rcu: Several rcu_segcblist functions can be static

None of rcu_segcblist_set_len(), rcu_segcblist_add_len(), or
rcu_segcblist_xchg_len() are used outside of kernel/rcu/rcu_segcblist.c.
This commit therefore makes them static.

Fixes: eda669a6a2 ("rcu/nocb: Atomic ->len field in rcu_segcblist structure")
Signed-off-by: kbuild test robot <lkp@intel.com>
[ paulmck: "Fixes:" updated per Stephen Rothwell feedback. ]
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

kernel/rcu/rcu_segcblist.c

@@ -88,7 +88,7 @@ struct rcu_head *rcu_cblist_dequeue(struct rcu_cblist *rclp)
 }
 
 /* Set the length of an rcu_segcblist structure. */
-void rcu_segcblist_set_len(struct rcu_segcblist *rsclp, long v)
+static void rcu_segcblist_set_len(struct rcu_segcblist *rsclp, long v)
 {
 #ifdef CONFIG_RCU_NOCB_CPU
 	atomic_long_set(&rsclp->len, v);
@@ -104,7 +104,7 @@ void rcu_segcblist_set_len(struct rcu_segcblist *rsclp, long v)
  * This increase is fully ordered with respect to the callers accesses
  * both before and after.
  */
-void rcu_segcblist_add_len(struct rcu_segcblist *rsclp, long v)
+static void rcu_segcblist_add_len(struct rcu_segcblist *rsclp, long v)
 {
 #ifdef CONFIG_RCU_NOCB_CPU
 	smp_mb__before_atomic(); /* Up to the caller! */
@@ -134,7 +134,7 @@ void rcu_segcblist_inc_len(struct rcu_segcblist *rsclp)
  * with the actual number of callbacks on the structure.  This exchange is
  * fully ordered with respect to the callers accesses both before and after.
  */
-long rcu_segcblist_xchg_len(struct rcu_segcblist *rsclp, long v)
+static long rcu_segcblist_xchg_len(struct rcu_segcblist *rsclp, long v)
 {
 #ifdef CONFIG_RCU_NOCB_CPU
 	return atomic_long_xchg(&rsclp->len, v);