linux-kernel - [PATCH] erofs: don't access kobject object members directly

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Date:   Wed, 12 Apr 2023 11:11:10 +0800
From:   Yangtao Li <frank.li@...o.com>
To:     Gao Xiang <xiang@...nel.org>, Chao Yu <chao@...nel.org>,
        Yue Hu <huyue2@...lpad.com>,
        Jeffle Xu <jefflexu@...ux.alibaba.com>
Cc:     Yangtao Li <frank.li@...o.com>, linux-erofs@...ts.ozlabs.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH] erofs: don't access kobject object members directly

It is better not to directly access the internal members of the
kobject object, especially kobject_init_and_add() may failure.
BTW remove unnecessary kobject_del(), kobject_put() actually covers
kobject removal automatically, which is single stage removal.

Signed-off-by: Yangtao Li <frank.li@...o.com>
---
 fs/erofs/internal.h | 1 +
 fs/erofs/sysfs.c    | 4 ++--
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
index f675050af2bb..f364b1e9b35b 100644
--- a/fs/erofs/internal.h
+++ b/fs/erofs/internal.h
@@ -177,6 +177,7 @@ struct erofs_sb_info {
 	/* sysfs support */
 	struct kobject s_kobj;		/* /sys/fs/erofs/<devname> */
 	struct completion s_kobj_unregister;
+	bool sysfs_registered;
 
 	/* fscache support */
 	struct fscache_volume *volume;
diff --git a/fs/erofs/sysfs.c b/fs/erofs/sysfs.c
index 435e515c0792..c38018d3c442 100644
--- a/fs/erofs/sysfs.c
+++ b/fs/erofs/sysfs.c
@@ -228,6 +228,7 @@ int erofs_register_sysfs(struct super_block *sb)
 	kfree(str);
 	if (err)
 		goto put_sb_kobj;
+	sbi->sysfs_registered = true;
 	return 0;
 
 put_sb_kobj:
@@ -240,8 +241,7 @@ void erofs_unregister_sysfs(struct super_block *sb)
 {
 	struct erofs_sb_info *sbi = EROFS_SB(sb);
 
-	if (sbi->s_kobj.state_in_sysfs) {
-		kobject_del(&sbi->s_kobj);
+	if (sbi->sysfs_registered) {
 		kobject_put(&sbi->s_kobj);
 		wait_for_completion(&sbi->s_kobj_unregister);
 	}
-- 
2.35.1