Ross Lagerwall 7bbda96776 blk-mq: Fix stall due to recursive flush plug ... [ Upstream commit 7090426351 ] We have seen rare IO stalls as follows: * blk_mq_plug_issue_direct() is entered with an mq_list containing two requests. * For the first request, it sets last == false and enters the driver's queue_rq callback. * The driver queue_rq callback indirectly calls schedule() which calls blk_flush_plug(). This may happen if the driver has the BLK_MQ_F_BLOCKING flag set and is allowed to sleep in ->queue_rq. * blk_flush_plug() handles the remaining request in the mq_list. mq_list is now empty. * The original call to queue_rq resumes (with last == false). * The loop in blk_mq_plug_issue_direct() terminates because there are no remaining requests in mq_list. The IO is now stalled because the last request submitted to the driver had last == false and there was no subsequent call to commit_rqs(). Fix this by returning early in blk_mq_flush_plug_list() if rq_count is 0 which it will be in the recursive case, rather than checking if the mq_list is empty. At the same time, adjust one of the callers to skip the mq_list empty check as it is not necessary. Fixes: dc5fc361d8 ("block: attempt direct issue of plug list") Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Link: https://lore.kernel.org/r/20230714101106.3635611-1-ross.lagerwall@citrix.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org>		2023-08-03 10:25:41 +02:00
..
partitions	block/partition: fix signedness issue for Amiga partitions	2023-07-19 16:37:03 +02:00
badblocks.c	block/badblocks: Remove redundant assignments	2022-04-23 07:15:26 -06:00
bdev.c	block: sync part's ->bd_has_submit_bio with disk's	2023-04-25 07:36:02 -06:00
bfq-cgroup.c	blkcg: Restructure blkg_conf_prep() and friends	2023-04-13 06:46:49 -06:00
bfq-iosched.c	block, bfq: Fix division by zero error on zero wsum	2023-04-16 13:01:43 -06:00
bfq-iosched.h	block, bfq: remove BFQ_WEIGHT_LEGACY_DFL	2023-04-06 16:17:32 -06:00
bfq-wf2q.c	block, bfq: inject I/O to underutilized actuators	2023-01-29 15:18:33 -07:00
bio-integrity.c	block: bio-integrity: Copy flags when bio_integrity_payload is cloned	2023-02-16 11:05:41 -07:00
bio.c	ext4: Convert ext4_bio_write_page() to use a folio	2023-04-06 13:39:50 -04:00
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	Revert "blk-cgroup: pin the gendisk in struct blkcg_gq"	2023-02-14 14:24:09 -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-throttle: Fix io statistics for cgroup v1	2023-07-19 16:36:40 +02:00
blk-cgroup.h	for-6.4/block-2023-04-21	2023-04-26 12:52:58 -07:00
blk-core.c	blk-mq: Fix stall due to recursive flush plug	2023-08-03 10:25:41 +02:00
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: 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	2023-07-23 13:53:39 +02:00
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	blk-mq: fix the blk_mq_add_to_requeue_list call in blk_kick_flush	2023-04-16 13:01:43 -06:00
blk-ia-ranges.c	block: make kobj_type structures constant	2023-02-09 09:38:16 -07:00
blk-integrity.c	blk-integrity: register sysfs attributes on struct device	2023-04-26 18:22:50 -06:00
blk-ioc.c	block: fix default IO priority handling again	2022-06-27 06:29:12 -06:00
blk-iocost.c	blk-iocost: use spin_lock_irqsave in adjust_inuse_and_calc_cost	2023-07-19 16:35:08 +02:00
blk-iolatency.c	blk-iolatency: Make initialization lazy	2023-04-13 06:46:49 -06:00
blk-ioprio.c	blk-cgroup: pass a gendisk to pd_alloc_fn	2023-02-03 08:20:05 -07:00
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: fix bio-cache for passthru IO	2023-05-23 11:11:29 -06:00
blk-merge.c	blk-mq: release crypto keyslot before reporting I/O complete	2023-03-16 09:35:09 -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-zoned.c	block: move zone related fields to struct gendisk	2022-07-06 06:46:26 -06:00
blk-mq-debugfs.c	blk-mq: fix potential io hang by wrong 'wake_batch'	2023-07-19 16:35:09 +02:00
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	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: cleanup __blk_mq_sched_dispatch_requests	2023-04-13 06:57:18 -06:00
blk-mq-sched.h	blk-mq: move blk_mq_sched_insert_request to blk-mq.c	2023-04-13 06:52:29 -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	blk-mq: fix potential io hang by wrong 'wake_batch'	2023-07-19 16:35:09 +02:00
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	blk-mq: Fix stall due to recursive flush plug	2023-08-03 10:25:41 +02:00
blk-mq.h	blk-mq: fix potential io hang by wrong 'wake_batch'	2023-07-19 16:35:09 +02:00
blk-pm.c	blk-mq: include <linux/blk-mq.h> in block/blk-mq.h	2023-04-13 06:52:29 -06:00
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: protect rq_qos apis with a new lock	2023-07-19 16:35:07 +02:00
blk-rq-qos.h	blk-iolatency: s/blkcg_rq_qos/iolat_rq_qos/	2023-04-13 06:46:49 -06:00
blk-settings.c	block: fix revalidate performance regression	2023-05-29 08:40:32 -06:00
blk-stat.c	blk-mq: include <linux/blk-mq.h> in block/blk-mq.h	2023-04-13 06:52:29 -06:00
blk-stat.h	block: make queue stat accounting a reference	2021-12-14 17:23:05 -07:00
blk-sysfs.c	blk-mq: include <linux/blk-mq.h> in block/blk-mq.h	2023-04-13 06:52:29 -06:00
blk-throttle.c	blk-throttle: Fix io statistics for cgroup v1	2023-07-19 16:36:40 +02:00
blk-throttle.h	blk-throttle: Fix io statistics for cgroup v1	2023-07-19 16:36:40 +02:00
blk-timeout.c	block: blk-timeout: delete duplicated word	2020-07-31 16:29:47 -06:00
blk-wbt.c	block/rq_qos: protect rq_qos apis with a new lock	2023-07-19 16:35:07 +02:00
blk-wbt.h	blk-wbt: move private information from blk-wbt.h to blk-wbt.c	2023-02-03 08:20:05 -07:00
blk-zoned.c	block: remove more NULL checks after bdev_get_queue()	2023-02-21 09:23:22 -07:00
blk.h	blk-integrity: register sysfs attributes on struct device	2023-04-26 18:22:50 -06:00
bounce.c	block: change the blk_queue_bounce calling convention	2022-08-02 17:22:54 -06:00
bsg-lib.c	blk-mq: move the call to blk_put_queue out of blk_mq_destroy_queue	2022-10-25 08:25:10 -06:00
bsg.c	driver core: class: remove module * from class_create()	2023-03-17 15:16:33 +01:00
disk-events.c	block: increment diskseq on all media change events	2023-07-19 16:36:22 +02:00
elevator.c	block: make kobj_type structures constant	2023-02-09 09:38:16 -07:00
elevator.h	blk-mq: pass a flags argument to elevator_type->insert_requests	2023-04-13 06:52:30 -06:00
fops.c	block: Deny writable memory mapping if block is read-only	2023-05-19 20:17:10 -06:00
genhd.c	block: fix blktrace debugfs entries leakage	2023-07-19 16:35:11 +02:00
holder.c	block: don't allow a disk link holder to itself	2022-11-16 15:19:56 -07:00
ioctl.c	block: fix scan partition for exclusively open device again	2023-02-17 06:15:57 -07:00
ioprio.c	block: Fix handling of tasks without ioprio in ioprio_get(2)	2022-06-27 06:29:12 -06:00
Kconfig	for-6.4/block-2023-04-21	2023-04-26 12:52:58 -07:00
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	blk-mq-rdma: remove queue mapping helper for rdma devices	2023-04-13 08:59:05 +02:00
mq-deadline.c	blk-mq: pass a flags argument to elevator_type->insert_requests	2023-04-13 06:52:30 -06:00
opal_proto.h	sed-opal: allow user authority to get locking range attributes.	2023-04-05 07:46:25 -06:00
sed-opal.c	sed-opal: geometry feature reporting command	2023-04-19 14:07:13 -06:00
t10-pi.c	block: add pi for extended integrity	2022-03-07 12:48:35 -07:00