+/**
+ * Priority inheritance update algorithm.
+ *
+ * The algorithm checks and boosts the priority of the semaphore's
+ * current owner and also processes in that block the owner, which
+ * form a chain of blocking processes.
+ *
+ * Note that the priority of a process in the chain of blocked
+ * processes is always greater or equal than the priority of a process
+ * before in the chain. See the diagram below:
+ * P1 --. S1 ---> P2 --. S2 ---> P3
+ * prio_proc(P2) >= prio_proc(P1) always.
+ */