btrfs: separate out the extent io init function

We are moving extent_io_tree into it's on file, so separate out the
extent_state init stuff from extent_io_tree_init().
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/extent_io.c

@@ -200,19 +200,23 @@ static int __must_check flush_write_bio(struct extent_page_data *epd)
 	return ret;
 }
 
-int __init extent_io_init(void)
+int __init extent_state_cache_init(void)
 {
 	extent_state_cache = kmem_cache_create("btrfs_extent_state",
 			sizeof(struct extent_state), 0,
 			SLAB_MEM_SPREAD, NULL);
 	if (!extent_state_cache)
 		return -ENOMEM;
+	return 0;
+}
 
+int __init extent_io_init(void)
+{
 	extent_buffer_cache = kmem_cache_create("btrfs_extent_buffer",
 			sizeof(struct extent_buffer), 0,
 			SLAB_MEM_SPREAD, NULL);
 	if (!extent_buffer_cache)
-		goto free_state_cache;
+		return -ENOMEM;
 
 	if (bioset_init(&btrfs_bioset, BIO_POOL_SIZE,
 			offsetof(struct btrfs_io_bio, bio),
@@ -230,24 +234,24 @@ int __init extent_io_init(void)
 free_buffer_cache:
 	kmem_cache_destroy(extent_buffer_cache);
 	extent_buffer_cache = NULL;
+	return -ENOMEM;
+}
 
-free_state_cache:
+void __cold extent_state_cache_exit(void)
+{
+	btrfs_extent_state_leak_debug_check();
 	kmem_cache_destroy(extent_state_cache);
-	extent_state_cache = NULL;
-	return -ENOMEM;
 }
 
 void __cold extent_io_exit(void)
 {
 	btrfs_extent_buffer_leak_debug_check();
-	btrfs_extent_state_leak_debug_check();
 
 	/*
 	 * Make sure all delayed rcu free are flushed before we
 	 * destroy caches.
 	 */
 	rcu_barrier();
-	kmem_cache_destroy(extent_state_cache);
 	kmem_cache_destroy(extent_buffer_cache);
 	bioset_exit(&btrfs_bioset);
 }

fs/btrfs/extent_io.h

@@ -556,4 +556,6 @@ bool find_lock_delalloc_range(struct inode *inode,
 struct extent_buffer *alloc_test_extent_buffer(struct btrfs_fs_info *fs_info,
 					       u64 start);
 
+int __init extent_state_cache_init(void);
+void __cold extent_state_cache_exit(void);
 #endif

fs/btrfs/super.c

@@ -2360,10 +2360,14 @@ static int __init init_btrfs_fs(void)
 	if (err)
 		goto free_cachep;
 
-	err = extent_map_init();
+	err = extent_state_cache_init();
 	if (err)
 		goto free_extent_io;
 
+	err = extent_map_init();
+	if (err)
+		goto free_extent_state_cache;
+
 	err = ordered_data_init();
 	if (err)
 		goto free_extent_map;
@@ -2422,6 +2426,8 @@ static int __init init_btrfs_fs(void)
 	ordered_data_exit();
 free_extent_map:
 	extent_map_exit();
+free_extent_state_cache:
+	extent_state_cache_exit();
 free_extent_io:
 	extent_io_exit();
 free_cachep:
@@ -2442,6 +2448,7 @@ static void __exit exit_btrfs_fs(void)
 	btrfs_prelim_ref_exit();
 	ordered_data_exit();
 	extent_map_exit();
+	extent_state_cache_exit();
 	extent_io_exit();
 	btrfs_interface_exit();
 	btrfs_end_io_wq_exit();