5 files changed, 46 insertions, 36 deletions

diff --git a/fs/sysfs/Kconfig b/fs/sysfs/Kconfig
index 8c41feacbac5..b2756014508c 100644
--- a/fs/sysfs/Kconfig
+++ b/fs/sysfs/Kconfig
@@ -1,6 +1,7 @@
 config SYSFS
 	bool "sysfs file system support" if EXPERT
 	default y
+	select KERNFS
 	help
 	The sysfs filesystem is a virtual filesystem that the kernel uses to
 	export internal kernel objects, their attributes, and their
diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c
index ee0d761c3179..0b45ff42f374 100644
--- a/fs/sysfs/dir.c
+++ b/fs/sysfs/dir.c
@@ -19,39 +19,18 @@
 
 DEFINE_SPINLOCK(sysfs_symlink_target_lock);
 
-/**
- *	sysfs_pathname - return full path to sysfs dirent
- *	@kn: kernfs_node whose path we want
- *	@path: caller allocated buffer of size PATH_MAX
- *
- *	Gives the name "/" to the sysfs_root entry; any path returned
- *	is relative to wherever sysfs is mounted.
- */
-static char *sysfs_pathname(struct kernfs_node *kn, char *path)
-{
-	if (kn->parent) {
-		sysfs_pathname(kn->parent, path);
-		strlcat(path, "/", PATH_MAX);
-	}
-	strlcat(path, kn->name, PATH_MAX);
-	return path;
-}
-
 void sysfs_warn_dup(struct kernfs_node *parent, const char *name)
 {
-	char *path;
+	char *buf, *path = NULL;
 
-	path = kzalloc(PATH_MAX, GFP_KERNEL);
-	if (path) {
-		sysfs_pathname(parent, path);
-		strlcat(path, "/", PATH_MAX);
-		strlcat(path, name, PATH_MAX);
-	}
+	buf = kzalloc(PATH_MAX, GFP_KERNEL);
+	if (buf)
+		path = kernfs_path(parent, buf, PATH_MAX);
 
-	WARN(1, KERN_WARNING "sysfs: cannot create duplicate filename '%s'\n",
-	     path ? path : name);
+	WARN(1, KERN_WARNING "sysfs: cannot create duplicate filename '%s/%s'\n",
+	     path, name);
 
-	kfree(path);
+	kfree(buf);
 }
 
 /**
@@ -122,9 +101,13 @@ void sysfs_remove_dir(struct kobject *kobj)
 int sysfs_rename_dir_ns(struct kobject *kobj, const char *new_name,
 			const void *new_ns)
 {
-	struct kernfs_node *parent = kobj->sd->parent;
+	struct kernfs_node *parent;
+	int ret;
 
-	return kernfs_rename_ns(kobj->sd, parent, new_name, new_ns);
+	parent = kernfs_get_parent(kobj->sd);
+	ret = kernfs_rename_ns(kobj->sd, parent, new_name, new_ns);
+	kernfs_put(parent);
+	return ret;
 }
 
 int sysfs_move_dir_ns(struct kobject *kobj, struct kobject *new_parent_kobj,
@@ -133,7 +116,6 @@ int sysfs_move_dir_ns(struct kobject *kobj, struct kobject *new_parent_kobj,
 	struct kernfs_node *kn = kobj->sd;
 	struct kernfs_node *new_parent;
 
-	BUG_ON(!kn->parent);
 	new_parent = new_parent_kobj && new_parent_kobj->sd ?
 		new_parent_kobj->sd : sysfs_root_kn;
 
diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c
index 810cf6e613e5..1b8b91b67fdb 100644
--- a/fs/sysfs/file.c
+++ b/fs/sysfs/file.c
@@ -372,6 +372,29 @@ void sysfs_remove_file_ns(struct kobject *kobj, const struct attribute *attr,
 }
 EXPORT_SYMBOL_GPL(sysfs_remove_file_ns);
 
+/**
+ * sysfs_remove_file_self - remove an object attribute from its own method
+ * @kobj: object we're acting for
+ * @attr: attribute descriptor
+ *
+ * See kernfs_remove_self() for details.
+ */
+bool sysfs_remove_file_self(struct kobject *kobj, const struct attribute *attr)
+{
+	struct kernfs_node *parent = kobj->sd;
+	struct kernfs_node *kn;
+	bool ret;
+
+	kn = kernfs_find_and_get(parent, attr->name);
+	if (WARN_ON_ONCE(!kn))
+		return false;
+
+	ret = kernfs_remove_self(kn);
+
+	kernfs_put(kn);
+	return ret;
+}
+
 void sysfs_remove_files(struct kobject *kobj, const struct attribute **ptr)
 {
 	int i;
diff --git a/fs/sysfs/group.c b/fs/sysfs/group.c
index 6b579387c67a..aa0406895b53 100644
--- a/fs/sysfs/group.c
+++ b/fs/sysfs/group.c
@@ -70,8 +70,11 @@ static int create_files(struct kernfs_node *parent, struct kobject *kobj,
 	if (grp->bin_attrs) {
 		for (bin_attr = grp->bin_attrs; *bin_attr; bin_attr++) {
 			if (update)
-				sysfs_remove_bin_file(kobj, *bin_attr);
-			error = sysfs_create_bin_file(kobj, *bin_attr);
+				kernfs_remove_by_name(parent,
+						(*bin_attr)->attr.name);
+			error = sysfs_add_file_mode_ns(parent,
+					&(*bin_attr)->attr, true,
+					(*bin_attr)->attr.mode, NULL);
 			if (error)
 				break;
 		}
diff --git a/fs/sysfs/mount.c b/fs/sysfs/mount.c
index 6211230814fd..a66ad6196f59 100644
--- a/fs/sysfs/mount.c
+++ b/fs/sysfs/mount.c
@@ -27,6 +27,7 @@ static struct dentry *sysfs_mount(struct file_system_type *fs_type,
 {
 	struct dentry *root;
 	void *ns;
+	bool new_sb;
 
 	if (!(flags & MS_KERNMOUNT)) {
 		if (!capable(CAP_SYS_ADMIN) && !fs_fully_visible(fs_type))
@@ -37,8 +38,8 @@ static struct dentry *sysfs_mount(struct file_system_type *fs_type,
 	}
 
 	ns = kobj_ns_grab_current(KOBJ_NS_TYPE_NET);
-	root = kernfs_mount_ns(fs_type, flags, sysfs_root, ns);
-	if (IS_ERR(root))
+	root = kernfs_mount_ns(fs_type, flags, sysfs_root, &new_sb, ns);
+	if (IS_ERR(root) || !new_sb)
 		kobj_ns_drop(KOBJ_NS_TYPE_NET, ns);
 	return root;
 }
@@ -62,7 +63,7 @@ int __init sysfs_init(void)
 {
 	int err;
 
-	sysfs_root = kernfs_create_root(NULL, NULL);
+	sysfs_root = kernfs_create_root(NULL, 0, NULL);
 	if (IS_ERR(sysfs_root))
 		return PTR_ERR(sysfs_root);