Commit 39f3ec8e authored by Johannes Weiner's avatar Johannes Weiner Committed by Andrew Morton
Browse files

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: default avatarJohannes Weiner <hannes@cmpxchg.org>
Reviewed-by: default avatarNhat Pham <nphamcs@gmail.com>
Cc: Chengming Zhou <zhouchengming@bytedance.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent a984649b

mm/zswap.c

+47 −47
Original line number Diff line number Diff line
@@ -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 @@ static void shrink_worker(struct work_struct *w) 
	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

**********************************/