513 lines
11 KiB
C
513 lines
11 KiB
C
/*
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* dir.c - Operations for sysfs directories.
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*/
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#undef DEBUG
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#include <linux/fs.h>
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#include <linux/mount.h>
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#include <linux/module.h>
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#include <linux/kobject.h>
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#include <linux/namei.h>
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#include "sysfs.h"
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DECLARE_RWSEM(sysfs_rename_sem);
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static void sysfs_d_iput(struct dentry * dentry, struct inode * inode)
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{
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struct sysfs_dirent * sd = dentry->d_fsdata;
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if (sd) {
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BUG_ON(sd->s_dentry != dentry);
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sd->s_dentry = NULL;
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sysfs_put(sd);
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}
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iput(inode);
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}
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static struct dentry_operations sysfs_dentry_ops = {
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.d_iput = sysfs_d_iput,
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};
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/*
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* Allocates a new sysfs_dirent and links it to the parent sysfs_dirent
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*/
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static struct sysfs_dirent * sysfs_new_dirent(struct sysfs_dirent * parent_sd,
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void * element)
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{
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struct sysfs_dirent * sd;
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sd = kmem_cache_alloc(sysfs_dir_cachep, GFP_KERNEL);
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if (!sd)
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return NULL;
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memset(sd, 0, sizeof(*sd));
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atomic_set(&sd->s_count, 1);
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INIT_LIST_HEAD(&sd->s_children);
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list_add(&sd->s_sibling, &parent_sd->s_children);
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sd->s_element = element;
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return sd;
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}
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/**
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*
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* Return -EEXIST if there is already a sysfs element with the same name for
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* the same parent.
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*
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* called with parent inode's i_mutex held
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*/
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int sysfs_dirent_exist(struct sysfs_dirent *parent_sd,
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const unsigned char *new)
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{
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struct sysfs_dirent * sd;
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list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
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if (sd->s_element) {
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const unsigned char *existing = sysfs_get_name(sd);
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if (strcmp(existing, new))
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continue;
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else
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return -EEXIST;
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}
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}
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return 0;
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}
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int sysfs_make_dirent(struct sysfs_dirent * parent_sd, struct dentry * dentry,
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void * element, umode_t mode, int type)
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{
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struct sysfs_dirent * sd;
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sd = sysfs_new_dirent(parent_sd, element);
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if (!sd)
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return -ENOMEM;
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sd->s_mode = mode;
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sd->s_type = type;
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sd->s_dentry = dentry;
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if (dentry) {
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dentry->d_fsdata = sysfs_get(sd);
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dentry->d_op = &sysfs_dentry_ops;
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}
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return 0;
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}
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static int init_dir(struct inode * inode)
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{
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inode->i_op = &sysfs_dir_inode_operations;
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inode->i_fop = &sysfs_dir_operations;
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/* directory inodes start off with i_nlink == 2 (for "." entry) */
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inode->i_nlink++;
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return 0;
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}
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static int init_file(struct inode * inode)
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{
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inode->i_size = PAGE_SIZE;
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inode->i_fop = &sysfs_file_operations;
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return 0;
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}
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static int init_symlink(struct inode * inode)
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{
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inode->i_op = &sysfs_symlink_inode_operations;
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return 0;
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}
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static int create_dir(struct kobject * k, struct dentry * p,
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const char * n, struct dentry ** d)
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{
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int error;
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umode_t mode = S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO;
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mutex_lock(&p->d_inode->i_mutex);
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*d = lookup_one_len(n, p, strlen(n));
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if (!IS_ERR(*d)) {
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if (sysfs_dirent_exist(p->d_fsdata, n))
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error = -EEXIST;
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else
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error = sysfs_make_dirent(p->d_fsdata, *d, k, mode,
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SYSFS_DIR);
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if (!error) {
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error = sysfs_create(*d, mode, init_dir);
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if (!error) {
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p->d_inode->i_nlink++;
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(*d)->d_op = &sysfs_dentry_ops;
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d_rehash(*d);
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}
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}
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if (error && (error != -EEXIST)) {
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struct sysfs_dirent *sd = (*d)->d_fsdata;
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if (sd) {
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list_del_init(&sd->s_sibling);
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sysfs_put(sd);
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}
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d_drop(*d);
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}
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dput(*d);
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} else
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error = PTR_ERR(*d);
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mutex_unlock(&p->d_inode->i_mutex);
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return error;
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}
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int sysfs_create_subdir(struct kobject * k, const char * n, struct dentry ** d)
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{
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return create_dir(k,k->dentry,n,d);
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}
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/**
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* sysfs_create_dir - create a directory for an object.
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* @parent: parent parent object.
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* @kobj: object we're creating directory for.
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*/
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int sysfs_create_dir(struct kobject * kobj)
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{
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struct dentry * dentry = NULL;
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struct dentry * parent;
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int error = 0;
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BUG_ON(!kobj);
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if (kobj->parent)
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parent = kobj->parent->dentry;
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else if (sysfs_mount && sysfs_mount->mnt_sb)
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parent = sysfs_mount->mnt_sb->s_root;
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else
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return -EFAULT;
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error = create_dir(kobj,parent,kobject_name(kobj),&dentry);
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if (!error)
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kobj->dentry = dentry;
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return error;
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}
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/* attaches attribute's sysfs_dirent to the dentry corresponding to the
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* attribute file
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*/
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static int sysfs_attach_attr(struct sysfs_dirent * sd, struct dentry * dentry)
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{
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struct attribute * attr = NULL;
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struct bin_attribute * bin_attr = NULL;
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int (* init) (struct inode *) = NULL;
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int error = 0;
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if (sd->s_type & SYSFS_KOBJ_BIN_ATTR) {
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bin_attr = sd->s_element;
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attr = &bin_attr->attr;
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} else {
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attr = sd->s_element;
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init = init_file;
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}
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dentry->d_fsdata = sysfs_get(sd);
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sd->s_dentry = dentry;
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error = sysfs_create(dentry, (attr->mode & S_IALLUGO) | S_IFREG, init);
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if (error) {
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sysfs_put(sd);
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return error;
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}
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if (bin_attr) {
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dentry->d_inode->i_size = bin_attr->size;
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dentry->d_inode->i_fop = &bin_fops;
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}
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dentry->d_op = &sysfs_dentry_ops;
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d_rehash(dentry);
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return 0;
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}
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static int sysfs_attach_link(struct sysfs_dirent * sd, struct dentry * dentry)
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{
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int err = 0;
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dentry->d_fsdata = sysfs_get(sd);
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sd->s_dentry = dentry;
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err = sysfs_create(dentry, S_IFLNK|S_IRWXUGO, init_symlink);
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if (!err) {
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dentry->d_op = &sysfs_dentry_ops;
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d_rehash(dentry);
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} else
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sysfs_put(sd);
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return err;
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}
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static struct dentry * sysfs_lookup(struct inode *dir, struct dentry *dentry,
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struct nameidata *nd)
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{
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struct sysfs_dirent * parent_sd = dentry->d_parent->d_fsdata;
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struct sysfs_dirent * sd;
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int err = 0;
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list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
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if (sd->s_type & SYSFS_NOT_PINNED) {
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const unsigned char * name = sysfs_get_name(sd);
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if (strcmp(name, dentry->d_name.name))
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continue;
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if (sd->s_type & SYSFS_KOBJ_LINK)
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err = sysfs_attach_link(sd, dentry);
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else
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err = sysfs_attach_attr(sd, dentry);
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break;
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}
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}
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return ERR_PTR(err);
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}
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struct inode_operations sysfs_dir_inode_operations = {
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.lookup = sysfs_lookup,
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.setattr = sysfs_setattr,
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};
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static void remove_dir(struct dentry * d)
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{
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struct dentry * parent = dget(d->d_parent);
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struct sysfs_dirent * sd;
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mutex_lock(&parent->d_inode->i_mutex);
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d_delete(d);
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sd = d->d_fsdata;
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list_del_init(&sd->s_sibling);
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sysfs_put(sd);
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if (d->d_inode)
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simple_rmdir(parent->d_inode,d);
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pr_debug(" o %s removing done (%d)\n",d->d_name.name,
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atomic_read(&d->d_count));
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mutex_unlock(&parent->d_inode->i_mutex);
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dput(parent);
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}
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void sysfs_remove_subdir(struct dentry * d)
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{
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remove_dir(d);
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}
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/**
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* sysfs_remove_dir - remove an object's directory.
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* @kobj: object.
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*
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* The only thing special about this is that we remove any files in
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* the directory before we remove the directory, and we've inlined
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* what used to be sysfs_rmdir() below, instead of calling separately.
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*/
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void sysfs_remove_dir(struct kobject * kobj)
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{
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struct dentry * dentry = dget(kobj->dentry);
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struct sysfs_dirent * parent_sd;
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struct sysfs_dirent * sd, * tmp;
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if (!dentry)
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return;
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pr_debug("sysfs %s: removing dir\n",dentry->d_name.name);
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mutex_lock(&dentry->d_inode->i_mutex);
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parent_sd = dentry->d_fsdata;
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list_for_each_entry_safe(sd, tmp, &parent_sd->s_children, s_sibling) {
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if (!sd->s_element || !(sd->s_type & SYSFS_NOT_PINNED))
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continue;
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list_del_init(&sd->s_sibling);
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sysfs_drop_dentry(sd, dentry);
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sysfs_put(sd);
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}
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mutex_unlock(&dentry->d_inode->i_mutex);
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remove_dir(dentry);
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/**
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* Drop reference from dget() on entrance.
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*/
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dput(dentry);
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kobj->dentry = NULL;
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}
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int sysfs_rename_dir(struct kobject * kobj, const char *new_name)
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{
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int error = 0;
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struct dentry * new_dentry, * parent;
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if (!strcmp(kobject_name(kobj), new_name))
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return -EINVAL;
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if (!kobj->parent)
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return -EINVAL;
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down_write(&sysfs_rename_sem);
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parent = kobj->parent->dentry;
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mutex_lock(&parent->d_inode->i_mutex);
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new_dentry = lookup_one_len(new_name, parent, strlen(new_name));
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if (!IS_ERR(new_dentry)) {
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if (!new_dentry->d_inode) {
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error = kobject_set_name(kobj, "%s", new_name);
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if (!error) {
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d_add(new_dentry, NULL);
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d_move(kobj->dentry, new_dentry);
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}
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else
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d_drop(new_dentry);
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} else
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error = -EEXIST;
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dput(new_dentry);
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}
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mutex_unlock(&parent->d_inode->i_mutex);
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up_write(&sysfs_rename_sem);
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return error;
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}
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static int sysfs_dir_open(struct inode *inode, struct file *file)
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{
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struct dentry * dentry = file->f_dentry;
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struct sysfs_dirent * parent_sd = dentry->d_fsdata;
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mutex_lock(&dentry->d_inode->i_mutex);
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file->private_data = sysfs_new_dirent(parent_sd, NULL);
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mutex_unlock(&dentry->d_inode->i_mutex);
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return file->private_data ? 0 : -ENOMEM;
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}
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static int sysfs_dir_close(struct inode *inode, struct file *file)
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{
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struct dentry * dentry = file->f_dentry;
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struct sysfs_dirent * cursor = file->private_data;
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mutex_lock(&dentry->d_inode->i_mutex);
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list_del_init(&cursor->s_sibling);
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mutex_unlock(&dentry->d_inode->i_mutex);
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release_sysfs_dirent(cursor);
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return 0;
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}
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/* Relationship between s_mode and the DT_xxx types */
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static inline unsigned char dt_type(struct sysfs_dirent *sd)
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{
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return (sd->s_mode >> 12) & 15;
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}
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static int sysfs_readdir(struct file * filp, void * dirent, filldir_t filldir)
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{
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struct dentry *dentry = filp->f_dentry;
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struct sysfs_dirent * parent_sd = dentry->d_fsdata;
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struct sysfs_dirent *cursor = filp->private_data;
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struct list_head *p, *q = &cursor->s_sibling;
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ino_t ino;
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int i = filp->f_pos;
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switch (i) {
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case 0:
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ino = dentry->d_inode->i_ino;
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if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0)
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break;
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filp->f_pos++;
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i++;
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/* fallthrough */
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case 1:
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ino = parent_ino(dentry);
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if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0)
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break;
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filp->f_pos++;
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i++;
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/* fallthrough */
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default:
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if (filp->f_pos == 2) {
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list_del(q);
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list_add(q, &parent_sd->s_children);
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}
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for (p=q->next; p!= &parent_sd->s_children; p=p->next) {
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struct sysfs_dirent *next;
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const char * name;
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int len;
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next = list_entry(p, struct sysfs_dirent,
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s_sibling);
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if (!next->s_element)
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continue;
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name = sysfs_get_name(next);
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len = strlen(name);
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if (next->s_dentry)
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ino = next->s_dentry->d_inode->i_ino;
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else
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ino = iunique(sysfs_sb, 2);
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if (filldir(dirent, name, len, filp->f_pos, ino,
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dt_type(next)) < 0)
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return 0;
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list_del(q);
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list_add(q, p);
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p = q;
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filp->f_pos++;
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}
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}
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return 0;
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}
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static loff_t sysfs_dir_lseek(struct file * file, loff_t offset, int origin)
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{
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struct dentry * dentry = file->f_dentry;
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mutex_lock(&dentry->d_inode->i_mutex);
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switch (origin) {
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case 1:
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offset += file->f_pos;
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case 0:
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if (offset >= 0)
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break;
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default:
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mutex_unlock(&file->f_dentry->d_inode->i_mutex);
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return -EINVAL;
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}
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if (offset != file->f_pos) {
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file->f_pos = offset;
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if (file->f_pos >= 2) {
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struct sysfs_dirent *sd = dentry->d_fsdata;
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struct sysfs_dirent *cursor = file->private_data;
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struct list_head *p;
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loff_t n = file->f_pos - 2;
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list_del(&cursor->s_sibling);
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p = sd->s_children.next;
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while (n && p != &sd->s_children) {
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struct sysfs_dirent *next;
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next = list_entry(p, struct sysfs_dirent,
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s_sibling);
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if (next->s_element)
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n--;
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p = p->next;
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}
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list_add_tail(&cursor->s_sibling, p);
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}
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}
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mutex_unlock(&dentry->d_inode->i_mutex);
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return offset;
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}
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struct file_operations sysfs_dir_operations = {
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.open = sysfs_dir_open,
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.release = sysfs_dir_close,
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.llseek = sysfs_dir_lseek,
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.read = generic_read_dir,
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.readdir = sysfs_readdir,
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};
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