linux/block
Yu Kuai 42c306ed72 block, bfq: don't break merge chain in bfq_split_bfqq()
Consider the following scenario:

    Process 1       Process 2       Process 3       Process 4
     (BIC1)          (BIC2)          (BIC3)          (BIC4)
      Λ               |               |                |
       \-------------\ \-------------\ \--------------\|
                      V               V                V
      bfqq1--------->bfqq2---------->bfqq3----------->bfqq4
ref    0              1               2                4

If Process 1 issue a new IO and bfqq2 is found, and then bfq_init_rq()
decide to spilt bfqq2 by bfq_split_bfqq(). Howerver, procress reference
of bfqq2 is 1 and bfq_split_bfqq() just clear the coop flag, which will
break the merge chain.

Expected result: caller will allocate a new bfqq for BIC1

    Process 1       Process 2       Process 3       Process 4
     (BIC1)          (BIC2)          (BIC3)          (BIC4)
                      |               |                |
                       \-------------\ \--------------\|
                                      V                V
      bfqq1--------->bfqq2---------->bfqq3----------->bfqq4
ref    0              0               1                3

Since the condition is only used for the last bfqq4 when the previous
bfqq2 and bfqq3 are already splited. Fix the problem by checking if
bfqq is the last one in the merge chain as well.

Fixes: 36eca89483 ("block, bfq: add Early Queue Merge (EQM)")
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Link: https://lore.kernel.org/r/20240902130329.3787024-4-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-09-03 09:51:54 -06:00
..
partitions Compactifying bdev flags 2024-05-21 13:02:56 -07:00
badblocks.c badblocks: avoid checking invalid range in badblocks_check() 2023-12-23 18:38:08 -07:00
bdev.c for-6.11/block-20240710 2024-07-15 14:20:22 -07:00
bfq-cgroup.c block, bfq: remove blkg_path() 2024-06-18 09:22:45 -06:00
bfq-iosched.c block, bfq: don't break merge chain in bfq_split_bfqq() 2024-09-03 09:51:54 -06:00
bfq-iosched.h block, bfq: remove blkg_path() 2024-06-18 09:22:45 -06:00
bfq-wf2q.c block, bfq: inject I/O to underutilized actuators 2023-01-29 15:18:33 -07:00
bio-integrity.c for-6.11/block-post-20240722 2024-07-22 11:04:09 -07:00
bio.c for-6.11/block-post-20240722 2024-07-22 11:04:09 -07:00
blk-cgroup-fc-appid.c block: Replace all non-returning strlcpy with strscpy 2023-06-01 09:13:31 -06:00
blk-cgroup-rwstat.c blk-cgroup: use group allocation/free of per-cpu counters API 2024-04-03 09:10:17 -06:00
blk-cgroup-rwstat.h block: Use the new blk_opf_t type 2022-07-14 12:14:30 -06:00
blk-cgroup.c blk-ioprio: remove per-disk structure 2024-07-28 16:47:51 -06:00
blk-cgroup.h blk-cgroup: Remove unused declaration blkg_path() 2024-08-16 15:07:27 -06:00
blk-core.c block: avoid polling configuration errors 2024-07-19 09:35:35 -06:00
blk-crypto-fallback.c block, fs: Restore the per-bio/request data lifetime fields 2024-02-06 14:31:05 +01:00
blk-crypto-internal.h blk-crypto: remove blk_crypto_insert_cloned_request() 2023-03-16 09:35:09 -06:00
blk-crypto-profile.c blk-crypto: use dynamic lock class for blk_crypto_profile::lock 2023-07-05 16:36:12 -06:00
blk-crypto-sysfs.c block: make kobj_type structures constant 2023-02-09 09:38:16 -07:00
blk-crypto.c blk-crypto: make blk_crypto_evict_key() more robust 2023-03-16 09:35:09 -06:00
blk-flush.c for-6.11/block-20240710 2024-07-15 14:20:22 -07:00
blk-ia-ranges.c block: make kobj_type structures constant 2023-02-09 09:38:16 -07:00
blk-integrity.c block: cleanup flag_{show,store} 2024-06-17 10:13:37 -06:00
blk-ioc.c blk-ioc: fix recursive spin_lock/unlock_irq() in ioc_clear_queue() 2023-06-07 07:51:00 -06:00
blk-iocost.c blk_iocost: fix more out of bound shifts 2024-08-26 14:13:22 -06:00
blk-iolatency.c block: add blk_time_get_ns() and blk_time_get() helpers 2024-02-05 10:07:22 -07:00
blk-ioprio.c blk-ioprio: remove per-disk structure 2024-07-28 16:47:51 -06:00
blk-ioprio.h blk-ioprio: remove per-disk structure 2024-07-28 16:47:51 -06:00
blk-lib.c blk-lib: check for kill signal in ioctl BLKZEROOUT 2024-07-05 00:53:15 -06:00
blk-map.c block: don't free the integrity payload in bio_integrity_unmap_free_user 2024-07-03 10:21:16 -06:00
blk-merge.c block: properly handle REQ_OP_ZONE_APPEND in __bio_split_to_limits 2024-08-29 04:32:32 -06:00
blk-mq-cpumap.c blk-mq: include <linux/blk-mq.h> in block/blk-mq.h 2023-04-13 06:52:29 -06:00
blk-mq-debugfs.c block: Catch possible entries missing from rqf_name[] 2024-07-19 09:32:49 -06:00
blk-mq-debugfs.h block: Replace zone_wlock debugfs entry with zone_wplugs entry 2024-04-17 08:44:03 -06:00
blk-mq-pci.c blk-mq: include <linux/blk-mq.h> in block/blk-mq.h 2023-04-13 06:52:29 -06:00
blk-mq-sched.c blk-mq: Remove the hctx 'run' debugfs attribute 2024-01-17 14:16:34 -07:00
blk-mq-sched.h blk-mq: make sure elevator callbacks aren't called for passthrough request 2023-05-18 19:42:54 -06:00
blk-mq-sysfs.c blk-mq: include <linux/blk-mq.h> in block/blk-mq.h 2023-04-13 06:52:29 -06:00
blk-mq-tag.c for-6.5/block-2023-06-23 2023-06-26 12:47:20 -07:00
blk-mq-virtio.c blk-mq: include <linux/blk-mq.h> in block/blk-mq.h 2023-04-13 06:52:29 -06:00
blk-mq.c block: rework bio splitting 2024-08-29 04:32:32 -06:00
blk-mq.h block: Relocate BLK_MQ_CPU_WORK_BATCH 2024-07-19 09:32:48 -06:00
blk-pm.c block: Remove blk_set_runtime_active() 2023-11-20 10:22:40 -07:00
blk-pm.h block: Remove unused blk_pm_*() function definitions 2021-02-22 06:33:48 -07:00
blk-rq-qos.c block: correct stale comment in rq_qos_wait 2023-09-18 14:15:28 -06:00
blk-rq-qos.h block: skip QUEUE_FLAG_STATS and rq-qos for passthrough io 2023-12-01 18:29:18 -07:00
blk-settings.c block: Validate logical block size in blk_validate_limits() 2024-07-09 00:00:17 -06:00
blk-stat.c blk-throttle: remove CONFIG_BLK_DEV_THROTTLING_LOW 2024-05-09 09:44:55 -06:00
blk-stat.h block: delete redundant function declaration 2024-05-27 13:58:06 -06:00
blk-sysfs.c block: pass a gendisk to the queue_sysfs_entry methods 2024-06-28 15:06:16 -06:00
blk-throttle.c blk-throttle: fix lower control under super low iops limit 2024-06-28 14:55:02 -06:00
blk-throttle.h blk-throttle: Fix incorrect display of io.max 2024-05-30 19:44:29 -06:00
blk-timeout.c block: blk-timeout: delete duplicated word 2020-07-31 16:29:47 -06:00
blk-wbt.c blk-wbt: don't throttle swap writes in direct reclaim 2024-07-01 06:51:53 -06:00
blk-wbt.h blk-wbt: remove the separate write cache tracking 2023-12-26 09:28:10 -07:00
blk-zoned.c for-6.11/block-20240710 2024-07-15 14:20:22 -07:00
blk.h block: don't use bio_split_rw on misc operations 2024-08-29 04:32:32 -06:00
bounce.c block: split integrity support out of bio.h 2024-07-03 10:21:15 -06:00
bsg-lib.c scsi: bsg: Pass dev to blk_mq_alloc_queue() 2024-05-30 20:22:15 -04:00
bsg.c SCSI misc on 20230629 2023-06-30 11:57:07 -07:00
disk-events.c block: move bdev_mark_dead out of disk_check_media_change 2023-10-28 13:29:23 +02:00
early-lookup.c wrapper for access to ->bd_partno 2024-05-02 17:48:09 -04:00
elevator.c block: pass a gendisk to the queue_sysfs_entry methods 2024-06-28 15:06:16 -06:00
elevator.h block: pass a gendisk to the queue_sysfs_entry methods 2024-06-28 15:06:16 -06:00
fops.c block: clean up the check in blkdev_iomap_begin() 2024-06-27 05:56:35 -06:00
genhd.c block: fix deadlock between sd_remove & sd_release 2024-07-24 09:51:21 -06:00
holder.c block: fix deadlock between bd_link_disk_holder and partition scan 2024-02-23 07:44:19 -07:00
ioctl.c blk-lib: check for kill signal in ioctl BLKZEROOUT 2024-07-05 00:53:15 -06:00
ioprio.c block: move __get_task_ioprio() into header file 2024-01-08 12:27:39 -07:00
Kconfig block: remove the blk_integrity_profile structure 2024-06-14 10:20:06 -06:00
Kconfig.iosched block: Default to use cgroup support for BFQ 2023-01-30 09:42:42 -07:00
kyber-iosched.c blk-mq: pass a flags argument to elevator_type->insert_requests 2023-04-13 06:52:30 -06:00
Makefile block: remove the blk_integrity_profile structure 2024-06-14 10:20:06 -06:00
mq-deadline.c block/mq-deadline: Fix the tag reservation code 2024-07-02 08:47:45 -06:00
opal_proto.h block: sed-opal: handle empty atoms when parsing response 2024-02-16 15:52:45 -07:00
sed-opal.c block: sed-opal: avoid possible wrong address reference in read_sed_opal_key() 2024-06-12 10:53:20 -06:00
t10-pi.c block: constify ext_pi_ref_escape() 2024-08-13 06:20:02 -06:00