[PATCH v5 0/8] implement async block discards and other ops via io_uring

[Pavel Begunkov <asml.silence@gmail.com>]

There is an interest in having asynchronous block operations like
discard and write zeroes. The series implements that as io_uring commands,
which is an io_uring request type allowing to implement custom file
specific operations.

First 4 are preparation patches. Patch 5 introduces the main chunk of
cmd infrastructure and discard commands. Patches 6-8 implement
write zeroes variants.

Branch with tests and docs:
https://github.com/isilence/liburing.git discard-cmd

The man page specifically (need to shuffle it to some cmd section):
https://github.com/isilence/liburing/commit/a6fa2bc2400bf7fcb80496e322b5db4c8b3191f0

v5: add uapi/linux/blkdev.h
    number block cmd opcodes starting from IOC seq 0
    don't export bio_discard_limit(), return to v2 and put bio if nowait
      can't proceed
    minor comment and stylistics changes

v4: fix failing to pass nowait (unused opf) in patch 7

v3: use GFP_NOWAIT for non-blocking allocation
    fail oversized nowait discards in advance
    drop secure erase and add zero page writes
    renamed function name + other cosmetic changes
    use IOC / ioctl encoding for cmd opcodes

v2: move out of CONFIG_COMPAT
    add write zeroes & secure erase
    drop a note about interaction with page cache

Pavel Begunkov (8):
  io_uring/cmd: expose iowq to cmds
  io_uring/cmd: give inline space in request to cmds
  filemap: introduce filemap_invalidate_pages
  block: introduce blk_validate_byte_range()
  block: implement async io_uring discard cmd
  block: implement write zeroes io_uring cmd
  block: add nowait flag for __blkdev_issue_zero_pages
  block: implement write zero pages cmd

 block/blk-lib.c              |  22 +++-
 block/blk.h                  |   1 +
 block/fops.c                 |   2 +
 block/ioctl.c                | 242 ++++++++++++++++++++++++++++++++---
 include/linux/bio.h          |   4 +
 include/linux/blkdev.h       |   1 +
 include/linux/io_uring/cmd.h |  15 +++
 include/linux/pagemap.h      |   2 +
 include/uapi/linux/blkdev.h  |  16 +++
 io_uring/io_uring.c          |  11 ++
 io_uring/io_uring.h          |   1 +
 io_uring/uring_cmd.c         |   7 +
 mm/filemap.c                 |  17 ++-
 13 files changed, 314 insertions(+), 27 deletions(-)
 create mode 100644 include/uapi/linux/blkdev.h

-- 
2.45.2