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sysfs, kernfs: move symlink core code to fs/kernfs/symlink.c
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Move core symlink code to fs/kernfs/symlink.c.  fs/sysfs/symlink.c now
only contains sysfs wrappers around kernfs interfaces.  The respective
declarations in fs/sysfs/sysfs.h are moved to
fs/kernfs/kernfs-internal.h.

This is pure relocation.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Tejun Heo authored and Greg Kroah-Hartman committed Nov 30, 2013
1 parent 414985a commit 2072f1a
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Showing 4 changed files with 144 additions and 138 deletions.
5 changes: 5 additions & 0 deletions fs/kernfs/kernfs-internal.h
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Original file line number Diff line number Diff line change
Expand Up @@ -149,4 +149,9 @@ extern const struct file_operations kernfs_file_operations;

void sysfs_unmap_bin_file(struct sysfs_dirent *sd);

/*
* symlink.c
*/
extern const struct inode_operations sysfs_symlink_inode_operations;

#endif /* __KERNFS_INTERNAL_H */
139 changes: 139 additions & 0 deletions fs/kernfs/symlink.c
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Original file line number Diff line number Diff line change
Expand Up @@ -7,3 +7,142 @@
*
* This file is released under the GPLv2.
*/

#include <linux/fs.h>
#include <linux/gfp.h>
#include <linux/namei.h>

#include "kernfs-internal.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;
kernfs_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;

kernfs_put(sd);
return ERR_PTR(error);
}

static int sysfs_get_target_path(struct sysfs_dirent *parent_sd,
struct sysfs_dirent *target_sd, char *path)
{
struct sysfs_dirent *base, *sd;
char *s = path;
int len = 0;

/* go up to the root, stop at the base */
base = parent_sd;
while (base->s_parent) {
sd = target_sd->s_parent;
while (sd->s_parent && base != sd)
sd = sd->s_parent;

if (base == sd)
break;

strcpy(s, "../");
s += 3;
base = base->s_parent;
}

/* determine end of target string for reverse fillup */
sd = target_sd;
while (sd->s_parent && sd != base) {
len += strlen(sd->s_name) + 1;
sd = sd->s_parent;
}

/* check limits */
if (len < 2)
return -EINVAL;
len--;
if ((s - path) + len > PATH_MAX)
return -ENAMETOOLONG;

/* reverse fillup of target string from target to base */
sd = target_sd;
while (sd->s_parent && sd != base) {
int slen = strlen(sd->s_name);

len -= slen;
strncpy(s + len, sd->s_name, slen);
if (len)
s[--len] = '/';

sd = sd->s_parent;
}

return 0;
}

static int sysfs_getlink(struct dentry *dentry, char *path)
{
struct sysfs_dirent *sd = dentry->d_fsdata;
struct sysfs_dirent *parent_sd = sd->s_parent;
struct sysfs_dirent *target_sd = sd->s_symlink.target_sd;
int error;

mutex_lock(&sysfs_mutex);
error = sysfs_get_target_path(parent_sd, target_sd, path);
mutex_unlock(&sysfs_mutex);

return error;
}

static void *sysfs_follow_link(struct dentry *dentry, struct nameidata *nd)
{
int error = -ENOMEM;
unsigned long page = get_zeroed_page(GFP_KERNEL);
if (page) {
error = sysfs_getlink(dentry, (char *) page);
if (error < 0)
free_page((unsigned long)page);
}
nd_set_link(nd, error ? ERR_PTR(error) : (char *)page);
return NULL;
}

static void sysfs_put_link(struct dentry *dentry, struct nameidata *nd,
void *cookie)
{
char *page = nd_get_link(nd);
if (!IS_ERR(page))
free_page((unsigned long)page);
}

const struct inode_operations sysfs_symlink_inode_operations = {
.setxattr = sysfs_setxattr,
.readlink = generic_readlink,
.follow_link = sysfs_follow_link,
.put_link = sysfs_put_link,
.setattr = sysfs_setattr,
.getattr = sysfs_getattr,
.permission = sysfs_permission,
};
137 changes: 0 additions & 137 deletions fs/sysfs/symlink.c
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Original file line number Diff line number Diff line change
Expand Up @@ -11,53 +11,13 @@
*/

#include <linux/fs.h>
#include <linux/gfp.h>
#include <linux/mount.h>
#include <linux/module.h>
#include <linux/kobject.h>
#include <linux/namei.h>
#include <linux/mutex.h>
#include <linux/security.h>

#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;
kernfs_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;

kernfs_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)
Expand Down Expand Up @@ -235,100 +195,3 @@ int sysfs_rename_link_ns(struct kobject *kobj, struct kobject *targ,
return result;
}
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)
{
struct sysfs_dirent *base, *sd;
char *s = path;
int len = 0;

/* go up to the root, stop at the base */
base = parent_sd;
while (base->s_parent) {
sd = target_sd->s_parent;
while (sd->s_parent && base != sd)
sd = sd->s_parent;

if (base == sd)
break;

strcpy(s, "../");
s += 3;
base = base->s_parent;
}

/* determine end of target string for reverse fillup */
sd = target_sd;
while (sd->s_parent && sd != base) {
len += strlen(sd->s_name) + 1;
sd = sd->s_parent;
}

/* check limits */
if (len < 2)
return -EINVAL;
len--;
if ((s - path) + len > PATH_MAX)
return -ENAMETOOLONG;

/* reverse fillup of target string from target to base */
sd = target_sd;
while (sd->s_parent && sd != base) {
int slen = strlen(sd->s_name);

len -= slen;
strncpy(s + len, sd->s_name, slen);
if (len)
s[--len] = '/';

sd = sd->s_parent;
}

return 0;
}

static int sysfs_getlink(struct dentry *dentry, char *path)
{
struct sysfs_dirent *sd = dentry->d_fsdata;
struct sysfs_dirent *parent_sd = sd->s_parent;
struct sysfs_dirent *target_sd = sd->s_symlink.target_sd;
int error;

mutex_lock(&sysfs_mutex);
error = sysfs_get_target_path(parent_sd, target_sd, path);
mutex_unlock(&sysfs_mutex);

return error;
}

static void *sysfs_follow_link(struct dentry *dentry, struct nameidata *nd)
{
int error = -ENOMEM;
unsigned long page = get_zeroed_page(GFP_KERNEL);
if (page) {
error = sysfs_getlink(dentry, (char *) page);
if (error < 0)
free_page((unsigned long)page);
}
nd_set_link(nd, error ? ERR_PTR(error) : (char *)page);
return NULL;
}

static void sysfs_put_link(struct dentry *dentry, struct nameidata *nd,
void *cookie)
{
char *page = nd_get_link(nd);
if (!IS_ERR(page))
free_page((unsigned long)page);
}

const struct inode_operations sysfs_symlink_inode_operations = {
.setxattr = sysfs_setxattr,
.readlink = generic_readlink,
.follow_link = sysfs_follow_link,
.put_link = sysfs_put_link,
.setattr = sysfs_setattr,
.getattr = sysfs_getattr,
.permission = sysfs_permission,
};
1 change: 0 additions & 1 deletion fs/sysfs/sysfs.h
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Original file line number Diff line number Diff line change
Expand Up @@ -50,7 +50,6 @@ int sysfs_add_file_mode_ns(struct sysfs_dirent *dir_sd,
/*
* symlink.c
*/
extern const struct inode_operations sysfs_symlink_inode_operations;
int sysfs_create_link_sd(struct sysfs_dirent *sd, struct kobject *target,
const char *name);

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