mm: zswap: function ordering: pool refcounting

Move pool refcounting functions into the pool section. First the
destroy functions, then the get and put which uses them.

__zswap_pool_empty() has an upward reference to the global
zswap_pools, to sanity check it's not the currently active pool that's
being freed. That gets the forward decl for zswap_pool_current().

This puts the get and put function above all callers, so kill the
forward decls as well.

Link: https://lkml.kernel.org/r/20240130014208.565554-12-hannes@cmpxchg.org
Signed-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>

diff --git a/mm/zswap.c b/mm/zswap.c
index 5947eeb8d799c4274f96cf453ed30c527564c3fc..6f4e1c22a0dec2f4a063f3dc88218fd234f1787a 100644 (file)
--- a/mm/zswap.c
+++ b/mm/zswap.c
@@ -278,8 +278,6 @@ static inline struct zswap_tree *swap_zswap_tree(swp_entry_t swp)
 
 static int zswap_writeback_entry(struct zswap_entry *entry,
                                 swp_entry_t swpentry);
-static int zswap_pool_get(struct zswap_pool *pool);
-static void zswap_pool_put(struct zswap_pool *pool);
 
 static bool zswap_is_full(void)
 {
@@ -472,6 +470,53 @@ static void zswap_pool_destroy(struct zswap_pool *pool)
        kfree(pool);
 }
 
+static void __zswap_pool_release(struct work_struct *work)
+{
+       struct zswap_pool *pool = container_of(work, typeof(*pool),
+                                               release_work);
+
+       synchronize_rcu();
+
+       /* nobody should have been able to get a kref... */
+       WARN_ON(kref_get_unless_zero(&pool->kref));
+
+       /* pool is now off zswap_pools list and has no references. */
+       zswap_pool_destroy(pool);
+}
+
+static struct zswap_pool *zswap_pool_current(void);
+
+static void __zswap_pool_empty(struct kref *kref)
+{
+       struct zswap_pool *pool;
+
+       pool = container_of(kref, typeof(*pool), kref);
+
+       spin_lock(&zswap_pools_lock);
+
+       WARN_ON(pool == zswap_pool_current());
+
+       list_del_rcu(&pool->list);
+
+       INIT_WORK(&pool->release_work, __zswap_pool_release);
+       schedule_work(&pool->release_work);
+
+       spin_unlock(&zswap_pools_lock);
+}
+
+static int __must_check zswap_pool_get(struct zswap_pool *pool)
+{
+       if (!pool)
+               return 0;
+
+       return kref_get_unless_zero(&pool->kref);
+}
+
+static void zswap_pool_put(struct zswap_pool *pool)
+{
+       kref_put(&pool->kref, __zswap_pool_empty);
+}
+
 /* should be called under RCU */
 #ifdef CONFIG_MEMCG
 static inline struct mem_cgroup *mem_cgroup_from_entry(struct zswap_entry *entry)
@@ -1121,51 +1166,6 @@ resched:
        zswap_pool_put(pool);
 }
 
-static int __must_check zswap_pool_get(struct zswap_pool *pool)
-{
-       if (!pool)
-               return 0;
-
-       return kref_get_unless_zero(&pool->kref);
-}
-
-static void __zswap_pool_release(struct work_struct *work)
-{
-       struct zswap_pool *pool = container_of(work, typeof(*pool),
-                                               release_work);
-
-       synchronize_rcu();
-
-       /* nobody should have been able to get a kref... */
-       WARN_ON(kref_get_unless_zero(&pool->kref));
-
-       /* pool is now off zswap_pools list and has no references. */
-       zswap_pool_destroy(pool);
-}
-
-static void __zswap_pool_empty(struct kref *kref)
-{
-       struct zswap_pool *pool;
-
-       pool = container_of(kref, typeof(*pool), kref);
-
-       spin_lock(&zswap_pools_lock);
-
-       WARN_ON(pool == zswap_pool_current());
-
-       list_del_rcu(&pool->list);
-
-       INIT_WORK(&pool->release_work, __zswap_pool_release);
-       schedule_work(&pool->release_work);
-
-       spin_unlock(&zswap_pools_lock);
-}
-
-static void zswap_pool_put(struct zswap_pool *pool)
-{
-       kref_put(&pool->kref, __zswap_pool_empty);
-}
-
 /*********************************
 * param callbacks
 **********************************/