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 in btrfs by using uring cmd.

v2:
 - don't export iou_vc, use bvec for btrfs
 - use io_is_compat for checking compat
 - reduce allocation/free for import fixed vec
 
Sidong Yang (2):
  io_uring: cmd: introduce io_uring_cmd_import_fixed_vec
  btrfs: ioctl: use registered buffer for IORING_URING_CMD_FIXED

 fs/btrfs/ioctl.c             | 27 ++++++++++++++++++++++-----
 include/linux/io_uring/cmd.h | 14 ++++++++++++++
 io_uring/uring_cmd.c         | 31 +++++++++++++++++++++++++++++++
 3 files changed, 67 insertions(+), 5 deletions(-)

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2.43.0