[PATCH v1 00/11] io_uring: add kernel-managed buffer rings

[Joanne Koong <joannelkoong@gmail.com>]

Currently, io_uring buffer rings require the application to allocate and
manage the backing buffers. This series introduces kernel-managed buffer
rings, where the kernel allocates and manages the buffers on behalf of
the application.

This is split out from the fuse over io_uring series in [1], which needs the
kernel to own and manage buffers shared between the fuse server and the
kernel.

This series is on top of the for-next branch in Jens' io-uring tree. The
corresponding liburing changes are in [2] and will be submitted after the
changes in this patchset are accepted.

Thanks,
Joanne

[1] https://lore.kernel.org/linux-fsdevel/20260116233044.1532965-1-joannelkoong@gmail.com/
[2] https://github.com/joannekoong/liburing/tree/kmbuf

Changelog
---------
Changes since [1]:
* add "if (bl)" check for recycling API (Bernd)
* check mul overflow, use GFP_USER, use PTR as return type (Christoph)
* fix bl->ring leak (me)

Joanne Koong (11):
  io_uring/kbuf: refactor io_register_pbuf_ring() logic into generic
    helpers
  io_uring/kbuf: rename io_unregister_pbuf_ring() to
    io_unregister_buf_ring()
  io_uring/kbuf: add support for kernel-managed buffer rings
  io_uring/kbuf: add mmap support for kernel-managed buffer rings
  io_uring/kbuf: support kernel-managed buffer rings in buffer selection
  io_uring/kbuf: add buffer ring pinning/unpinning
  io_uring/kbuf: add recycling for kernel managed buffer rings
  io_uring/kbuf: add io_uring_is_kmbuf_ring()
  io_uring/kbuf: export io_ring_buffer_select()
  io_uring/kbuf: return buffer id in buffer selection
  io_uring/cmd: set selected buffer index in __io_uring_cmd_done()

 include/linux/io_uring/cmd.h   |  53 ++++-
 include/linux/io_uring_types.h |  10 +-
 include/uapi/linux/io_uring.h  |  17 +-
 io_uring/kbuf.c                | 365 +++++++++++++++++++++++++++------
 io_uring/kbuf.h                |  19 +-
 io_uring/memmap.c              | 116 ++++++++++-
 io_uring/memmap.h              |   4 +
 io_uring/register.c            |   9 +-
 io_uring/uring_cmd.c           |   6 +-
 9 files changed, 526 insertions(+), 73 deletions(-)

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2.47.3