[PATCH 1/3] f2fs: make module init/exit match their sequence

[Youling Tang <youling.tang@linux.dev>]

From: Youling Tang <tangyouling@kylinos.cn>

Use init_sequence to ensure that modules init and exit are in sequence
and to simplify the code.

Signed-off-by: Youling Tang <tangyouling@kylinos.cn>
---
 fs/f2fs/debug.c |   3 +-
 fs/f2fs/f2fs.h  |   4 +-
 fs/f2fs/super.c | 210 ++++++++++++++++++++++++------------------------
 3 files changed, 107 insertions(+), 110 deletions(-)

diff --git a/fs/f2fs/debug.c b/fs/f2fs/debug.c
index 8b0e1e71b667..c08ecf807066 100644
--- a/fs/f2fs/debug.c
+++ b/fs/f2fs/debug.c
@@ -727,7 +727,7 @@ void f2fs_destroy_stats(struct f2fs_sb_info *sbi)
 	kfree(si);
 }
 
-void __init f2fs_create_root_stats(void)
+int __init f2fs_create_root_stats(void)
 {
 #ifdef CONFIG_DEBUG_FS
 	f2fs_debugfs_root = debugfs_create_dir("f2fs", NULL);
@@ -735,6 +735,7 @@ void __init f2fs_create_root_stats(void)
 	debugfs_create_file("status", 0444, f2fs_debugfs_root, NULL,
 			    &stat_fops);
 #endif
+	return 0;
 }
 
 void f2fs_destroy_root_stats(void)
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 1974b6aff397..d546bd301565 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -4086,7 +4086,7 @@ static inline struct f2fs_stat_info *F2FS_STAT(struct f2fs_sb_info *sbi)
 
 int f2fs_build_stats(struct f2fs_sb_info *sbi);
 void f2fs_destroy_stats(struct f2fs_sb_info *sbi);
-void __init f2fs_create_root_stats(void);
+int __init f2fs_create_root_stats(void);
 void f2fs_destroy_root_stats(void);
 void f2fs_update_sit_info(struct f2fs_sb_info *sbi);
 #else
@@ -4128,7 +4128,7 @@ void f2fs_update_sit_info(struct f2fs_sb_info *sbi);
 
 static inline int f2fs_build_stats(struct f2fs_sb_info *sbi) { return 0; }
 static inline void f2fs_destroy_stats(struct f2fs_sb_info *sbi) { }
-static inline void __init f2fs_create_root_stats(void) { }
+static inline int __init f2fs_create_root_stats(void) { }
 static inline void f2fs_destroy_root_stats(void) { }
 static inline void f2fs_update_sit_info(struct f2fs_sb_info *sbi) {}
 #endif
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 1f1b3647a998..19509942b837 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -4940,120 +4940,116 @@ static void destroy_inodecache(void)
 	kmem_cache_destroy(f2fs_inode_cachep);
 }
 
-static int __init init_f2fs_fs(void)
+static int register_f2fs(void)
 {
-	int err;
+	return register_filesystem(&f2fs_fs_type);
+}
 
-	err = init_inodecache();
-	if (err)
-		goto fail;
-	err = f2fs_create_node_manager_caches();
-	if (err)
-		goto free_inodecache;
-	err = f2fs_create_segment_manager_caches();
-	if (err)
-		goto free_node_manager_caches;
-	err = f2fs_create_checkpoint_caches();
-	if (err)
-		goto free_segment_manager_caches;
-	err = f2fs_create_recovery_cache();
-	if (err)
-		goto free_checkpoint_caches;
-	err = f2fs_create_extent_cache();
-	if (err)
-		goto free_recovery_cache;
-	err = f2fs_create_garbage_collection_cache();
-	if (err)
-		goto free_extent_cache;
-	err = f2fs_init_sysfs();
-	if (err)
-		goto free_garbage_collection_cache;
-	err = f2fs_init_shrinker();
-	if (err)
-		goto free_sysfs;
-	err = register_filesystem(&f2fs_fs_type);
-	if (err)
-		goto free_shrinker;
-	f2fs_create_root_stats();
-	err = f2fs_init_post_read_processing();
-	if (err)
-		goto free_root_stats;
-	err = f2fs_init_iostat_processing();
-	if (err)
-		goto free_post_read;
-	err = f2fs_init_bio_entry_cache();
-	if (err)
-		goto free_iostat;
-	err = f2fs_init_bioset();
-	if (err)
-		goto free_bio_entry_cache;
-	err = f2fs_init_compress_mempool();
-	if (err)
-		goto free_bioset;
-	err = f2fs_init_compress_cache();
-	if (err)
-		goto free_compress_mempool;
-	err = f2fs_create_casefold_cache();
-	if (err)
-		goto free_compress_cache;
-	return 0;
-free_compress_cache:
-	f2fs_destroy_compress_cache();
-free_compress_mempool:
-	f2fs_destroy_compress_mempool();
-free_bioset:
-	f2fs_destroy_bioset();
-free_bio_entry_cache:
-	f2fs_destroy_bio_entry_cache();
-free_iostat:
-	f2fs_destroy_iostat_processing();
-free_post_read:
-	f2fs_destroy_post_read_processing();
-free_root_stats:
-	f2fs_destroy_root_stats();
+static void unregister_f2fs(void)
+{
 	unregister_filesystem(&f2fs_fs_type);
-free_shrinker:
-	f2fs_exit_shrinker();
-free_sysfs:
-	f2fs_exit_sysfs();
-free_garbage_collection_cache:
-	f2fs_destroy_garbage_collection_cache();
-free_extent_cache:
-	f2fs_destroy_extent_cache();
-free_recovery_cache:
-	f2fs_destroy_recovery_cache();
-free_checkpoint_caches:
-	f2fs_destroy_checkpoint_caches();
-free_segment_manager_caches:
-	f2fs_destroy_segment_manager_caches();
-free_node_manager_caches:
-	f2fs_destroy_node_manager_caches();
-free_inodecache:
-	destroy_inodecache();
-fail:
-	return err;
+}
+
+/* Helper structure for long init/exit functions. */
+struct init_sequence {
+	int (*init_func)(void);
+	/* Can be NULL if the init_func doesn't need cleanup. */
+	void (*exit_func)(void);
+};
+
+static const struct init_sequence mod_init_seq[] = {
+	{
+		.init_func = init_inodecache,
+		.exit_func = destroy_inodecache,
+	}, {
+		.init_func = f2fs_create_node_manager_caches,
+		.exit_func = f2fs_destroy_node_manager_caches,
+	}, {
+		.init_func = f2fs_create_segment_manager_caches,
+		.exit_func = f2fs_destroy_segment_manager_caches,
+	}, {
+		.init_func = f2fs_create_checkpoint_caches,
+		.exit_func = f2fs_destroy_checkpoint_caches,
+	}, {
+		.init_func = f2fs_create_recovery_cache,
+		.exit_func = f2fs_destroy_recovery_cache,
+	}, {
+		.init_func = f2fs_create_extent_cache,
+		.exit_func = f2fs_destroy_extent_cache,
+	}, {
+		.init_func = f2fs_create_garbage_collection_cache,
+		.exit_func = f2fs_destroy_garbage_collection_cache,
+	}, {
+		.init_func = f2fs_init_sysfs,
+		.exit_func = f2fs_exit_sysfs,
+	}, {
+		.init_func = f2fs_init_shrinker,
+		.exit_func = f2fs_exit_shrinker,
+	}, {
+		.init_func = register_f2fs,
+		.exit_func = unregister_f2fs,
+	}, {
+		.init_func = f2fs_create_root_stats,
+		.exit_func = f2fs_destroy_root_stats,
+	}, {
+		.init_func = f2fs_init_post_read_processing,
+		.exit_func = f2fs_destroy_post_read_processing,
+	}, {
+		.init_func = f2fs_init_iostat_processing,
+		.exit_func = f2fs_destroy_iostat_processing,
+	}, {
+		.init_func = f2fs_init_bio_entry_cache,
+		.exit_func = f2fs_destroy_bio_entry_cache,
+	}, {
+		.init_func = f2fs_init_bioset,
+		.exit_func = f2fs_destroy_bioset,
+	}, {
+		.init_func = f2fs_init_compress_mempool,
+		.exit_func = f2fs_destroy_compress_mempool,
+	}, {
+		.init_func = f2fs_init_compress_cache,
+		.exit_func = f2fs_destroy_compress_cache,
+	}, {
+		.init_func = f2fs_create_casefold_cache,
+		.exit_func = f2fs_destroy_casefold_cache,
+	}
+};
+
+static bool mod_init_result[ARRAY_SIZE(mod_init_seq)];
+
+static __always_inline void f2fs_exit_f2fs_fs(void)
+{
+	int i;
+
+	for (i = ARRAY_SIZE(mod_init_seq) - 1; i >= 0; i--) {
+		if (!mod_init_result[i])
+			continue;
+		if (mod_init_seq[i].exit_func)
+			mod_init_seq[i].exit_func();
+		mod_init_result[i] = false;
+	}
 }
 
 static void __exit exit_f2fs_fs(void)
 {
-	f2fs_destroy_casefold_cache();
-	f2fs_destroy_compress_cache();
-	f2fs_destroy_compress_mempool();
-	f2fs_destroy_bioset();
-	f2fs_destroy_bio_entry_cache();
-	f2fs_destroy_iostat_processing();
-	f2fs_destroy_post_read_processing();
-	f2fs_destroy_root_stats();
-	unregister_filesystem(&f2fs_fs_type);
-	f2fs_exit_shrinker();
-	f2fs_exit_sysfs();
-	f2fs_destroy_garbage_collection_cache();
-	f2fs_destroy_extent_cache();
-	f2fs_destroy_recovery_cache();
-	f2fs_destroy_checkpoint_caches();
-	f2fs_destroy_segment_manager_caches();
-	f2fs_destroy_node_manager_caches();
-	destroy_inodecache();
+	f2fs_exit_f2fs_fs();
+}
+
+static int __init init_f2fs_fs(void)
+{
+	int ret;
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(mod_init_seq); i++) {
+		BUG_ON(mod_init_result[i]);
+		ret = mod_init_seq[i].init_func();
+		if (ret < 0) {
+			f2fs_exit_f2fs_fs();
+			return ret;
+		}
+		mod_init_result[i] = true;
+	}
+	return 0;
 }
 
 module_init(init_f2fs_fs)
-- 
2.34.1