[RFC PATCH v5 0/5] introduce io_uring_cmd_import_fixed_vec

[Sidong Yang <sidong.yang@furiosa.ai>]

This patche series introduce io_uring_cmd_import_vec. With this function,
Multiple fixed buffer could be used in uring cmd. It's vectored version
for io_uring_cmd_import_fixed(). Also this patch series includes a usage
for new api for encoded read/write in btrfs by using uring cmd.

There was approximately 10 percent of performance improvements through benchmark.
The benchmark code is in
https://github.com/SidongYang/btrfs-encoded-io-test/blob/main/main.c

./main -l
Elapsed time: 0.598997 seconds
./main -l -f
Elapsed time: 0.540332 seconds

Additionally, There is a commit that fixed a memory bug in btrfs uring encoded
read.

v2:
 - don't export iou_vc, use bvec for btrfs
 - use io_is_compat for checking compat
 - reduce allocation/free for import fixed vec

v3:
 - add iou_vec cache in io_uring_cmd and use it
 - also encoded write fixed supported

v4:
 - add a patch that introduce io_async_cmd
 - add a patch that fixes a bug in btrfs encoded read

v5:
 - use Pavel's original patches rebased for axboe/for-6.15/io_uring-reg-vec
 - pop a patch that fixes btrfs encoded read
 
Pavel Begunkov (4):
  io_uring: rename the data cmd cache
  io_uring/cmd: don't expose entire cmd async data
  io_uring/cmd: add iovec cache for commands
  io_uring/cmd: introduce io_uring_cmd_import_fixed_vec

Sidong Yang (1):
  btrfs: ioctl: introduce btrfs_uring_import_iovec()

 fs/btrfs/ioctl.c               | 34 ++++++++++++++------
 include/linux/io_uring/cmd.h   | 13 ++++++++
 include/linux/io_uring_types.h |  2 +-
 io_uring/io_uring.c            |  6 ++--
 io_uring/opdef.c               |  3 +-
 io_uring/uring_cmd.c           | 59 +++++++++++++++++++++++++++++-----
 io_uring/uring_cmd.h           | 17 ++++++++++
 7 files changed, 112 insertions(+), 22 deletions(-)

-- 
2.43.0