[PATCH 01/20] sysfs: Implement sysfs_rename_link

Eric W. Biederman
2009-05-21T00:28:34Z

From: Eric W. Biederman <ebiederm@xmission.com>

Because of rename ordering problems we occassionally give false
warnings about invalid sysfs operations, so implement a helper
function for this common sysfs idiom.

This is a stripped down version of an earlier patch that
also added sysfs_delete_link.

Cc: Benjamin Thery <benjamin.thery@bull.net>
Cc: Daniel Lezcano <dlezcano@fr.ibm.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Eric W. Biederman <ebiederm@aristanetworks.com>
---
fs/sysfs/symlink.c | 16 ++++++++++++++++
include/linux/sysfs.h | 9 +++++++++
2 files changed, 25 insertions(+), 0 deletions(-)

diff --git a/fs/sysfs/symlink.c b/fs/sysfs/symlink.c
index a3ba217..11c4da5 100644
--- a/fs/sysfs/symlink.c
+++ b/fs/sysfs/symlink.c
@@ -122,6 +122,22 @@ void sysfs_remove_link(struct kobject * kobj, const char * name)
sysfs_hash_and_remove(parent_sd, name);
}

+/**
+ * sysfs_rename_link - rename symlink in object's directory.
+ * @kobj: object we're acting for.
+ * @targ: object we're pointing to.
+ * @old: previous name of the symlink.
+ * @new: new name of the symlink.
+ *
+ * A helper function for the common rename symlink idiom.
+ */
+int sysfs_rename_link(struct kobject *kobj, struct kobject *targ,
+ const char *old, const char *new)
+{
+ sysfs_remove_link(kobj, old);
+ return sysfs_create_link(kobj, targ, new);
+}
+
static int sysfs_get_target_path(struct sysfs_dirent *parent_sd,
struct sysfs_dirent *target_sd, char *path)
{
diff --git a/include/linux/sysfs.h b/include/linux/sysfs.h
index 9d68fed..18c8e70 100644
--- a/include/linux/sysfs.h
+++ b/include/linux/sysfs.h
@@ -109,6 +109,9 @@ int __must_check sysfs_create_link_nowarn(struct kobject *kobj,
const char *name);
void sysfs_remove_link(struct kobject *kobj, const char *name);

+int sysfs_rename_link(struct kobject *kobj, struct kobject *target,
+ const char *old_name, const char *new_name);
+
int __must_check sysfs_create_group(struct kobject *kobj,
const struct attribute_group *grp);
int sysfs_update_group(struct kobject *kobj,
@@ -202,6 +205,12 @@ static inline void sysfs_remove_link(struct kobject *kobj, const char *name)
{
}

+static inline int sysfs_rename_link(struct kobject *k, struct kobject *t,
+ const char *old_name, const char *new_name)
+{
+ return 0;
+}
+
static inline int sysfs_create_group(struct kobject *kobj,
const struct attribute_group *grp)
{
--
1.6.1.2.350.g88cc