- * the per-thread rcu_reader.ctr) has the upper bits containing a count of
- * _urcu_mb_read_lock() nesting, and a lower-order bit that contains either zero
- * or URCU_GP_CTR_PHASE. The cmm_smp_mb() ensures that the accesses in
+ * the per-thread rcu_reader.ctr) has the lower-order bits containing a count of
+ * _urcu_mb_read_lock() nesting, and a single high-order URCU_BP_GP_CTR_PHASE bit
+ * that contains either zero or one. The cmm_smp_mb() ensures that the accesses in