Man page 9 : round_jiffies_up_relative

round_jiffies_up_relative - function to round jiffies up to a full second

unsigned long round_jiffies_up_relative(unsigned long  j );

j
    the time in (relative) jiffies that should be rounded

This is the same as round_jiffies_relative except that it will never round down. This is useful for timeouts for which the exact time of firing does not matter too much, as long as they donAqt fire too early.