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c9b3007fec
linux/block
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Dennis Zhou c9b3007fec blk-iolatency: fix STS_AGAIN handling 
The iolatency controller is based on rq_qos. It increments on
rq_qos_throttle() and decrements on either rq_qos_cleanup() or
rq_qos_done_bio(). a3fb01ba5a fixes the double accounting issue where
blk_mq_make_request() may call both rq_qos_cleanup() and
rq_qos_done_bio() on REQ_NO_WAIT. So checking STS_AGAIN prevents the
double decrement.

The above works upstream as the only way we can get STS_AGAIN is from
blk_mq_get_request() failing. The STS_AGAIN handling isn't a real
problem as bio_endio() skipping only happens on reserved tag allocation
failures which can only be caused by driver bugs and already triggers
WARN.

However, the fix creates a not so great dependency on how STS_AGAIN can
be propagated. Internally, we (Facebook) carry a patch that kills read
ahead if a cgroup is io congested or a fatal signal is pending. This
combined with chained bios progagate their bi_status to the parent is
not already set can can cause the parent bio to not clean up properly
even though it was successful. This consequently leaks the inflight
counter and can hang all IOs under that blkg.

To nip the adverse interaction early, this removes the rq_qos_cleanup()
callback in iolatency in favor of cleaning up always on the
rq_qos_done_bio() path.

Fixes: a3fb01ba5a ("blk-iolatency: only account submitted bios")
Debugged-by: Tejun Heo <tj@kernel.org>
Debugged-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Dennis Zhou <dennis@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-07-05 15:14:00 -06:00
..
partitions block/partitions/ldm: Convert a kernel-doc header into a non-kernel-doc header 2019-05-31 15:12:34 -06:00
badblocks.c block: switch all files cleared marked as GPLv2 to SPDX tags 2019-04-30 16:11:57 -06:00
bfq-cgroup.c block: rename CONFIG_DEBUG_BLK_CGROUP to CONFIG_BFQ_CGROUP_DEBUG 2019-06-20 10:32:35 -06:00
bfq-iosched.c block, bfq: NULL out the bic when it's no longer valid 2019-06-28 07:44:19 -06:00
bfq-iosched.h block, bfq: detect wakers and unconditionally inject their I/O 2019-06-25 09:07:34 -06:00
bfq-wf2q.c block: switch all files cleared marked as GPLv2 or later to SPDX tags 2019-04-30 16:11:59 -06:00
bio-integrity.c block/bio-integrity: use struct_size() in kmalloc() 2019-05-16 08:48:48 -06:00
bio.c block: fix .bi_size overflow 2019-07-01 08:18:54 -06:00
blk-cgroup.c blk-cgroup: move struct blkg_stat to bfq 2019-06-20 10:32:34 -06:00
blk-core.c block: update print_req_error() 2019-06-20 13:03:51 -06:00
blk-exec.c block: add SPDX tags to block layer files missing licensing information 2019-04-30 16:12:03 -06:00
blk-flush.c block: switch all files cleared marked as GPLv2 to SPDX tags 2019-04-30 16:11:57 -06:00
blk-integrity.c for-5.2/block-20190507 2019-05-07 18:14:36 -07:00
blk-ioc.c block: remove the queue_lock indirection 2018-11-15 12:17:28 -07:00
blk-iolatency.c blk-iolatency: fix STS_AGAIN handling 2019-07-05 15:14:00 -06:00
blk-lib.c block: fix 32 bit overflow in __blkdev_issue_discard() 2018-11-14 08:17:18 -07:00
blk-map.c block: remove the bi_phys_segments field in struct bio 2019-06-20 10:29:22 -06:00
blk-merge.c block: nr_phys_segments needs to be zero for REQ_OP_WRITE_ZEROES 2019-07-03 07:20:40 -06:00
blk-mq-cpumap.c blk-mq: Document the blk_mq_hw_queue_to_node() arguments 2019-05-31 15:12:34 -06:00
blk-mq-debugfs-zoned.c block: Cleanup license notice 2019-01-17 21:21:40 -07:00
blk-mq-debugfs.c block: use blk_op_str() in blk-mq-debugfs.c 2019-06-20 13:03:51 -06:00
blk-mq-debugfs.h blk-mq: no need to check return value of debugfs_create functions 2019-06-13 03:00:30 -06:00
blk-mq-pci.c block: Fix blk_mq_*_map_queues() kernel-doc headers 2019-05-31 15:12:34 -06:00
blk-mq-rdma.c block: Fix blk_mq_*_map_queues() kernel-doc headers 2019-05-31 15:12:34 -06:00
blk-mq-sched.c blk-mq: remove blk_mq_put_ctx() 2019-07-02 21:03:27 -06:00
blk-mq-sched.h block: remove the bi_phys_segments field in struct bio 2019-06-20 10:29:22 -06:00
blk-mq-sysfs.c for-5.2/block-20190507 2019-05-07 18:14:36 -07:00
blk-mq-tag.c blk-mq: remove blk_mq_put_ctx() 2019-07-02 21:03:27 -06:00
blk-mq-tag.h Merge branch 'for-4.15/block' of git://git.kernel.dk/linux-block 2017-11-14 15:32:19 -08:00
blk-mq-virtio.c block: Fix blk_mq_*_map_queues() kernel-doc headers 2019-05-31 15:12:34 -06:00
blk-mq.c blk-mq: simplify blk_mq_make_request() 2019-07-02 21:03:38 -06:00
blk-mq.h blk-mq: remove blk_mq_put_ctx() 2019-07-02 21:03:27 -06:00
blk-pm.c block: remove the queue_lock indirection 2018-11-15 12:17:28 -07:00
blk-pm.h block: remove the queue_lock indirection 2018-11-15 12:17:28 -07:00
blk-rq-qos.c block: Fix rq_qos_wait() kernel-doc header 2019-05-31 15:12:34 -06:00
blk-rq-qos.h block: add SPDX tags to block layer files missing licensing information 2019-04-30 16:12:03 -06:00
blk-settings.c block: force an unlimited segment size on queues with a virt boundary 2019-05-23 10:25:26 -06:00
blk-softirq.c block: remove a few unused exports 2018-11-15 12:13:25 -07:00
blk-stat.c block: add SPDX tags to block layer files missing licensing information 2019-04-30 16:12:03 -06:00
blk-stat.h block: deactivate blk_stat timer in wbt_disable_default() 2018-12-12 06:47:51 -07:00
blk-sysfs.c block: free sched's request pool in blk_cleanup_queue 2019-06-06 22:39:39 -06:00
blk-throttle.c block: Fix throtl_pending_timer_fn() kernel-doc header 2019-05-31 15:12:34 -06:00
blk-timeout.c block: add SPDX tags to block layer files missing licensing information 2019-04-30 16:12:03 -06:00
blk-wbt.c block: add SPDX tags to block layer files missing licensing information 2019-04-30 16:12:03 -06:00
blk-wbt.h block: remove external dependency on wbt_flags 2018-07-09 09:07:54 -06:00
blk-zoned.c block: add SPDX tags to block layer files missing licensing information 2019-04-30 16:12:03 -06:00
blk.h block: mark blk_rq_bio_prep as inline 2019-06-20 10:29:22 -06:00
bounce.c block: remove the i argument to bio_for_each_segment_all 2019-04-30 09:26:13 -06:00
bsg-lib.c block: Fix bsg_setup_queue() kernel-doc header 2019-05-31 15:12:34 -06:00
bsg.c block: switch all files cleared marked as GPLv2 to SPDX tags 2019-04-30 16:11:57 -06:00
cmdline-parser.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
compat_ioctl.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
elevator.c block: free sched's request pool in blk_cleanup_queue 2019-06-06 22:39:39 -06:00
genhd.c block: genhd: Use struct_size() helper 2019-06-15 01:46:09 -06:00
ioctl.c block: add SPDX tags to block layer files missing licensing information 2019-04-30 16:12:03 -06:00
ioprio.c block: add SPDX tags to block layer files missing licensing information 2019-04-30 16:12:03 -06:00
Kconfig block: force select mq-deadline for zoned block devices 2019-06-13 03:00:31 -06:00
Kconfig.iosched block: rename CONFIG_DEBUG_BLK_CGROUP to CONFIG_BFQ_CGROUP_DEBUG 2019-06-20 10:32:35 -06:00
kyber-iosched.c blk-mq: remove blk_mq_put_ctx() 2019-07-02 21:03:27 -06:00
Makefile block: remove legacy IO schedulers 2018-11-07 13:42:32 -07:00
mq-deadline.c block: remove the bi_phys_segments field in struct bio 2019-06-20 10:29:22 -06:00
opal_proto.h block: sed-opal: check size of shadow mbr 2019-06-29 10:34:08 -06:00
partition-generic.c block: fix use-after-free on gendisk 2019-04-22 09:48:12 -06:00
scsi_ioctl.c block: switch all files cleared marked as GPLv2 to SPDX tags 2019-04-30 16:11:57 -06:00
sed-opal.c block: sed-opal: check size of shadow mbr 2019-06-29 10:34:08 -06:00
t10-pi.c block: switch all files cleared marked as GPLv2 to SPDX tags 2019-04-30 16:11:57 -06:00