linux-imx

/* -*- mode: c; c-basic-offset: 8; -*-

 * vim: noexpandtab sw=8 ts=8 sts=0:

 *

 * symlink.c - operations for configfs symlinks.

 *

 * This program is free software; you can redistribute it and/or

 * modify it under the terms of the GNU General Public

 * License as published by the Free Software Foundation; either

 * version 2 of the License, or (at your option) any later version.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * General Public License for more details.

 *

 * You should have received a copy of the GNU General Public

 * License along with this program; if not, write to the

 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,

 * Boston, MA 021110-1307, USA.

 *

 * Based on sysfs:

 *  sysfs is Copyright (C) 2001, 2002, 2003 Patrick Mochel

 *

 * configfs Copyright (C) 2005 Oracle.  All rights reserved.

 */

​

#include <linux/fs.h>

#include <linux/module.h>

#include <linux/namei.h>

#include <linux/slab.h>

​

#include <linux/configfs.h>

#include "configfs_internal.h"

​

/* Protects attachments of new symlinks */

DEFINE_MUTEX(configfs_symlink_mutex);

​

static int item_depth(struct config_item * item)

{

    struct config_item * p = item;

    int depth = 0;

    do { depth++; } while ((p = p->ci_parent) && !configfs_is_root(p));

    return depth;

}

​

static int item_path_length(struct config_item * item)

{

    struct config_item * p = item;

    int length = 1;

    do {

        length += strlen(config_item_name(p)) + 1;

        p = p->ci_parent;

    } while (p && !configfs_is_root(p));

    return length;

}

​

static void fill_item_path(struct config_item * item, char * buffer, int length)

{

    struct config_item * p;

​

    --length;

    for (p = item; p && !configfs_is_root(p); p = p->ci_parent) {

        int cur = strlen(config_item_name(p));

​

        /* back up enough to print this bus id with '/' */

        length -= cur;

        memcpy(buffer + length, config_item_name(p), cur);

        *(buffer + --length) = '/';

    }

}

​

static int create_link(struct config_item *parent_item,

               struct config_item *item,

               struct dentry *dentry)

{

    struct configfs_dirent *target_sd = item->ci_dentry->d_fsdata;

    struct configfs_symlink *sl;

    int ret;

​

    ret = -ENOENT;

    if (!configfs_dirent_is_ready(target_sd))

        goto out;

    ret = -ENOMEM;

    sl = kmalloc(sizeof(struct configfs_symlink), GFP_KERNEL);

    if (sl) {

        spin_lock(&configfs_dirent_lock);

        if (target_sd->s_type & CONFIGFS_USET_DROPPING) {

            spin_unlock(&configfs_dirent_lock);

            kfree(sl);

            return -ENOENT;

        }

        sl->sl_target = config_item_get(item);