block: add blk_time_get_ns() and blk_time_get() helpers

Convert any user of ktime_get_ns() to use blk_time_get_ns(), and
ktime_get() to blk_time_get(), so we have a unified API for querying the
curr

block: add blk_time_get_ns() and blk_time_get() helpers

Convert any user of ktime_get_ns() to use blk_time_get_ns(), and
ktime_get() to blk_time_get(), so we have a unified API for querying the
current time in nanoseconds or as ktime.

No functional changes intended, this patch just wraps ktime_get_ns()
and ktime_get() with a block helper.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

show more ...

blkcg: Restructure blkg_conf_prep() and friends

We want to support lazy init of rq-qos policies so that iolatency is enabled
lazily on configuration instead of gendisk initialization. The way blkg
c

blkcg: Restructure blkg_conf_prep() and friends

We want to support lazy init of rq-qos policies so that iolatency is enabled
lazily on configuration instead of gendisk initialization. The way blkg
config helpers are structured now is a bit awkward for that. Let's
restructure:

* blkcg_conf_open_bdev() is renamed to blkg_conf_open_bdev(). The blkcg_
prefix was used because the bdev opening step is blkg-independent.
However, the distinction is too subtle and confuses more than helps. Let's
switch to blkg prefix so that it's consistent with the type and other
helper names.

* struct blkg_conf_ctx now remembers the original input string and is always
initialized by the new blkg_conf_init().

* blkg_conf_open_bdev() is updated to take a pointer to blkg_conf_ctx like
blkg_conf_prep() and can be called multiple times safely. Instead of
modifying the double pointer to input string directly,
blkg_conf_open_bdev() now sets blkg_conf_ctx->body.

* blkg_conf_finish() is renamed to blkg_conf_exit() for symmetry and now
must be called on all blkg_conf_ctx's which were initialized with
blkg_conf_init().

Combined, this allows the users to either open the bdev first or do it
altogether with blkg_conf_prep() which will help implementing lazy init of
rq-qos policies.

blkg_conf_init/exit() will also be used implement synchronization against
device removal. This is necessary because iolat / iocost are configured
through cgroupfs instead of one of the files under /sys/block/DEVICE. As
cgroupfs operations aren't synchronized with block layer, the lazy init and
other configuration operations may race against device removal. This patch
makes blkg_conf_init/exit() used consistently for all cgroup-orginating
configurations making them a good place to implement explicit
synchronization.

Users are updated accordingly. No behavior change is intended by this patch.

v2: bfq wasn't updated in v1 causing a build error. Fixed.

v3: Update the description to include future use of blkg_conf_init/exit() as
synchronization points.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Yu Kuai <yukuai1@huaweicloud.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20230413000649.115785-3-tj@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>

show more ...

blk-cgroup: delete cpd_init_fn of blkcg_policy

blkcg_policy cpd_init_fn() is used to just initialize some default
fields of policy data, which is enough to do in cpd_alloc_fn().

This patch delete t

blk-cgroup: delete cpd_init_fn of blkcg_policy

blkcg_policy cpd_init_fn() is used to just initialize some default
fields of policy data, which is enough to do in cpd_alloc_fn().

This patch delete the only user bfq_cpd_init(), and remove cpd_init_fn
from blkcg_policy.

Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20230406145050.49914-4-zhouchengming@bytedance.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

show more ...

block, bfq: remove BFQ_WEIGHT_LEGACY_DFL

BFQ_WEIGHT_LEGACY_DFL is the same as CGROUP_WEIGHT_DFL, which means
we don't need cpd_bind_fn() callback to update default weight when
attached to a hierarch

block, bfq: remove BFQ_WEIGHT_LEGACY_DFL

BFQ_WEIGHT_LEGACY_DFL is the same as CGROUP_WEIGHT_DFL, which means
we don't need cpd_bind_fn() callback to update default weight when
attached to a hierarchy.

This patch remove BFQ_WEIGHT_LEGACY_DFL and cpd_bind_fn().

Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20230406145050.49914-2-zhouchengming@bytedance.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

show more ...

Revert "blk-cgroup: pin the gendisk in struct blkcg_gq"

This reverts commit 84d7d462b16dd5f0bf7c7ca9254bf81db2c952a2.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/2

Revert "blk-cgroup: pin the gendisk in struct blkcg_gq"

This reverts commit 84d7d462b16dd5f0bf7c7ca9254bf81db2c952a2.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20230214183308.1658775-6-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

show more ...

Revert "blk-cgroup: move the cgroup information to struct gendisk"

This reverts commit 3f13ab7c80fdb0ada86a8e3e818960bc1ccbaa59 as a patch
it depends on caused a few problems.

Signed-off-by: Christ

Revert "blk-cgroup: move the cgroup information to struct gendisk"

This reverts commit 3f13ab7c80fdb0ada86a8e3e818960bc1ccbaa59 as a patch
it depends on caused a few problems.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20230214183308.1658775-2-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

show more ...

block, bfq: cleanup 'bfqg->online'

After commit dfd6200a0954 ("blk-cgroup: support to track if policy is
online"), there is no need to do this again in bfq.

However, 'pd->online' is not protected b

block, bfq: cleanup 'bfqg->online'

After commit dfd6200a0954 ("blk-cgroup: support to track if policy is
online"), there is no need to do this again in bfq.

However, 'pd->online' is not protected by 'bfqd->lock', in order to make
sure bfq won't see that 'pd->online' is still set after bfq_pd_offline(),
clear it before bfq_pd_offline() is called. This is fine because other
polices doesn't use 'pd->online' and bfq_pd_offline() will move active
bfqq to root cgroup anyway.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230202134913.2364549-1-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

show more ...

blk-cgroup: move the cgroup information to struct gendisk

cgroup information only makes sense on a live gendisk that allows
file system I/O (which includes the raw block device). So move over
the c

blk-cgroup: move the cgroup information to struct gendisk

cgroup information only makes sense on a live gendisk that allows
file system I/O (which includes the raw block device). So move over
the cgroup related members.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Andreas Herrmann <aherrmann@suse.de>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20230203150400.3199230-20-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

show more ...

blk-cgroup: pass a gendisk to pd_alloc_fn

No need to the request_queue here, pass a gendisk and extract the
node ids from that.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Andreas He

blk-cgroup: pass a gendisk to pd_alloc_fn

No need to the request_queue here, pass a gendisk and extract the
node ids from that.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Andreas Herrmann <aherrmann@suse.de>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20230203150400.3199230-18-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

show more ...

blk-cgroup: pass a gendisk to blkcg_{de,}activate_policy

Prepare for storing the blkcg information in the gendisk instead of
the request_queue.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewe

blk-cgroup: pass a gendisk to blkcg_{de,}activate_policy

Prepare for storing the blkcg information in the gendisk instead of
the request_queue.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Andreas Herrmann <aherrmann@suse.de>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20230203150400.3199230-17-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

show more ...

blk-cgroup: pin the gendisk in struct blkcg_gq

Currently each blkcg_gq holds a request_queue reference, which is what
is used in the policies. But a lot of these interfaces will move over to
use a

blk-cgroup: pin the gendisk in struct blkcg_gq

Currently each blkcg_gq holds a request_queue reference, which is what
is used in the policies. But a lot of these interfaces will move over to
use a gendisk, so store a disk in struct blkcg_gq and hold a reference to
it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Andreas Herrmann <aherrmann@suse.de>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20230203150400.3199230-7-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

show more ...

block, bfq: fix uaf for bfqq in bic_set_bfqq()

After commit 64dc8c732f5c ("block, bfq: fix possible uaf for 'bfqq->bic'"),
bic->bfqq will be accessed in bic_set_bfqq(), however, in some context
bic-

block, bfq: fix uaf for bfqq in bic_set_bfqq()

After commit 64dc8c732f5c ("block, bfq: fix possible uaf for 'bfqq->bic'"),
bic->bfqq will be accessed in bic_set_bfqq(), however, in some context
bic->bfqq will be freed, and bic_set_bfqq() is called with the freed
bic->bfqq.

Fix the problem by always freeing bfqq after bic_set_bfqq().

Fixes: 64dc8c732f5c ("block, bfq: fix possible uaf for 'bfqq->bic'")
Reported-and-tested-by: Shinichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230130014136.591038-1-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

show more ...

block, bfq: inject I/O to underutilized actuators

The main service scheme of BFQ for sync I/O is serving one sync
bfq_queue at a time, for a while. In particular, BFQ enforces this
scheme when it de

block, bfq: inject I/O to underutilized actuators

The main service scheme of BFQ for sync I/O is serving one sync
bfq_queue at a time, for a while. In particular, BFQ enforces this
scheme when it deems the latter necessary to boost throughput or
to preserve service guarantees. Unfortunately, when BFQ enforces
this policy, only one actuator at a time gets served for a while,
because each bfq_queue contains I/O only for one actuator. The
other actuators may remain underutilized.

Actually, BFQ may serve (inject) extra I/O, taken from other
bfq_queues, in parallel with that of the in-service queue. This
injection mechanism may provide the ground for dealing also with
the above actuator-underutilization problem. Yet BFQ does not take
the actuator load into account when choosing which queue to pick
extra I/O from. In addition, BFQ may happen to inject extra I/O
only when the in-service queue is temporarily empty.

In view of these facts, this commit extends the
injection mechanism in such a way that the latter:
(1) takes into account also the actuator load;
(2) checks such a load on each dispatch, and injects I/O for an
underutilized actuator, if there is one and there is I/O for it.

To perform the check in (2), this commit introduces a load
threshold, currently set to 4. A linear scan of each actuator is
performed, until an actuator is found for which the following two
conditions hold: the load of the actuator is below the threshold,
and there is at least one non-in-service queue that contains I/O
for that actuator. If such a pair (actuator, queue) is found, then
the head request of that queue is returned for dispatch, instead
of the head request of the in-service queue.

We have set the threshold, empirically, to the minimum possible
value for which an actuator is fully utilized, or close to be
fully utilized. By doing so, injected I/O 'steals' as few
drive-queue slots as possibile to the in-service queue. This
reduces as much as possible the probability that the service of
I/O from the in-service bfq_queue gets delayed because of slot
exhaustion, i.e., because all the slots of the drive queue are
filled with I/O injected from other queues (NCQ provides for 32
slots).

This new mechanism also counters actuator underutilization in the
case of asymmetric configurations of bfq_queues. Namely if there
are few bfq_queues containing I/O for some actuators and many
bfq_queues containing I/O for other actuators. Or if the
bfq_queues containing I/O for some actuators have lower weights
than the other bfq_queues.

Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Signed-off-by: Paolo Valente <paolo.valente@linaro.org>
Signed-off-by: Davide Zini <davidezini2@gmail.com>
Link: https://lore.kernel.org/r/20230103145503.71712-8-paolo.valente@linaro.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>

show more ...

block, bfq: split sync bfq_queues on a per-actuator basis

Single-LUN multi-actuator SCSI drives, as well as all multi-actuator
SATA drives appear as a single device to the I/O subsystem [1]. Yet
th

block, bfq: split sync bfq_queues on a per-actuator basis

Single-LUN multi-actuator SCSI drives, as well as all multi-actuator
SATA drives appear as a single device to the I/O subsystem [1]. Yet
they address commands to different actuators internally, as a function
of Logical Block Addressing (LBAs). A given sector is reachable by
only one of the actuators. For example, Seagate’s Serial Advanced
Technology Attachment (SATA) version contains two actuators and maps
the lower half of the SATA LBA space to the lower actuator and the
upper half to the upper actuator.

Evidently, to fully utilize actuators, no actuator must be left idle
or underutilized while there is pending I/O for it. The block layer
must somehow control the load of each actuator individually. This
commit lays the ground for allowing BFQ to provide such a per-actuator
control.

BFQ associates an I/O-request sync bfq_queue with each process doing
synchronous I/O, or with a group of processes, in case of queue
merging. Then BFQ serves one bfq_queue at a time. While in service, a
bfq_queue is emptied in request-position order. Yet the same process,
or group of processes, may generate I/O for different actuators. In
this case, different streams of I/O (each for a different actuator)
get all inserted into the same sync bfq_queue. So there is basically
no individual control on when each stream is served, i.e., on when the
I/O requests of the stream are picked from the bfq_queue and
dispatched to the drive.

This commit enables BFQ to control the service of each actuator
individually for synchronous I/O, by simply splitting each sync
bfq_queue into N queues, one for each actuator. In other words, a sync
bfq_queue is now associated to a pair (process, actuator). As a
consequence of this split, the per-queue proportional-share policy
implemented by BFQ will guarantee that the sync I/O generated for each
actuator, by each process, receives its fair share of service.

This is just a preparatory patch. If the I/O of the same process
happens to be sent to different queues, then each of these queues may
undergo queue merging. To handle this event, the bfq_io_cq data
structure must be properly extended. In addition, stable merging must
be disabled to avoid loss of control on individual actuators. Finally,
also async queues must be split. These issues are described in detail
and addressed in next commits. As for this commit, although multiple
per-process bfq_queues are provided, the I/O of each process or group
of processes is still sent to only one queue, regardless of the
actuator the I/O is for. The forwarding to distinct bfq_queues will be
enabled after addressing the above issues.

[1] https://www.linaro.org/blog/budget-fair-queueing-bfq-linux-io-scheduler-optimizations-for-multi-actuator-sata-hard-drives/

Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Signed-off-by: Gabriele Felici <felicigb@gmail.com>
Signed-off-by: Carmine Zaccagnino <carmine@carminezacc.com>
Signed-off-by: Paolo Valente <paolo.valente@linaro.org>
Link: https://lore.kernel.org/r/20230103145503.71712-2-paolo.valente@linaro.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>

show more ...

block, bfq: switch 'bfqg->ref' to use atomic refcount apis

The updating of 'bfqg->ref' should be protected by 'bfqd->lock', however,
during code review, we found that bfq_pd_free() update 'bfqg->ref

block, bfq: switch 'bfqg->ref' to use atomic refcount apis

The updating of 'bfqg->ref' should be protected by 'bfqd->lock', however,
during code review, we found that bfq_pd_free() update 'bfqg->ref'
without holding the lock, which is problematic:

1) bfq_pd_free() triggered by removing cgroup is called asynchronously;
2) bfqq will grab bfqg reference, and exit bfqq will drop the reference,
which can concurrent with 1).

Unfortunately, 'bfqd->lock' can't be held here because 'bfqd' might already
be freed in bfq_pd_free(). Fix the problem by using atomic refcount apis.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230103084755.1256479-1-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

show more ...

block, bfq: replace 0/1 with false/true in bic apis

Just to make the code a litter cleaner, there are no functional changes.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Jan Kara <jack@

block, bfq: replace 0/1 with false/true in bic apis

Just to make the code a litter cleaner, there are no functional changes.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20221214033155.3455754-3-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

show more ...

block, bfq: don't return bfqg from __bfq_bic_change_cgroup()

The return value is not used, hence remove it.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: ht

block, bfq: don't return bfqg from __bfq_bic_change_cgroup()

The return value is not used, hence remove it.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20221214033155.3455754-2-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

show more ...

block, bfq: fix null pointer dereference in bfq_bio_bfqg()

Out test found a following problem in kernel 5.10, and the same problem
should exist in mainline:

BUG: kernel NULL pointer dereference, ad

block, bfq: fix null pointer dereference in bfq_bio_bfqg()

Out test found a following problem in kernel 5.10, and the same problem
should exist in mainline:

BUG: kernel NULL pointer dereference, address: 0000000000000094
PGD 0 P4D 0
Oops: 0000 [#1] SMP
CPU: 7 PID: 155 Comm: kworker/7:1 Not tainted 5.10.0-01932-g19e0ace2ca1d-dirty 4
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS ?-20190727_073836-b4
Workqueue: kthrotld blk_throtl_dispatch_work_fn
RIP: 0010:bfq_bio_bfqg+0x52/0xc0
Code: 94 00 00 00 00 75 2e 48 8b 40 30 48 83 05 35 06 c8 0b 01 48 85 c0 74 3d 4b
RSP: 0018:ffffc90001a1fba0 EFLAGS: 00010002
RAX: ffff888100d60400 RBX: ffff8881132e7000 RCX: 0000000000000000
RDX: 0000000000000017 RSI: ffff888103580a18 RDI: ffff888103580a18
RBP: ffff8881132e7000 R08: 0000000000000000 R09: ffffc90001a1fe10
R10: 0000000000000a20 R11: 0000000000034320 R12: 0000000000000000
R13: ffff888103580a18 R14: ffff888114447000 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff88881fdc0000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000094 CR3: 0000000100cdb000 CR4: 00000000000006e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
bfq_bic_update_cgroup+0x3c/0x350
? ioc_create_icq+0x42/0x270
bfq_init_rq+0xfd/0x1060
bfq_insert_requests+0x20f/0x1cc0
? ioc_create_icq+0x122/0x270
blk_mq_sched_insert_requests+0x86/0x1d0
blk_mq_flush_plug_list+0x193/0x2a0
blk_flush_plug_list+0x127/0x170
blk_finish_plug+0x31/0x50
blk_throtl_dispatch_work_fn+0x151/0x190
process_one_work+0x27c/0x5f0
worker_thread+0x28b/0x6b0
? rescuer_thread+0x590/0x590
kthread+0x153/0x1b0
? kthread_flush_work+0x170/0x170
ret_from_fork+0x1f/0x30
Modules linked in:
CR2: 0000000000000094
---[ end trace e2e59ac014314547 ]---
RIP: 0010:bfq_bio_bfqg+0x52/0xc0
Code: 94 00 00 00 00 75 2e 48 8b 40 30 48 83 05 35 06 c8 0b 01 48 85 c0 74 3d 4b
RSP: 0018:ffffc90001a1fba0 EFLAGS: 00010002
RAX: ffff888100d60400 RBX: ffff8881132e7000 RCX: 0000000000000000
RDX: 0000000000000017 RSI: ffff888103580a18 RDI: ffff888103580a18
RBP: ffff8881132e7000 R08: 0000000000000000 R09: ffffc90001a1fe10
R10: 0000000000000a20 R11: 0000000000034320 R12: 0000000000000000
R13: ffff888103580a18 R14: ffff888114447000 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff88881fdc0000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000094 CR3: 0000000100cdb000 CR4: 00000000000006e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

Root cause is quite complex:

1) use bfq elevator for the test device.
2) create a cgroup CG
3) config blk throtl in CG

blkg_conf_prep
blkg_create

4) create a thread T1 and issue async io in CG:

bio_init
bio_associate_blkg
...
submit_bio
submit_bio_noacct
blk_throtl_bio -> io is throttled
// io submit is done

5) switch elevator:

bfq_exit_queue
blkcg_deactivate_policy
list_for_each_entry(blkg, &q->blkg_list, q_node)
blkg->pd[] = NULL
// bfq policy is removed

5) thread t1 exist, then remove the cgroup CG:

blkcg_unpin_online
blkcg_destroy_blkgs
blkg_destroy
list_del_init(&blkg->q_node)
// blkg is removed from queue list

6) switch elevator back to bfq

bfq_init_queue
bfq_create_group_hierarchy
blkcg_activate_policy
list_for_each_entry_reverse(blkg, &q->blkg_list)
// blkg is removed from list, hence bfq policy is still NULL

7) throttled io is dispatched to bfq:

bfq_insert_requests
bfq_init_rq
bfq_bic_update_cgroup
bfq_bio_bfqg
bfqg = blkg_to_bfqg(blkg)
// bfqg is NULL because bfq policy is NULL

The problem is only possible in bfq because only bfq can be deactivated and
activated while queue is online, while others can only be deactivated while
the device is removed.

Fix the problem in bfq by checking if blkg is online before calling
blkg_to_bfqg().

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20221108103434.2853269-1-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

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block, bfq: don't declare 'bfqd' as type 'void *' in bfq_group

Prevent unnecessary format conversion for bfqg->bfqd in multiple
places.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Jan

block, bfq: don't declare 'bfqd' as type 'void *' in bfq_group

Prevent unnecessary format conversion for bfqg->bfqd in multiple
places.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Acked-by: Paolo Valente <paolo.valente@unimore.it>
Link: https://lore.kernel.org/r/20221102022542.3621219-6-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

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block, bfq: record how many queues have pending requests

Prepare to refactor the counting of 'num_groups_with_pending_reqs'.

Add a counter in bfq_group, update it while tracking if bfqq have pendin

block, bfq: record how many queues have pending requests

Prepare to refactor the counting of 'num_groups_with_pending_reqs'.

Add a counter in bfq_group, update it while tracking if bfqq have pending
requests and when bfq_bfqq_move() is called.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Acked-by: Paolo Valente <paolo.valente@linaro.org>
Link: https://lore.kernel.org/r/20220916071942.214222-3-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

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block, bfq: remove unused functions

While doing code coverage testing(CONFIG_BFQ_CGROUP_DEBUG is disabled), we
found that some functions doesn't have caller, thus remove them.

Signed-off-by: Yu Kua

block, bfq: remove unused functions

While doing code coverage testing(CONFIG_BFQ_CGROUP_DEBUG is disabled), we
found that some functions doesn't have caller, thus remove them.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20220816015631.1323948-2-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

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block/bfq: Use the new blk_opf_t type

Use the new blk_opf_t type for arguments and variables that represent
request flags or a bitwise combination of a request operation and
request flags. Rename th

block/bfq: Use the new blk_opf_t type

Use the new blk_opf_t type for arguments and variables that represent
request flags or a bitwise combination of a request operation and
request flags. Rename those variables from 'op' into 'opf'.

This patch does not change any functionality.

Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20220714180729.1065367-8-bvanassche@acm.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>

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block: bfq: Fix kernel-doc headers

Fix the following warnings:

block/bfq-cgroup.c:721: warning: Function parameter or member 'bfqg' not described in '__bfq_bic_change_cgroup'
block/bfq-cgroup.c:721

block: bfq: Fix kernel-doc headers

Fix the following warnings:

block/bfq-cgroup.c:721: warning: Function parameter or member 'bfqg' not described in '__bfq_bic_change_cgroup'
block/bfq-cgroup.c:721: warning: Excess function parameter 'blkcg' description in '__bfq_bic_change_cgroup'
block/bfq-cgroup.c:870: warning: Function parameter or member 'ioprio_class' not described in 'bfq_reparent_leaf_entity'
block/bfq-cgroup.c:900: warning: Function parameter or member 'ioprio_class' not described in 'bfq_reparent_active_queues'

Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Link: https://lore.kernel.org/r/20220617210859.106623-1-bvanassche@acm.org

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block: bfq: Remove an unused function definition

This patch is the result of the analysis of a sparse report.

Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-

block: bfq: Remove an unused function definition

This patch is the result of the analysis of a sparse report.

Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Link: https://lore.kernel.org/r/20220617204433.102022-1-bvanassche@acm.org

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bfq: Make sure bfqg for which we are queueing requests is online

Bios queued into BFQ IO scheduler can be associated with a cgroup that
was already offlined. This may then cause insertion of this bf

bfq: Make sure bfqg for which we are queueing requests is online

Bios queued into BFQ IO scheduler can be associated with a cgroup that
was already offlined. This may then cause insertion of this bfq_group
into a service tree. But this bfq_group will get freed as soon as last
bio associated with it is completed leading to use after free issues for
service tree users. Fix the problem by making sure we always operate on
online bfq_group. If the bfq_group associated with the bio is not
online, we pick the first online parent.

CC: stable@vger.kernel.org
Fixes: e21b7a0b9887 ("block, bfq: add full hierarchical scheduling and cgroups support")
Tested-by: "yukuai (C)" <yukuai3@huawei.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20220401102752.8599-9-jack@suse.cz
Signed-off-by: Jens Axboe <axboe@kernel.dk>

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