[PATCH] sched/fair: fix variable "done" set but not used

[Qian Cai]

The commit f643ea220701 ("sched/nohz: Stop NOHZ stats when decayed")
introduced a compilation warning if CONFIG_NO_HZ_COMMON=n,

kernel/sched/fair.c: In function 'update_blocked_averages':
kernel/sched/fair.c:7750:7: warning: variable 'done' set but not used
[-Wunused-but-set-variable]

Fix it by adding a couple of "ifdef" macros as the variable is only
needed when CONFIG_NO_HZ_COMMON=y.

Signed-off-by: Qian Cai <c...@lca.pw>
---
 kernel/sched/fair.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index f35930f5e528..c8682acf4508 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -7747,7 +7747,9 @@ static void update_blocked_averages(int cpu)
        struct cfs_rq *cfs_rq, *pos;
        const struct sched_class *curr_class;
        struct rq_flags rf;
+#ifdef CONFIG_NO_HZ_COMMON
        bool done = true;
+#endif
 
        rq_lock_irqsave(rq, &rf);
        update_rq_clock(rq);
@@ -7774,20 +7776,22 @@ static void update_blocked_averages(int cpu)
                if (cfs_rq_is_decayed(cfs_rq))
                        list_del_leaf_cfs_rq(cfs_rq);
 
+#ifdef CONFIG_NO_HZ_COMMON
                /* Don't need periodic decay once load/util_avg are null */
                if (cfs_rq_has_blocked(cfs_rq))
                        done = false;
        }
+#endif
 
        curr_class = rq->curr->sched_class;
        update_rt_rq_load_avg(rq_clock_pelt(rq), rq, curr_class == 
&rt_sched_class);
        update_dl_rq_load_avg(rq_clock_pelt(rq), rq, curr_class == 
&dl_sched_class);
        update_irq_load_avg(rq, 0);
+#ifdef CONFIG_NO_HZ_COMMON
        /* Don't need periodic decay once load/util_avg are null */
        if (others_have_blocked(rq))
                done = false;
 
-#ifdef CONFIG_NO_HZ_COMMON
        rq->last_blocked_load_update_tick = jiffies;
        if (done)
                rq->has_blocked_load = 0;
-- 
2.20.1 (Apple Git-117)