduler', we use the queue flag of
QUEUE_FLAG_REGISTERED with .sysfs_lock for avoiding the race, then
we can avoid to hold .sysfs_lock during removing/adding kobjects.[1] lockdep warning
======================================================
WARNING: possible circular locking dependency detected
5.3.0-rc3-00044-g73277fc75ea0 #1380 Not tainted
------------------------------------------------------
rmmod/777 is trying to acquire lock:
00000000ac50e981 (kn->count#202){++++}, at: kernfs_remove_by_name_ns+0x59/0x72but task is already holding lock:
00000000fb16ae21 (&q->sysfs_lock){+.+.}, at: blk_unregister_queue+0x78/0x10bwhich lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #1 (&q->sysfs_lock){+.+.}:
__lock_acquire+0x95f/0xa2f
lock_acquire+0x1b4/0x1e8
__mutex_lock+0x14a/0xa9b
blk_mq_hw_sysfs_show+0x63/0xb6
sysfs_kf_seq_show+0x11f/0x196
seq_read+0x2cd/0x5f2
vfs_read+0xc7/0x18c
ksys_read+0xc4/0x13e
do_syscall_64+0xa7/0x295
entry_SYSCALL_64_after_hwframe+0x49/0xbe-> #0 (kn->count#202){++++}:
check_prev_add+0x5d2/0xc45
validate_chain+0xed3/0xf94
__lock_acquire+0x95f/0xa2f
lock_acquire+0x1b4/0x1e8
__kernfs_remove+0x237/0x40b
kernfs_remove_by_name_ns+0x59/0x72
remove_files+0x61/0x96
sysfs_remove_group+0x81/0xa4
sysfs_remove_groups+0x3b/0x44
kobject_del+0x44/0x94
blk_mq_unregister_dev+0x83/0xdd
blk_unregister_queue+0xa0/0x10b
del_gendisk+0x259/0x3fa
null_del_dev+0x8b/0x1c3 [null_blk]
null_exit+0x5c/0x95 [null_blk]
__se_sys_delete_module+0x204/0x337
do_syscall_64+0xa7/0x295
entry_SYSCALL_64_after_hwframe+0x49/0xbeother info that might help us debug this:
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&q->sysfs_lock);
lock(kn->count#202);
lock(&q->sysfs_lock);
lock(kn->count#202);*** DEADLOCK ***
2 locks held by rmmod/777:
#0: 00000000e69bd9de (&lock){+.+.}, at: null_exit+0x2e/0x95 [null_blk]
#1: 00000000fb16ae21 (&q->sysfs_lock){+.+.}, at: blk_unregister_queue+0x78/0x10bstack backtrace:
CPU: 0 PID: 777 Comm: rmmod Not tainted 5.3.0-rc3-00044-g73277fc75ea0 #1380
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS ?-20180724_192412-buildhw-07.phx4
Call Trace:
dump_stack+0x9a/0xe6
check_noncircular+0x207/0x251
? print_circular_bug+0x32a/0x32a
? find_usage_backwards+0x84/0xb0
check_prev_add+0x5d2/0xc45
validate_chain+0xed3/0xf94
? check_prev_add+0xc45/0xc45
? mark_lock+0x11b/0x804
? check_usage_forwards+0x1ca/0x1ca
__lock_acquire+0x95f/0xa2f
lock_acquire+0x1b4/0x1e8
? kernfs_remove_by_name_ns+0x59/0x72
__kernfs_remove+0x237/0x40b
? kernfs_remove_by_name_ns+0x59/0x72
? kernfs_next_descendant_post+0x7d/0x7d
? strlen+0x10/0x23
? strcmp+0x22/0x44
kernfs_remove_by_name_ns+0x59/0x72
remove_files+0x61/0x96
sysfs_remove_group+0x81/0xa4
sysfs_remove_groups+0x3b/0x44
kobject_del+0x44/0x94
blk_mq_unregister_dev+0x83/0xdd
blk_unregister_queue+0xa0/0x10b
del_gendisk+0x259/0x3fa
? disk_events_poll_msecs_store+0x12b/0x12b
? check_flags+0x1ea/0x204
? mark_held_locks+0x1f/0x7a
null_del_dev+0x8b/0x1c3 [null_blk]
null_exit+0x5c/0x95 [null_blk]
__se_sys_delete_module+0x204/0x337
? free_module+0x39f/0x39f
? blkcg_maybe_throttle_current+0x8a/0x718
? rwlock_bug+0x62/0x62
? __blkcg_punt_bio_submit+0xd0/0xd0
? trace_hardirqs_on_thunk+0x1a/0x20
? mark_held_locks+0x1f/0x7a
? do_syscall_64+0x4c/0x295
do_syscall_64+0xa7/0x295
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7fb696cdbe6b
Code: 73 01 c3 48 8b 0d 1d 20 0c 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 008
RSP: 002b:00007ffec9588788 EFLAGS: 00000206 ORIG_RAX: 00000000000000b0
RAX: ffffffffffffffda RBX: 0000559e589137c0 RCX: 00007fb696cdbe6b
RDX: 000000000000000a RSI: 0000000000000800 RDI: 0000559e58913828
RBP: 0000000000000000 R08: 00007ffec9587701 R09: 0000000000000000
R10: 00007fb696d4eae0 R11: 0000000000000206 R12: 00007ffec95889b0
R13: 00007ffec95896b3 R14: 0000559e58913260 R15: 0000559e589137c0Cc: Christoph Hellwig
Cc: Hannes Reinecke
Cc: Greg KH
Cc: Mike Snitzer
Reviewed-by: Bart Van Assche
Signed-off-by: Ming Lei
Signed-off-by: Jens Axboe -
There are 4 users which check if queue is registered, so add one helper
to check it.Cc: Christoph Hellwig
Cc: Hannes Reinecke
Cc: Greg KH
Cc: Mike Snitzer
Cc: Bart Van Assche
Reviewed-by: Bart Van Assche
Signed-off-by: Ming Lei
Signed-off-by: Jens Axboe -
The original comment says:
q->sysfs_lock must be held to provide mutual exclusion between
elevator_switch() and here.Which is simply wrong. elevator_init_mq() is only called from
blk_mq_init_allocated_queue, which is always called before the request
queue is registered via blk_register_queue(), for dm-rq or normal rq
based driver. However, queue's kobject is only exposed and added to sysfs
in blk_register_queue(). So there isn't such race between elevator_switch()
and elevator_init_mq().So avoid to hold q->sysfs_lock in elevator_init_mq().
Cc: Christoph Hellwig
Cc: Hannes Reinecke
Cc: Greg KH
Cc: Mike Snitzer
Cc: Bart Van Assche
Cc: Damien Le Moal
Reviewed-by: Bart Van Assche
Signed-off-by: Ming Lei
Signed-off-by: Jens Axboe
07 Jun, 2019
1 commit
-
In theory, IO scheduler belongs to request queue, and the request pool
of sched tags belongs to the request queue too.However, the current tags allocation interfaces are re-used for both
driver tags and sched tags, and driver tags is definitely host wide,
and doesn't belong to any request queue, same with its request pool.
So we need tagset instance for freeing request of sched tags.Meantime, blk_mq_free_tag_set() often follows blk_cleanup_queue() in case
of non-BLK_MQ_F_TAG_SHARED, this way requires that request pool of sched
tags to be freed before calling blk_mq_free_tag_set().Commit 47cdee29ef9d94e ("block: move blk_exit_queue into __blk_release_queue")
moves blk_exit_queue into __blk_release_queue for simplying the fast
path in generic_make_request(), then causes oops during freeing requests
of sched tags in __blk_release_queue().Fix the above issue by move freeing request pool of sched tags into
blk_cleanup_queue(), this way is safe becasue queue has been frozen and no any
in-queue requests at that time. Freeing sched tags has to be kept in queue's
release handler becasue there might be un-completed dispatch activity
which might refer to sched tags.Cc: Bart Van Assche
Cc: Christoph Hellwig
Fixes: 47cdee29ef9d94e485eb08f962c74943023a5271 ("block: move blk_exit_queue into __blk_release_queue")
Tested-by: Yi Zhang
Reported-by: kernel test robot
Signed-off-by: Ming Lei
Signed-off-by: Jens Axboe
01 May, 2019
1 commit
-
Various block layer files do not have any licensing information at all.
Add SPDX tags for the default kernel GPLv2 license to those.Reviewed-by: Chaitanya Kulkarni
Signed-off-by: Christoph Hellwig
Signed-off-by: Jens Axboe
08 Apr, 2019
1 commit
-
The 'def' local variable became unused after commit f382fb0bcef4 ("block: remove
legacy IO schedulers"), let's remove it.Reviewed-by: Christoph Hellwig
Signed-off-by: Hisao Tanabe
Signed-off-by: Jens Axboe
11 Feb, 2019
1 commit
-
There's no reason to freeze queue and remove scheduler
if there's no scheduler already.Signed-off-by: Aleksei Zakharov
Signed-off-by: Jens Axboe
16 Nov, 2018
1 commit
-
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
Signed-off-by: Jens Axboe
15 Nov, 2018
1 commit
-
The boolean next_sorted is set to false and is never changed, hence
the code that checks if it is true is dead code and can now be
removed. This dead code occurred from a previous commit that cleaned
up the elevator and removed the setting of next_sorted to true.Detected by CoverityScan, CID#1475401 ("'Constant' variable guards
dead code")Fixes: a1ce35fa4985 ("block: remove dead elevator code")
Signed-off-by: Colin Ian King
Signed-off-by: Jens Axboe
08 Nov, 2018
3 commits
-
This is a remnant of when we had ops for both SQ and MQ
schedulers. Now it's just MQ, so get rid of the union.Reviewed-by: Omar Sandoval
Signed-off-by: Jens Axboe -
This removes a bunch of core and elevator related code. On the core
front, we remove anything related to queue running, draining,
initialization, plugging, and congestions. We also kill anything
related to request allocation, merging, retrieval, and completion.Remove any checking for single queue IO schedulers, as they no
longer exist. This means we can also delete a bunch of code related
to request issue, adding, completion, etc - and all the SQ related
ops and helpers.Also kill the load_default_modules(), as all that did was provide
for a way to load the default single queue elevator.Tested-by: Ming Lei
Reviewed-by: Omar Sandoval
Signed-off-by: Jens Axboe -
Retain the deadline documentation, as that carries over to mq-deadline
as well.Tested-by: Ming Lei
Reviewed-by: Omar Sandoval
Signed-off-by: Jens Axboe
01 Oct, 2018
1 commit
-
Merge -rc6 in, for two reasons:
1) Resolve a trivial conflict in the blk-mq-tag.c documentation
2) A few important regression fixes went into upstream directly, so
they aren't in the 4.20 branch.Signed-off-by: Jens Axboe
* tag 'v4.19-rc6': (780 commits)
Linux 4.19-rc6
MAINTAINERS: fix reference to moved drivers/{misc => auxdisplay}/panel.c
cpufreq: qcom-kryo: Fix section annotations
perf/core: Add sanity check to deal with pinned event failure
xen/blkfront: correct purging of persistent grants
Revert "xen/blkfront: When purging persistent grants, keep them in the buffer"
selftests/powerpc: Fix Makefiles for headers_install change
blk-mq: I/O and timer unplugs are inverted in blktrace
dax: Fix deadlock in dax_lock_mapping_entry()
x86/boot: Fix kexec booting failure in the SEV bit detection code
bcache: add separate workqueue for journal_write to avoid deadlock
drm/amd/display: Fix Edid emulation for linux
drm/amd/display: Fix Vega10 lightup on S3 resume
drm/amdgpu: Fix vce work queue was not cancelled when suspend
Revert "drm/panel: Add device_link from panel device to DRM device"
xen/blkfront: When purging persistent grants, keep them in the buffer
clocksource/drivers/timer-atmel-pit: Properly handle error cases
block: fix deadline elevator drain for zoned block devices
ACPI / hotplug / PCI: Don't scan for non-hotplug bridges if slot is not bridge
drm/syncobj: Don't leak fences when WAIT_FOR_SUBMIT is set
...Signed-off-by: Jens Axboe
27 Sep, 2018
4 commits
-
When the deadline scheduler is used with a zoned block device, writes
to a zone will be dispatched one at a time. This causes the warning
message:deadline: forced dispatching is broken (nr_sorted=X), please report this
to be displayed when switching to another elevator with the legacy I/O
path while write requests to a zone are being retained in the scheduler
queue.Prevent this message from being displayed when executing
elv_drain_elevator() for a zoned block device. __blk_drain_queue() will
loop until all writes are dispatched and completed, resulting in the
desired elevator queue drain without extensive modifications to the
deadline code itself to handle forced-dispatch calls.Signed-off-by: Damien Le Moal
Fixes: 8dc8146f9c92 ("deadline-iosched: Introduce zone locking support")
Cc: stable@vger.kernel.org
Signed-off-by: Jens Axboe -
Instead of scheduling runtime resume of a request queue after a
request has been queued, schedule asynchronous resume during request
allocation. The new pm_request_resume() calls occur after
blk_queue_enter() has increased the q_usage_counter request queue
member. This change is needed for a later patch that will make request
allocation block while the queue status is not RPM_ACTIVE.Signed-off-by: Bart Van Assche
Reviewed-by: Ming Lei
Reviewed-by: Christoph Hellwig
Cc: Jianchao Wang
Cc: Hannes Reinecke
Cc: Johannes Thumshirn
Cc: Alan Stern
Signed-off-by: Jens Axboe -
Move the pm_request_resume() and pm_runtime_mark_last_busy() calls into
two new functions and thereby separate legacy block layer code from code
that works for both the legacy block layer and blk-mq. A later patch will
add calls to the new functions in the blk-mq code.Signed-off-by: Bart Van Assche
Reviewed-by: Ming Lei
Reviewed-by: Christoph Hellwig
Cc: Martin K. Petersen
Cc: Jianchao Wang
Cc: Hannes Reinecke
Cc: Johannes Thumshirn
Cc: Alan Stern
Signed-off-by: Jens Axboe -
Move the code for runtime power management from blk-core.c into the
new source file blk-pm.c. Move the corresponding declarations from
into . For CONFIG_PM=n, leave out
the declarations of the functions that are not used in that mode.
This patch not only reduces the number of #ifdefs in the block layer
core code but also reduces the size of header file
and hence should help to reduce the build time of the Linux kernel
if CONFIG_PM is not defined.Signed-off-by: Bart Van Assche
Reviewed-by: Ming Lei
Reviewed-by: Christoph Hellwig
Cc: Jianchao Wang
Cc: Hannes Reinecke
Cc: Johannes Thumshirn
Cc: Alan Stern
Signed-off-by: Jens Axboe
28 Aug, 2018
1 commit
-
kmem_cache_destroy() can handle NULL pointer correctly, so there is
no need to check e->icq_cache before calling kmem_cache_destroy().Signed-off-by: Chengguang Xu
Signed-off-by: Jens Axboe
21 Aug, 2018
1 commit
-
Currently, when update nr_hw_queues, IO scheduler's init_hctx will
be invoked before the mapping between ctx and hctx is adapted
correctly by blk_mq_map_swqueue. The IO scheduler init_hctx (kyber)
may depend on this mapping and get wrong result and panic finally.
A simply way to fix this is that switch the IO scheduler to 'none'
before update the nr_hw_queues, and then switch it back after
update nr_hw_queues. blk_mq_sched_init_/exit_hctx are removed due
to nobody use them any more.Signed-off-by: Jianchao Wang
Signed-off-by: Jens Axboe
01 Jun, 2018
5 commits
-
There is almost no shared logic, which leads to a very confusing code
flow.Signed-off-by: Christoph Hellwig
Reviewed-by: Damien Le Moal
Tested-by: Damien Le Moal
Signed-off-by: Jens Axboe -
Both callers take just around so function call, so move it in.
Also remove the now pointless blk_mq_sched_init wrapper.Signed-off-by: Christoph Hellwig
Reviewed-by: Damien Le Moal
Tested-by: Damien Le Moal
Signed-off-by: Jens Axboe -
Reported-by: Damien Le Moal
Signed-off-by: Christoph Hellwig
Reviewed-by: Damien Le Moal
Tested-by: Damien Le Moal
Signed-off-by: Jens Axboe -
These are only used by the block core. Also move the declarations to
block/blk.h.Reported-by: Damien Le Moal
Signed-off-by: Christoph Hellwig
Reviewed-by: Damien Le Moal
Tested-by: Damien Le Moal
Signed-off-by: Jens Axboe -
No point in doing this in elevator_init.
Signed-off-by: Christoph Hellwig
Reported-by: Damien Le Moal
Reviewed-by: Damien Le Moal
Tested-by: Damien Le Moal
Signed-off-by: Jens Axboe
19 Jan, 2018
2 commits
-
This patch does not change any functionality.
Reviewed-by: Christoph Hellwig
Signed-off-by: Bart Van Assche
Signed-off-by: Jens Axboe -
These two functions are only called from inside the block layer so
unexport them.Reviewed-by: Christoph Hellwig
Signed-off-by: Bart Van Assche
Signed-off-by: Jens Axboe
07 Jan, 2018
1 commit
-
Dispatch may still be in-progress after queue is frozen, so we have to
quiesce queue before switching IO scheduler and updating nr_requests.Also when switching io schedulers, blk_mq_run_hw_queue() may still be
called somewhere(such as from nvme_reset_work()), and io scheduler's
per-hctx data may not be setup yet, so cause oops even inside
blk_mq_hctx_has_pending(), such as it can be run just between:ret = e->ops.mq.init_sched(q, e);
AND
ret = e->ops.mq.init_hctx(hctx, i)inside blk_mq_init_sched().
This reverts commit 7a148c2fcff8330(block: don't call blk_mq_quiesce_queue()
after queue is frozen) basically, and makes sure blk_mq_hctx_has_pending
won't be called if queue is quiesced.Reviewed-by: Christoph Hellwig
Fixes: 7a148c2fcff83309(block: don't call blk_mq_quiesce_queue() after queue is frozen)
Reported-by: Yi Zhang
Tested-by: Yi Zhang
Signed-off-by: Ming Lei
Signed-off-by: Jens Axboe
26 Oct, 2017
2 commits
-
Since we now lookup elevator types with the appropriate multiqueue
capability, allow schedulers to register with an alias alongside
the real name. This is in preparation for allowing 'mq-deadline'
to register an alias of 'deadline' as well.Reviewed-by: Omar Sandoval
Signed-off-by: Jens Axboe -
If an IO scheduler is selected via elevator= and it doesn't match
the driver in question wrt blk-mq support, then we fail to boot.The elevator= parameter is deprecated and only supported for
non-mq devices. Augment the elevator lookup API so that we
pass in if we're looking for an mq capable scheduler or not,
so that we only ever return a valid type for the queue in
question.Fixes: https://bugzilla.kernel.org/show_bug.cgi?id=196695
Reviewed-by: Omar Sandoval
Signed-off-by: Jens Axboe
06 Oct, 2017
1 commit
-
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
Signed-off-by: Christoph Hellwig
Signed-off-by: Jens Axboe
29 Aug, 2017
1 commit
-
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+0x103/0x2d0To 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: David Jeffery
Tested-by: Ming Lei
Reviewed-by: Ming Lei
Signed-off-by: Jens Axboe
