Jan Kara 11c7aa0dde rq-qos: fix missed wake-ups in rq_qos_throttle try two ... Commit 545fbd0775 ("rq-qos: fix missed wake-ups in rq_qos_throttle") tried to fix a problem that a process could be sleeping in rq_qos_wait() without anyone to wake it up. However the fix is not complete and the following can still happen: CPU1 (waiter1) CPU2 (waiter2) CPU3 (waker) rq_qos_wait() rq_qos_wait() acquire_inflight_cb() -> fails acquire_inflight_cb() -> fails completes IOs, inflight decreased prepare_to_wait_exclusive() prepare_to_wait_exclusive() has_sleeper = !wq_has_single_sleeper() -> true as there are two sleepers has_sleeper = !wq_has_single_sleeper() -> true io_schedule() io_schedule() Deadlock as now there's nobody to wakeup the two waiters. The logic automatically blocking when there are already sleepers is really subtle and the only way to make it work reliably is that we check whether there are some waiters in the queue when adding ourselves there. That way, we are guaranteed that at least the first process to enter the wait queue will recheck the waiting condition before going to sleep and thus guarantee forward progress. Fixes: 545fbd0775 ("rq-qos: fix missed wake-ups in rq_qos_throttle") CC: stable@vger.kernel.org Signed-off-by: Jan Kara <jack@suse.cz> Link: https://lore.kernel.org/r/20210607112613.25344-1-jack@suse.cz Signed-off-by: Jens Axboe <axboe@kernel.dk>		2021-06-08 15:12:57 -06:00
..
partitions	block: remove bdget_disk	2021-06-01 07:47:14 -06:00
badblocks.c	treewide: Use fallthrough pseudo-keyword	2020-08-23 17:36:59 -05:00
bfq-cgroup.c	block, bfq: merge bursts of newly-created queues	2021-03-25 10:50:07 -06:00
bfq-iosched.c	block, bfq: avoid circular stable merges	2021-05-12 07:39:23 -06:00
bfq-iosched.h	block, bfq: merge bursts of newly-created queues	2021-03-25 10:50:07 -06:00
bfq-wf2q.c	block, bfq: always inject I/O of queues blocked by wakers	2021-03-25 10:50:07 -06:00
bio-integrity.c	block: remove BLK_BOUNCE_ISA support	2021-04-06 09:28:17 -06:00
bio.c	Revert "bio: limit bio max size"	2021-05-08 21:49:48 -06:00
blk-cgroup-rwstat.c	blk-cgroup: Fix the recursive blkg rwstat	2021-03-05 11:32:15 -07:00
blk-cgroup-rwstat.h	blk-cgroup: separate out blkg_rwstat under CONFIG_BLK_CGROUP_RWSTAT	2019-11-07 12:28:13 -07:00
blk-cgroup.c	blkcg: drop CLONE_IO check in blkcg_can_attach()	2021-05-24 06:47:21 -06:00
blk-core.c	block: Update blk_update_request() documentation	2021-06-03 14:37:24 -06:00
blk-crypto-fallback.c	block: rename BIO_MAX_PAGES to BIO_MAX_VECS	2021-03-11 07:47:48 -07:00
blk-crypto-internal.h	block: make blk_crypto_rq_bio_prep() able to fail	2020-10-05 10:47:43 -06:00
blk-crypto.c	dm: support key eviction from keyslot managers of underlying devices	2021-02-11 09:45:25 -05:00
blk-exec.c	block: drop removed argument from kernel-doc of blk_execute_rq()	2021-01-29 07:43:29 -07:00
blk-flush.c	block: avoid double io accounting for flush request	2021-05-24 06:47:21 -06:00
blk-integrity.c	block: remove the unused blk_integrity_merge_bio export	2020-10-06 07:29:53 -06:00
blk-ioc.c	block: remove retry loop in ioc_release_fn()	2020-07-16 10:22:15 -06:00
blk-iocost.c	blk-iocost: fix weight updates of inner active iocgs	2021-05-11 20:50:35 -06:00
blk-iolatency.c	block: Remove redundant 'return' statement	2020-10-08 07:59:48 -06:00
blk-lib.c	block: rename BIO_MAX_PAGES to BIO_MAX_VECS	2021-03-11 07:47:48 -07:00
blk-map.c	block: remove an incorrect check from blk_rq_append_bio	2021-04-12 06:45:12 -06:00
blk-merge.c	block: recalculate segment count for multi-segment discards correctly	2021-03-23 10:39:57 -06:00
blk-mq-cpumap.c	blk-mq: remove the calling of local_memory_node()	2020-10-20 07:08:17 -06:00
blk-mq-debugfs-zoned.c	block: Cleanup license notice	2019-01-17 21:21:40 -07:00
blk-mq-debugfs.c	for-5.13/block-2021-04-27	2021-04-28 14:27:12 -07:00
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	block: Do not pull requests from the scheduler when we cannot dispatch them	2021-06-03 12:01:27 -06:00
blk-mq-sched.h	blk-mq: Use request queue-wide tags for tagset-wide sbitmap	2021-05-24 06:47:22 -06:00
blk-mq-sysfs.c	blk-mq: move cancel of hctx->run_work to the front of blk_exit_queue	2020-10-09 12:46:28 -06:00
blk-mq-tag.c	blk-mq: Use request queue-wide tags for tagset-wide sbitmap	2021-05-24 06:47:22 -06:00
blk-mq-tag.h	blk-mq: Some tag allocation code refactoring	2021-05-24 06:47:22 -06:00
blk-mq-virtio.c	blk-mq: Fix typo in comment	2020-03-17 20:55:21 +01:00
blk-mq.c	block: Do not pull requests from the scheduler when we cannot dispatch them	2021-06-03 12:01:27 -06:00
blk-mq.h	block: Do not pull requests from the scheduler when we cannot dispatch them	2021-06-03 12:01:27 -06:00
blk-pm.c	scsi: block: Fix a race in the runtime power management code	2020-12-09 11:41:41 -05:00
blk-pm.h	block: Remove unused blk_pm_*() function definitions	2021-02-22 06:33:48 -07:00
blk-rq-qos.c	rq-qos: fix missed wake-ups in rq_qos_throttle try two	2021-06-08 15:12:57 -06:00
blk-rq-qos.h	blk-rq-qos: fix first node deletion of rq_qos_del()	2019-10-15 10:13:13 -06:00
blk-settings.c	block-5.13-2021-05-09	2021-05-09 13:25:14 -07:00
blk-stat.c	blk-stat: make q->stats->lock irqsafe	2020-09-01 16:48:46 -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: remove unneeded parenthesis from blk-sysfs	2021-05-24 06:47:21 -06:00
blk-throttle.c	block: store a block_device pointer in struct bio	2021-01-24 18:17:20 -07:00
blk-timeout.c	block: blk-timeout: delete duplicated word	2020-07-31 16:29:47 -06:00
blk-wbt.c	blk: wbt: remove unused parameter from wbt_should_throttle	2021-01-26 13:13:00 -07:00
blk-wbt.h	blk-wbt: remove wbt_update_limits	2020-05-29 16:30:39 -06:00
blk-zoned.c	blk-zoned: Remove the definition of blk_zone_start()	2021-04-07 14:31:45 -06:00
blk.h	block: unexport blk_alloc_queue	2021-06-01 07:42:24 -06:00
bounce.c	block: stop calling blk_queue_bounce for passthrough requests	2021-04-06 09:28:18 -06:00
bsg-lib.c	block: drop double zeroing	2020-09-23 09:18:13 -06:00
bsg.c	block: remove unnecessary argument from blk_execute_rq	2021-01-24 21:52:39 -07:00
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
elevator.c	blk-mq: set default elevator as deadline in case of hctx shared tagset	2021-04-07 10:15:23 -06:00
genhd.c	block: remove bdget_disk	2021-06-01 07:47:14 -06:00
ioctl.c	block: move bd_part_count to struct gendisk	2021-06-01 07:45:27 -06:00
ioprio.c	block: Fix sys_ioprio_set(.which=IOPRIO_WHO_PGRP) task iteration	2021-04-08 13:43:53 -06:00
Kconfig	blk-wbt: Remove obsolete multiqueue I/O scheduling comment	2020-09-01 16:49:26 -06:00
Kconfig.iosched	treewide: replace '---help---' in Kconfig files with 'help'	2020-06-14 01:57:21 +09:00
keyslot-manager.c	- Fix DM integrity's HMAC support to provide enhanced security of	2021-02-22 10:22:54 -08:00
kyber-iosched.c	kyber: fix out of bounds access when preempted	2021-05-11 08:12:14 -06:00
Makefile	blk-mq: merge blk-softirq.c into blk-mq.c	2020-06-24 09:15:56 -06:00
mq-deadline.c	kyber: fix out of bounds access when preempted	2021-05-11 08:12:14 -06:00
opal_proto.h	block: sed-opal: Change the check condition for regular session validity	2020-03-12 08:00:10 -06:00
scsi_ioctl.c	block: Remove an obsolete comment from sg_io()	2021-04-13 11:23:52 -06:00
sed-opal.c	block: sed-opal: Change the check condition for regular session validity	2020-03-12 08:00:10 -06:00
t10-pi.c	block: Allow t10-pi to be modular	2020-01-06 20:59:04 -07:00