mm: zswap: function ordering: public lru api

The zswap entry section sits awkwardly in the middle of LRU-related
functions. Group the external LRU API functions first.

Link: https://lkml.kernel.org/r/20240130014208.565554-15-hannes@cmpxchg.orgSigned-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Nhat Pham <nphamcs@gmail.com>
Cc: Chengming Zhou <zhouchengming@bytedance.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/zswap.c

@@ -746,6 +746,10 @@ static int zswap_enabled_param_set(const char *val,
 	return ret;
 }
 
+/*********************************
+* lru functions
+**********************************/
+
 /* should be called under RCU */
 #ifdef CONFIG_MEMCG
 static inline struct mem_cgroup *mem_cgroup_from_entry(struct zswap_entry *entry)
@@ -764,6 +768,21 @@ static inline int entry_to_nid(struct zswap_entry *entry)
 	return page_to_nid(virt_to_page(entry));
 }
 
+void zswap_lruvec_state_init(struct lruvec *lruvec)
+{
+	atomic_long_set(&lruvec->zswap_lruvec_state.nr_zswap_protected, 0);
+}
+
+void zswap_folio_swapin(struct folio *folio)
+{
+	struct lruvec *lruvec;
+
+	if (folio) {
+		lruvec = folio_lruvec(folio);
+		atomic_long_inc(&lruvec->zswap_lruvec_state.nr_zswap_protected);
+	}
+}
+
 void zswap_memcg_offline_cleanup(struct mem_cgroup *memcg)
 {
 	struct zswap_pool *pool;
@@ -798,23 +817,6 @@ static void zswap_entry_cache_free(struct zswap_entry *entry)
 	kmem_cache_free(zswap_entry_cache, entry);
 }
 
-/*********************************
-* zswap lruvec functions
-**********************************/
-void zswap_lruvec_state_init(struct lruvec *lruvec)
-{
-	atomic_long_set(&lruvec->zswap_lruvec_state.nr_zswap_protected, 0);
-}
-
-void zswap_folio_swapin(struct folio *folio)
-{
-	struct lruvec *lruvec;
-
-	VM_WARN_ON_ONCE(!folio_test_locked(folio));
-	lruvec = folio_lruvec(folio);
-	atomic_long_inc(&lruvec->zswap_lruvec_state.nr_zswap_protected);
-}
-
 /*********************************
 * lru functions
 **********************************/