sysfs: switch to ->s_d_op and ->d_release()

a) ->d_iput() is wrong here - what we do to inode is completely usual, it's
dentry->d_fsdata that we want to drop.  Just use ->d_release().

b) switch to ->s_d_op - no need to play with d_set_d_op()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/sysfs/dir.c

@@ -300,7 +300,7 @@ void release_sysfs_dirent(struct sysfs_dirent * sd)
 static int sysfs_dentry_delete(const struct dentry *dentry)
 {
 	struct sysfs_dirent *sd = dentry->d_fsdata;
-	return !!(sd->s_flags & SYSFS_FLAG_REMOVED);
+	return !(sd && !(sd->s_flags & SYSFS_FLAG_REMOVED));
 }
 
 static int sysfs_dentry_revalidate(struct dentry *dentry, unsigned int flags)
@@ -355,18 +355,15 @@ static int sysfs_dentry_revalidate(struct dentry *dentry, unsigned int flags)
 	return 0;
 }
 
-static void sysfs_dentry_iput(struct dentry *dentry, struct inode *inode)
+static void sysfs_dentry_release(struct dentry *dentry)
 {
-	struct sysfs_dirent * sd = dentry->d_fsdata;
-
-	sysfs_put(sd);
-	iput(inode);
+	sysfs_put(dentry->d_fsdata);
 }
 
-static const struct dentry_operations sysfs_dentry_ops = {
+const struct dentry_operations sysfs_dentry_ops = {
 	.d_revalidate	= sysfs_dentry_revalidate,
 	.d_delete	= sysfs_dentry_delete,
-	.d_iput		= sysfs_dentry_iput,
+	.d_release	= sysfs_dentry_release,
 };
 
 struct sysfs_dirent *sysfs_new_dirent(const char *name, umode_t mode, int type)
@@ -786,6 +783,7 @@ static struct dentry * sysfs_lookup(struct inode *dir, struct dentry *dentry,
 		ret = ERR_PTR(-ENOENT);
 		goto out_unlock;
 	}
+	dentry->d_fsdata = sysfs_get(sd);
 
 	/* attach dentry and inode */
 	inode = sysfs_get_inode(dir->i_sb, sd);
@@ -797,8 +795,6 @@ static struct dentry * sysfs_lookup(struct inode *dir, struct dentry *dentry,
 	/* instantiate and hash dentry */
 	ret = d_find_alias(inode);
 	if (!ret) {
-		d_set_d_op(dentry, &sysfs_dentry_ops);
-		dentry->d_fsdata = sysfs_get(sd);
 		d_add(dentry, inode);
 	} else {
 		d_move(ret, dentry);

fs/sysfs/mount.c

@@ -68,6 +68,7 @@ static int sysfs_fill_super(struct super_block *sb, void *data, int silent)
 	}
 	root->d_fsdata = &sysfs_root;
 	sb->s_root = root;
+	sb->s_d_op = &sysfs_dentry_ops;
 	return 0;
 }
 

fs/sysfs/sysfs.h

@@ -157,6 +157,7 @@ extern struct kmem_cache *sysfs_dir_cachep;
  */
 extern struct mutex sysfs_mutex;
 extern spinlock_t sysfs_assoc_lock;
+extern const struct dentry_operations sysfs_dentry_ops;
 
 extern const struct file_operations sysfs_dir_operations;
 extern const struct inode_operations sysfs_dir_inode_operations;