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Filename Latest commit message Latest commit date
Laibin Qiu 20f4ee3c33 block/wbt: fix negative inflight counter when remove scsi device
commit e92bc4cd34de2ce454bdea8cd198b8067ee4e123 upstream.

Now that we disable wbt by set WBT_STATE_OFF_DEFAULT in
wbt_disable_default() when switch elevator to bfq. And when
we remove scsi device, wbt will be enabled by wbt_enable_default.
If it become false positive between wbt_wait() and wbt_track()
when submit write request.

The following is the scenario that triggered the problem.

T1                          T2                           T3
                            elevator_switch_mq
                            bfq_init_queue
                            wbt_disable_default <= Set
                            rwb->enable_state (OFF)
Submit_bio
blk_mq_make_request
rq_qos_throttle
<= rwb->enable_state (OFF)
                                                         scsi_remove_device
                                                         sd_remove
                                                         del_gendisk
                                                         blk_unregister_queue
                                                         elv_unregister_queue
                                                         wbt_enable_default
                                                         <= Set rwb->enable_state (ON)
q_qos_track
<= rwb->enable_state (ON)
^^^^^^ this request will mark WBT_TRACKED without inflight add and will
lead to drop rqw->inflight to -1 in wbt_done() which will trigger IO hung.

Fix this by move wbt_enable_default() from elv_unregister to
bfq_exit_queue(). Only re-enable wbt when bfq exit.

Fixes: 76a8040817b4b ("blk-wbt: make sure throttle is enabled properly")

Remove oneline stale comment, and kill one oneshot local variable.

Signed-off-by: Ming Lei <ming.lei@rehdat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/linux-block/20211214133103.551813-1-qiulaibin@huawei.com/
Signed-off-by: Laibin Qiu <qiulaibin@huawei.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-02-23 11:59:59 +01:00
arch powerpc/lib/sstep: fix 'ptesync' build error 2022-02-23 11:59:58 +01:00
block block/wbt: fix negative inflight counter when remove scsi device 2022-02-23 11:59:59 +01:00
certs
crypto
Documentation bpf: Add kconfig knob for disabling unpriv bpf by default 2022-02-16 12:52:49 +01:00
drivers mtd: rawnand: gpmi: don't leak PM reference in error path 2022-02-23 11:59:59 +01:00
fs ext4: prevent partial update of the extent blocks 2022-02-23 11:59:57 +01:00
include bonding: fix data-races around agg_select_timer 2022-02-23 11:59:58 +01:00
init bpf: Add kconfig knob for disabling unpriv bpf by default 2022-02-16 12:52:49 +01:00
ipc
kernel taskstats: Cleanup the use of task->exit_code 2022-02-23 11:59:57 +01:00
lib
LICENSES
mm mm/kmemleak: avoid scanning potential huge holes 2022-02-08 18:24:28 +01:00
net drop_monitor: fix data-race in dropmon_net_event / trace_napi_poll_hit 2022-02-23 11:59:58 +01:00
samples
scripts Makefile.extrawarn: Move -Wunaligned-access to W=1 2022-02-23 11:59:54 +01:00
security ima: Do not print policy rule with inactive LSM labels 2022-02-16 12:52:47 +01:00
sound ASoC: ops: Fix stereo change notifications in snd_soc_put_volsw_range() 2022-02-23 11:59:58 +01:00
tools libsubcmd: Fix use-after-free for realloc(..., 0) 2022-02-23 11:59:58 +01:00
usr
virt
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS
Makefile Linux 5.4.180 2022-02-16 12:52:54 +01:00
README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.