linux-stable/block
Jinlong Chen 8ed40ee35d block: fix up elevator_type refcounting
The current reference management logic of io scheduler modules contains
refcnt problems. For example, blk_mq_init_sched may fail before or after
the calling of e->ops.init_sched. If it fails before the calling, it does
nothing to the reference to the io scheduler module. But if it fails after
the calling, it releases the reference by calling kobject_put(&eq->kobj).

As the callers of blk_mq_init_sched can't know exactly where the failure
happens, they can't handle the reference to the io scheduler module
properly: releasing the reference on failure results in double-release if
blk_mq_init_sched has released it, and not releasing the reference results
in ghost reference if blk_mq_init_sched did not release it either.

The same problem also exists in io schedulers' init_sched implementations.

We can address the problem by adding releasing statements to the error
handling procedures of blk_mq_init_sched and init_sched implementations.
But that is counterintuitive and requires modifications to existing io
schedulers.

Instead, We make elevator_alloc get the io scheduler module references
that will be released by elevator_release. And then, we match each
elevator_get with an elevator_put. Therefore, each reference to an io
scheduler module explicitly has its own getter and releaser, and we no
longer need to worry about the refcnt problems.

The bugs and the patch can be validated with tools here:
https://github.com/nickyc975/linux_elv_refcnt_bug.git

[hch: split out a few bits into separate patches, use a non-try
      module_get in elevator_alloc]

Signed-off-by: Jinlong Chen <nickyc975@zju.edu.cn>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20221020064819.1469928-5-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-10-23 18:59:17 -06:00
..
partitions block: don't add partitions if GD_SUPPRESS_PART_SCAN is set 2022-09-03 11:29:03 -06:00
badblocks.c block/badblocks: Remove redundant assignments 2022-04-23 07:15:26 -06:00
bdev.c vfs: support STATX_DIOALIGN on block devices 2022-09-11 19:47:12 -05:00
bfq-cgroup.c block, bfq: remove unused functions 2022-08-22 10:07:56 -06:00
bfq-iosched.c blk-wbt: don't enable throttling if default elevator is bfq 2022-10-23 18:59:17 -06:00
bfq-iosched.h block, bfq: remove unused variable for bfq_queue 2022-10-20 05:46:49 -07:00
bfq-wf2q.c block, bfq: remove useless parameter for bfq_add/del_bfqq_busy() 2022-08-22 10:07:56 -06:00
bio-integrity.c block: pass struct queue_limits to the bio splitting helpers 2022-08-02 21:08:53 -06:00
bio.c block-6.1-2022-10-20 2022-10-21 15:14:14 -07:00
blk-cgroup-fc-appid.c cgroup: Homogenize cgroup_get_from_id() return value 2022-08-26 10:57:41 -10:00
blk-cgroup-rwstat.c blk-cgroup: Fix the recursive blkg rwstat 2021-03-05 11:32:15 -07:00
blk-cgroup-rwstat.h block: Use the new blk_opf_t type 2022-07-14 12:14:30 -06:00
blk-cgroup.c blk-cgroup: don't update the blkg lookup hint in blkg_conf_prep 2022-09-27 11:50:05 -06:00
blk-cgroup.h blk-cgroup: pass a gendisk to blkcg_init_queue and blkcg_exit_queue 2022-09-26 19:09:31 -06:00
blk-core.c for-6.1/block-2022-10-03 2022-10-07 09:19:14 -07:00
blk-crypto-fallback.c treewide: use get_random_bytes() when possible 2022-10-11 17:42:58 -06:00
blk-crypto-internal.h blk-crypto: show crypto capabilities in sysfs 2022-02-28 06:40:23 -07:00
blk-crypto-profile.c blk-crypto: remove blk_crypto_unregister() 2021-11-29 06:38:51 -07:00
blk-crypto-sysfs.c blk-crypto: show crypto capabilities in sysfs 2022-02-28 06:40:23 -07:00
blk-crypto.c blk-crypto: show crypto capabilities in sysfs 2022-02-28 06:40:23 -07:00
blk-flush.c block: change request end_io handler to pass back a return value 2022-09-30 07:49:09 -06:00
blk-ia-ranges.c block: simplify disk_set_independent_access_ranges 2022-06-29 08:36:46 -06:00
blk-integrity.c blk-crypto: remove blk_crypto_unregister() 2021-11-29 06:38:51 -07:00
blk-ioc.c block: fix default IO priority handling again 2022-06-27 06:29:12 -06:00
blk-iocost.c blk-iocost: read 'ioc->params' inside 'ioc->lock' in ioc_timer_fn() 2022-10-23 18:59:17 -06:00
blk-iolatency.c blk-cgroup: pass a gendisk to blkcg_schedule_throttle 2022-09-26 19:17:28 -06:00
blk-ioprio.c blk-ioprio: pass a gendisk to blk_ioprio_init and blk_ioprio_exit 2022-09-26 19:09:31 -06:00
blk-ioprio.h blk-ioprio: pass a gendisk to blk_ioprio_init and blk_ioprio_exit 2022-09-26 19:09:31 -06:00
blk-lib.c blk-lib: fix blkdev_issue_secure_erase 2022-09-15 00:25:17 -06:00
blk-map.c block: extend functionality to map bvec iterator 2022-09-30 07:51:13 -06:00
blk-merge.c block: pass struct queue_limits to the bio splitting helpers 2022-08-02 21:08:53 -06:00
blk-mq-cpumap.c block: Change the return type of blk_mq_map_queues() into void 2022-08-22 10:07:53 -06:00
blk-mq-debugfs-zoned.c block: move zone related fields to struct gendisk 2022-07-06 06:46:26 -06:00
blk-mq-debugfs.c for-6.1/block-2022-10-03 2022-10-07 09:19:14 -07:00
blk-mq-debugfs.h block: remove per-disk debugfs files in blk_unregister_queue 2022-06-17 07:31:05 -06:00
blk-mq-pci.c block: Change the return type of blk_mq_map_queues() into void 2022-08-22 10:07:53 -06:00
blk-mq-rdma.c block: Change the return type of blk_mq_map_queues() into void 2022-08-22 10:07:53 -06:00
blk-mq-sched.c block: fix up elevator_type refcounting 2022-10-23 18:59:17 -06:00
blk-mq-sched.h block: move blk_mq_sched_assign_ioc to blk-ioc.c 2021-11-29 06:41:29 -07:00
blk-mq-sysfs.c blk-mq: cleanup disk sysfs registration 2022-06-28 11:32:42 -06:00
blk-mq-tag.c sbitmap: fix batched wait_cnt accounting 2022-09-12 00:10:34 -06:00
blk-mq-tag.h blk-mq: blk_mq_tag_busy is no need to return a value 2022-06-27 06:29:12 -06:00
blk-mq-virtio.c block: Change the return type of blk_mq_map_queues() into void 2022-08-22 10:07:53 -06:00
blk-mq.c block: fix up elevator_type refcounting 2022-10-23 18:59:17 -06:00
blk-mq.h block: adapt blk_mq_plug() to not plug for writes that require a zone lock 2022-09-29 07:45:47 -06:00
blk-pm.c scsi: block: pm: Always set request queue runtime active in blk_post_runtime_resume() 2021-12-22 23:38:29 -05:00
blk-pm.h block: Remove unused blk_pm_*() function definitions 2021-02-22 06:33:48 -07:00
blk-rq-qos.c block/rq_qos: Use atomic_try_cmpxchg in atomic_inc_below 2022-07-12 14:38:52 -06:00
blk-rq-qos.h block/blk-rq-qos: delete useless enmu RQ_QOS_IOPRIO 2022-09-21 19:50:53 -06:00
blk-settings.c block: pass a gendisk to blk_queue_clear_zone_settings 2022-07-06 06:46:26 -06:00
blk-stat.c block: make queue stat accounting a reference 2021-12-14 17:23:05 -07:00
blk-stat.h block: make queue stat accounting a reference 2021-12-14 17:23:05 -07:00
blk-sysfs.c blk-wbt: don't show valid wbt_lat_usec in sysfs while wbt is disabled 2022-10-23 18:59:17 -06:00
blk-throttle.c blk-throttle: pass a gendisk to blk_throtl_cancel_bios 2022-09-26 19:17:28 -06:00
blk-throttle.h blk-throttle: pass a gendisk to blk_throtl_cancel_bios 2022-09-26 19:17:28 -06:00
blk-timeout.c
blk-wbt.c blk-wbt: don't enable throttling if default elevator is bfq 2022-10-23 18:59:17 -06:00
blk-wbt.h blk-wbt: don't show valid wbt_lat_usec in sysfs while wbt is disabled 2022-10-23 18:59:17 -06:00
blk-zoned.c block: adapt blk_mq_plug() to not plug for writes that require a zone lock 2022-09-29 07:45:47 -06:00
blk.h - Yu Zhao's Multi-Gen LRU patches are here. They've been under test in 2022-10-10 17:53:04 -07:00
bounce.c block: change the blk_queue_bounce calling convention 2022-08-02 17:22:54 -06:00
bsg-lib.c blk-mq: Drop blk_mq_ops.timeout 'reserved' arg 2022-07-06 06:33:53 -06:00
bsg.c scsi: core: bsg: Remove usage of the deprecated ida_simple_xxx() API 2022-06-21 21:22:51 -04:00
disk-events.c block: remove genhd.h 2022-02-02 07:49:59 -07:00
elevator.c block: fix up elevator_type refcounting 2022-10-23 18:59:17 -06:00
elevator.h block: add proper helpers for elevator_type module refcount management 2022-10-23 18:59:17 -06:00
fops.c new iov_iter flavour - ITER_UBUF 2022-08-08 22:37:15 -04:00
genhd.c Merge branch 'for-6.1/block' into block-6.1 2022-10-10 11:26:40 -06:00
holder.c block: remove WARN_ON() from bd_link_disk_holder 2022-06-23 07:48:05 -06:00
ioctl.c block: replace blkdev_nr_zones with bdev_nr_zones 2022-07-06 06:46:26 -06:00
ioprio.c block: Fix handling of tasks without ioprio in ioprio_get(2) 2022-06-27 06:29:12 -06:00
Kconfig block: remove "select BLK_RQ_IO_DATA_LEN" from BLK_CGROUP_IOCOST dependency 2022-06-29 08:35:57 -06:00
Kconfig.iosched block: only build the icq tracking code when needed 2021-12-16 10:59:02 -07:00
kyber-iosched.c block/kyber: Use the new blk_opf_t type 2022-07-14 12:14:30 -06:00
Makefile blk-cgroup: move blkcg_{get,set}_fc_appid out of line 2022-05-02 14:06:20 -06:00
mq-deadline.c block/mq-deadline: Use the new blk_opf_t type 2022-07-14 12:14:30 -06:00
opal_proto.h block: sed-opal: Add ioctl to return device status 2022-08-22 07:52:51 -06:00
sed-opal.c block: sed-opal: Add ioctl to return device status 2022-08-22 07:52:51 -06:00
t10-pi.c block: add pi for extended integrity 2022-03-07 12:48:35 -07:00