Hey Greg!
2018-05-20 9:49 GMT+02:00 <gregkh@xxxxxxxxxxxxxxxxxxx>:
>
> The patch below does not apply to the 4.16-stable tree.
> If someone wants it applied there, or to any other stable or longterm
> tree, then please email the backport, including the original git commit
> id to <stable@xxxxxxxxxxxxxxx>.
The v1 version applied for me but it shows a compiler warning. I
didn't try the newer version yet.
I could prepare a back-ported version.
Regards,
Kai
> ------------------ original commit in Linus's tree ------------------
>
> From 1c1a2ee1b53b006754073eefc65d2b2cedb5264b Mon Sep 17 00:00:00 2001
> From: Coly Li <colyli@xxxxxxx>
> Date: Thu, 17 May 2018 23:33:26 +0800
> Subject: [PATCH] bcache: return 0 from bch_debug_init() if CONFIG_DEBUG_FS=n
>
> 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@xxxxxxxxxxxxxxx
> Signed-off-by: Coly Li <colyli@xxxxxxx>
> Reported-by: Massimo B. <massimo.b@xxxxxxx>
> Reported-by: Kai Krakow <kai@xxxxxxxxxxx>
> Tested-by: Kai Krakow <kai@xxxxxxxxxxx>
> Acked-by: Kent Overstreet <kent.overstreet@xxxxxxxxx>
> Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
>
> diff --git a/drivers/md/bcache/debug.c b/drivers/md/bcache/debug.c
> index 4e63c6f6c04d..d030ce3025a6 100644
> --- a/drivers/md/bcache/debug.c
> +++ b/drivers/md/bcache/debug.c
> @@ -250,7 +250,9 @@ void bch_debug_exit(void)
>
> int __init bch_debug_init(struct kobject *kobj)
> {
> - bcache_debug = debugfs_create_dir("bcache", NULL);
> + if (!IS_ENABLED(CONFIG_DEBUG_FS))
> + return 0;
>
> + bcache_debug = debugfs_create_dir("bcache", NULL);
> return IS_ERR_OR_NULL(bcache_debug);
> }
>
