Man page 9 : execute_in_process_context

execute_in_process_context - reliably execute the routine with user context

int execute_in_process_context(work_func_t  fn , struct execute_work *  ew );

fn
    the function to execute

ew
    guaranteed storage for the execute work structure (must be available when the work executes)

Executes the function immediately if process context is available, otherwise schedules the function for delayed execution.

0 - function was executed 1 - function was scheduled for execution