mm: zswap: function ordering: zswap_pools

Move the operations against the global zswap_pools list (current pool,
last, find) to the pool section.

Link: https://lkml.kernel.org/r/20240130014208.565554-13-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

@@ -517,6 +517,79 @@ static void zswap_pool_put(struct zswap_pool *pool)
 	kref_put(&pool->kref, __zswap_pool_empty);
 }
 
+static struct zswap_pool *__zswap_pool_current(void)
+{
+	struct zswap_pool *pool;
+
+	pool = list_first_or_null_rcu(&zswap_pools, typeof(*pool), list);
+	WARN_ONCE(!pool && zswap_has_pool,
+		  "%s: no page storage pool!\n", __func__);
+
+	return pool;
+}
+
+static struct zswap_pool *zswap_pool_current(void)
+{
+	assert_spin_locked(&zswap_pools_lock);
+
+	return __zswap_pool_current();
+}
+
+static struct zswap_pool *zswap_pool_current_get(void)
+{
+	struct zswap_pool *pool;
+
+	rcu_read_lock();
+
+	pool = __zswap_pool_current();
+	if (!zswap_pool_get(pool))
+		pool = NULL;
+
+	rcu_read_unlock();
+
+	return pool;
+}
+
+static struct zswap_pool *zswap_pool_last_get(void)
+{
+	struct zswap_pool *pool, *last = NULL;
+
+	rcu_read_lock();
+
+	list_for_each_entry_rcu(pool, &zswap_pools, list)
+		last = pool;
+	WARN_ONCE(!last && zswap_has_pool,
+		  "%s: no page storage pool!\n", __func__);
+	if (!zswap_pool_get(last))
+		last = NULL;
+
+	rcu_read_unlock();
+
+	return last;
+}
+
+/* type and compressor must be null-terminated */
+static struct zswap_pool *zswap_pool_find_get(char *type, char *compressor)
+{
+	struct zswap_pool *pool;
+
+	assert_spin_locked(&zswap_pools_lock);
+
+	list_for_each_entry_rcu(pool, &zswap_pools, list) {
+		if (strcmp(pool->tfm_name, compressor))
+			continue;
+		/* all zpools share the same type */
+		if (strcmp(zpool_get_type(pool->zpools[0]), type))
+			continue;
+		/* if we can't get it, it's about to be destroyed */
+		if (!zswap_pool_get(pool))
+			continue;
+		return pool;
+	}
+
+	return NULL;
+}
+
 /* should be called under RCU */
 #ifdef CONFIG_MEMCG
 static inline struct mem_cgroup *mem_cgroup_from_entry(struct zswap_entry *entry)
@@ -937,83 +1010,6 @@ static int zswap_cpu_comp_dead(unsigned int cpu, struct hlist_node *node)
 	return 0;
 }
 
-/*********************************
-* pool functions
-**********************************/
-
-static struct zswap_pool *__zswap_pool_current(void)
-{
-	struct zswap_pool *pool;
-
-	pool = list_first_or_null_rcu(&zswap_pools, typeof(*pool), list);
-	WARN_ONCE(!pool && zswap_has_pool,
-		  "%s: no page storage pool!\n", __func__);
-
-	return pool;
-}
-
-static struct zswap_pool *zswap_pool_current(void)
-{
-	assert_spin_locked(&zswap_pools_lock);
-
-	return __zswap_pool_current();
-}
-
-static struct zswap_pool *zswap_pool_current_get(void)
-{
-	struct zswap_pool *pool;
-
-	rcu_read_lock();
-
-	pool = __zswap_pool_current();
-	if (!zswap_pool_get(pool))
-		pool = NULL;
-
-	rcu_read_unlock();
-
-	return pool;
-}
-
-static struct zswap_pool *zswap_pool_last_get(void)
-{
-	struct zswap_pool *pool, *last = NULL;
-
-	rcu_read_lock();
-
-	list_for_each_entry_rcu(pool, &zswap_pools, list)
-		last = pool;
-	WARN_ONCE(!last && zswap_has_pool,
-		  "%s: no page storage pool!\n", __func__);
-	if (!zswap_pool_get(last))
-		last = NULL;
-
-	rcu_read_unlock();
-
-	return last;
-}
-
-/* type and compressor must be null-terminated */
-static struct zswap_pool *zswap_pool_find_get(char *type, char *compressor)
-{
-	struct zswap_pool *pool;
-
-	assert_spin_locked(&zswap_pools_lock);
-
-	list_for_each_entry_rcu(pool, &zswap_pools, list) {
-		if (strcmp(pool->tfm_name, compressor))
-			continue;
-		/* all zpools share the same type */
-		if (strcmp(zpool_get_type(pool->zpools[0]), type))
-			continue;
-		/* if we can't get it, it's about to be destroyed */
-		if (!zswap_pool_get(pool))
-			continue;
-		return pool;
-	}
-
-	return NULL;
-}
-
 static enum lru_status shrink_memcg_cb(struct list_head *item, struct list_lru_one *l,
 				       spinlock_t *lock, void *arg)
 {