rcu: Eliminate rcu_implicit_dynticks_qs() local variable ruqp

The rcu_implicit_dynticks_qs() function's local variable ruqp references
the ->rcu_urgent_qs field in the rcu_data structure referenced by the
function parameter rdp, with a rather odd method for computing the
pointer to this field.  This commit therefore simplifies things and
saves a couple of lines of code by replacing each instance of ruqp with
&rdp->need_heavy_qs.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 18d2f35..0bfebec 100644 (file)
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -1219,7 +1219,6 @@ static int dyntick_save_progress_counter(struct rcu_data *rdp)
 static int rcu_implicit_dynticks_qs(struct rcu_data *rdp)
 {
        unsigned long jtsq;
-       bool *ruqp;
        struct rcu_node *rnp = rdp->mynode;
 
        /*
@@ -1284,16 +1283,15 @@ static int rcu_implicit_dynticks_qs(struct rcu_data *rdp)
         * is set way high.
         */
        jtsq = READ_ONCE(jiffies_to_sched_qs);
-       ruqp = per_cpu_ptr(&rcu_data.rcu_urgent_qs, rdp->cpu);
        if (!READ_ONCE(rdp->rcu_need_heavy_qs) &&
            (time_after(jiffies, rcu_state.gp_start + jtsq * 2) ||
             time_after(jiffies, rcu_state.jiffies_resched) ||
             rcu_state.cbovld)) {
                WRITE_ONCE(rdp->rcu_need_heavy_qs, true);
                /* Store rcu_need_heavy_qs before rcu_urgent_qs. */
-               smp_store_release(ruqp, true);
+               smp_store_release(&rdp->rcu_urgent_qs, true);
        } else if (time_after(jiffies, rcu_state.gp_start + jtsq)) {
-               WRITE_ONCE(*ruqp, true);
+               WRITE_ONCE(rdp->rcu_urgent_qs, true);
        }
 
        /*
@@ -1307,7 +1305,7 @@ static int rcu_implicit_dynticks_qs(struct rcu_data *rdp)
        if (tick_nohz_full_cpu(rdp->cpu) &&
            (time_after(jiffies, READ_ONCE(rdp->last_fqs_resched) + jtsq * 3) ||
             rcu_state.cbovld)) {
-               WRITE_ONCE(*ruqp, true);
+               WRITE_ONCE(rdp->rcu_urgent_qs, true);
                resched_cpu(rdp->cpu);
                WRITE_ONCE(rdp->last_fqs_resched, jiffies);
        }