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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Coly Li <colyli@suse.de>,
        "Massimo B." <massimo.b@gmx.net>, Kai Krakow <kai@kaishome.de>,
        Kent Overstreet <kent.overstreet@gmail.com>,
        Jens Axboe <axboe@kernel.dk>
Subject: [PATCH 4.16 044/110] bcache: return 0 from bch_debug_init() if CONFIG_DEBUG_FS=n
Date:   Mon, 21 May 2018 23:11:41 +0200
Message-Id: <20180521210508.025108599@linuxfoundation.org>
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4.16-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Coly Li <colyli@suse.de>

commit 1c1a2ee1b53b006754073eefc65d2b2cedb5264b upstream.

Commit 539d39eb2708 ("bcache: fix wrong return value in bch_debug_init()")
returns the return value of debugfs_create_dir() to bcache_init(). When
CONFIG_DEBUG_FS=n, bch_debug_init() always returns 1 and makes
bcache_init() failedi.

This patch makes bch_debug_init() always returns 0 if CONFIG_DEBUG_FS=n,
so bcache can continue to work for the kernels which don't have debugfs
enanbled.

Changelog:
v4: Add Acked-by from Kent Overstreet.
v3: Use IS_ENABLED(CONFIG_DEBUG_FS) to replace #ifdef DEBUG_FS.
v2: Remove a warning information
v1: Initial version.

Fixes: Commit 539d39eb2708 ("bcache: fix wrong return value in bch_debug_init()")
Cc: stable@vger.kernel.org
Signed-off-by: Coly Li <colyli@suse.de>
Reported-by: Massimo B. <massimo.b@gmx.net>
Reported-by: Kai Krakow <kai@kaishome.de>
Tested-by: Kai Krakow <kai@kaishome.de>
Acked-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Kai Krakow <kai@kaishome.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/md/bcache/debug.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/drivers/md/bcache/debug.c
+++ b/drivers/md/bcache/debug.c
@@ -251,6 +251,9 @@ void bch_debug_exit(void)
 
 int __init bch_debug_init(struct kobject *kobj)
 {
+	if (!IS_ENABLED(CONFIG_DEBUG_FS))
+		return 0;
+
 	debug = debugfs_create_dir("bcache", NULL);
 
 	return IS_ERR_OR_NULL(debug);