sysfs: remove ktype->namespace() invocations in symlink code

There's no reason for sysfs to be calling ktype->namespace().  It is
backwards, obfuscates what's going on and unnecessarily tangles two
separate layers.

There are two places where symlink code calls ktype->namespace().

* sysfs_do_create_link_sd() calls it to find out the namespace tag of
  the target directory.  Unless symlinking races with cross-namespace
  renaming, this equals @target_sd->s_ns.

* sysfs_rename_link() uses it to find out the new namespace to rename
  to and the new namespace can be different from the existing one.
  The function is renamed to sysfs_rename_link_ns() with an explicit
  @ns argument and the ktype->namespace() invocation is shifted to the
  device layer.

While this patch replaces ktype->namespace() invocation with the
recorded result in @target_sd, this shouldn't result in any behvior
difference.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Kay Sievers <kay@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 7 insertions, 9 deletions

diff --git a/fs/sysfs/symlink.c b/fs/sysfs/symlink.c
index 2dd4507..12d58ad 100644
--- a/fs/sysfs/symlink.c
+++ b/fs/sysfs/symlink.c
@@ -52,7 +52,7 @@ static int sysfs_do_create_link_sd(struct sysfs_dirent *parent_sd,
 
 	ns_type = sysfs_ns_type(parent_sd);
 	if (ns_type)
-		sd->s_ns = target->ktype->namespace(target);
+		sd->s_ns = target_sd->s_ns;
 	sd->s_symlink.target_sd = target_sd;
 	target_sd = NULL;	/* reference is now owned by the symlink */
 
@@ -181,19 +181,20 @@ void sysfs_remove_link(struct kobject *kobj, const char *name)
 EXPORT_SYMBOL_GPL(sysfs_remove_link);
 
 /**
- *	sysfs_rename_link - rename symlink in object's directory.
+ *	sysfs_rename_link_ns - 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.
+ *	@new_ns: new namespace 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)
+int sysfs_rename_link_ns(struct kobject *kobj, struct kobject *targ,
+			 const char *old, const char *new, const void *new_ns)
 {
 	struct sysfs_dirent *parent_sd, *sd = NULL;
-	const void *old_ns = NULL, *new_ns = NULL;
+	const void *old_ns = NULL;
 	int result;
 
 	if (!kobj)
@@ -215,16 +216,13 @@ int sysfs_rename_link(struct kobject *kobj, struct kobject *targ,
 	if (sd->s_symlink.target_sd->s_dir.kobj != targ)
 		goto out;
 
-	if (sysfs_ns_type(parent_sd))
-		new_ns = targ->ktype->namespace(targ);
-
 	result = sysfs_rename(sd, parent_sd, new_ns, new);
 
 out:
 	sysfs_put(sd);
 	return result;
 }
-EXPORT_SYMBOL_GPL(sysfs_rename_link);
+EXPORT_SYMBOL_GPL(sysfs_rename_link_ns);
 
 static int sysfs_get_target_path(struct sysfs_dirent *parent_sd,
 				 struct sysfs_dirent *target_sd, char *path)