Hello,
Draining FS I/O on del_gendisk() is added for just avoiding to refer to
recently added q->disk in IO path, and it isn't actually reliable:
1) queue freezing can't drain FS I/O for bio based driver, so blk-cgroup
shutdown can't be moved into del_gendisk()
2) freezing queue can't drain in-progress IO issue/dispatch activities,
so elevator shutdown can't be moved into del_gendisk()
3) the added flag of GD_DEAD may not be observed reliably in
__bio_queue_enter() because queue freezing might not imply rcu grace
period.
4) passthrough IO accounting code can refer to q->disk after disk is
released
When releasing disk, all FS IOs are guaranteed to be done, so this
patchset tries to shutdown elevator/blk-cgroup/rq qos there, then
referring to q->disk can be avoided after disk is released.
Also add flag of BLK_MQ_REQ_USER_IO for accounting passthrough IO
only if the IO is from userspace, since disk is live for user
passthrough IO.
V2:
- take new approach to make current referring to q->disk reliable
Laibin Qiu (1):
block/wbt: fix negative inflight counter when remove scsi device
Ming Lei (12):
block: declare blkcg_[init|exit]_queue in private header
block: move initialization of q->blkg_list into blkcg_init_queue
block: move blkcg initialization/destroy into disk allocation/release
handler
block: only account passthrough IO from userspace
block: don't remove hctx debugfs dir from blk_mq_exit_queue
block: move q_usage_counter release into blk_queue_release
block: export __blk_mq_unfreeze_queue
scsi: force unfreezing queue into atomic mode
block: add helper of disk_release_queue for release queue data for
disk
block: move blk_exit_queue into disk_release
block: move rq_qos_exit() into disk_release()
block: don't drain file system I/O on del_gendisk
block/bfq-iosched.c | 2 +
block/blk-cgroup.c | 2 +
block/blk-core.c | 31 ++++----------
block/blk-mq.c | 27 ++++++++++--
block/blk-sysfs.c | 25 +-----------
block/blk.h | 10 ++++-
block/elevator.c | 2 -
block/genhd.c | 84 +++++++++++++++++++++++++++-----------
drivers/nvme/host/ioctl.c | 2 +-
drivers/scsi/scsi_ioctl.c | 3 +-
drivers/scsi/sd.c | 2 +-
include/linux/blk-cgroup.h | 4 --
include/linux/blk-mq.h | 3 ++
include/linux/genhd.h | 1 -
14 files changed, 114 insertions(+), 84 deletions(-)
--
2.31.1
