user/sven/linux.git/include/uapi/linux/ublk_cmd.h, branch v6.1.100

ublk_drv: add START_USER_RECOVERY and END_USER_RECOVERY support

2022-09-24T01:09:56Z

START_USER_RECOVERY and END_USER_RECOVERY are two new control commands to support user recovery feature. After a crash, user should send START_USER_RECOVERY, it will: (1) check if (a)current ublk_device is UBLK_S_DEV_QUIESCED which was set by quiesce_work and (b)chardev is released (2) reinit all ubqs, including: (a) put the task_struct and reset ->ubq_daemon to NULL. (b) reset all ublk_io. (3) reset ub->mm to NULL. Then, user should start a new process and send FETCH_REQ on each ubq_daemon. Finally, user should send END_USER_RECOVERY, it will: (1) wait for all new ubq_daemons getting ready. (2) update ublksrv_pid (3) unquiesce the request queue and expect incoming ublk_queue_rq() (4) convert ub's state to UBLK_S_DEV_LIVE Note: we can handle STOP_DEV between START_USER_RECOVERY and END_USER_RECOVERY. This is helpful to users who cannot start new process after sending START_USER_RECOVERY ctrl-cmd. Signed-off-by: ZiyangZhang Reviewed-by: Ming Lei Link: https://lore.kernel.org/r/20220923153919.44078-7-ZiyangZhang@linux.alibaba.com Signed-off-by: Jens Axboe

ublk_drv: support UBLK_F_USER_RECOVERY_REISSUE

2022-09-24T01:09:56Z

UBLK_F_USER_RECOVERY_REISSUE implies that: With a dying ubq_daemon, ublk_drv let monitor_work requeues rq issued to userspace(ublksrv) before the ubq_daemon is dying. UBLK_F_USER_RECOVERY_REISSUE is designed for backends which: (1) tolerate double-write since ublk_drv may issue the same rq twice. (2) does not let frontend users get I/O error, such as read-only FS and VM backend. Signed-off-by: ZiyangZhang Reviewed-by: Ming Lei Link: https://lore.kernel.org/r/20220923153919.44078-6-ZiyangZhang@linux.alibaba.com Signed-off-by: Jens Axboe

ublk_drv: define macros for recovery feature and check them

2022-09-24T01:09:56Z

Define some macros for recovery feature. UBLK_S_DEV_QUIESCED implies that ublk_device is quiesced and is ready for recovery. This state can be observed by userspace. UBLK_F_USER_RECOVERY implies that: (1) ublk_drv enables recovery feature. It won't let monitor_work to automatically abort rqs and release the device. (2) With a dying ubq_daemon, ublk_drv ends(aborts) rqs issued to userspace(ublksrv) before crash. (3) With a dying ubq_daemon, in task work and ublk_queue_rq(), ublk_drv requeues rqs. Signed-off-by: ZiyangZhang Reviewed-by: Ming Lei Link: https://lore.kernel.org/r/20220923153919.44078-3-ZiyangZhang@linux.alibaba.com Signed-off-by: Jens Axboe

ublk_cmd.h: add one new ublk command: UBLK_IO_NEED_GET_DATA

2022-08-03T03:13:40Z

Add one new ublk command: UBLK_IO_NEED_GET_DATA. It is prepared for a new feature designed for a user application who wants to allocate IO buffer and set IO buffer address only after it receives an IO request from ublksrv. Reviewed-by: Ming Lei Signed-off-by: ZiyangZhang Link: https://lore.kernel.org/r/c8a64b6b51c78340da7daa9e1054608695e79619.1659011443.git.ZiyangZhang@linux.alibaba.com Signed-off-by: Jens Axboe

ublk_drv: cleanup ublksrv_ctrl_dev_info

2022-08-03T03:13:40Z

Remove all block device related info from ublksrv_ctrl_dev_info, meantime reduce its size into 64 bytes because: 1) ublksrv_ctrl_dev_info becomes cleaner without including any block related info 2) generic set/get parameter command can be used to set block related setting easily and cleanly 3) generic set/get parameter command can be used for extending ublk without needing more info in ublksrv_ctrl_dev_info Signed-off-by: Ming Lei Link: https://lore.kernel.org/r/20220730092750.1118167-5-ming.lei@redhat.com Signed-off-by: Jens Axboe

ublk_drv: add SET_PARAMS/GET_PARAMS control command

2022-08-03T03:13:40Z

Add two commands to set/get parameters generically. One important goal of ublk is to provide generic framework for making block device by userspace flexibly. As one generic block device, there are still lots of block parameters, such as max_sectors, write_cache/fua, discard related limits, zoned parameters, ...., so this patch starts to add generic mechanism for set/get device parameters. Both generic block parameters(all kinds of queue settings) and ublk feature parameters can be covered with this way, then it becomes quite easy to extend in future. Add two parameter types are used so far: basic(covers basic queue setting and misc settings which can't be grouped easily) and discard, basic type must be set, and discard type becomes optional now This way provides mechanism to simulate any kind of generic block device from userspace easily, from both block queue setting viewpoint or ublk feature viewpoint. The style of putting all parameters together is suggested by Christoph. Suggested-by: Christoph Hellwig Signed-off-by: Ming Lei Link: https://lore.kernel.org/r/20220730092750.1118167-4-ming.lei@redhat.com Signed-off-by: Jens Axboe

ublk_drv: make sure that correct flags(features) returned to userspace

2022-07-22T15:22:53Z

Userspace may support more features or new added flags, but the driver side can be old, so make sure correct flags(features) returned to userpsace, then userspace can work as expected. Also mark the 2nd flags as reversed, just use the 1st one. When we run out of flags, the reserved one can be handled at that time. Reviewed-by: Christoph Hellwig Reviewed-by: ZiyangZhang Signed-off-by: Ming Lei Link: https://lore.kernel.org/r/20220722103817.631258-3-ming.lei@redhat.com Signed-off-by: Jens Axboe

ublk: remove UBLK_IO_F_PREFLUSH

2022-07-21T16:52:12Z

REQ_PREFLUSH is turned into REQ_OP_FLUSH by the flush state machine and thus never seen by a blk-mq based driver. Signed-off-by: Christoph Hellwig Reviewed-by: Ming Lei Link: https://lore.kernel.org/r/20220721130916.1869719-3-hch@lst.de Signed-off-by: Jens Axboe

ublk: remove UBLK_IO_F_INTEGRITY

2022-07-18T19:10:47Z

The ublk protocol has no mechanism to actually transfer the integrity metadata, so don't define this flag, which requires that an integrity payload is attached to a bio. Signed-off-by: Christoph Hellwig Link: https://lore.kernel.org/r/20220718063013.335531-1-hch@lst.de Signed-off-by: Jens Axboe

ublk_drv: support to complete io command via task_work_add

2022-07-14T13:15:48Z

Use task_work_add if it is available, since task_work_add can bring up better performance, especially batching signaling ->ubq_daemon can be done. It is observed that task_work_add() can boost iops by +4% on random 4k io test. Also except for completing io command, all other code paths are same with completing io command via io_uring_cmd_complete_in_task. Meantime add one flag of UBLK_F_URING_CMD_COMP_IN_TASK for comparing the mode easily. Signed-off-by: Ming Lei Link: https://lore.kernel.org/r/20220713140711.97356-3-ming.lei@redhat.com Signed-off-by: Jens Axboe