io_uring_prep_timeoute_update − prepare a request to update an existing timeout
#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);
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.
None
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.
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).
io_uring_get_sqe(3), io_uring_submit(3), io_uring_prep_timeout(3)