io_uring_register_buffers(3) liburing Manualio_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_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 email@example.com. This page was obtained from the project's upstream Git repository ⟨https://github.com/axboe/liburing⟩ on 2023-06-23. (At that time, the date of the most recent commit that was found in the repository was 2023-06-22.) 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 firstname.lastname@example.org liburing-2.1 November 15, 2021io_uring_register_buffers(3)
Pages that refer to this page: io_uring_register_buffers(3), io_uring_register_buffers_sparse(3), io_uring_register_buffers_tags(3), io_uring_register_buffers_update_tag(3)