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>

diff --git a/kernel/rcutree.c b/kernel/rcutree.c
index dc8c5284fe06a889e156f9b2d7599aeacd40cb58..81e0394e46af6550b53b21e15f4184c34e28dc02 100644 (file)
--- a/kernel/rcutree.c
+++ b/kernel/rcutree.c
@@ -936,6 +936,18 @@ check_for_new_grace_period(struct rcu_state *rsp, struct rcu_data *rdp)
        return ret;
 }
 
+/*
+ * 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
@@ -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);