Commit 4b30ee58 authored by Tejun Heo's avatar Tejun Heo Committed by Greg Kroah-Hartman
Browse files

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: default avatarTejun Heo <tj@kernel.org>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Kay Sievers <kay@vrfy.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent e34ff490

drivers/base/core.c

+5 −3
Original line number Diff line number Diff line
@@ -1881,6 +1881,7 @@ EXPORT_SYMBOL_GPL(device_destroy); 
 */

int device_rename(struct device *dev, const char *new_name)

{

	struct kobject *kobj = &dev->kobj;

	char *old_device_name = NULL;

	int error;
@@ -1898,13 +1899,14 @@ int device_rename(struct device *dev, const char *new_name) 
	}



	if (dev->class) {

		error = sysfs_rename_link(&dev->class->p->subsys.kobj,

			&dev->kobj, old_device_name, new_name);

		error = sysfs_rename_link_ns(&dev->class->p->subsys.kobj,

					     kobj, old_device_name,

					     new_name, kobject_namespace(kobj));

		if (error)

			goto out;

	}



	error = kobject_rename(&dev->kobj, new_name);

	error = kobject_rename(kobj, new_name);

	if (error)

		goto out;

fs/sysfs/symlink.c

+7 −9
Original line number Diff line number Diff line
@@ -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)

include/linux/sysfs.h

+12 −4
Original line number Diff line number Diff line
@@ -213,8 +213,9 @@ 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 sysfs_rename_link_ns(struct kobject *kobj, struct kobject *target,

			 const char *old_name, const char *new_name,

			 const void *new_ns);



void sysfs_delete_link(struct kobject *dir, struct kobject *targ,

			const char *name);
@@ -340,8 +341,9 @@ 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)

static inline int sysfs_rename_link_ns(struct kobject *k, struct kobject *t,

				       const char *old_name,

				       const char *new_name, const void *ns)

{

	return 0;

}
@@ -454,4 +456,10 @@ static inline void sysfs_remove_file(struct kobject *kobj, 
	return sysfs_remove_file_ns(kobj, attr, NULL);

}



static inline int sysfs_rename_link(struct kobject *kobj, struct kobject *target,

				    const char *old_name, const char *new_name)

{

	return sysfs_rename_link_ns(kobj, target, old_name, new_name, NULL);

}



#endif /* _SYSFS_H_ */

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