- * At the head of the wait queue now, wait until the writer state
- * goes to 0 and then try to increment the reader count and get
- * the lock. It is possible that an incoming writer may steal the
- * lock in the interim, so it is necessary to check the writer byte
- * to make sure that the write lock isn't taken.
+ * The ACQUIRE semantics of the following spinning code ensure
+ * that accesses can't leak upwards out of our subsequent critical
+ * section in the case that the lock is currently held for write.