From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wr0-f195.google.com ([209.85.128.195]:46872 "EHLO mail-wr0-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752644AbeEVT4E (ORCPT ); Tue, 22 May 2018 15:56:04 -0400 Received: by mail-wr0-f195.google.com with SMTP id x9-v6so19447577wrl.13 for ; Tue, 22 May 2018 12:56:03 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <20180522071011.8950-1-colyli@suse.de> References: <20180522071011.8950-1-colyli@suse.de> From: Kai Krakow Date: Tue, 22 May 2018 21:56:02 +0200 Message-ID: Subject: Re: [PATCH] bcache: do not check return value of debugfs_create_dir() To: Coly Li Cc: linux-bcache@vger.kernel.org, linux-block@vger.kernel.org, Kent Overstreet Content-Type: text/plain; charset="UTF-8" Sender: linux-block-owner@vger.kernel.org List-Id: linux-block@vger.kernel.org Hello Coly! 2018-05-22 9:10 GMT+02:00 Coly Li : > 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 > Suggested-by: Greg Kroah-Hartman > Cc: Kai Krakow > Cc: Kent Overstreet > --- > 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 >