rcu: Consolidate duplicate callback-list initialization

There are a couple of open-coded initializations of the rcu_data
structure's RCU callback list.  This commit therefore consolidates
them into a new init_callback_list() function.

Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>

1 files changed, 14 insertions, 9 deletions

diff --git a/kernel/rcutree.c b/kernel/rcutree.c
index dc8c5284fe06..81e0394e46af 100644
--- a/kernel/rcutree.c
+++ b/kernel/rcutree.c
@@ -937,6 +937,18 @@ check_for_new_grace_period(struct rcu_state *rsp, struct rcu_data *rdp)
 }
 
 /*
+ * Initialize the specified rcu_data structure's callback list to empty.
+ */
+static void init_callback_list(struct rcu_data *rdp)
+{
+        int i;
+
+        rdp->nxtlist = NULL;
+        for (i = 0; i < RCU_NEXT_SIZE; i++)
+                rdp->nxttail[i] = &rdp->nxtlist;
+}
+
+/*
  * Advance this CPU's callbacks, but only if the current grace period
  * has ended.  This may be called only from the CPU to whom the rdp
  * belongs.  In addition, the corresponding leaf rcu_node structure's
@@ -1328,8 +1340,6 @@ static void
 rcu_send_cbs_to_orphanage(int cpu, struct rcu_state *rsp,
                           struct rcu_node *rnp, struct rcu_data *rdp)
 {
-        int i;
-
         /*
          * Orphan the callbacks.  First adjust the counts.  This is safe
          * because ->onofflock excludes _rcu_barrier()'s adoption of
@@ -1369,9 +1379,7 @@ rcu_send_cbs_to_orphanage(int cpu, struct rcu_state *rsp,
         }
 
         /* Finally, initialize the rcu_data structure's list to empty.  */
-        rdp->nxtlist = NULL;
-        for (i = 0; i < RCU_NEXT_SIZE; i++)
-                rdp->nxttail[i] = &rdp->nxtlist;
+        init_callback_list(rdp);
 }
 
 /*
@@ -2407,16 +2415,13 @@ static void __init
 rcu_boot_init_percpu_data(int cpu, struct rcu_state *rsp)
 {
         unsigned long flags;
-        int i;
         struct rcu_data *rdp = per_cpu_ptr(rsp->rda, cpu);
         struct rcu_node *rnp = rcu_get_root(rsp);
 
         /* Set up local state, ensuring consistent view of global state. */
         raw_spin_lock_irqsave(&rnp->lock, flags);
         rdp->grpmask = 1UL << (cpu - rdp->mynode->grplo);
-        rdp->nxtlist = NULL;
-        for (i = 0; i < RCU_NEXT_SIZE; i++)
-                rdp->nxttail[i] = &rdp->nxtlist;
+        init_callback_list(rdp);
         rdp->qlen_lazy = 0;
         rdp->qlen = 0;
         rdp->dynticks = &per_cpu(rcu_dynticks, cpu);