The patch below was submitted to be applied to the 4.18-stable tree.

I fail to see how this patch meets the stable kernel rules as found at Documentation/process/stable-kernel-rules.rst.

I could be totally wrong, and if so, please respond to stable@vger.kernel.org and let me know why this patch should be applied. Otherwise, it is now dropped from my patch queues, never to be seen again.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 78ac2107176baa0daf65b0fb8e561d2ed14c83ca Mon Sep 17 00:00:00 2001

From: Coly Li colyli@suse.de Date: Thu, 9 Aug 2018 15:48:42 +0800 Subject: [PATCH] bcache: do not check return value of debugfs_create_dir()

Greg KH suggests that normal code should not care about debugfs. Therefore no matter successful or failed of debugfs_create_dir() execution, it is unncessary to check its return value.

There are two functions called debugfs_create_dir() and check the return value, which are bch_debug_init() and closure_debug_init(). This patch changes these two functions from int to void type, and ignore return values of debugfs_create_dir().

This patch does not fix exact bug, just makes things work as they should.

Signed-off-by: Coly Li colyli@suse.de Suggested-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Cc: stable@vger.kernel.org Cc: Kai Krakow kai@kaishome.de Cc: Kent Overstreet kent.overstreet@gmail.com Signed-off-by: Jens Axboe axboe@kernel.dk

diff --git a/drivers/md/bcache/bcache.h b/drivers/md/bcache/bcache.h index 872ef4d67711..0a3e82b0876d 100644 --- a/drivers/md/bcache/bcache.h +++ b/drivers/md/bcache/bcache.h @@ -1001,7 +1001,7 @@ void bch_open_buckets_free(struct cache_set *); int bch_cache_allocator_start(struct cache *ca);

void bch_debug_exit(void); -int bch_debug_init(struct kobject *); +void bch_debug_init(struct kobject *kobj); void bch_request_exit(void); int bch_request_init(void);

diff --git a/drivers/md/bcache/closure.c b/drivers/md/bcache/closure.c index 0e14969182c6..618253683d40 100644 --- a/drivers/md/bcache/closure.c +++ b/drivers/md/bcache/closure.c @@ -199,11 +199,16 @@ static const struct file_operations debug_ops = { .release = single_release };

-int __init closure_debug_init(void) +void __init closure_debug_init(void) { - closure_debug = debugfs_create_file("closures", - 0400, bcache_debug, NULL, &debug_ops); - return IS_ERR_OR_NULL(closure_debug); + if (!IS_ERR_OR_NULL(bcache_debug)) + /* + * it is unnecessary to check return value of + * debugfs_create_file(), we should not care + * about this. + */ + closure_debug = debugfs_create_file( + "closures", 0400, bcache_debug, NULL, &debug_ops); } #endif

diff --git a/drivers/md/bcache/closure.h b/drivers/md/bcache/closure.h index 71427eb5fdae..7c2c5bc7c88b 100644 --- a/drivers/md/bcache/closure.h +++ b/drivers/md/bcache/closure.h @@ -186,13 +186,13 @@ static inline void closure_sync(struct closure *cl)

#ifdef CONFIG_BCACHE_CLOSURES_DEBUG

-int closure_debug_init(void); +void closure_debug_init(void); void closure_debug_create(struct closure *cl); void closure_debug_destroy(struct closure *cl);

#else

-static inline int closure_debug_init(void) { return 0; } +static inline void closure_debug_init(void) {} static inline void closure_debug_create(struct closure *cl) {} static inline void closure_debug_destroy(struct closure *cl) {}

diff --git a/drivers/md/bcache/debug.c b/drivers/md/bcache/debug.c index 04d146711950..12034c07257b 100644 --- a/drivers/md/bcache/debug.c +++ b/drivers/md/bcache/debug.c @@ -252,11 +252,12 @@ void bch_debug_exit(void) debugfs_remove_recursive(bcache_debug); }

-int __init bch_debug_init(struct kobject *kobj) +void __init bch_debug_init(struct kobject *kobj) { - if (!IS_ENABLED(CONFIG_DEBUG_FS)) - return 0; - + /* + * it is unnecessary to check return value of + * debugfs_create_file(), we should not care + * about this. + */ bcache_debug = debugfs_create_dir("bcache", NULL); - return IS_ERR_OR_NULL(bcache_debug); } diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c index e0a92104ca23..c7ffa6ef3f82 100644 --- a/drivers/md/bcache/super.c +++ b/drivers/md/bcache/super.c @@ -2345,10 +2345,12 @@ static int __init bcache_init(void) goto err;

if (bch_request_init() || - bch_debug_init(bcache_kobj) || closure_debug_init() || sysfs_create_files(bcache_kobj, files)) goto err;

+ bch_debug_init(bcache_kobj); + closure_debug_init(); + return 0; err: bcache_exit();