document rcu_seq_snap
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
diff --git a/kernel/rcu/rcu.h b/kernel/rcu/rcu.h
index 98c1544..acce7d4 100644
--- a/kernel/rcu/rcu.h
+++ b/kernel/rcu/rcu.h
@@ -121,6 +121,10 @@ static inline void rcu_seq_end(unsigned long *sp)
* current time. This value is the current grace-period number plus two to the
* power of the number of low-order bits reserved for state, then rounded up to
* the next value in which the state bits are all zero.
+ *
+ * Basically, if any of the bits are set in the state portion of the sequence
+ * number, then return (COUNTER_PORTION + 2) << RCU_SEQ_CTR_SHIFT.
+ * Otherwise, return (COUNTER_PORTION + 1) << RCU_SEQ_CTR_SHIFT.
*/
static inline unsigned long rcu_seq_snap(unsigned long *sp)
{
