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NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | SEE ALSO | COLOPHON |
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io_uring_register_buffers(3) liburing Manual io_uring_register_buffers(3)
io_uring_register_buffers - register buffers for fixed buffer
operations
#include <liburing.h>
int io_uring_register_buffers(struct io_uring *ring,
const struct iovec *iovecs,
unsigned nr_iovecs);
int io_uring_register_buffers_tags(struct io_uring *ring,
const struct iovec *iovecs,
const __u64 *tags,
unsigned nr);
int io_uring_register_buffers_sparse(struct io_uring *ring,
unsigned nr_iovecs);
int io_uring_register_buffers_update_tag(struct io_uring *ring,
unsigned off,
const struct iovec *iovecs,
const __u64 *tags,
unsigned nr);
The io_uring_register_buffers(3) function registers nr_iovecs
number of buffers defined by the array iovecs belonging to the
ring.
The io_uring_register_buffers_tags(3) function behaves the same as
io_uring_register_buffers(3) function but additionally takes tags
parameter. See IORING_REGISTER_BUFFERS2 for the resource tagging
description.
The io_uring_register_buffers_sparse(3) function registers
nr_iovecs empty buffers belonging to the ring. These buffers must
be updated before use, using eg
io_uring_register_buffers_update_tag(3).
After the caller has registered the buffers, they can be used with
one of the fixed buffers functions.
Registered buffers is an optimization that is useful in
conjunction with O_DIRECT reads and writes, where it maps the
specified range into the kernel once when the buffer is registered
rather than doing a map and unmap for each IO every time IO is
performed to that region. Additionally, it also avoids
manipulating the page reference counts for each IO.
The io_uring_register_buffers_update_tag(3) function updates
registered buffers with new ones, either turning a sparse entry
into a real one, or replacing an existing entry. The off is offset
on which to start the update nr number of buffers defined by the
array iovecs belonging to the ring. The tags points to an array
of tags. See IORING_REGISTER_BUFFERS2 for the resource tagging
description.
On success io_uring_register_buffers(3),
io_uring_register_buffers_tags(3) and
io_uring_register_buffers_sparse(3) return 0.
io_uring_register_buffers_update_tag(3) return number of buffers
updated. On failure they return -errno.
io_uring_register(2), io_uring_get_sqe(3),
io_uring_unregister_buffers(3), io_uring_clone_buffers(3),
io_uring_register_buf_ring(3), io_uring_prep_read_fixed(3),
io_uring_prep_write_fixed(3)
This page is part of the liburing (A library for io_uring)
project. Information about the project can be found at
⟨https://github.com/axboe/liburing⟩. If you have a bug report for
this manual page, send it to io-uring@vger.kernel.org. This page
was obtained from the project's upstream Git repository
⟨https://github.com/axboe/liburing⟩ on 2025-02-02. (At that time,
the date of the most recent commit that was found in the
repository was 2025-01-22.) If you discover any rendering
problems in this HTML version of the page, or you believe there is
a better or more up-to-date source for the page, or you have
corrections or improvements to the information in this COLOPHON
(which is not part of the original manual page), send a mail to
man-pages@man7.org
liburing-2.1 November 15, 2021io_uring_register_buffers(3)
Pages that refer to this page: io_uring_clone_buffers(3), io_uring_clone_buffers_offset(3), io_uring_prep_read_fixed(3), io_uring_prep_send_zc(3), io_uring_prep_send_zc_fixed(3), io_uring_prep_write_fixed(3), io_uring_register_buffers(3), io_uring_register_buffers_sparse(3), io_uring_register_buffers_tags(3), io_uring_register_buffers_update_tag(3), io_uring_sqe_set_flags(3), io_uring_unregister_buffers(3)
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HTML rendering created 2025-02-02 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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