NAME

       io_uring_prep_timeoute_update - prepare a request to update an existing timeout

SYNOPSIS

       #include <liburing.h>

       void io_uring_prep_timeout_update(struct io_uring_sqe *sqe,
                                         struct __kernel_timespec *ts,
                                         __u64 user_data,
                                         unsigned flags);

       void io_uring_prep_timeout_remove(struct io_uring_sqe *sqe,
                                         __u64 user_data,
                                         unsigned flags);

DESCRIPTION

       These  functions  modify or cancel an existing timeout request. The submission queue entry
       sqe is setup to arm a timeout update or removal specified by user_data and  with  modifier
       flags  given  by  flags.   Additionally, the update request includes a ts structure, which
       contains new timeout information.

       For an update request, the flags member may contain a bitmask of the following values:

       IORING_TIMEOUT_ABS
              The value specified in ts is an absolute value rather than a relative one.

       IORING_TIMEOUT_BOOTTIME
              The boottime clock source should be used.

       IORING_TIMEOUT_REALTIME
              The realtime clock source should be used.

       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 -ETIME CQE res value.

       The timeout remove command does not currently accept any flags.

RETURN VALUE

       None

ERRORS

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

       -ENOENT
              The  timeout  identified  by  user_data  could  not be found. It may be invalid, or
              triggered before the update or removal request was processed.

       -EALREADY
              The timeout identified by user_data is already firing and cannot be canceled.

       -EINVAL
              One of the fields set in the SQE was invalid. For example, two  clocksources  where
              given, or the specified timeout seconds or nanoseconds where < 0.

       -EFAULT
              io_uring was unable to access the data specified by ts.

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  IORING_FEAT_SUBMIT_STABLE  flag passed back from
       io_uring_queue_init_params(3).

SEE ALSO

       io_uring_get_sqe(3), io_uring_submit(3), io_uring_prep_timeout(3)