Add two functions sysfs_create_mount_point and sysfs_remove_mount_point
that hang a permanently empty directory off of a kobject or remove a
permanently emptpy directory hanging from a kobject. Export these new
functions so modular filesystems can use them.
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
---
fs/sysfs/dir.c | 34 ++++++++++++++++++++++++++++++++++
include/linux/sysfs.h | 16 ++++++++++++++++
2 files changed, 50 insertions(+)
diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c
index 0b45ff42f374..94374e435025 100644
--- a/fs/sysfs/dir.c
+++ b/fs/sysfs/dir.c
@@ -121,3 +121,37 @@ int sysfs_move_dir_ns(struct kobject *kobj, struct kobject *new_parent_kobj,
return kernfs_rename_ns(kn, new_parent, kn->name, new_ns);
}
+
+/**
+ * sysfs_create_mount_point - create an always empty directory
+ * @parent_kobj: kobject that will contain this always empty directory
+ * @name: The name of the always empty directory to add
+ */
+int sysfs_create_mount_point(struct kobject *parent_kobj, const char *name)
+{
+ struct kernfs_node *kn, *parent = parent_kobj->sd;
+
+ kn = kernfs_create_empty_dir(parent, name);
+ if (IS_ERR(kn)) {
+ if (PTR_ERR(kn) == -EEXIST)
+ sysfs_warn_dup(parent, name);
+ return PTR_ERR(kn);
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(sysfs_create_mount_point);
+
+/**
+ * sysfs_remove_mount_point - remove an always empty directory.
+ * @parent_kobj: kobject that will contain this always empty directory
+ * @name: The name of the always empty directory to remove
+ *
+ */
+void sysfs_remove_mount_point(struct kobject *parent_kobj, const char *name)
+{
+ struct kernfs_node *parent = parent_kobj->sd;
+
+ kernfs_remove_by_name_ns(parent, name, NULL);
+}
+EXPORT_SYMBOL_GPL(sysfs_remove_mount_point);
diff --git a/include/linux/sysfs.h b/include/linux/sysfs.h
index 99382c0df17e..3e7e41acc451 100644
--- a/include/linux/sysfs.h
+++ b/include/linux/sysfs.h
@@ -210,6 +210,10 @@ int __must_check sysfs_rename_dir_ns(struct kobject *kobj, const char *new_name,
int __must_check sysfs_move_dir_ns(struct kobject *kobj,
struct kobject *new_parent_kobj,
const void *new_ns);
+int __must_check sysfs_create_mount_point(struct kobject *parent_kobj,
+ const char *name);
+void sysfs_remove_mount_point(struct kobject *parent_kobj,
+ const char *name);
int __must_check sysfs_create_file_ns(struct kobject *kobj,
const struct attribute *attr,
@@ -298,6 +302,18 @@ static inline int sysfs_move_dir_ns(struct kobject *kobj,
return 0;
}
+static inline int sysfs_create_mount_point(struct kobject *parent_kobj,
+ const char *name)
+{
+ return 0;
+}
+
+static inline void sysfs_remove_mount_point(struct kobject *parent_kobj,
+ const char *name)
+{
+ return 0;
+}
+
static inline int sysfs_create_file_ns(struct kobject *kobj,
const struct attribute *attr,
const void *ns)
--
2.2.1
--
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