mm/list_lru.c: pass struct list_lru_node* as an argument to __list_lru_walk_one()

__list_lru_walk_one() is invoked with struct list_lru *lru, int nid as
the first two argument.  Those two are only used to retrieve struct
list_lru_node.  Since this is already done by the caller of the function
for the locking, we can pass struct list_lru_node* directly and avoid
the dance around it.

Link: http://lkml.kernel.org/r/20180716111921.5365-4-bigeasy@linutronix.deSigned-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/list_lru.c

@@ -209,12 +209,11 @@ unsigned long list_lru_count_node(struct list_lru *lru, int nid)
 EXPORT_SYMBOL_GPL(list_lru_count_node);
 
 static unsigned long
-__list_lru_walk_one(struct list_lru *lru, int nid, int memcg_idx,
+__list_lru_walk_one(struct list_lru_node *nlru, int memcg_idx,
 		    list_lru_walk_cb isolate, void *cb_arg,
 		    unsigned long *nr_to_walk)
 {
 
-	struct list_lru_node *nlru = &lru->node[nid];
 	struct list_lru_one *l;
 	struct list_head *item, *n;
 	unsigned long isolated = 0;
@@ -276,8 +275,8 @@ list_lru_walk_one(struct list_lru *lru, int nid, struct mem_cgroup *memcg,
 	unsigned long ret;
 
 	spin_lock(&nlru->lock);
-	ret = __list_lru_walk_one(lru, nid, memcg_cache_id(memcg),
-				  isolate, cb_arg, nr_to_walk);
+	ret = __list_lru_walk_one(nlru, memcg_cache_id(memcg), isolate, cb_arg,
+				  nr_to_walk);
 	spin_unlock(&nlru->lock);
 	return ret;
 }
@@ -297,8 +296,9 @@ unsigned long list_lru_walk_node(struct list_lru *lru, int nid,
 			struct list_lru_node *nlru = &lru->node[nid];
 
 			spin_lock(&nlru->lock);
-			isolated += __list_lru_walk_one(lru, nid, memcg_idx,
-						isolate, cb_arg, nr_to_walk);
+			isolated += __list_lru_walk_one(nlru, memcg_idx,
+							isolate, cb_arg,
+							nr_to_walk);
 			spin_unlock(&nlru->lock);
 
 			if (*nr_to_walk <= 0)