| .\" Copyright (C) 2022 Jens Axboe <axboe@kernel.dk> |
| .\" |
| .\" SPDX-License-Identifier: LGPL-2.0-or-later |
| .\" |
| .TH io_uring_prep_poll_timeout_update 3 "March 12, 2022" "liburing-2.2" "liburing Manual" |
| .SH NAME |
| io_uring_prep_timeout_update \- prepare a request to update an existing timeout |
| .SH SYNOPSIS |
| .nf |
| .B #include <liburing.h> |
| .PP |
| .BI "void io_uring_prep_timeout_update(struct io_uring_sqe *" sqe "," |
| .BI " struct __kernel_timespec *" ts "," |
| .BI " __u64 " user_data "," |
| .BI " unsigned " flags ");" |
| .PP |
| .BI "void io_uring_prep_timeout_remove(struct io_uring_sqe *" sqe "," |
| .BI " __u64 " user_data "," |
| .BI " unsigned " flags ");" |
| .fi |
| .SH DESCRIPTION |
| .PP |
| These functions modify or cancel an existing timeout request. The submission |
| queue entry |
| .I sqe |
| is setup to arm a timeout update or removal specified by |
| .I user_data |
| and with modifier flags given by |
| .IR flags . |
| Additionally, the update request includes a |
| .I ts |
| structure, which contains new timeout information. |
| |
| For an update request, the |
| .I flags |
| member may contain a bitmask of the following values: |
| .TP |
| .B IORING_TIMEOUT_ABS |
| The value specified in |
| .I ts |
| is an absolute value rather than a relative one. |
| .TP |
| .B IORING_TIMEOUT_BOOTTIME |
| The boottime clock source should be used. |
| .TP |
| .B IORING_TIMEOUT_REALTIME |
| The realtime clock source should be used. |
| .TP |
| .B IORING_TIMEOUT_ETIME_SUCCESS |
| Consider an expired timeout a success in terms of the posted completion. |
| Normally a timeout that triggers would return in a |
| .B -ETIME |
| CQE |
| .I res |
| value. |
| .PP |
| The timeout remove command does not currently accept any flags. |
| |
| .SH RETURN VALUE |
| None |
| .SH ERRORS |
| These are the errors that are reported in the CQE |
| .I res |
| field. On success, |
| .B 0 |
| is returned. |
| .TP |
| .B -ENOENT |
| The timeout identified by |
| .I user_data |
| could not be found. It may be invalid, or triggered before the update or |
| removal request was processed. |
| .TP |
| .B -EALREADY |
| The timeout identified by |
| .I user_data |
| is already firing and cannot be canceled. |
| .TP |
| .B -EINVAL |
| One of the fields set in the SQE was invalid. For example, two clocksources |
| were given, or the specified timeout seconds or nanoseconds were < 0. |
| .TP |
| .B -EFAULT |
| io_uring was unable to access the data specified by |
| .IR ts . |
| .SH NOTES |
| As with any request that passes in data in a struct, that data must remain |
| valid until the request has been successfully submitted. It need not remain |
| valid until completion. Once a request has been submitted, the in-kernel |
| state is stable. Very early kernels (5.4 and earlier) required state to be |
| stable until the completion occurred. Applications can test for this |
| behavior by inspecting the |
| .B IORING_FEAT_SUBMIT_STABLE |
| flag passed back from |
| .BR io_uring_queue_init_params (3). |
| .SH SEE ALSO |
| .BR io_uring_get_sqe (3), |
| .BR io_uring_submit (3), |
| .BR io_uring_prep_timeout (3) |
