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Commit 5d0e26bb authored by Tejun Heo's avatar Tejun Heo Committed by Greg Kroah-Hartman
Browse files

sysfs, kernfs: introduce kernfs_create_link() 



Separate out kernfs symlink interface - kernfs_create_link() - which
takes and returns sysfs_dirents, from sysfs_do_create_link_sd().
sysfs_do_create_link_sd() now just determines the parent and target
sysfs_dirents and invokes the new interface and handles dup warning.

This patch doesn't introduce behavior changes.

v2: Dummy implementation for !CONFIG_SYSFS updated to return -ENOSYS.

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 879f40d1

fs/sysfs/symlink.c

+46 −30
Original line number Diff line number Diff line
@@ -21,14 +21,48 @@ 


#include "sysfs.h"



/**

 * kernfs_create_link - create a symlink

 * @parent: directory to create the symlink in

 * @name: name of the symlink

 * @target: target node for the symlink to point to

 *

 * Returns the created node on success, ERR_PTR() value on error.

 */

struct sysfs_dirent *kernfs_create_link(struct sysfs_dirent *parent,

					const char *name,

					struct sysfs_dirent *target)

{

	struct sysfs_dirent *sd;

	struct sysfs_addrm_cxt acxt;

	int error;



	sd = sysfs_new_dirent(name, S_IFLNK|S_IRWXUGO, SYSFS_KOBJ_LINK);

	if (!sd)

		return ERR_PTR(-ENOMEM);



	if (parent->s_flags & SYSFS_FLAG_NS)

		sd->s_ns = target->s_ns;

	sd->s_symlink.target_sd = target;

	sysfs_get(target);	/* ref owned by symlink */



	sysfs_addrm_start(&acxt);

	error = __sysfs_add_one(&acxt, sd, parent);

	sysfs_addrm_finish(&acxt);



	if (!error)

		return sd;



	sysfs_put(sd);

	return ERR_PTR(error);

}





static int sysfs_do_create_link_sd(struct sysfs_dirent *parent_sd,

				   struct kobject *target,

				   const char *name, int warn)

{

	struct sysfs_dirent *target_sd = NULL;

	struct sysfs_dirent *sd = NULL;

	struct sysfs_addrm_cxt acxt;

	int error;

	struct sysfs_dirent *sd, *target_sd = NULL;



	BUG_ON(!name || !parent_sd);
@@ -42,36 +76,18 @@ static int sysfs_do_create_link_sd(struct sysfs_dirent *parent_sd, 
		target_sd = sysfs_get(target->sd);

	spin_unlock(&sysfs_symlink_target_lock);



	error = -ENOENT;

	if (!target_sd)

		goto out_put;



	error = -ENOMEM;

	sd = sysfs_new_dirent(name, S_IFLNK|S_IRWXUGO, SYSFS_KOBJ_LINK);

	if (!sd)

		goto out_put;



	if (parent_sd->s_flags & SYSFS_FLAG_NS)

		sd->s_ns = target_sd->s_ns;

	sd->s_symlink.target_sd = target_sd;

	target_sd = NULL;	/* reference is now owned by the symlink */

		return -ENOENT;



	sysfs_addrm_start(&acxt);

	if (warn)

		error = sysfs_add_one(&acxt, sd, parent_sd);

	else

		error = __sysfs_add_one(&acxt, sd, parent_sd);

	sysfs_addrm_finish(&acxt);



	if (error)

		goto out_put;

	sd = kernfs_create_link(parent_sd, name, target_sd);

	sysfs_put(target_sd);



	if (!IS_ERR(sd))

		return 0;



 out_put:

	sysfs_put(target_sd);

	sysfs_put(sd);

	return error;

	if (warn && PTR_ERR(sd) == -EEXIST)

		sysfs_warn_dup(parent_sd, name);

	return PTR_ERR(sd);

}



/**

include/linux/kernfs.h

+9 −0
Original line number Diff line number Diff line
@@ -8,17 +8,26 @@ 
#define __LINUX_KERNFS_H



#include <linux/kernel.h>

#include <linux/err.h>



struct sysfs_dirent;



#ifdef CONFIG_SYSFS



struct sysfs_dirent *kernfs_create_link(struct sysfs_dirent *parent,

					const char *name,

					struct sysfs_dirent *target);

void kernfs_remove(struct sysfs_dirent *sd);

int kernfs_remove_by_name_ns(struct sysfs_dirent *parent, const char *name,

			     const void *ns);



#else	/* CONFIG_SYSFS */



static inline struct sysfs_dirent *

kernfs_create_link(struct sysfs_dirent *parent, const char *name,

		   struct sysfs_dirent *target)

{ return ERR_PTR(-ENOSYS); }



static inline void kernfs_remove(struct sysfs_dirent *sd) { }



static inline int kernfs_remove_by_name_ns(struct sysfs_dirent *parent,