nilfs2: cleanup multi kmem_cache_{create,destroy} code

This cleanup patch gives several improvements:

 - Moving all kmem_cache_{create_destroy} calls into one place, which removes
 some small function calls, cleans up error check code and clarify the logic.

 - Mark all initial code in __init section.

 - Remove some very obvious comments.

 - Adjust some declarations.

 - Fix some space-tab issues.

Signed-off-by: Li Hong <lihong.hi@gmail.com>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

1 files changed, 74 insertions, 60 deletions

diff --git a/fs/nilfs2/super.c b/fs/nilfs2/super.c
index 0b1758bf0726..5a08c82e7e25 100644
--- a/fs/nilfs2/super.c
+++ b/fs/nilfs2/super.c
@@ -67,6 +67,11 @@ MODULE_DESCRIPTION("A New Implementation of the Log-structured Filesystem "
                    "(NILFS)");
 MODULE_LICENSE("GPL");
 
+struct kmem_cache *nilfs_inode_cachep;
+struct kmem_cache *nilfs_transaction_cachep;
+struct kmem_cache *nilfs_segbuf_cachep;
+struct kmem_cache *nilfs_btree_path_cache;
+
 static int nilfs_remount(struct super_block *sb, int *flags, char *data);
 
 /**
@@ -129,7 +134,6 @@ void nilfs_warning(struct super_block *sb, const char *function,
         va_end(args);
 }
 
-static struct kmem_cache *nilfs_inode_cachep;
 
 struct inode *nilfs_alloc_inode_common(struct the_nilfs *nilfs)
 {
@@ -155,34 +159,6 @@ void nilfs_destroy_inode(struct inode *inode)
         kmem_cache_free(nilfs_inode_cachep, NILFS_I(inode));
 }
 
-static void init_once(void *obj)
-{
-        struct nilfs_inode_info *ii = obj;
-
-        INIT_LIST_HEAD(&ii->i_dirty);
-#ifdef CONFIG_NILFS_XATTR
-        init_rwsem(&ii->xattr_sem);
-#endif
-        nilfs_btnode_cache_init_once(&ii->i_btnode_cache);
-        ii->i_bmap = (struct nilfs_bmap *)&ii->i_bmap_union;
-        inode_init_once(&ii->vfs_inode);
-}
-
-static int nilfs_init_inode_cache(void)
-{
-        nilfs_inode_cachep = kmem_cache_create("nilfs2_inode_cache",
-                                               sizeof(struct nilfs_inode_info),
-                                               0, SLAB_RECLAIM_ACCOUNT,
-                                               init_once);
-
-        return (nilfs_inode_cachep == NULL) ? -ENOMEM : 0;
-}
-
-static inline void nilfs_destroy_inode_cache(void)
-{
-        kmem_cache_destroy(nilfs_inode_cachep);
-}
-
 static void nilfs_clear_inode(struct inode *inode)
 {
         struct nilfs_inode_info *ii = NILFS_I(inode);
@@ -1139,54 +1115,92 @@ struct file_system_type nilfs_fs_type = {
         .fs_flags = FS_REQUIRES_DEV,
 };
 
-static int __init init_nilfs_fs(void)
+static void nilfs_inode_init_once(void *obj)
 {
-        int err;
-
-        err = nilfs_init_inode_cache();
-        if (err)
-                goto failed;
+        struct nilfs_inode_info *ii = obj;
 
-        err = nilfs_init_transaction_cache();
-        if (err)
-                goto failed_inode_cache;
+        INIT_LIST_HEAD(&ii->i_dirty);
+#ifdef CONFIG_NILFS_XATTR
+        init_rwsem(&ii->xattr_sem);
+#endif
+        nilfs_btnode_cache_init_once(&ii->i_btnode_cache);
+        ii->i_bmap = (struct nilfs_bmap *)&ii->i_bmap_union;
+        inode_init_once(&ii->vfs_inode);
+}
 
-        err = nilfs_init_segbuf_cache();
-        if (err)
-                goto failed_transaction_cache;
+static void nilfs_segbuf_init_once(void *obj)
+{
+        memset(obj, 0, sizeof(struct nilfs_segment_buffer));
+}
 
-        err = nilfs_btree_path_cache_init();
-        if (err)
-                goto failed_segbuf_cache;
+static void nilfs_destroy_cachep(void)
+{
+         if (nilfs_inode_cachep)
+                kmem_cache_destroy(nilfs_inode_cachep);
+         if (nilfs_transaction_cachep)
+                kmem_cache_destroy(nilfs_transaction_cachep);
+         if (nilfs_segbuf_cachep)
+                kmem_cache_destroy(nilfs_segbuf_cachep);
+         if (nilfs_btree_path_cache)
+                kmem_cache_destroy(nilfs_btree_path_cache);
+}
 
-        err = register_filesystem(&nilfs_fs_type);
-        if (err)
-                goto failed_btree_path_cache;
+static int __init nilfs_init_cachep(void)
+{
+        nilfs_inode_cachep = kmem_cache_create("nilfs2_inode_cache",
+                        sizeof(struct nilfs_inode_info), 0,
+                        SLAB_RECLAIM_ACCOUNT, nilfs_inode_init_once);
+        if (!nilfs_inode_cachep)
+                goto fail;
+
+        nilfs_transaction_cachep = kmem_cache_create("nilfs2_transaction_cache",
+                        sizeof(struct nilfs_transaction_info), 0,
+                        SLAB_RECLAIM_ACCOUNT, NULL);
+        if (!nilfs_transaction_cachep)
+                goto fail;
+
+        nilfs_segbuf_cachep = kmem_cache_create("nilfs2_segbuf_cache",
+                        sizeof(struct nilfs_segment_buffer), 0,
+                        SLAB_RECLAIM_ACCOUNT, nilfs_segbuf_init_once);
+        if (!nilfs_segbuf_cachep)
+                goto fail;
+
+        nilfs_btree_path_cache = kmem_cache_create("nilfs2_btree_path_cache",
+                        sizeof(struct nilfs_btree_path) * NILFS_BTREE_LEVEL_MAX,
+                        0, 0, NULL);
+        if (!nilfs_btree_path_cache)
+                goto fail;
 
         return 0;
 
- failed_btree_path_cache:
-        nilfs_btree_path_cache_destroy();
+fail:
+        nilfs_destroy_cachep();
+        return -ENOMEM;
+}
+
+static int __init init_nilfs_fs(void)
+{
+        int err;
 
- failed_segbuf_cache:
-        nilfs_destroy_segbuf_cache();
+        err = nilfs_init_cachep();
+        if (err)
+                goto fail;
 
- failed_transaction_cache:
-        nilfs_destroy_transaction_cache();
+        err = register_filesystem(&nilfs_fs_type);
+        if (err)
+                goto free_cachep;
 
- failed_inode_cache:
-        nilfs_destroy_inode_cache();
+        return 0;
 
- failed:
+free_cachep:
+        nilfs_destroy_cachep();
+fail:
         return err;
 }
 
 static void __exit exit_nilfs_fs(void)
 {
-        nilfs_destroy_segbuf_cache();
-        nilfs_destroy_transaction_cache();
-        nilfs_destroy_inode_cache();
-        nilfs_btree_path_cache_destroy();
+        nilfs_destroy_cachep();
         unregister_filesystem(&nilfs_fs_type);
 }