linux/block
David Jeffery fdc61af371 block: recalculate segment count for multi-segment discards correctly
[ Upstream commit a958937ff166fc60d1c3a721036f6ff41bfa2821 ]

When a stacked block device inserts a request into another block device
using blk_insert_cloned_request, the request's nr_phys_segments field gets
recalculated by a call to blk_recalc_rq_segments in
blk_cloned_rq_check_limits. But blk_recalc_rq_segments does not know how to
handle multi-segment discards. For disk types which can handle
multi-segment discards like nvme, this results in discard requests which
claim a single segment when it should report several, triggering a warning
in nvme and causing nvme to fail the discard from the invalid state.

 WARNING: CPU: 5 PID: 191 at drivers/nvme/host/core.c:700 nvme_setup_discard+0x170/0x1e0 [nvme_core]
 ...
 nvme_setup_cmd+0x217/0x270 [nvme_core]
 nvme_loop_queue_rq+0x51/0x1b0 [nvme_loop]
 __blk_mq_try_issue_directly+0xe7/0x1b0
 blk_mq_request_issue_directly+0x41/0x70
 ? blk_account_io_start+0x40/0x50
 dm_mq_queue_rq+0x200/0x3e0
 blk_mq_dispatch_rq_list+0x10a/0x7d0
 ? __sbitmap_queue_get+0x25/0x90
 ? elv_rb_del+0x1f/0x30
 ? deadline_remove_request+0x55/0xb0
 ? dd_dispatch_request+0x181/0x210
 __blk_mq_do_dispatch_sched+0x144/0x290
 ? bio_attempt_discard_merge+0x134/0x1f0
 __blk_mq_sched_dispatch_requests+0x129/0x180
 blk_mq_sched_dispatch_requests+0x30/0x60
 __blk_mq_run_hw_queue+0x47/0xe0
 __blk_mq_delay_run_hw_queue+0x15b/0x170
 blk_mq_sched_insert_requests+0x68/0xe0
 blk_mq_flush_plug_list+0xf0/0x170
 blk_finish_plug+0x36/0x50
 xlog_cil_committed+0x19f/0x290 [xfs]
 xlog_cil_process_committed+0x57/0x80 [xfs]
 xlog_state_do_callback+0x1e0/0x2a0 [xfs]
 xlog_ioend_work+0x2f/0x80 [xfs]
 process_one_work+0x1b6/0x350
 worker_thread+0x53/0x3e0
 ? process_one_work+0x350/0x350
 kthread+0x11b/0x140
 ? __kthread_bind_mask+0x60/0x60
 ret_from_fork+0x22/0x30

This patch fixes blk_recalc_rq_segments to be aware of devices which can
have multi-segment discards. It calculates the correct discard segment
count by counting the number of bio as each discard bio is considered its
own segment.

Fixes: 1e739730c5 ("block: optionally merge discontiguous discard bios into a single request")
Signed-off-by: David Jeffery <djeffery@redhat.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Laurence Oberman <loberman@redhat.com>
Link: https://lore.kernel.org/r/20210211143807.GA115624@redhat
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-03-30 14:35:28 +02:00
..
partitions
badblocks.c
bfq-cgroup.c
bfq-iosched.c bfq: Avoid false bfq queue merging 2021-03-04 10:26:10 +01:00
bfq-iosched.h
bfq-wf2q.c
bio-integrity.c
bio.c
blk-cgroup.c blk-cgroup: Use cond_resched() when destroy blkgs 2021-02-13 13:52:56 +01:00
blk-core.c Revert "Revert "block: end bio with BLK_STS_AGAIN in case of non-mq devs and REQ_NOWAIT"" 2021-02-07 15:35:47 +01:00
blk-exec.c
blk-flush.c
blk-integrity.c
blk-ioc.c
blk-iocost.c
blk-iolatency.c
blk-lib.c
blk-map.c
blk-merge.c block: recalculate segment count for multi-segment discards correctly 2021-03-30 14:35:28 +02:00
blk-mq-cpumap.c
blk-mq-debugfs-zoned.c
blk-mq-debugfs.c
blk-mq-debugfs.h
blk-mq-pci.c
blk-mq-rdma.c
blk-mq-sched.c
blk-mq-sched.h
blk-mq-sysfs.c
blk-mq-tag.c
blk-mq-tag.h
blk-mq-virtio.c
blk-mq.c blk-mq: In blk_mq_dispatch_rq_list() "no budget" is a reason to kick 2020-12-30 11:50:54 +01:00
blk-mq.h
blk-pm.c scsi: block: Fix a race in the runtime power management code 2021-01-06 14:48:37 +01:00
blk-pm.h
blk-rq-qos.c
blk-rq-qos.h
blk-settings.c blk-settings: align max_sectors on "logical_block_size" boundary 2021-03-04 10:26:40 +01:00
blk-softirq.c
blk-stat.c
blk-stat.h
blk-sysfs.c
blk-throttle.c
blk-timeout.c
blk-wbt.c
blk-wbt.h
blk-zoned.c block: Simplify REQ_OP_ZONE_RESET_ALL handling 2020-12-30 11:50:54 +01:00
blk.h
bounce.c
bsg-lib.c
bsg.c bsg: free the request before return error code 2021-03-04 10:26:22 +01:00
cmdline-parser.c
compat_ioctl.c
elevator.c
genhd.c block: Suppress uevent for hidden device when removed 2021-03-30 14:35:23 +02:00
ioctl.c
ioprio.c
Kconfig
Kconfig.iosched
kyber-iosched.c
Makefile
mq-deadline.c
opal_proto.h
partition-generic.c
scsi_ioctl.c
sed-opal.c
t10-pi.c