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    Subject[RFC][PATCH 2 of 4] Configfs is really sysfs
    Date
    Sysfs rearranged as a single file for analysis purposes.

    diff -up --recursive 2.6.13-rc5-mm1.clean/fs/sysfs/Makefile 2.6.13-rc5-mm1/fs/sysfs/Makefile
    --- 2.6.13-rc5-mm1.clean/fs/sysfs/Makefile 2005-06-17 15:48:29.000000000 -0400
    +++ 2.6.13-rc5-mm1/fs/sysfs/Makefile 2005-08-29 17:13:59.000000000 -0400
    @@ -2,5 +2,4 @@
    # Makefile for the sysfs virtual filesystem
    #

    -obj-y := inode.o file.o dir.o symlink.o mount.o bin.o \
    - group.o
    +obj-y := sysfs.o
    diff -up --recursive 2.6.13-rc5-mm1.clean/fs/sysfs/sysfs.c 2.6.13-rc5-mm1/fs/sysfs/sysfs.c
    --- 2.6.13-rc5-mm1.clean/fs/sysfs/sysfs.c 2005-08-30 17:52:35.000000000 -0400
    +++ 2.6.13-rc5-mm1/fs/sysfs/sysfs.c 2005-08-29 21:04:40.000000000 -0400
    @@ -0,0 +1,1680 @@
    +#include <linux/fs.h>
    +#include <linux/namei.h>
    +#include <linux/module.h>
    +#include <linux/mount.h>
    +#include <linux/backing-dev.h>
    +#include <linux/pagemap.h>
    +#include <linux/fsnotify.h>
    +
    +struct sysfs_symlink {
    + char *link_name;
    + struct kobject *sl_target;
    +};
    +
    +static inline struct kobject *to_kobj(struct dentry *dentry)
    +{
    + struct sysfs_dirent *sd = dentry->d_fsdata;
    + return ((struct kobject *)sd->s_element);
    +}
    +
    +static inline struct attribute *to_attr(struct dentry *dentry)
    +{
    + struct sysfs_dirent *sd = dentry->d_fsdata;
    + return ((struct attribute *)sd->s_element);
    +}
    +
    +static inline struct kobject *sysfs_get_kobject(struct dentry *dentry)
    +{
    + struct kobject *kobj = NULL;
    +
    + spin_lock(&dcache_lock);
    + if (!d_unhashed(dentry)) {
    + struct sysfs_dirent *sd = dentry->d_fsdata;
    + if (sd->s_type & SYSFS_KOBJ_LINK) {
    + struct sysfs_symlink *sl = sd->s_element;
    + kobj = kobject_get(sl->sl_target);
    + } else
    + kobj = kobject_get(sd->s_element);
    + }
    + spin_unlock(&dcache_lock);
    +
    + return kobj;
    +}
    +
    +static kmem_cache_t *sysfs_dir_cachep;
    +
    +static void release_sysfs_dirent(struct sysfs_dirent *sd)
    +{
    + if (sd->s_type & SYSFS_KOBJ_LINK) {
    + struct sysfs_symlink *sl = sd->s_element;
    + kfree(sl->link_name);
    + kobject_put(sl->sl_target);
    + kfree(sl);
    + }
    + kfree(sd->s_iattr);
    + kmem_cache_free(sysfs_dir_cachep, sd);
    +}
    +
    +static struct sysfs_dirent *sysfs_get(struct sysfs_dirent *sd)
    +{
    + if (sd) {
    + WARN_ON(!atomic_read(&sd->s_count));
    + atomic_inc(&sd->s_count);
    + }
    + return sd;
    +}
    +
    +static void sysfs_put(struct sysfs_dirent *sd)
    +{
    + WARN_ON(!atomic_read(&sd->s_count));
    + if (atomic_dec_and_test(&sd->s_count))
    + release_sysfs_dirent(sd);
    +}
    +
    +/*
    + * inode.c - basic inode and dentry operations.
    + */
    +
    +int sysfs_setattr(struct dentry *dentry, struct iattr *iattr)
    +{
    + struct inode *inode = dentry->d_inode;
    + struct sysfs_dirent *sd = dentry->d_fsdata;
    + struct iattr *sd_iattr;
    + unsigned int ia_valid = iattr->ia_valid;
    + int error;
    +
    + if (!sd)
    + return -EINVAL;
    +
    + sd_iattr = sd->s_iattr;
    +
    + error = inode_change_ok(inode, iattr);
    + if (error)
    + return error;
    +
    + error = inode_setattr(inode, iattr);
    + if (error)
    + return error;
    +
    + if (!sd_iattr) {
    + /* setting attributes for the first time, allocate now */
    + sd_iattr = kmalloc(sizeof(struct iattr), GFP_KERNEL);
    + if (!sd_iattr)
    + return -ENOMEM;
    + /* assign default attributes */
    + memset(sd_iattr, 0, sizeof(struct iattr));
    + sd_iattr->ia_mode = sd->s_mode;
    + sd_iattr->ia_uid = 0;
    + sd_iattr->ia_gid = 0;
    + sd_iattr->ia_atime = sd_iattr->ia_mtime = sd_iattr->ia_ctime =
    + CURRENT_TIME;
    + sd->s_iattr = sd_iattr;
    + }
    +
    + /* attributes were changed atleast once in past */
    +
    + if (ia_valid & ATTR_UID)
    + sd_iattr->ia_uid = iattr->ia_uid;
    + if (ia_valid & ATTR_GID)
    + sd_iattr->ia_gid = iattr->ia_gid;
    + if (ia_valid & ATTR_ATIME)
    + sd_iattr->ia_atime = timespec_trunc(iattr->ia_atime,
    + inode->i_sb->s_time_gran);
    + if (ia_valid & ATTR_MTIME)
    + sd_iattr->ia_mtime = timespec_trunc(iattr->ia_mtime,
    + inode->i_sb->s_time_gran);
    + if (ia_valid & ATTR_CTIME)
    + sd_iattr->ia_ctime = timespec_trunc(iattr->ia_ctime,
    + inode->i_sb->s_time_gran);
    + if (ia_valid & ATTR_MODE) {
    + umode_t mode = iattr->ia_mode;
    +
    + if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID))
    + mode &= ~S_ISGID;
    + sd_iattr->ia_mode = sd->s_mode = mode;
    + }
    +
    + return error;
    +}
    +
    +static struct inode_operations sysfs_inode_operations = {
    + .setattr = sysfs_setattr,
    +};
    +
    +static struct super_block *sysfs_sb;
    +
    +static struct address_space_operations sysfs_aops = {
    + .readpage = simple_readpage,
    + .prepare_write = simple_prepare_write,
    + .commit_write = simple_commit_write
    +};
    +
    +static struct backing_dev_info sysfs_backing_dev_info = {
    + .ra_pages = 0, /* No readahead */
    + .capabilities = BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_WRITEBACK,
    +};
    +
    +static struct inode *sysfs_new_inode(mode_t mode, struct sysfs_dirent *sd)
    +{
    + struct inode *inode = new_inode(sysfs_sb);
    + if (inode) {
    + inode->i_blksize = PAGE_CACHE_SIZE;
    + inode->i_blocks = 0;
    + inode->i_mapping->a_ops = &sysfs_aops;
    + inode->i_mapping->backing_dev_info = &sysfs_backing_dev_info;
    + inode->i_op = &sysfs_inode_operations;
    +
    + if (sd->s_iattr) {
    + /* sysfs_dirent has non-default attributes
    + * get them for the new inode from persistent copy
    + * in sysfs_dirent */
    + struct iattr *iattr = sd->s_iattr;
    + inode->i_mode = iattr->ia_mode;
    + inode->i_uid = iattr->ia_uid;
    + inode->i_gid = iattr->ia_gid;
    + inode->i_atime = iattr->ia_atime;
    + inode->i_mtime = iattr->ia_mtime;
    + inode->i_ctime = iattr->ia_ctime;
    + } else {
    + inode->i_mode = mode;
    + inode->i_uid = 0;
    + inode->i_gid = 0;
    + inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
    + }
    + }
    + return inode;
    +}
    +
    +static int sysfs_create(struct dentry *dentry, int mode, int (*init) (struct inode *))
    +{
    + int error = 0;
    + struct inode *inode = NULL;
    + if (dentry) {
    + if (!dentry->d_inode) {
    + struct sysfs_dirent *sd = dentry->d_fsdata;
    + if ((inode = sysfs_new_inode(mode, sd))) {
    + if (dentry->d_parent
    + && dentry->d_parent->d_inode) {
    + struct inode *p_inode =
    + dentry->d_parent->d_inode;
    + p_inode->i_mtime = p_inode->i_ctime =
    + CURRENT_TIME;
    + }
    + goto Proceed;
    + } else
    + error = -ENOMEM;
    + } else
    + error = -EEXIST;
    + } else
    + error = -ENOENT;
    + goto Done;
    +
    + Proceed:
    + if (init)
    + error = init(inode);
    + if (!error) {
    + d_instantiate(dentry, inode);
    + if (S_ISDIR(mode)) /* pin only directory dentry in core */
    + dget(dentry);
    + } else
    + iput(inode);
    + Done:
    + return error;
    +}
    +
    +/*
    + * Get the name for corresponding element represented by the given sysfs_dirent
    + */
    +static const unsigned char *sysfs_get_name(struct sysfs_dirent *sd)
    +{
    + struct attribute *attr;
    + struct bin_attribute *bin_attr;
    + struct sysfs_symlink *sl;
    +
    + if (!sd || !sd->s_element)
    + BUG();
    +
    + switch (sd->s_type) {
    + case SYSFS_DIR:
    + /* Always have a dentry so use that */
    + return sd->s_dentry->d_name.name;
    +
    + case SYSFS_KOBJ_ATTR:
    + attr = sd->s_element;
    + return attr->name;
    +
    + case SYSFS_KOBJ_BIN_ATTR:
    + bin_attr = sd->s_element;
    + return bin_attr->attr.name;
    +
    + case SYSFS_KOBJ_LINK:
    + sl = sd->s_element;
    + return sl->link_name;
    + }
    + return NULL;
    +}
    +
    +/*
    + * Unhashes the dentry corresponding to given sysfs_dirent
    + * Called with parent inode's i_sem held.
    + */
    +static void sysfs_drop_dentry(struct sysfs_dirent *sd, struct dentry *parent)
    +{
    + struct dentry *dentry = sd->s_dentry;
    +
    + if (dentry) {
    + spin_lock(&dcache_lock);
    + spin_lock(&dentry->d_lock);
    + if (!(d_unhashed(dentry) && dentry->d_inode)) {
    + dget_locked(dentry);
    + __d_drop(dentry);
    + spin_unlock(&dentry->d_lock);
    + spin_unlock(&dcache_lock);
    + simple_unlink(parent->d_inode, dentry);
    + } else {
    + spin_unlock(&dentry->d_lock);
    + spin_unlock(&dcache_lock);
    + }
    + }
    +}
    +
    +static void sysfs_hash_and_remove(struct dentry *dir, const char *name)
    +{
    + struct sysfs_dirent *sd;
    + struct sysfs_dirent *parent_sd = dir->d_fsdata;
    +
    + down(&dir->d_inode->i_sem);
    + list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
    + if (!sd->s_element)
    + continue;
    + if (!strcmp(sysfs_get_name(sd), name)) {
    + list_del_init(&sd->s_sibling);
    + sysfs_drop_dentry(sd, dir);
    + sysfs_put(sd);
    + break;
    + }
    + }
    + up(&dir->d_inode->i_sem);
    +}
    +
    +/*
    + * symlink.c - operations for sysfs symlinks.
    + */
    +
    +static int object_depth(struct kobject *kobj)
    +{
    + struct kobject *p = kobj;
    + int depth = 0;
    + do {
    + depth++;
    + } while ((p = p->parent));
    + return depth;
    +}
    +
    +static int object_path_length(struct kobject *kobj)
    +{
    + struct kobject *p = kobj;
    + int length = 1;
    + do {
    + length += strlen(kobject_name(p)) + 1;
    + p = p->parent;
    + } while (p);
    + return length;
    +}
    +
    +static void fill_object_path(struct kobject *kobj, char *buffer, int length)
    +{
    + struct kobject *p;
    +
    + --length;
    + for (p = kobj; p; p = p->parent) {
    + int cur = strlen(kobject_name(p));
    +
    + /* back up enough to print this bus id with '/' */
    + length -= cur;
    + strncpy(buffer + length, kobject_name(p), cur);
    + *(buffer + --length) = '/';
    + }
    +}
    +
    +static int sysfs_get_target_path(struct kobject *kobj, struct kobject *target, char *path)
    +{
    + char *s;
    + int depth, size;
    +
    + depth = object_depth(kobj);
    + size = object_path_length(target) + depth * 3 - 1;
    + if (size > PATH_MAX)
    + return -ENAMETOOLONG;
    +
    + pr_debug("%s: depth = %d, size = %d\n", __FUNCTION__, depth, size);
    +
    + for (s = path; depth--; s += 3)
    + strcpy(s, "../");
    +
    + fill_object_path(target, path, size);
    + pr_debug("%s: path = '%s'\n", __FUNCTION__, path);
    +
    + return 0;
    +}
    +
    +DECLARE_RWSEM(sysfs_rename_sem);
    +
    +static int sysfs_getlink(struct dentry *dentry, char *path)
    +{
    + struct kobject *kobj, *sl_target;
    + int error = 0;
    +
    + kobj = sysfs_get_kobject(dentry->d_parent);
    + if (!kobj)
    + return -EINVAL;
    +
    + sl_target = sysfs_get_kobject(dentry);
    + if (!sl_target) {
    + kobject_put(kobj);
    + return -EINVAL;
    + }
    +
    + down_read(&sysfs_rename_sem);
    + error = sysfs_get_target_path(kobj, sl_target, path);
    + up_read(&sysfs_rename_sem);
    +
    + kobject_put(kobj);
    + kobject_put(sl_target);
    + return error;
    +
    +}
    +
    +static int 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);
    + nd_set_link(nd, error ? ERR_PTR(error) : (char *)page);
    + return 0;
    +}
    +
    +static void sysfs_put_link(struct dentry *dentry, struct nameidata *nd)
    +{
    + char *page = nd_get_link(nd);
    + if (!IS_ERR(page))
    + free_page((unsigned long)page);
    +}
    +
    +static struct inode_operations sysfs_symlink_inode_operations = {
    + .readlink = generic_readlink,
    + .follow_link = sysfs_follow_link,
    + .put_link = sysfs_put_link,
    +};
    +
    +static int init_symlink(struct inode *inode)
    +{
    + inode->i_op = &sysfs_symlink_inode_operations;
    + return 0;
    +}
    +
    +/*
    + * file.c - operations for regular (text) files.
    + */
    +
    +#define to_subsys(k) container_of(k, struct subsystem, kset.kobj)
    +#define to_sattr(a) container_of(a, struct subsys_attribute, attr)
    +
    +/*
    + * Subsystem file operations.
    + * These operations allow subsystems to have files that can be
    + * read/written.
    + */
    +static ssize_t subsys_attr_show(struct kobject *kobj, struct attribute *attr,
    + char *page)
    +{
    + struct subsystem *s = to_subsys(kobj);
    + struct subsys_attribute *sattr = to_sattr(attr);
    + ssize_t ret = -EIO;
    +
    + if (sattr->show)
    + ret = sattr->show(s, page);
    + return ret;
    +}
    +
    +static ssize_t subsys_attr_store(struct kobject *kobj, struct attribute *attr,
    + const char *page, size_t count)
    +{
    + struct subsystem *s = to_subsys(kobj);
    + struct subsys_attribute *sattr = to_sattr(attr);
    + ssize_t ret = -EIO;
    +
    + if (sattr->store)
    + ret = sattr->store(s, page, count);
    + return ret;
    +}
    +
    +static struct sysfs_ops subsys_sysfs_ops = {
    + .show = subsys_attr_show,
    + .store = subsys_attr_store,
    +};
    +
    +/*
    + * file.c - operations for regular (text) files.
    + */
    +
    +struct sysfs_buffer {
    + size_t count;
    + loff_t pos;
    + char *page;
    + struct sysfs_ops *ops;
    + struct semaphore sem;
    + int needs_read_fill;
    +};
    +
    +/*
    + * Allocate @buffer->page, if it hasn't been already, then call the
    + * kobject's show() method to fill the buffer with this attribute's
    + * data. This is called only once, on the file's first read.
    + */
    +static int fill_read_buffer(struct dentry *dentry, struct sysfs_buffer *buffer)
    +{
    + struct attribute *attr = to_attr(dentry);
    + struct kobject *kobj = to_kobj(dentry->d_parent);
    + struct sysfs_ops *ops = buffer->ops;
    + int ret = 0;
    + ssize_t count;
    +
    + if (!buffer->page)
    + buffer->page = (char *)get_zeroed_page(GFP_KERNEL);
    + if (!buffer->page)
    + return -ENOMEM;
    +
    + count = ops->show(kobj, attr, buffer->page);
    + buffer->needs_read_fill = 0;
    + BUG_ON(count > (ssize_t) PAGE_SIZE);
    + if (count >= 0)
    + buffer->count = count;
    + else
    + ret = count;
    + return ret;
    +}
    +
    +/*
    + * Copy the buffer we filled in fill_read_buffer() to userspace.
    + * This is done at the reader's leisure, copying and advancing
    + * the amount they specify each time.
    + * This may be called continuously until the buffer is empty.
    + */
    +static int flush_read_buffer(struct sysfs_buffer *buffer, char __user *buf,
    + size_t count, loff_t *ppos)
    +{
    + int error;
    +
    + if (*ppos > buffer->count)
    + return 0;
    +
    + if (count > (buffer->count - *ppos))
    + count = buffer->count - *ppos;
    +
    + error = copy_to_user(buf, buffer->page + *ppos, count);
    + if (!error)
    + *ppos += count;
    + return error ? -EFAULT : count;
    +}
    +
    +/*
    + * Allocate @buffer->page if it hasn't been already, then
    + * copy the user-supplied buffer into it.
    + */
    +static int fill_write_buffer(struct sysfs_buffer *buffer, const char __user *buf,
    + size_t count)
    +{
    + int error;
    +
    + if (!buffer->page)
    + buffer->page = (char *)get_zeroed_page(GFP_KERNEL);
    + if (!buffer->page)
    + return -ENOMEM;
    +
    + if (count > PAGE_SIZE)
    + count = PAGE_SIZE;
    + error = copy_from_user(buffer->page, buf, count);
    + buffer->needs_read_fill = 1;
    + return error ? -EFAULT : count;
    +}
    +
    +/*
    + * Get the correct pointers for the kobject and the attribute we're
    + * dealing with, then call the store method for the attribute,
    + * passing the buffer that we acquired in fill_write_buffer().
    + */
    +static int flush_write_buffer(struct dentry *dentry, struct sysfs_buffer *buffer,
    + size_t count)
    +{
    + struct attribute *attr = to_attr(dentry);
    + struct kobject *kobj = to_kobj(dentry->d_parent);
    + struct sysfs_ops *ops = buffer->ops;
    +
    + return ops->store(kobj, attr, buffer->page, count);
    +}
    +
    +static int check_perm(struct inode *inode, struct file *file)
    +{
    + struct kobject *kobj = sysfs_get_kobject(file->f_dentry->d_parent);
    + struct attribute *attr = to_attr(file->f_dentry);
    + struct sysfs_buffer *buffer;
    + struct sysfs_ops *ops = NULL;
    + int error = 0;
    +
    + if (!kobj || !attr)
    + goto Einval;
    +
    + /* Grab the module reference for this attribute if we have one */
    + if (!try_module_get(attr->owner)) {
    + error = -ENODEV;
    + goto Done;
    + }
    +
    + /* if the kobject has no ktype, then we assume that it is a subsystem
    + * itself, and use ops for it.
    + */
    + if (kobj->kset && kobj->kset->ktype)
    + ops = kobj->kset->ktype->sysfs_ops;
    + else if (kobj->ktype)
    + ops = kobj->ktype->sysfs_ops;
    + else
    + ops = &subsys_sysfs_ops;
    +
    + /* No sysfs operations, either from having no subsystem,
    + * or the subsystem have no operations.
    + */
    + if (!ops)
    + goto Eaccess;
    +
    + /* File needs write support.
    + * The inode's perms must say it's ok, and we must have a store method.
    + */
    + if (file->f_mode & FMODE_WRITE) {
    +
    + if (!(inode->i_mode & S_IWUGO) || !ops->store)
    + goto Eaccess;
    +
    + }
    +
    + /* File needs read support.
    + * The inode's perms must say it's ok, and we there
    + * must be a show method for it.
    + */
    + if (file->f_mode & FMODE_READ) {
    + if (!(inode->i_mode & S_IRUGO) || !ops->show)
    + goto Eaccess;
    + }
    +
    + /* No error? Great, allocate a buffer for the file, and store it
    + * it in file->private_data for easy access.
    + */
    + buffer = kmalloc(sizeof(struct sysfs_buffer), GFP_KERNEL);
    + if (buffer) {
    + memset(buffer, 0, sizeof(struct sysfs_buffer));
    + init_MUTEX(&buffer->sem);
    + buffer->needs_read_fill = 1;
    + buffer->ops = ops;
    + file->private_data = buffer;
    + } else
    + error = -ENOMEM;
    + goto Done;
    +
    + Einval:
    + error = -EINVAL;
    + goto Done;
    + Eaccess:
    + error = -EACCES;
    + module_put(attr->owner);
    + Done:
    + if (error && kobj)
    + kobject_put(kobj);
    + return error;
    +}
    +
    +/*
    + * Userspace wants to read an attribute file. The attribute descriptor
    + * is in the file's ->d_fsdata. The target object is in the directory's
    + * ->d_fsdata.
    + *
    + * We call fill_read_buffer() to allocate and fill the buffer from the
    + * object's show() method exactly once (if the read is happening from
    + * the beginning of the file). That should fill the entire buffer with
    + * all the data the object has to offer for that attribute.
    + * We then call flush_read_buffer() to copy the buffer to userspace
    + * in the increments specified.
    + */
    +static ssize_t sysfs_read_file(struct file *file, char __user *buf,
    + size_t count, loff_t *ppos)
    +{
    + struct sysfs_buffer *buffer = file->private_data;
    + ssize_t retval = 0;
    +
    + down(&buffer->sem);
    + if (buffer->needs_read_fill) {
    + if ((retval = fill_read_buffer(file->f_dentry, buffer)))
    + goto out;
    + }
    + pr_debug("%s: count = %d, ppos = %lld, buf = %s\n",
    + __FUNCTION__, count, *ppos, buffer->page);
    + retval = flush_read_buffer(buffer, buf, count, ppos);
    + out:
    + up(&buffer->sem);
    + return retval;
    +}
    +
    +/*
    + * Similar to sysfs_read_file(), though working in the opposite direction.
    + * We allocate and fill the data from the user in fill_write_buffer(),
    + * then push it to the kobject in flush_write_buffer().
    + * There is no easy way for us to know if userspace is only doing a partial
    + * write, so we don't support them. We expect the entire buffer to come
    + * on the first write.
    + * Hint: if you're writing a value, first read the file, modify only the
    + * the value you're changing, then write entire buffer back.
    + */
    +static ssize_t sysfs_write_file(struct file *file, const char __user *buf,
    + size_t count, loff_t *ppos)
    +{
    + struct sysfs_buffer *buffer = file->private_data;
    +
    + down(&buffer->sem);
    + count = fill_write_buffer(buffer, buf, count);
    + if (count > 0)
    + count = flush_write_buffer(file->f_dentry, buffer, count);
    + if (count > 0)
    + *ppos += count;
    + up(&buffer->sem);
    + return count;
    +}
    +
    +static int sysfs_open_file(struct inode *inode, struct file *filp)
    +{
    + return check_perm(inode, filp);
    +}
    +
    +static int sysfs_release(struct inode *inode, struct file *filp)
    +{
    + struct kobject *kobj = to_kobj(filp->f_dentry->d_parent);
    + struct attribute *attr = to_attr(filp->f_dentry);
    + struct module *owner = attr->owner;
    + struct sysfs_buffer *buffer = filp->private_data;
    +
    + if (kobj)
    + kobject_put(kobj);
    + /* After this point, attr should not be accessed. */
    + module_put(owner);
    +
    + if (buffer) {
    + if (buffer->page)
    + free_page((unsigned long)buffer->page);
    + kfree(buffer);
    + }
    + return 0;
    +}
    +
    +static struct file_operations sysfs_file_operations = {
    + .read = sysfs_read_file,
    + .write = sysfs_write_file,
    + .llseek = generic_file_llseek,
    + .open = sysfs_open_file,
    + .release = sysfs_release,
    +};
    +
    +static int init_file(struct inode *inode)
    +{
    + inode->i_size = PAGE_SIZE;
    + inode->i_fop = &sysfs_file_operations;
    + return 0;
    +}
    +
    +static void sysfs_d_iput(struct dentry *dentry, struct inode *inode)
    +{
    + struct sysfs_dirent *sd = dentry->d_fsdata;
    +
    + if (sd) {
    + BUG_ON(sd->s_dentry != dentry);
    + sd->s_dentry = NULL;
    + sysfs_put(sd);
    + }
    + iput(inode);
    +}
    +
    +static struct dentry_operations sysfs_dentry_ops = {
    + .d_iput = sysfs_d_iput,
    +};
    +
    +/*
    + * Allocates a new sysfs_dirent and links it to the parent sysfs_dirent
    + */
    +static struct sysfs_dirent *sysfs_new_dirent(struct sysfs_dirent *parent_sd,
    + void *element)
    +{
    + struct sysfs_dirent *sd;
    +
    + sd = kmem_cache_alloc(sysfs_dir_cachep, GFP_KERNEL);
    + if (!sd)
    + return NULL;
    +
    + memset(sd, 0, sizeof(*sd));
    + atomic_set(&sd->s_count, 1);
    + INIT_LIST_HEAD(&sd->s_children);
    + list_add(&sd->s_sibling, &parent_sd->s_children);
    + sd->s_element = element;
    +
    + return sd;
    +}
    +
    +int sysfs_make_dirent(struct sysfs_dirent *parent_sd, struct dentry *dentry,
    + void *element, umode_t mode, int type)
    +{
    + struct sysfs_dirent *sd;
    +
    + sd = sysfs_new_dirent(parent_sd, element);
    + if (!sd)
    + return -ENOMEM;
    +
    + sd->s_mode = mode;
    + sd->s_type = type;
    + sd->s_dentry = dentry;
    + if (dentry) {
    + dentry->d_fsdata = sysfs_get(sd);
    + dentry->d_op = &sysfs_dentry_ops;
    + }
    +
    + return 0;
    +}
    +
    +static int sysfs_add_file(struct dentry *dir, const struct attribute *attr, int type)
    +{
    + struct sysfs_dirent *parent_sd = dir->d_fsdata;
    + umode_t mode = (attr->mode & S_IALLUGO) | S_IFREG;
    + int error = 0;
    +
    + down(&dir->d_inode->i_sem);
    + error = sysfs_make_dirent(parent_sd, NULL, (void *)attr, mode, type);
    + up(&dir->d_inode->i_sem);
    +
    + return error;
    +}
    +
    +int sysfs_create_file(struct kobject *kobj, const struct attribute *attr)
    +{
    + BUG_ON(!kobj || !kobj->dentry || !attr);
    +
    + return sysfs_add_file(kobj->dentry, attr, SYSFS_KOBJ_ATTR);
    +}
    +
    +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;
    + int error = 0;
    +
    + error = -ENOMEM;
    + sl = kmalloc(sizeof(*sl), GFP_KERNEL);
    + if (!sl)
    + goto exit1;
    +
    + sl->link_name = kmalloc(strlen(name) + 1, GFP_KERNEL);
    + if (!sl->link_name)
    + goto exit2;
    +
    + strcpy(sl->link_name, name);
    + sl->sl_target = kobject_get(target);
    +
    + error = sysfs_make_dirent(parent_sd, NULL, sl, S_IFLNK | S_IRWXUGO,
    + SYSFS_KOBJ_LINK);
    + if (!error)
    + return 0;
    +
    + kfree(sl->link_name);
    + exit2:
    + kfree(sl);
    + exit1:
    + return error;
    +}
    +
    +/*
    + * dir.c - Operations for directories.
    + */
    +
    +static int sysfs_dir_open(struct inode *inode, struct file *file)
    +{
    + struct dentry *dentry = file->f_dentry;
    + struct sysfs_dirent *parent_sd = dentry->d_fsdata;
    +
    + down(&dentry->d_inode->i_sem);
    + file->private_data = sysfs_new_dirent(parent_sd, NULL);
    + up(&dentry->d_inode->i_sem);
    +
    + return file->private_data ? 0 : -ENOMEM;
    +}
    +
    +static int sysfs_dir_close(struct inode *inode, struct file *file)
    +{
    + struct dentry *dentry = file->f_dentry;
    + struct sysfs_dirent *cursor = file->private_data;
    +
    + down(&dentry->d_inode->i_sem);
    + list_del_init(&cursor->s_sibling);
    + up(&dentry->d_inode->i_sem);
    +
    + release_sysfs_dirent(cursor);
    +
    + return 0;
    +}
    +
    +/* Relationship between s_mode and the DT_xxx types */
    +static inline unsigned char dt_type(struct sysfs_dirent *sd)
    +{
    + return (sd->s_mode >> 12) & 15;
    +}
    +
    +static int sysfs_readdir(struct file *filp, void *dirent, filldir_t filldir)
    +{
    + struct dentry *dentry = filp->f_dentry;
    + struct sysfs_dirent *parent_sd = dentry->d_fsdata;
    + struct sysfs_dirent *cursor = filp->private_data;
    + struct list_head *p, *q = &cursor->s_sibling;
    + ino_t ino;
    + int i = filp->f_pos;
    +
    + switch (i) {
    + case 0:
    + ino = dentry->d_inode->i_ino;
    + if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0)
    + break;
    + filp->f_pos++;
    + i++;
    + /* fallthrough */
    + case 1:
    + ino = parent_ino(dentry);
    + if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0)
    + break;
    + filp->f_pos++;
    + i++;
    + /* fallthrough */
    + default:
    + if (filp->f_pos == 2) {
    + list_del(q);
    + list_add(q, &parent_sd->s_children);
    + }
    + for (p = q->next; p != &parent_sd->s_children; p = p->next) {
    + struct sysfs_dirent *next;
    + const char *name;
    + int len;
    +
    + next = list_entry(p, struct sysfs_dirent, s_sibling);
    + if (!next->s_element)
    + continue;
    +
    + name = sysfs_get_name(next);
    + len = strlen(name);
    + if (next->s_dentry)
    + ino = next->s_dentry->d_inode->i_ino;
    + else
    + ino = iunique(sysfs_sb, 2);
    +
    + if (filldir(dirent, name, len, filp->f_pos, ino,
    + dt_type(next)) < 0)
    + return 0;
    +
    + list_del(q);
    + list_add(q, p);
    + p = q;
    + filp->f_pos++;
    + }
    + }
    + return 0;
    +}
    +
    +static loff_t sysfs_dir_lseek(struct file *file, loff_t offset, int origin)
    +{
    + struct dentry *dentry = file->f_dentry;
    +
    + down(&dentry->d_inode->i_sem);
    + switch (origin) {
    + case 1:
    + offset += file->f_pos;
    + case 0:
    + if (offset >= 0)
    + break;
    + default:
    + up(&file->f_dentry->d_inode->i_sem);
    + return -EINVAL;
    + }
    + if (offset != file->f_pos) {
    + file->f_pos = offset;
    + if (file->f_pos >= 2) {
    + struct sysfs_dirent *sd = dentry->d_fsdata;
    + struct sysfs_dirent *cursor = file->private_data;
    + struct list_head *p;
    + loff_t n = file->f_pos - 2;
    +
    + list_del(&cursor->s_sibling);
    + p = sd->s_children.next;
    + while (n && p != &sd->s_children) {
    + struct sysfs_dirent *next;
    + next = list_entry(p, struct sysfs_dirent,
    + s_sibling);
    + if (next->s_element)
    + n--;
    + p = p->next;
    + }
    + list_add_tail(&cursor->s_sibling, p);
    + }
    + }
    + up(&dentry->d_inode->i_sem);
    + return offset;
    +}
    +
    +static struct file_operations sysfs_dir_operations = {
    + .open = sysfs_dir_open,
    + .release = sysfs_dir_close,
    + .llseek = sysfs_dir_lseek,
    + .read = generic_read_dir,
    + .readdir = sysfs_readdir,
    +};
    +
    +/*
    + * bin.c - binary file operations for sysfs.
    + *
    + * Copyright (c) 2003 Patrick Mochel
    + * Copyright (c) 2003 Matthew Wilcox
    + * Copyright (c) 2004 Silicon Graphics, Inc.
    + */
    +
    +static inline struct bin_attribute *to_bin_attr(struct dentry *dentry)
    +{
    + struct sysfs_dirent *sd = dentry->d_fsdata;
    + return ((struct bin_attribute *)sd->s_element);
    +}
    +
    +static int fill_read(struct dentry *dentry, char *buffer, loff_t off,
    + size_t count)
    +{
    + struct bin_attribute *attr = to_bin_attr(dentry);
    + struct kobject *kobj = to_kobj(dentry->d_parent);
    +
    + if (!attr->read)
    + return -EIO;
    +
    + return attr->read(kobj, buffer, off, count);
    +}
    +
    +static ssize_t read(struct file *file, char __user *userbuf, size_t count, loff_t *off)
    +{
    + char *buffer = file->private_data;
    + struct dentry *dentry = file->f_dentry;
    + int size = dentry->d_inode->i_size;
    + loff_t offs = *off;
    + int ret;
    +
    + if (count > PAGE_SIZE)
    + count = PAGE_SIZE;
    +
    + if (size) {
    + if (offs > size)
    + return 0;
    + if (offs + count > size)
    + count = size - offs;
    + }
    +
    + ret = fill_read(dentry, buffer, offs, count);
    + if (ret < 0)
    + return ret;
    + count = ret;
    +
    + if (copy_to_user(userbuf, buffer, count))
    + return -EFAULT;
    +
    + pr_debug("offs = %lld, *off = %lld, count = %zd\n", offs, *off, count);
    +
    + *off = offs + count;
    +
    + return count;
    +}
    +
    +static int flush_write(struct dentry *dentry, char *buffer, loff_t offset, size_t count)
    +{
    + struct bin_attribute *attr = to_bin_attr(dentry);
    + struct kobject *kobj = to_kobj(dentry->d_parent);
    +
    + if (!attr->write)
    + return -EIO;
    +
    + return attr->write(kobj, buffer, offset, count);
    +}
    +
    +static ssize_t write(struct file *file, const char __user *userbuf, size_t count, loff_t *off)
    +{
    + char *buffer = file->private_data;
    + struct dentry *dentry = file->f_dentry;
    + int size = dentry->d_inode->i_size;
    + loff_t offs = *off;
    +
    + if (count > PAGE_SIZE)
    + count = PAGE_SIZE;
    + if (size) {
    + if (offs > size)
    + return 0;
    + if (offs + count > size)
    + count = size - offs;
    + }
    +
    + if (copy_from_user(buffer, userbuf, count))
    + return -EFAULT;
    +
    + count = flush_write(dentry, buffer, offs, count);
    + if (count > 0)
    + *off = offs + count;
    + return count;
    +}
    +
    +static int mmap(struct file *file, struct vm_area_struct *vma)
    +{
    + struct dentry *dentry = file->f_dentry;
    + struct bin_attribute *attr = to_bin_attr(dentry);
    + struct kobject *kobj = to_kobj(dentry->d_parent);
    +
    + if (!attr->mmap)
    + return -EINVAL;
    +
    + return attr->mmap(kobj, attr, vma);
    +}
    +
    +static int open(struct inode *inode, struct file *file)
    +{
    + struct kobject *kobj = sysfs_get_kobject(file->f_dentry->d_parent);
    + struct bin_attribute *attr = to_bin_attr(file->f_dentry);
    + int error = -EINVAL;
    +
    + if (!kobj || !attr)
    + goto Done;
    +
    + /* Grab the module reference for this attribute if we have one */
    + error = -ENODEV;
    + if (!try_module_get(attr->attr.owner))
    + goto Done;
    +
    + error = -EACCES;
    + if ((file->f_mode & FMODE_WRITE) && !(attr->write || attr->mmap))
    + goto Error;
    + if ((file->f_mode & FMODE_READ) && !(attr->read || attr->mmap))
    + goto Error;
    +
    + error = -ENOMEM;
    + file->private_data = kmalloc(PAGE_SIZE, GFP_KERNEL);
    + if (!file->private_data)
    + goto Error;
    +
    + error = 0;
    + goto Done;
    +
    + Error:
    + module_put(attr->attr.owner);
    + Done:
    + if (error && kobj)
    + kobject_put(kobj);
    + return error;
    +}
    +
    +static int release(struct inode *inode, struct file *file)
    +{
    + struct kobject *kobj = to_kobj(file->f_dentry->d_parent);
    + struct bin_attribute *attr = to_bin_attr(file->f_dentry);
    + u8 *buffer = file->private_data;
    +
    + if (kobj)
    + kobject_put(kobj);
    + module_put(attr->attr.owner);
    + kfree(buffer);
    + return 0;
    +}
    +
    +struct file_operations bin_fops = {
    + .read = read,
    + .write = write,
    + .mmap = mmap,
    + .llseek = generic_file_llseek,
    + .open = open,
    + .release = release,
    +};
    +
    +int sysfs_create_bin_file(struct kobject *kobj, struct bin_attribute *attr)
    +{
    + BUG_ON(!kobj || !kobj->dentry || !attr);
    +
    + return sysfs_add_file(kobj->dentry, &attr->attr, SYSFS_KOBJ_BIN_ATTR);
    +}
    +
    +int sysfs_remove_bin_file(struct kobject *kobj, struct bin_attribute *attr)
    +{
    + sysfs_hash_and_remove(kobj->dentry, attr->attr.name);
    + return 0;
    +}
    +
    +/* attaches attribute's sysfs_dirent to the dentry corresponding to the
    + * attribute file
    + */
    +static int sysfs_attach_attr(struct sysfs_dirent *sd, struct dentry *dentry)
    +{
    + struct attribute *attr = NULL;
    + struct bin_attribute *bin_attr = NULL;
    + int (*init) (struct inode *) = NULL;
    + int error = 0;
    +
    + if (sd->s_type & SYSFS_KOBJ_BIN_ATTR) {
    + bin_attr = sd->s_element;
    + attr = &bin_attr->attr;
    + } else {
    + attr = sd->s_element;
    + init = init_file;
    + }
    +
    + dentry->d_fsdata = sysfs_get(sd);
    + sd->s_dentry = dentry;
    + error = sysfs_create(dentry, (attr->mode & S_IALLUGO) | S_IFREG, init);
    + if (error) {
    + sysfs_put(sd);
    + return error;
    + }
    +
    + if (bin_attr) {
    + dentry->d_inode->i_size = bin_attr->size;
    + dentry->d_inode->i_fop = &bin_fops;
    + }
    + dentry->d_op = &sysfs_dentry_ops;
    + d_rehash(dentry);
    +
    + return 0;
    +}
    +
    +static int sysfs_attach_link(struct sysfs_dirent *sd, struct dentry *dentry)
    +{
    + int err = 0;
    +
    + dentry->d_fsdata = sysfs_get(sd);
    + sd->s_dentry = dentry;
    + err = sysfs_create(dentry, S_IFLNK | S_IRWXUGO, init_symlink);
    + if (!err) {
    + dentry->d_op = &sysfs_dentry_ops;
    + d_rehash(dentry);
    + } else
    + sysfs_put(sd);
    +
    + return err;
    +}
    +
    +static struct dentry *sysfs_lookup(struct inode *dir, struct dentry *dentry,
    + struct nameidata *nd)
    +{
    + struct sysfs_dirent *parent_sd = dentry->d_parent->d_fsdata;
    + struct sysfs_dirent *sd;
    + int err = 0;
    +
    + list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
    + if (sd->s_type & SYSFS_NOT_PINNED) {
    + const unsigned char *name = sysfs_get_name(sd);
    +
    + if (strcmp(name, dentry->d_name.name))
    + continue;
    +
    + if (sd->s_type & SYSFS_KOBJ_LINK)
    + err = sysfs_attach_link(sd, dentry);
    + else
    + err = sysfs_attach_attr(sd, dentry);
    + break;
    + }
    + }
    +
    + return ERR_PTR(err);
    +}
    +
    +struct inode_operations sysfs_dir_inode_operations = {
    + .lookup = sysfs_lookup,
    + .setattr = sysfs_setattr,
    +};
    +
    +static int init_dir(struct inode *inode)
    +{
    + inode->i_op = &sysfs_dir_inode_operations;
    + inode->i_fop = &sysfs_dir_operations;
    +
    + /* directory inodes start off with i_nlink == 2 (for "." entry) */
    + inode->i_nlink++;
    + return 0;
    +}
    +
    +static int create_dir(struct kobject *k, struct dentry *p, const char *n, struct dentry **d)
    +{
    + int error;
    + umode_t mode = S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO;
    +
    + down(&p->d_inode->i_sem);
    + *d = lookup_one_len(n, p, strlen(n));
    + if (!IS_ERR(*d)) {
    + error = sysfs_make_dirent(p->d_fsdata, *d, k, mode, SYSFS_DIR);
    + if (!error) {
    + error = sysfs_create(*d, mode, init_dir);
    + if (!error) {
    + p->d_inode->i_nlink++;
    + (*d)->d_op = &sysfs_dentry_ops;
    + d_rehash(*d);
    + }
    + }
    + if (error && (error != -EEXIST)) {
    + sysfs_put((*d)->d_fsdata);
    + d_drop(*d);
    + }
    + dput(*d);
    + } else
    + error = PTR_ERR(*d);
    + up(&p->d_inode->i_sem);
    + return error;
    +}
    +
    +int sysfs_create_subdir(struct kobject *k, const char *n, struct dentry **d)
    +{
    + return create_dir(k, k->dentry, n, d);
    +}
    +
    +struct vfsmount *sysfs_mount;
    +
    +int sysfs_create_dir(struct kobject *kobj)
    +{
    + struct dentry *dentry = NULL;
    + struct dentry *parent;
    + int error = 0;
    +
    + BUG_ON(!kobj);
    +
    + if (kobj->parent)
    + parent = kobj->parent->dentry;
    + else if (sysfs_mount && sysfs_mount->mnt_sb)
    + parent = sysfs_mount->mnt_sb->s_root;
    + else
    + return -EFAULT;
    +
    + error = create_dir(kobj, parent, kobject_name(kobj), &dentry);
    + if (!error)
    + kobj->dentry = dentry;
    + return error;
    +}
    +
    +static void remove_dir(struct dentry *d)
    +{
    + struct dentry *parent = dget(d->d_parent);
    + struct sysfs_dirent *sd;
    +
    + down(&parent->d_inode->i_sem);
    + d_delete(d);
    + sd = d->d_fsdata;
    + list_del_init(&sd->s_sibling);
    + sysfs_put(sd);
    + if (d->d_inode)
    + simple_rmdir(parent->d_inode, d);
    +
    + pr_debug(" o %s removing done (%d)\n", d->d_name.name, atomic_read(&d->d_count));
    +
    + up(&parent->d_inode->i_sem);
    + dput(parent);
    +}
    +
    +void sysfs_remove_subdir(struct dentry *d)
    +{
    + remove_dir(d);
    +}
    +
    +/*
    + * sysfs_remove_dir - remove a kobject's directory.
    + * @kobj: object.
    + *
    + * The only thing special about this is that we remove any files in
    + * the directory before we remove the directory.
    + */
    +void sysfs_remove_dir(struct kobject *kobj)
    +{
    + struct dentry *dentry = dget(kobj->dentry);
    + struct sysfs_dirent *parent_sd;
    + struct sysfs_dirent *sd, *tmp;
    +
    + if (!dentry)
    + return;
    +
    + pr_debug("sysfs %s: removing dir\n", dentry->d_name.name);
    + down(&dentry->d_inode->i_sem);
    + parent_sd = dentry->d_fsdata;
    + list_for_each_entry_safe(sd, tmp, &parent_sd->s_children, s_sibling) {
    + if (!sd->s_element || !(sd->s_type & SYSFS_NOT_PINNED))
    + continue;
    + list_del_init(&sd->s_sibling);
    + sysfs_drop_dentry(sd, dentry);
    + sysfs_put(sd);
    + }
    + up(&dentry->d_inode->i_sem);
    +
    + remove_dir(dentry);
    + /* Drop reference from dget() on entrance. */
    + dput(dentry);
    +}
    +
    +int sysfs_rename_dir(struct kobject *kobj, const char *new_name)
    +{
    + int error = 0;
    + struct dentry *new_dentry, *parent;
    +
    + if (!strcmp(kobject_name(kobj), new_name))
    + return -EINVAL;
    +
    + if (!kobj->parent)
    + return -EINVAL;
    +
    + down_write(&sysfs_rename_sem);
    + parent = kobj->parent->dentry;
    +
    + down(&parent->d_inode->i_sem);
    +
    + new_dentry = lookup_one_len(new_name, parent, strlen(new_name));
    + if (!IS_ERR(new_dentry)) {
    + if (!new_dentry->d_inode) {
    + error = kobject_set_name(kobj, "%s", new_name);
    + if (!error) {
    + d_add(new_dentry, NULL);
    + d_move(kobj->dentry, new_dentry);
    + } else
    + d_drop(new_dentry);
    + } else
    + error = -EEXIST;
    + dput(new_dentry);
    + }
    + up(&parent->d_inode->i_sem);
    + up_write(&sysfs_rename_sem);
    +
    + return error;
    +}
    +
    +/**
    + * sysfs_update_file - update the modified timestamp on an object attribute.
    + * @kobj: object we're acting for.
    + * @attr: attribute descriptor.
    + */
    +int sysfs_update_file(struct kobject *kobj, const struct attribute *attr)
    +{
    + struct dentry *dir = kobj->dentry;
    + struct dentry *victim;
    + int res = -ENOENT;
    +
    + down(&dir->d_inode->i_sem);
    + victim = lookup_one_len(attr->name, dir, strlen(attr->name));
    + if (!IS_ERR(victim)) {
    + /* make sure dentry is really there */
    + if (victim->d_inode &&
    + (victim->d_parent->d_inode == dir->d_inode)) {
    + victim->d_inode->i_mtime = CURRENT_TIME;
    + fsnotify_modify(victim);
    +
    + /**
    + * Drop reference from initial sysfs_get_dentry().
    + */
    + dput(victim);
    + res = 0;
    + } else
    + d_drop(victim);
    +
    + /**
    + * Drop the reference acquired from sysfs_get_dentry() above.
    + */
    + dput(victim);
    + }
    + up(&dir->d_inode->i_sem);
    +
    + return res;
    +}
    +
    +/**
    + * sysfs_chmod_file - update the modified mode value on an object attribute.
    + * @kobj: object we're acting for.
    + * @attr: attribute descriptor.
    + * @mode: file permissions.
    + *
    + */
    +int sysfs_chmod_file(struct kobject *kobj, struct attribute *attr, mode_t mode)
    +{
    + struct dentry *dir = kobj->dentry;
    + struct dentry *victim;
    + struct inode *inode;
    + struct iattr newattrs;
    + int res = -ENOENT;
    +
    + down(&dir->d_inode->i_sem);
    + victim = lookup_one_len(attr->name, dir, strlen(attr->name));
    + if (!IS_ERR(victim)) {
    + if (victim->d_inode &&
    + (victim->d_parent->d_inode == dir->d_inode)) {
    + inode = victim->d_inode;
    + down(&inode->i_sem);
    + newattrs.ia_mode = (mode & S_IALLUGO) |
    + (inode->i_mode & ~S_IALLUGO);
    + newattrs.ia_valid = ATTR_MODE | ATTR_CTIME;
    + res = notify_change(victim, &newattrs);
    + up(&inode->i_sem);
    + }
    + dput(victim);
    + }
    + up(&dir->d_inode->i_sem);
    +
    + return res;
    +}
    +
    +/**
    + * sysfs_remove_file - remove an object attribute.
    + * @kobj: object we're acting for.
    + * @attr: attribute descriptor.
    + *
    + * Hash the attribute name and kill the victim.
    + */
    +void sysfs_remove_file(struct kobject *kobj, const struct attribute *attr)
    +{
    + sysfs_hash_and_remove(kobj->dentry, attr->name);
    +}
    +
    +/*
    + * fs/sysfs/group.c - Operations for adding/removing multiple files at once.
    + *
    + * Copyright (c) 2003 Patrick Mochel
    + * Copyright (c) 2003 Open Source Development Lab
    + *
    + * This file is released undert the GPL v2.
    + *
    + */
    +static void remove_files(struct dentry *dir, const struct attribute_group *grp)
    +{
    + struct attribute *const *attr;
    +
    + for (attr = grp->attrs; *attr; attr++)
    + sysfs_hash_and_remove(dir, (*attr)->name);
    +}
    +
    +static int create_files(struct dentry *dir, const struct attribute_group *grp)
    +{
    + struct attribute *const *attr;
    + int error = 0;
    +
    + for (attr = grp->attrs; *attr && !error; attr++) {
    + error = sysfs_add_file(dir, *attr, SYSFS_KOBJ_ATTR);
    + }
    + if (error)
    + remove_files(dir, grp);
    + return error;
    +}
    +
    +int sysfs_create_group(struct kobject *kobj, const struct attribute_group *grp)
    +{
    + struct dentry *dir;
    + int error;
    +
    + BUG_ON(!kobj || !kobj->dentry);
    +
    + if (grp->name) {
    + error = sysfs_create_subdir(kobj, grp->name, &dir);
    + if (error)
    + return error;
    + } else
    + dir = kobj->dentry;
    + dir = dget(dir);
    + if ((error = create_files(dir, grp))) {
    + if (grp->name)
    + sysfs_remove_subdir(dir);
    + }
    + dput(dir);
    + return error;
    +}
    +
    +void sysfs_remove_group(struct kobject *kobj, const struct attribute_group *grp)
    +{
    + struct dentry *dir;
    +
    + if (grp->name)
    + dir = lookup_one_len(grp->name, kobj->dentry,
    + strlen(grp->name));
    + else
    + dir = dget(kobj->dentry);
    +
    + remove_files(dir, grp);
    + if (grp->name)
    + sysfs_remove_subdir(dir);
    + /* release the ref. taken in this routine */
    + dput(dir);
    +}
    +
    +/*
    + * mount.c - operations for initializing and mounting
    + */
    +
    +#define SYSFS_MAGIC 0x62656572
    +
    +static struct super_operations sysfs_ops = {
    + .statfs = simple_statfs,
    + .drop_inode = generic_delete_inode,
    +};
    +
    +static struct sysfs_dirent sysfs_root = {
    + .s_sibling = LIST_HEAD_INIT(sysfs_root.s_sibling),
    + .s_children = LIST_HEAD_INIT(sysfs_root.s_children),
    + .s_type = SYSFS_ROOT,
    +};
    +
    +static int sysfs_fill_super(struct super_block *sb, void *data, int silent)
    +{
    + struct inode *inode;
    + struct dentry *root;
    +
    + sb->s_blocksize = PAGE_CACHE_SIZE;
    + sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
    + sb->s_magic = SYSFS_MAGIC;
    + sb->s_op = &sysfs_ops;
    + sb->s_time_gran = 1;
    + sysfs_sb = sb;
    +
    + inode = sysfs_new_inode(S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO, &sysfs_root);
    + if (inode) {
    + inode->i_op = &sysfs_dir_inode_operations;
    + inode->i_fop = &sysfs_dir_operations;
    + /* directory inodes start off with i_nlink == 2 (for "." entry) */
    + inode->i_nlink++;
    + } else {
    + pr_debug("sysfs: could not get root inode\n");
    + return -ENOMEM;
    + }
    +
    + root = d_alloc_root(inode);
    + if (!root) {
    + pr_debug("%s: could not get root dentry!\n", __FUNCTION__);
    + iput(inode);
    + return -ENOMEM;
    + }
    + root->d_fsdata = &sysfs_root;
    + sb->s_root = root;
    + return 0;
    +}
    +
    +static struct super_block *sysfs_get_sb(struct file_system_type *fs_type,
    + int flags, const char *dev_name, void *data)
    +{
    + return get_sb_single(fs_type, flags, data, sysfs_fill_super);
    +}
    +
    +static struct file_system_type sysfs_fs_type = {
    + .name = "sysfs",
    + .get_sb = sysfs_get_sb,
    + .kill_sb = kill_litter_super,
    +};
    +
    +int __init sysfs_init(void)
    +{
    + int err = -ENOMEM;
    +
    + sysfs_dir_cachep = kmem_cache_create("sysfs_dir_cache",
    + sizeof(struct sysfs_dirent), 0, 0, NULL, NULL);
    + if (!sysfs_dir_cachep)
    + goto out;
    +
    + err = register_filesystem(&sysfs_fs_type);
    + if (err)
    + goto out_err;
    + sysfs_mount = kern_mount(&sysfs_fs_type);
    + if (IS_ERR(sysfs_mount)) {
    + printk(KERN_ERR "sysfs: could not mount!\n");
    + err = PTR_ERR(sysfs_mount);
    + sysfs_mount = NULL;
    + unregister_filesystem(&sysfs_fs_type);
    + goto out_err;
    + }
    + out:
    + return err;
    + out_err:
    + kmem_cache_destroy(sysfs_dir_cachep);
    + sysfs_dir_cachep = NULL;
    + goto out;
    +}
    +
    +/*
    + * sysfs_create_link - create symlink between two objects.
    + * @kobj: object whose directory we're creating the link in.
    + * @target: object we're pointing to.
    + * @name: name of the symlink.
    + */
    +int sysfs_create_link(struct kobject *kobj, struct kobject *target, const char *name)
    +{
    + struct dentry *dentry = kobj->dentry;
    + int error = 0;
    +
    + BUG_ON(!kobj || !kobj->dentry || !name);
    +
    + down(&dentry->d_inode->i_sem);
    + error = sysfs_add_link(dentry, name, target);
    + up(&dentry->d_inode->i_sem);
    + return error;
    +}
    +
    +void sysfs_remove_link(struct kobject *kobj, const char *name)
    +{
    + sysfs_hash_and_remove(kobj->dentry, name);
    +}
    +
    +EXPORT_SYMBOL_GPL(sysfs_create_bin_file);
    +EXPORT_SYMBOL_GPL(sysfs_remove_bin_file);
    +EXPORT_SYMBOL_GPL(sysfs_create_dir);
    +EXPORT_SYMBOL_GPL(sysfs_remove_dir);
    +EXPORT_SYMBOL_GPL(sysfs_rename_dir);
    +EXPORT_SYMBOL_GPL(sysfs_chmod_file);
    +EXPORT_SYMBOL_GPL(sysfs_create_file);
    +EXPORT_SYMBOL_GPL(sysfs_remove_file);
    +EXPORT_SYMBOL_GPL(sysfs_update_file);
    +EXPORT_SYMBOL_GPL(sysfs_create_group);
    +EXPORT_SYMBOL_GPL(sysfs_remove_group);
    +EXPORT_SYMBOL_GPL(sysfs_create_link);
    +EXPORT_SYMBOL_GPL(sysfs_remove_link);
    -
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      Last update: 2005-08-31 01:00    [W:5.493 / U:0.252 seconds]
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