io_uring_prep_link_timeout(3) liburing Manual io_uring_prep_link_timeout(3)

io_uring_prep_link_timeout - a timeout request for linked sqes

#include <liburing.h>
void io_uring_prep_link_timeout(struct io_uring_sqe *sqe,
                                struct __kernel_timespec *ts,
                                unsigned flags);

The io_uring_prep_link_timeout(3) function prepares a timeout request for linked sqes. The submission queue entry sqe is setup a timeout specified by ts. The flags argument holds modifier flags for the timeout behaviour of the request.

The ts argument must be filled in with the appropriate information for the timeout. It looks as follows:

struct __kernel_timespec {
    __kernel_time64_t tv_sec;
    long long tv_nsec;

The flags argument may contain:

The value specified in ts is an absolute value rather than a relative one.
The boottime clock source should be used.
The realtime clock source should be used.
Consider an expired timeout a success in terms of the posted completion.

It is invalid to create a chain (linked sqes) consisting only of a link timeout request. If all the requests in the chain are completed before timeout, then the link timeout request gets cancelled. Upon timeout, all the uncompleted requests in the chain get cancelled.


These are the errors that are reported in the CQE res field. On success, 0 is returned.

The specified timeout occurred and triggered the completion event.
One of the fields set in the SQE was invalid. For example, two clock sources where given, or the specified timeout seconds or nanoseconds where < 0.
io_uring was unable to access the data specified by ts.
The timeout was canceled because all submitted requests were completed successfully or one of the requests resulted in failure.

io_uring_get_sqe(3), io_uring_prep_timeout(3)

January 23, 2023 liburing-2.4