It checks if plug->cached_rq is empty before merging bio. But the merge action
doesn't have relationship with plug->cached_rq, it trys to merge bio with
requests within plug->mq_list. Now it checks if ->cached_rq is empty before
merging bio. If it's empty, it will miss the merge chances. So move the merge
function before checking ->cached_rq.
Signed-off-by: Xiao Ni <xni@redhat.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20230209031930.27354-1-xni@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
It turns out this was too soon. blkg_conf_prep does to funky locking games
with the queue lock for this to work properly.
This reverts commit 27b642b07a.
Reported-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20230209053523.437927-1-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
While del_gendisk ensures there is no outstanding I/O on the queue,
it can't prevent block layer users from building new I/O.
This leads to a NULL ->root_blkg reference in bio_associate_blkg when
allocating a new bio on a shut down file system. Delay freeing the
blk-cgroup subsystems from del_gendisk until disk_release to make
sure the blkg and throttle information is still avaіlable for bio
submitters, even if those bios will immediately fail.
This now can cause a case where disk_release is called on a disk
that hasn't been added. That's mostly harmless, except for a case
in blk_throttl_exit that now needs to check for a NULL ->td pointer.
Fixes: 178fa7d498 ("blk-cgroup: delay blk-cgroup initialization until add_disk")
Reported-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20230208063514.171485-1-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
After commit dfd6200a09 ("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>
Commit 88022d7201 ("blk-mq: don't handle failure in .get_budget")
remove BLK_STS_RESOURCE return value and we only check if we can get
the budget from .get_budget() now.
Correct stale comment that ".get_budget() returns BLK_STS_NO_RESOURCE"
to ".get_budget() fails to get the budget".
Fixes: 88022d7201 ("blk-mq: don't handle failure in .get_budget")
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Use switch/case handle error as other function do to improve
readability in blk_mq_try_issue_list_directly.
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Commit 113285b473 ("blk-mq: ensure that bd->last is always set
correctly") will set last if we failed to get driver tag for next
request to avoid flush miss as we break the list walk and will not
send the last request in the list which will be sent with last set
normally.
This code seems stale now becase the flush introduced is always
redundant as:
For case tag is really out, we will send a extra flush if we find
list is not empty after list walk.
For case some tag is freed before retry in blk_mq_prep_dispatch_rq for
next, then we can get a tag for next request in retry and flush notified
already is not necessary.
Just remove these stale codes.
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
blk_mq_dispatch_rq_list will notify if hctx is busy in return bool. It will
return true if we are not busy and can handle more and return false on the
opposite. Inside blk_mq_dispatch_rq_list, errors is only used if list is
empty and we will return true if list is empty and (errors + queued) != 0.
There are three types of status returned from request:
-busy error BLK_STS*_RESOURCE: the failed request will be added back
to list and list will not be empty.
-BLK_STS_OK: We count queued for BLK_STS_OK
-rest error: We count errors for rest error
If list is empty, there is no request gets busy error then (errors +
queued) will be total requests in the list which is checked not empty at
beginning of blk_mq_dispatch_rq_list. So (errors + queued) != 0 is always
met if list is empty. Then the (errors + queued) != 0 check and errors
number count is not needed.
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
1. Remove check of needs_resource and ret == BLK_STS_DEV_RESOURCE.
For busy error BLK_STS*_RESOURCE, request will always be added
back to list, so need_resource will not be true and ret will
not be == BLK_STS_DEV_RESOURCE if list is empty. We could remove
these dead check.
2. Check ret of last request instead of errors
If list is empty, we only need to explicitly commit_rqs
if error happens at last request which is stored in ret. So check
ret of last request instead of errors to remove unnecessary
commit_rqs triggered by errors returned from previous request.
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Call blk_mq_commit_rqs instead of access ->commit_rqs directly. As you
can see in comment of blk_mq_commit_rqs, we only need explicitly call
this in two cases:
-did not queue everything initially scheduled to queue
-the last attempt to queue a request failed
Both cases can be checked with ret of last request which breaks list
walk. Then we can remove unnecessary error count and unnecessary
commit triggered by error besides cases described above.
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We need only to explicitly commit in two error cases:
-did not queue everything initially scheduled to queue
-the last attempt to queue a request failed
(see comment of blk_mq_commit_rqs for more details).
Both cases can be checked with ret of last request which breaks list walk.
Remove unnecessary error count and unnecessary commit triggered by error
which is not covered by cases described above.
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
1. move blk_mq_commit_rqs forward before functions need commits.
2. add queued check and only commits request if any request was queued
in blk_mq_commit_rqs to keep commit behavior consistent and remove
unnecessary commit.
3. split the queued clearing from blk_mq_plug_commit_rqs as it is
not wanted general.
4. sync current caller of blk_mq_commit_rqs with new general
blk_mq_commit_rqs.
5. document rule for unusual cases which need explicit commit_rqs.
Suggested-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Function blk_mq_plug_issue_direct tries to issue batch requests in plug
list to driver directly. We will only issue plug request to driver if we
are not from scheduler, so from_scheduler parameter of
blk_mq_plug_issue_direct is always false.
Remove unncessary from_scheduler of blk_mq_plug_issue_direct.
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We only break the list walk if we get 'BLK_STS_*RESOURCE'. We also
count errors for 'BLK_STS_*RESOURCE' error. If list is not empty,
errors will always be non-zero. So we can remove unnecessary list_empty
check. This will remove redundant list_empty check for case that
error happened at sending last request in list.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Commit f906a6a0f4 ("blk-mq: improve tag waiting setup for non-shared
tags") mark restart for unshared tags for improvement. At that time,
tags is only shared betweens queues and we can check if tags is shared
by test BLK_MQ_F_TAG_SHARED.
Afterwards, commit 32bc15afed ("blk-mq: Facilitate a shared sbitmap per
tagset") enabled tags share betweens hctxs inside a queue. We only
mark restart for shared hctxs inside a queue and may cause io hung if
there is no tag currently allocated by hctxs going to be marked restart.
Wait on sbitmap_queue instead of mark restart for shared hctxs case to
fix this.
Fixes: 32bc15afed ("blk-mq: Facilitate a shared sbitmap per tagset")
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
For shared queues case, we will only wait on bitmap_tags if we fail to get
driver tag. However, rq could be from breserved_tags, then two problems
will occur:
1. io hung if no tag is currently allocated from bitmap_tags.
2. unnecessary wakeup when tag is freed to bitmap_tags while no tag is
freed to breserved_tags.
Wait on the bitmap which rq from to fix this.
Fixes: f906a6a0f4 ("blk-mq: improve tag waiting setup for non-shared tags")
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Commit 97889f9ac2 ("blk-mq: remove synchronize_rcu() from
blk_mq_del_queue_tag_set()") remove handle of TAG_SHARED in restart,
then shared_hctx_restart counted for how many hardware queues are marked
for restart is removed too.
Remove the stale comment that we still count hardware queues need restart.
Fixes: 97889f9ac2 ("blk-mq: remove synchronize_rcu() from blk_mq_del_queue_tag_set()")
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Commit 1f5bd336b9 ("blk-mq: add blk_mq_alloc_request_hctx") add
blk_mq_alloc_request_hctx to send commands to a specific queue. If
BLK_MQ_REQ_NOWAIT is not set in tag allocation, we may change to different
hctx after sleep and get tag from unexpected hctx. So BLK_MQ_REQ_NOWAIT
must be set in flags for blk_mq_alloc_request_hctx.
After commit 600c3b0cea ("blk-mq: open code __blk_mq_alloc_request in
blk_mq_alloc_request_hctx"), blk_mq_alloc_request_hctx return -EINVAL
if both BLK_MQ_REQ_NOWAIT and BLK_MQ_REQ_RESERVED are not set instead of
if BLK_MQ_REQ_NOWAIT is not set. So if BLK_MQ_REQ_NOWAIT is not set and
BLK_MQ_REQ_RESERVED is set, blk_mq_alloc_request_hctx could alloc tag
from unexpected hctx. I guess what we need here is that return -EINVAL
if either BLK_MQ_REQ_NOWAIT or BLK_MQ_REQ_RESERVED is not set.
Currently both BLK_MQ_REQ_NOWAIT and BLK_MQ_REQ_RESERVED will be set if
specific hctx is needed in nvme_auth_submit, nvmf_connect_io_queue
and nvmf_connect_admin_queue. Fix the potential BLK_MQ_REQ_NOWAIT missed
case in future.
Fixes: 600c3b0cea ("blk-mq: open code __blk_mq_alloc_request in blk_mq_alloc_request_hctx")
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The capability attribute was added in 2017 to expose the kernel internal
GENHD_FL_MEDIA_CHANGE_NOTIFY to userspace without ever adding a value to
an UAPI header, and without ever setting it in any driver until it was
finally removed in Linux 5.7.
Deprecate the file and always return 0 instead of exposing the other
internal and frequently renumbered other gendisk flags.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20230203150209.3199115-1-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
new_blkg can be NULL if the caller didn't pass in a pre-allocated blkg.
Don't try to free it in that case.
Fixes: 27b642b07a ("blk-cgroup: simplify blkg freeing from initialization failure paths")
Reported-by: Yi Zhang <yi.zhang@redhat.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Link: https://lore.kernel.org/r/20230206150201.3438972-1-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Add a helper to initialize a bvec based of a page pointer. This will help
removing various open code bvec initializations.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20230203150634.3199647-2-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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>
Pass a gendisk to blkg_lookup and use that to find the match as part
of phasing out usage of the request_queue in the blk-cgroup code.
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/20230203150400.3199230-19-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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>
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>
This is what about half of the users already want, and it's only going to
grow more.
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/20230203150400.3199230-16-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
These op vectors are constant, so mark them const.
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/20230203150400.3199230-15-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Switch to passing a gendisk, and make rq_qos_add initialize all required
fields and drop the not required q argument from rq_qos_del.
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/20230203150400.3199230-14-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
These two functions are rather larger and not in a fast path, so move
them out of line.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20230203150400.3199230-13-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
wbt_queue_depth_changed just updates a field and calls another function.
Open code it in wbt_init, so that the local queue variable can be used
instead of the one stored in the rq_qos. This will allow delaying that
rq_qos->queue assignment in a subsequent patch.
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/20230203150400.3199230-12-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
A large part of blk-wbt.h is only used in blk-wbt.c, so move it there.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20230203150400.3199230-11-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Pass a gendisk to wbt_init to prepare for phasing out usage of the
request_queue in the blk-cgroup code.
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/20230203150400.3199230-10-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Pass a gendisk to wbt_enable_default and wbt_disable_default to
prepare for phasing out usage of the request_queue in the blk-cgroup
code.
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/20230203150400.3199230-9-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Switch from a request_queue pointer and reference to a gendisk once
for the throttle information in struct task_struct.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Andreas Herrmann <aherrmann@suse.de>
Link: https://lore.kernel.org/r/20230203150400.3199230-8-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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>
There is no need to delay freeing a blkg to a workqueue when freeing it
after an initialization failure.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20230203150400.3199230-5-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Unwind only the previous initialization steps that happened in blkg_alloc
using goto based unwinding. This avoids the need for the !queue special
case in blkg_free and thus ensures that any blkg seens outside of
blkg_alloc is always fully constructed.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20230203150400.3199230-4-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
There is no need to initialize the cgroup code before the disk is marked
live. Moving the cgroup initialization earlier will help to have a
fully initialized struct device in the gendisk for the cgroup code to
use in the future. Similarly tear the cgroup information down in
del_gendisk to be symmetric and because none of the cgroup tracking is
needed once non-passthrough I/O stops.
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/20230203150400.3199230-3-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
blk_throtl_stat_add is called from blk_stat_add explicitly, unlike the
other stats that go through q->stats->callbacks. To prepare for cgroup
data moving to the gendisk, ensure blk_throtl_stat_add is only called
for the plain READ and WRITE commands that it actually handles internally,
as blk_stat_add can also be called for passthrough commands on queues that
do not have a gendisk associated with them.
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/20230203150400.3199230-2-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Assuming that both Kconfig options, BLK_CGROUP and IOSCHED_BFQ are set, we
most likely want cgroup support for BFQ too (BFQ_GROUP_IOSCHED), so let's
make it default y.
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20230130121240.159456-1-ulf.hansson@linaro.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
bfqd->bfq_wr_max_time is set to 0 in bfq_init_queue and is never changed.
It is only used in bfq_wr_duration when bfq_wr_max_time > 0 which never
meets, so bfqd->bfq_wr_max_time is not used actually. Just remove it.
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230116095153.3810101-9-shikemeng@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We jump to tag only for returning current rq. Return directly to
remove this tag.
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Link: https://lore.kernel.org/r/20230116095153.3810101-8-shikemeng@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We have already avoided a circular list in bfq_setup_merge (see comments
in bfq_setup_merge() for details), so bfq_queue will not appear in it's
new_bfqq list. Just remove this check.
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230116095153.3810101-7-shikemeng@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Inject limit is updated or reset when time_is_before_eq_jiffies(
decrease_time_jif + several msecs) or think-time state changes.
decrease_time_jif is initialized to 0 and will be set to current jiffies
when inject limit is updated or reset. If the jiffies is slightly greater
than LONG_MAX, time_is_after_eq_jiffies(0) will keep for a long time, so as
time_is_after_eq_jiffies(decrease_time_jif + several msecs). If the
think-time state never chages, then the injection will not work as expected
for long time.
To be more specific:
Function bfq_update_inject_limit maybe triggered when jiffies pasts
decrease_time_jif + msecs_to_jiffies(10) in bfq_add_request by setting
bfqd->wait_dispatch to true.
Function bfq_reset_inject_limit are called in two conditions:
1. jiffies pasts bfqq->decrease_time_jif + msecs_to_jiffies(1000) in
function bfq_add_request.
2. jiffies pasts bfqq->decrease_time_jif + msecs_to_jiffies(100) or
bfq think-time state change from short to long.
Fix this by initializing bfqq->decrease_time_jif to current jiffies
to trigger service injection soon when service injection conditions
are met.
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230116095153.3810101-4-shikemeng@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Function bfq_choose_bfqq_for_injection may temporarily raise inject limit
to one request if current inject_limit is 0 before search of the source
queue for injection. However the search below will reset inject limit to
bfqd->in_service_queue which is zero for raised inject limit. Then the
temporarily raised inject limit never works as expected.
Assigment limit to bfqd->in_service_queue in search is needed as limit
maybe overwriten to min_t(unsigned int, 1, limit) for condition that
a large in-flight request is on non-rotational devices in found queue.
So we need to reset limit to bfqd->in_service_queue for normal case.
Actually, we have already make sure bfqd->rq_in_driver is < limit before
search, then
-Limit is >= 1 as bfqd->rq_in_driver is >= 0. Then min_t(unsigned int,
1, limit) is always 1. So we can simply check bfqd->rq_in_driver with
1 instead of result of min_t(unsigned int, 1, limit) for larget request in
non-rotational device case to avoid overwritting limit and the bug is gone.
-For normal case, we have already check bfqd->rq_in_driver is < limit,
so we can return found bfqq unconditionally to remove unncessary check.
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230116095153.3810101-2-shikemeng@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Currently parent pd can be freed before child pd:
t1: remove cgroup C1
blkcg_destroy_blkgs
blkg_destroy
list_del_init(&blkg->q_node)
// remove blkg from queue list
percpu_ref_kill(&blkg->refcnt)
blkg_release
call_rcu
t2: from t1
__blkg_release
blkg_free
schedule_work
t4: deactivate policy
blkcg_deactivate_policy
pd_free_fn
// parent of C1 is freed first
t3: from t2
blkg_free_workfn
pd_free_fn
If policy(for example, ioc_timer_fn() from iocost) access parent pd from
child pd after pd_offline_fn(), then UAF can be triggered.
Fix the problem by delaying 'list_del_init(&blkg->q_node)' from
blkg_destroy() to blkg_free_workfn(), and using a new disk level mutex to
synchronize blkg_free_workfn() and blkcg_deactivate_policy().
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Acked-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20230119110350.2287325-4-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
