/*
- * symlink.c - operations for sysfs symlinks.
+ * fs/sysfs/symlink.c - sysfs symlink implementation
+ *
+ * Copyright (c) 2001-3 Patrick Mochel
+ * Copyright (c) 2007 SUSE Linux Products GmbH
+ * Copyright (c) 2007 Tejun Heo <teheo@suse.de>
+ *
+ * This file is released under the GPLv2.
+ *
+ * Please see Documentation/filesystems/sysfs.txt for more information.
*/
#include <linux/fs.h>
#include <linux/module.h>
#include <linux/kobject.h>
#include <linux/namei.h>
-#include <asm/semaphore.h>
+#include <linux/mutex.h>
#include "sysfs.h"
-static int object_depth(struct kobject * kobj)
+static int object_depth(struct sysfs_dirent *sd)
{
- struct kobject * p = kobj;
int depth = 0;
- do { depth++; } while ((p = p->parent));
+
+ for (; sd->s_parent; sd = sd->s_parent)
+ depth++;
+
return depth;
}
-static int object_path_length(struct kobject * kobj)
+static int object_path_length(struct sysfs_dirent * sd)
{
- struct kobject * p = kobj;
int length = 1;
- do {
- length += strlen(kobject_name(p)) + 1;
- p = p->parent;
- } while (p);
+
+ for (; sd->s_parent; sd = sd->s_parent)
+ length += strlen(sd->s_name) + 1;
+
return length;
}
-static void fill_object_path(struct kobject * kobj, char * buffer, int length)
+static void fill_object_path(struct sysfs_dirent *sd, char *buffer, int length)
{
- struct kobject * p;
-
--length;
- for (p = kobj; p; p = p->parent) {
- int cur = strlen(kobject_name(p));
+ for (; sd->s_parent; sd = sd->s_parent) {
+ int cur = strlen(sd->s_name);
/* back up enough to print this bus id with '/' */
length -= cur;
- strncpy(buffer + length,kobject_name(p),cur);
+ strncpy(buffer + length, sd->s_name, cur);
*(buffer + --length) = '/';
}
}
-static int sysfs_add_link(struct dentry * parent, const char * name, struct kobject * target)
-{
- struct sysfs_dirent * parent_sd = parent->d_fsdata;
- struct sysfs_symlink * sl;
- struct sysfs_dirent * sd;
- int error;
-
- error = -ENOMEM;
- sl = kzalloc(sizeof(*sl), GFP_KERNEL);
- if (!sl)
- goto err_out;
-
- sl->link_name = kmalloc(strlen(name) + 1, GFP_KERNEL);
- if (!sl->link_name)
- goto err_out;
-
- strcpy(sl->link_name, name);
- sl->target_kobj = kobject_get(target);
-
- sd = sysfs_new_dirent(sl, S_IFLNK|S_IRWXUGO, SYSFS_KOBJ_LINK);
- if (!sd)
- goto err_out;
- sysfs_attach_dirent(sd, parent_sd, NULL);
-
- return 0;
-
- err_out:
- if (sl) {
- kobject_put(sl->target_kobj);
- kfree(sl->link_name);
- kfree(sl);
- }
- return error;
-}
-
/**
* sysfs_create_link - create symlink between two objects.
* @kobj: object whose directory we're creating the link in.
*/
int sysfs_create_link(struct kobject * kobj, struct kobject * target, const char * name)
{
- struct dentry *dentry = NULL;
- int error = -EEXIST;
+ struct sysfs_dirent *parent_sd = NULL;
+ struct sysfs_dirent *target_sd = NULL;
+ struct sysfs_dirent *sd = NULL;
+ struct sysfs_addrm_cxt acxt;
+ int error;
BUG_ON(!name);
- if (!kobj) {
- if (sysfs_mount && sysfs_mount->mnt_sb)
- dentry = sysfs_mount->mnt_sb->s_root;
- } else
- dentry = kobj->dentry;
+ if (!kobj)
+ parent_sd = &sysfs_root;
+ else
+ parent_sd = kobj->sd;
+
+ error = -EFAULT;
+ if (!parent_sd)
+ goto out_put;
+
+ /* target->sd can go away beneath us but is protected with
+ * sysfs_assoc_lock. Fetch target_sd from it.
+ */
+ spin_lock(&sysfs_assoc_lock);
+ if (target->sd)
+ target_sd = sysfs_get(target->sd);
+ spin_unlock(&sysfs_assoc_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;
+
+ sd->s_symlink.target_sd = target_sd;
+ target_sd = NULL; /* reference is now owned by the symlink */
- if (!dentry)
- return -EFAULT;
+ sysfs_addrm_start(&acxt, parent_sd);
+ error = sysfs_add_one(&acxt, sd);
+ sysfs_addrm_finish(&acxt);
- mutex_lock(&dentry->d_inode->i_mutex);
- if (!sysfs_dirent_exist(dentry->d_fsdata, name))
- error = sysfs_add_link(dentry, name, target);
- mutex_unlock(&dentry->d_inode->i_mutex);
+ if (error)
+ goto out_put;
+
+ return 0;
+
+ out_put:
+ sysfs_put(target_sd);
+ sysfs_put(sd);
return error;
}
void sysfs_remove_link(struct kobject * kobj, const char * name)
{
- sysfs_hash_and_remove(kobj->dentry,name);
+ sysfs_hash_and_remove(kobj->sd, name);
}
-static int sysfs_get_target_path(struct kobject * kobj, struct kobject * target,
- char *path)
+static int sysfs_get_target_path(struct sysfs_dirent * parent_sd,
+ struct sysfs_dirent * target_sd, char *path)
{
char * s;
int depth, size;
- depth = object_depth(kobj);
- size = object_path_length(target) + depth * 3 - 1;
+ depth = object_depth(parent_sd);
+ size = object_path_length(target_sd) + depth * 3 - 1;
if (size > PATH_MAX)
return -ENAMETOOLONG;
for (s = path; depth--; s += 3)
strcpy(s,"../");
- fill_object_path(target, path, size);
+ fill_object_path(target_sd, path, size);
pr_debug("%s: path = '%s'\n", __FUNCTION__, path);
return 0;
static int sysfs_getlink(struct dentry *dentry, char * path)
{
- struct kobject *kobj, *target_kobj;
- int error = 0;
-
- kobj = sysfs_get_kobject(dentry->d_parent);
- if (!kobj)
- return -EINVAL;
+ 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;
- target_kobj = sysfs_get_kobject(dentry);
- if (!target_kobj) {
- kobject_put(kobj);
- return -EINVAL;
- }
+ mutex_lock(&sysfs_mutex);
+ error = sysfs_get_target_path(parent_sd, target_sd, path);
+ mutex_unlock(&sysfs_mutex);
- down_read(&sysfs_rename_sem);
- error = sysfs_get_target_path(kobj, target_kobj, path);
- up_read(&sysfs_rename_sem);
-
- kobject_put(kobj);
- kobject_put(target_kobj);
return error;
-
}
static void *sysfs_follow_link(struct dentry *dentry, struct nameidata *nd)
projects / powerpc.git / blobdiff