failslab: simplify debugfs initialization

Now cleanup_fault_attr_dentries() recursively removes a directory, So we
can simplify the error handling in the initialization code and no need
to hold dentry structs for each debugfs file.
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Matt Mackall <mpm@selenic.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/failslab.c

@@ -5,10 +5,6 @@ static struct {
 	struct fault_attr attr;
 	u32 ignore_gfp_wait;
 	int cache_filter;
-#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
-	struct dentry *ignore_gfp_wait_file;
-	struct dentry *cache_filter_file;
-#endif
 } failslab = {
 	.attr = FAULT_ATTR_INITIALIZER,
 	.ignore_gfp_wait = 1,
@@ -39,31 +35,24 @@ __setup("failslab=", setup_failslab);
 static int __init failslab_debugfs_init(void)
 {
 	mode_t mode = S_IFREG | S_IRUSR | S_IWUSR;
-	struct dentry *dir;
 	int err;
 
 	err = init_fault_attr_dentries(&failslab.attr, "failslab");
 	if (err)
 		return err;
-	dir = failslab.attr.dir;
-
-	failslab.ignore_gfp_wait_file =
-		debugfs_create_bool("ignore-gfp-wait", mode, dir,
-				      &failslab.ignore_gfp_wait);
 
-	failslab.cache_filter_file =
-		debugfs_create_bool("cache-filter", mode, dir,
-				      &failslab.cache_filter);
+	if (!debugfs_create_bool("ignore-gfp-wait", mode, failslab.attr.dir,
+				&failslab.ignore_gfp_wait))
+		goto fail;
+	if (!debugfs_create_bool("cache-filter", mode, failslab.attr.dir,
+				&failslab.cache_filter))
+		goto fail;
 
-	if (!failslab.ignore_gfp_wait_file ||
-	    !failslab.cache_filter_file) {
-		err = -ENOMEM;
-		debugfs_remove(failslab.cache_filter_file);
-		debugfs_remove(failslab.ignore_gfp_wait_file);
-		cleanup_fault_attr_dentries(&failslab.attr);
-	}
+	return 0;
+fail:
+	cleanup_fault_attr_dentries(&failslab.attr);
 
-	return err;
+	return -ENOMEM;
 }
 
 late_initcall(failslab_debugfs_init);