sysfs: reimplement symlink using sysfs_dirent tree
sysfs symlink is implemented by referencing dentry and kobject from
sysfs_dirent - symlink entry references kobject, dentry is used to
walk the tree. This complicates object lifetimes rules and is
dangerous - for example, there is no way to tell to which module the
target of a symlink belongs and referencing that kobject can make it
linger after the module is gone.
This patch reimplements symlink using only sysfs_dirent tree. sd for
a symlink points and holds reference to the target sysfs_dirent and
all walking is done using sysfs_dirent tree. Simpler and safer.
Please read the following message for more info.
http://article.gmane.org/gmane.linux.kernel/510293
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c
index e9fddcc..2a94dc3 100644
--- a/fs/sysfs/dir.c
+++ b/fs/sysfs/dir.c
@@ -54,7 +54,7 @@
parent_sd = sd->s_parent;
if (sd->s_type & SYSFS_KOBJ_LINK)
- kobject_put(sd->s_elem.symlink.target_kobj);
+ sysfs_put(sd->s_elem.symlink.target_sd);
if (sd->s_type & SYSFS_COPY_NAME)
kfree(sd->s_name);
kfree(sd->s_iattr);