[PATCH v4 0/5] Write-placement hints and FDP

[Kanchan Joshi <joshi.k@samsung.com>]

Current write-hint infrastructure supports 6 temperature-based data life
hints.
The series extends the infrastructure with a new temperature-agnostic
placement-type hint. New fcntl codes F_{SET/GET}_RW_HINT_EX allow to
send the hint type/value on file. See patch #3 commit description for
the details.

Overall this creates 128 placement hint values [*] that users can pass.
Patch #5 adds the ability to map these new hint values to nvme-specific
placement-identifiers.
Patch #4 restricts SCSI to use only life hint values.
Patch #1 and #2 are simple prep patches.

[*] While the user-interface can support more, this limit is due to the
in-kernel plumbing consideration of the inode size. Pahole showed 32-bit
hole in the inode, but the code had this comment too:

/* 32-bit hole reserved for expanding i_fsnotify_mask */

Not must, but it will be good to know if a byte (or two) can be used
here.

Changes since v3:
- 4 new patches to introduce write-placement hints
- Make nvme patch use the placement hints rather than write-life hints

Changes since v2:
- Base it on nvme-6.11 and resolve a merge conflict

Changes since v1:
- Reduce the fetched plids from 128 to 6 (Keith)
- Use struct_size for a calculation (Keith)
- Handle robot/sparse warning

Kanchan Joshi (4):
  fs, block: refactor enum rw_hint
  fcntl: rename rw_hint_* to rw_life_hint_*
  fcntl: add F_{SET/GET}_RW_HINT_EX
  nvme: enable FDP support

Nitesh Shetty (1):
  sd: limit to use write life hints

 drivers/nvme/host/core.c   | 81 ++++++++++++++++++++++++++++++++++++++
 drivers/nvme/host/nvme.h   |  4 ++
 drivers/scsi/sd.c          |  7 ++--
 fs/buffer.c                |  4 +-
 fs/f2fs/f2fs.h             |  4 +-
 fs/f2fs/segment.c          |  4 +-
 fs/fcntl.c                 | 79 ++++++++++++++++++++++++++++++++++---
 include/linux/blk-mq.h     |  2 +-
 include/linux/blk_types.h  |  2 +-
 include/linux/fs.h         |  2 +-
 include/linux/nvme.h       | 19 +++++++++
 include/linux/rw_hint.h    | 20 +++++++---
 include/uapi/linux/fcntl.h | 14 +++++++
 13 files changed, 218 insertions(+), 24 deletions(-)

-- 
2.25.1