sched: Fix/remove redundant cfs_rq checks

Since updates are against an entity's queuing cfs_rq it's not possible to
enter update_cfs_{shares,load} with a NULL cfs_rq.  (Indeed, update_cfs_load
would crash prior to the check if we did anyway since we load is examined
during the initializers).

Also, in the update_cfs_load case there's no point
in maintaining averages for rq->cfs_rq since we don't perform shares
distribution at that level -- NULL check is replaced accordingly.

Thanks to Dan Carpenter for pointing out the deference before NULL check.

Signed-off-by: Paul Turner <[email protected]>
Signed-off-by: Peter Zijlstra <[email protected]>
LKML-Reference: <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>

kernel/sched_fair.c

@@ -722,7 +722,7 @@ static void update_cfs_load(struct cfs_rq *cfs_rq, int global_update)
 	u64 now, delta;
 	unsigned long load = cfs_rq->load.weight;
 
-	if (!cfs_rq)
+	if (cfs_rq->tg == &root_task_group)
 		return;
 
 	now = rq_of(cfs_rq)->clock;
@@ -830,9 +830,6 @@ static void update_cfs_shares(struct cfs_rq *cfs_rq, long weight_delta)
 	struct sched_entity *se;
 	long shares;
 
-	if (!cfs_rq)
-		return;
-
 	tg = cfs_rq->tg;
 	se = tg->se[cpu_of(rq_of(cfs_rq))];
 	if (!se)