[RFC PATCH v3 0/3] 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

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

Sidong Yang (3):
  io-uring/cmd: add iou_vec field for io_uring_cmd
  io-uring/cmd: introduce io_uring_cmd_import_fixed_vec
  btrfs: ioctl: introduce btrfs_uring_import_iovec()

 fs/btrfs/ioctl.c             | 32 +++++++++++++++++++++--------
 include/linux/io_uring/cmd.h | 15 ++++++++++++++
 io_uring/io_uring.c          |  2 +-
 io_uring/opdef.c             |  1 +
 io_uring/uring_cmd.c         | 39 ++++++++++++++++++++++++++++++++++++
 io_uring/uring_cmd.h         |  3 +++
 6 files changed, 83 insertions(+), 9 deletions(-)

-- 
2.43.0