[RFC PATCH 0/9] io_uring: support sqe group and provide group kbuf

[Ming Lei <ming.lei@redhat.com>]

Hello,

This patch adds sqe user ext flags, generic sqe group usage, and
provide group kbuf based on sqe group. sqe group provides one efficient
way to share resource among one group of sqes, such as, it can be for
implementing multiple copying(copy data from single source to multiple
destinations) via single syscall.

Finally implements provide group kbuf for uring command, and ublk use this
for supporting zero copy, and actually this feature can be used to support
generic device zero copy.

The last liburing patch adds helpers for using sqe group, also adds
tests for sqe group. 

ublksrv userspace implements zero copy by sqe group & provide group
kbuf:

	https://github.com/ublk-org/ublksrv/commits/group-provide-buf/
	git clone https://github.com/ublk-org/ublksrv.git -b group-provide-buf

	make test T=loop/009:nbd/061:nbd/062	#ublk zc tests

Any comments are welcome!

Ming Lei (9):
  io_uring: net: don't check sqe->__pad2[0] for send zc
  io_uring: support user sqe ext flags
  io_uring: add helper for filling cqes in
    __io_submit_flush_completions()
  io_uring: add one output argument to io_submit_sqe
  io_uring: support SQE group
  io_uring: support providing sqe group buffer
  io_uring/uring_cmd: support provide group kernel buffer
  ublk: support provide io buffer
  liburing: support sqe ext_flags & sqe group

 drivers/block/ublk_drv.c       | 156 ++++++++++++++++++-
 include/linux/io_uring/cmd.h   |   9 ++
 include/linux/io_uring_types.h |  46 +++++-
 include/uapi/linux/io_uring.h  |  24 ++-
 include/uapi/linux/ublk_cmd.h  |   7 +-
 io_uring/filetable.h           |   2 +-
 io_uring/io_uring.c            | 268 +++++++++++++++++++++++++++++----
 io_uring/io_uring.h            |  17 ++-
 io_uring/kbuf.c                |  62 ++++++++
 io_uring/kbuf.h                |  12 ++
 io_uring/net.c                 |  31 +++-
 io_uring/opdef.c               |   5 +
 io_uring/opdef.h               |   2 +
 io_uring/rw.c                  |  20 ++-
 io_uring/uring_cmd.c           |  25 ++-
 15 files changed, 640 insertions(+), 46 deletions(-)

-- 
2.42.0