linux-kernel - [PATCH] backing-dev: no need to check return value of debugfs

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Date:   Tue, 22 Jan 2019 16:21:07 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Anders Roxell <anders.roxell@...aro.org>,
        Arnd Bergmann <arnd@...db.de>,
        Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
        Michal Hocko <mhocko@...e.com>, linux-mm@...ck.org
Subject: [PATCH] backing-dev: no need to check return value of debugfs_create functions

When calling debugfs functions, there is no need to ever check the
return value.  The function can work or not, but the code logic should
never do something different based on this.

And as the return value does not matter at all, no need to save the
dentry in struct backing_dev_info, so delete it.

Cc: Andrew Morton <akpm@...ux-foundation.org>
Cc: Anders Roxell <anders.roxell@...aro.org>
Cc: Arnd Bergmann <arnd@...db.de>
Cc: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
Cc: Michal Hocko <mhocko@...e.com>
Cc: linux-mm@...ck.org
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 include/linux/backing-dev-defs.h |  1 -
 mm/backing-dev.c                 | 24 +++++-------------------
 2 files changed, 5 insertions(+), 20 deletions(-)

diff --git a/include/linux/backing-dev-defs.h b/include/linux/backing-dev-defs.h
index c31157135598..7f64d813580b 100644
--- a/include/linux/backing-dev-defs.h
+++ b/include/linux/backing-dev-defs.h
@@ -202,7 +202,6 @@ struct backing_dev_info {
 
 #ifdef CONFIG_DEBUG_FS
 	struct dentry *debug_dir;
-	struct dentry *debug_stats;
 #endif
 };
 
diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index 8a8bb8796c6c..85ef344a9c67 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -102,39 +102,25 @@ static int bdi_debug_stats_show(struct seq_file *m, void *v)
 }
 DEFINE_SHOW_ATTRIBUTE(bdi_debug_stats);
 
-static int bdi_debug_register(struct backing_dev_info *bdi, const char *name)
+static void bdi_debug_register(struct backing_dev_info *bdi, const char *name)
 {
-	if (!bdi_debug_root)
-		return -ENOMEM;
-
 	bdi->debug_dir = debugfs_create_dir(name, bdi_debug_root);
-	if (!bdi->debug_dir)
-		return -ENOMEM;
-
-	bdi->debug_stats = debugfs_create_file("stats", 0444, bdi->debug_dir,
-					       bdi, &bdi_debug_stats_fops);
-	if (!bdi->debug_stats) {
-		debugfs_remove(bdi->debug_dir);
-		bdi->debug_dir = NULL;
-		return -ENOMEM;
-	}
 
-	return 0;
+	debugfs_create_file("stats", 0444, bdi->debug_dir, bdi,
+			    &bdi_debug_stats_fops);
 }
 
 static void bdi_debug_unregister(struct backing_dev_info *bdi)
 {
-	debugfs_remove(bdi->debug_stats);
-	debugfs_remove(bdi->debug_dir);
+	debugfs_remove_recursive(bdi->debug_dir);
 }
 #else
 static inline void bdi_debug_init(void)
 {
 }
-static inline int bdi_debug_register(struct backing_dev_info *bdi,
+static inline void bdi_debug_register(struct backing_dev_info *bdi,
 				      const char *name)
 {
-	return 0;
 }
 static inline void bdi_debug_unregister(struct backing_dev_info *bdi)
 {
-- 
2.20.1