Re: [PATCH v3 0/8] io_uring: add kernel-managed buffer rings

[Jens Axboe <axboe@kernel.dk>]

On Thu, 05 Mar 2026 16:32:16 -0800, Joanne Koong wrote:
> Currently, io_uring buffer rings require the application to allocate and
> manage the backing buffers. This series introduces buffer rings where the
> kernel allocates and manages the buffers on behalf of the application. From
> the uapi side, this goes through the pbuf ring interface, through the
> IOU_PBUF_RING_KERNEL_MANAGED flag.
> 
> There was a long discussion with Pavel on v1 [1] regarding the design. The
> alternatives were to have the buffers allocated and registered through a
> memory region or through the registered buffers interface and have fuse
> implement ring buffer logic internally outside of io-uring. However, because
> the buffers need to be contiguous for DMA and some high-performance fuse
> servers may need non-fuse io-uring requests to use the buffer ring directly,
> v3 keeps the design.
> 
> [...]

Applied, thanks!

[1/8] io_uring/kbuf: add support for kernel-managed buffer rings
      commit: ff168843d80cd1855b646c5e8be2c6aa5bfb8adb
[2/8] io_uring/kbuf: support kernel-managed buffer rings in buffer selection
      commit: bf4a6eb27f8135f36a5286bd5ba87bf6468c1283
[3/8] io_uring/kbuf: add buffer ring pinning/unpinning
      commit: b6ffe5399bc04abab4da9afb2ba092e6269d7077
[4/8] io_uring/kbuf: return buffer id in buffer selection
      commit: 9aa9e55e8bad1b65c9bcc2892101b06ae00c96d9
[5/8] io_uring/kbuf: add recycling for kernel managed buffer rings
      commit: de48bc0efc58d1ebf7e35c36dde6eb0e6b246b8c
[6/8] io_uring/kbuf: add io_uring_is_kmbuf_ring()
      commit: 08b57b67602a98abf4b454a363263cba9fcfc91f
[7/8] io_uring/kbuf: export io_ring_buffer_select()
      commit: 4706d1f235ff94f19b5c818bc0a3abd735903695
[8/8] io_uring/cmd: set selected buffer index in __io_uring_cmd_done()
      commit: 3515a2aedcdf459fc851df40a3712fc4a9a060f7

Best regards,
-- 
Jens Axboe