Hello Coly!
2018-05-22 9:10 GMT+02:00 Coly Li <colyli@xxxxxxx>:
> 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.
I applied the patch to master and cherry-picked to my 4.16 branch
(cleaning up the conflicts).
I'm not sure if I did the conflict in closure_debug right but as I
compiled with CONFIG_DEBUG_FS=n, I think it doesn't matter for my
configuration.
The resulting patch works, currently running it while writing this message.
So you can add my tested-by if it makes sense.
Regards,
Kai
> Signed-off-by: Coly Li <colyli@xxxxxxx>
> Suggested-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> Cc: Kai Krakow <kai@xxxxxxxxxxx>
> Cc: Kent Overstreet <kent.overstreet@xxxxxxxxx>
> ---
> drivers/md/bcache/bcache.h | 2 +-
> drivers/md/bcache/closure.c | 13 +++++++++----
> drivers/md/bcache/closure.h | 4 ++--
> drivers/md/bcache/debug.c | 11 ++++++-----
> drivers/md/bcache/super.c | 4 +++-
> 5 files changed, 21 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/md/bcache/bcache.h b/drivers/md/bcache/bcache.h
> index 3a0cfb237af9..bee6251d2d40 100644
> --- a/drivers/md/bcache/bcache.h
> +++ b/drivers/md/bcache/bcache.h
> @@ -995,7 +995,7 @@ 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 *);
> 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 d030ce3025a6..57f8f5aeee55 100644
> --- a/drivers/md/bcache/debug.c
> +++ b/drivers/md/bcache/debug.c
> @@ -248,11 +248,12 @@ 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 3dea06b41d43..2b62671e4d83 100644
> --- a/drivers/md/bcache/super.c
> +++ b/drivers/md/bcache/super.c
> @@ -2301,10 +2301,12 @@ static int __init bcache_init(void)
> if (!(bcache_wq = alloc_workqueue("bcache", WQ_MEM_RECLAIM, 0)) ||
> !(bcache_kobj = kobject_create_and_add("bcache", fs_kobj)) ||
> 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();
> --
> 2.16.3
>
