expires
delta
mode
Make the current task sleep until the given expiry time has elapsed. The routine will return immediately unless the current task state has been set (see set_current_state).
The delta argument gives the kernel the freedom to schedule the actual wakeup to a time that is both power and performance friendly. The kernel give the normal best effort behavior for lqexpires+deltarq, but may decide to fire the timer earlier, but no earlier than expires.
You can set the task state as follows -
TASK_UNINTERRUPTIBLE - at least timeout time is guaranteed to pass before the routine returns.
TASK_INTERRUPTIBLE - the routine may return early if a signal is delivered to the current task.
The current task state is guaranteed to be TASK_RUNNING when this routine returns.
Returns 0 when the timer has expired otherwise -EINTR