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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: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Tejun Heo 2013-11-23 17:21:50 -05:00 committed by Greg Kroah-Hartman
parent 879f40d193
commit 5d0e26bb59
2 changed files with 56 additions and 31 deletions
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78
fs/sysfs/symlink.c
View File

@ -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;
return -ENOENT;
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 */
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;
return 0;
out_put:
sd = kernfs_create_link(parent_sd, name, target_sd);
sysfs_put(target_sd);
sysfs_put(sd);
return error;
if (!IS_ERR(sd))
return 0;
if (warn && PTR_ERR(sd) == -EEXIST)
sysfs_warn_dup(parent_sd, name);
return PTR_ERR(sd);
}
/**

9
include/linux/kernfs.h
View File

@ -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,