io_uring_clone_buffers(3)       liburing Manual      io_uring_clone_buffers(3)

NAME
       io_uring_clone_buffers - Clones registered buffers between rings

SYNOPSIS
       #include <liburing.h>

       int io_uring_clone_buffers(struct io_uring *dst,
                                  struct io_uring * src);

       int io_uring_clone_buffers_offset(struct io_uring *dst,
                                         struct io_uring * src,
                                         unsigned int dst_off,
                                         unsigned int src_off,
                                         unsigned int nr,
                                         unsigned int flags);


DESCRIPTION
       The io_uring_clone_buffers(3) function clones registered buffers from
       the ring indicated by src to the ring indicated by dst.  Upon
       successful completion of this operation, src and dst will have the same
       set of registered buffers. This operation is identical to performing a
       io_uring_register_buffers(3) operation on the dst ring, if the src ring
       previously had that same buffer registration operating done.

       The dst ring must not have any buffers currently registered. If buffers
       are currently registered on the destination ring, they must be
       unregistered with io_uring_unregister_buffers(3) first.

       Available since kernel 6.12.

       The io_uring_clone_buffers_offset(3) function also clones buffers from
       the src ring to the dst ring, however it supports cloning only a subset
       of the buffers, where io_uring_clone_buffers(3) always clones all of
       them.  dst_off indicates at what offset cloning should start in the
       destination, src_off indicates at what offset cloning should start in
       the source, and nr indicates how many buffers to clone at the given
       offset. If both dst_off, src_off, and nr are given as 0 , then
       io_uring_clone_buffers_offset(3) performs the same action as
       io_uring_clone_buffers(3).

       flags may be set to the following value:

       IORING_REGISTER_DST_REPLACE
              If set, cloning may happen for a destination ring that already
              has a buffer table assigned. In that case, existing nodes that
              overlap with the specified range will be released and
              replaced.IORING_REGISTER_DST_REPLACE If set, cloning may happen
              for a destination ring that already has a buffer table assigned.
              In that case, existing nodes that overlap with the specified
              range will be released and replaced.

       Available since kernel 6.13.


NOTES
       The source and target ring must shared address spaces, and hence
       internal kernel accounting.

RETURN VALUE
       On success io_uring_clone_buffers(3) and
       io_uring_clone_buffers_offset(3) return 0.  On failure, they returns
       -errno, specifically

       -EBUSY The destination ring already has buffers registered, and
              IORING_REGISTER_DST_REPLACE wasn't set.

       -ENOMEM
              The kernel ran out of memory.

       -ENXIO The source ring doesn't have any buffers registered.

SEE ALSO
       io_uring_register(2), io_uring_unregister_buffers(3),
       io_uring_register_buffers(3), io_uring_prep_read_fixed(3),
       io_uring_prep_write_fixed(3)

liburing-2.9                  September 12, 2024     io_uring_clone_buffers(3)