JBD2: debug code cleanup.

Mostly stolen from akpm's JBD cleanup patch.

- use `#ifdef foo' instead of `#if defined(foo)'

- Make journal_enable_debug __read_mostly just for the heck of it

- Make jbd_debugfs_dir and jbd_debug static

- debugfs_remove(NULL) is legal: remove unneeded tests

- remove unnecessary empty loops

Signed-off-by: Jose R. Santos <jrs@us.ibm.com>
Cc: <linux-ext4@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

fs/jbd2/journal.c

@@ -1864,16 +1864,14 @@ void jbd2_journal_put_journal_head(struct journal_head *jh)
 /*
  * debugfs tunables
  */
-#if defined(CONFIG_JBD2_DEBUG)
-u8 jbd2_journal_enable_debug;
+#ifdef CONFIG_JBD2_DEBUG
+u8 jbd2_journal_enable_debug __read_mostly;
 EXPORT_SYMBOL(jbd2_journal_enable_debug);
-#endif
-
-#if defined(CONFIG_JBD2_DEBUG) && defined(CONFIG_DEBUG_FS)
 
 #define JBD2_DEBUG_NAME "jbd2-debug"
 
-struct dentry *jbd2_debugfs_dir, *jbd2_debug;
+static struct dentry *jbd2_debugfs_dir;
+static struct dentry *jbd2_debug;
 
 static void __init jbd2_create_debugfs_entry(void)
 {
@@ -1886,24 +1884,18 @@ static void __init jbd2_create_debugfs_entry(void)
 
 static void __exit jbd2_remove_debugfs_entry(void)
 {
-	if (jbd2_debug)
-		debugfs_remove(jbd2_debug);
-	if (jbd2_debugfs_dir)
-		debugfs_remove(jbd2_debugfs_dir);
+	debugfs_remove(jbd2_debug);
+	debugfs_remove(jbd2_debugfs_dir);
 }
 
 #else
 
 static void __init jbd2_create_debugfs_entry(void)
 {
-	do {
-	} while (0);
 }
 
 static void __exit jbd2_remove_debugfs_entry(void)
 {
-	do {
-	} while (0);
 }
 
 #endif