[PATCH 2/4] btrfs: Use module_subinit{_noexit} and module_subeixt helper macros

[Youling Tang]

From: Youling Tang <tangyoul...@kylinos.cn>

Use module_{subinit, subinit} to ensure that modules init and exit
are in sequence and to simplify the code.

Signed-off-by: Youling Tang <tangyoul...@kylinos.cn>
---
 fs/btrfs/super.c | 123 +++++++++--------------------------------------
 1 file changed, 23 insertions(+), 100 deletions(-)

diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 08d33cb372fb..620493b3f319 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -2490,115 +2490,38 @@ static void unregister_btrfs(void)
        unregister_filesystem(&btrfs_fs_type);
 }
 
-/* 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 = btrfs_props_init,
-               .exit_func = NULL,
-       }, {
-               .init_func = btrfs_init_sysfs,
-               .exit_func = btrfs_exit_sysfs,
-       }, {
-               .init_func = btrfs_init_compress,
-               .exit_func = btrfs_exit_compress,
-       }, {
-               .init_func = btrfs_init_cachep,
-               .exit_func = btrfs_destroy_cachep,
-       }, {
-               .init_func = btrfs_init_dio,
-               .exit_func = btrfs_destroy_dio,
-       }, {
-               .init_func = btrfs_transaction_init,
-               .exit_func = btrfs_transaction_exit,
-       }, {
-               .init_func = btrfs_ctree_init,
-               .exit_func = btrfs_ctree_exit,
-       }, {
-               .init_func = btrfs_free_space_init,
-               .exit_func = btrfs_free_space_exit,
-       }, {
-               .init_func = extent_state_init_cachep,
-               .exit_func = extent_state_free_cachep,
-       }, {
-               .init_func = extent_buffer_init_cachep,
-               .exit_func = extent_buffer_free_cachep,
-       }, {
-               .init_func = btrfs_bioset_init,
-               .exit_func = btrfs_bioset_exit,
-       }, {
-               .init_func = extent_map_init,
-               .exit_func = extent_map_exit,
-       }, {
-               .init_func = ordered_data_init,
-               .exit_func = ordered_data_exit,
-       }, {
-               .init_func = btrfs_delayed_inode_init,
-               .exit_func = btrfs_delayed_inode_exit,
-       }, {
-               .init_func = btrfs_auto_defrag_init,
-               .exit_func = btrfs_auto_defrag_exit,
-       }, {
-               .init_func = btrfs_delayed_ref_init,
-               .exit_func = btrfs_delayed_ref_exit,
-       }, {
-               .init_func = btrfs_prelim_ref_init,
-               .exit_func = btrfs_prelim_ref_exit,
-       }, {
-               .init_func = btrfs_interface_init,
-               .exit_func = btrfs_interface_exit,
-       }, {
-               .init_func = btrfs_print_mod_info,
-               .exit_func = NULL,
-       }, {
-               .init_func = btrfs_run_sanity_tests,
-               .exit_func = NULL,
-       }, {
-               .init_func = register_btrfs,
-               .exit_func = unregister_btrfs,
-       }
-};
-
-static bool mod_init_result[ARRAY_SIZE(mod_init_seq)];
-
-static __always_inline void btrfs_exit_btrfs_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 struct subexitcall_rollback rollback;
 
 static void __exit exit_btrfs_fs(void)
 {
-       btrfs_exit_btrfs_fs();
+       module_subexit(&rollback);
        btrfs_cleanup_fs_uuids();
 }
 
 static int __init init_btrfs_fs(void)
 {
-       int ret;
-       int i;
+       module_subinit_noexit(btrfs_props_init, &rollback);
+       module_subinit(btrfs_init_sysfs, btrfs_exit_sysfs, &rollback);
+       module_subinit(btrfs_init_compress, btrfs_exit_compress, &rollback);
+       module_subinit(btrfs_init_cachep, btrfs_destroy_cachep, &rollback);
+       module_subinit(btrfs_init_dio, btrfs_destroy_dio, &rollback);
+       module_subinit(btrfs_transaction_init, btrfs_transaction_exit, 
&rollback);
+       module_subinit(btrfs_ctree_init, btrfs_ctree_exit, &rollback);
+       module_subinit(btrfs_free_space_init, btrfs_free_space_exit, &rollback);
+       module_subinit(extent_state_init_cachep, extent_state_free_cachep, 
&rollback);
+       module_subinit(extent_buffer_init_cachep, extent_buffer_free_cachep, 
&rollback);
+       module_subinit(btrfs_bioset_init, btrfs_bioset_exit, &rollback);
+       module_subinit(extent_map_init, extent_map_exit, &rollback);
+       module_subinit(ordered_data_init, ordered_data_exit, &rollback);
+       module_subinit(btrfs_delayed_inode_init, btrfs_delayed_inode_exit, 
&rollback);
+       module_subinit(btrfs_auto_defrag_init, btrfs_auto_defrag_exit, 
&rollback);
+       module_subinit(btrfs_delayed_ref_init, btrfs_delayed_ref_exit, 
&rollback);
+       module_subinit(btrfs_prelim_ref_init, btrfs_prelim_ref_exit, &rollback);
+       module_subinit(btrfs_interface_init, btrfs_interface_exit, &rollback);
+       module_subinit_noexit(btrfs_print_mod_info, &rollback);
+       module_subinit_noexit(btrfs_run_sanity_tests, &rollback);
+       module_subinit(register_btrfs, unregister_btrfs, &rollback);
 
-       for (i = 0; i < ARRAY_SIZE(mod_init_seq); i++) {
-               ASSERT(!mod_init_result[i]);
-               ret = mod_init_seq[i].init_func();
-               if (ret < 0) {
-                       btrfs_exit_btrfs_fs();
-                       return ret;
-               }
-               mod_init_result[i] = true;
-       }
        return 0;
 }
 
-- 
2.34.1