diff options
Diffstat (limited to 'fs/sysfs')
| -rw-r--r-- | fs/sysfs/Makefile | 6 | ||||
| -rw-r--r-- | fs/sysfs/bin.c | 204 | ||||
| -rw-r--r-- | fs/sysfs/dir.c | 475 | ||||
| -rw-r--r-- | fs/sysfs/file.c | 447 | ||||
| -rw-r--r-- | fs/sysfs/group.c | 84 | ||||
| -rw-r--r-- | fs/sysfs/inode.c | 165 | ||||
| -rw-r--r-- | fs/sysfs/mount.c | 107 | ||||
| -rw-r--r-- | fs/sysfs/symlink.c | 180 | ||||
| -rw-r--r-- | fs/sysfs/sysfs.h | 95 |
9 files changed, 1763 insertions, 0 deletions
diff --git a/fs/sysfs/Makefile b/fs/sysfs/Makefile new file mode 100644 index 00000000000..7a1ceb946b8 --- /dev/null +++ b/fs/sysfs/Makefile @@ -0,0 +1,6 @@ +# +# Makefile for the sysfs virtual filesystem +# + +obj-y := inode.o file.o dir.o symlink.o mount.o bin.o \ + group.o diff --git a/fs/sysfs/bin.c b/fs/sysfs/bin.c new file mode 100644 index 00000000000..d4aaa88d021 --- /dev/null +++ b/fs/sysfs/bin.c @@ -0,0 +1,204 @@ +/* + * bin.c - binary file operations for sysfs. + * + * Copyright (c) 2003 Patrick Mochel + * Copyright (c) 2003 Matthew Wilcox + * Copyright (c) 2004 Silicon Graphics, Inc. + */ + +#undef DEBUG + +#include <linux/errno.h> +#include <linux/fs.h> +#include <linux/kobject.h> +#include <linux/module.h> +#include <linux/slab.h> + +#include <asm/uaccess.h> + +#include "sysfs.h" + +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 -EINVAL; + + 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 -EINVAL; + + 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, +}; + +/** + * sysfs_create_bin_file - create binary file for object. + * @kobj: object. + * @attr: attribute descriptor. + * + */ + +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); +} + + +/** + * sysfs_remove_bin_file - remove binary file for object. + * @kobj: object. + * @attr: attribute descriptor. + * + */ + +int sysfs_remove_bin_file(struct kobject * kobj, struct bin_attribute * attr) +{ + sysfs_hash_and_remove(kobj->dentry,attr->attr.name); + return 0; +} + +EXPORT_SYMBOL_GPL(sysfs_create_bin_file); +EXPORT_SYMBOL_GPL(sysfs_remove_bin_file); diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c new file mode 100644 index 00000000000..fe198210bc2 --- /dev/null +++ b/fs/sysfs/dir.c @@ -0,0 +1,475 @@ +/* + * dir.c - Operations for sysfs directories. + */ + +#undef DEBUG + +#include <linux/fs.h> +#include <linux/mount.h> +#include <linux/module.h> +#include <linux/kobject.h> +#include "sysfs.h" + +DECLARE_RWSEM(sysfs_rename_sem); + +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 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 init_file(struct inode * inode) +{ + inode->i_size = PAGE_SIZE; + inode->i_fop = &sysfs_file_operations; + return 0; +} + +static int init_symlink(struct inode * inode) +{ + inode->i_op = &sysfs_symlink_inode_operations; + 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 = sysfs_get_dentry(p,n); + if (!IS_ERR(*d)) { + error = sysfs_create(*d, mode, init_dir); + if (!error) { + error = sysfs_make_dirent(p->d_fsdata, *d, k, mode, + SYSFS_DIR); + if (!error) { + p->d_inode->i_nlink++; + (*d)->d_op = &sysfs_dentry_ops; + d_rehash(*d); + } + } + if (error && (error != -EEXIST)) + 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); +} + +/** + * sysfs_create_dir - create a directory for an object. + * @parent: parent parent object. + * @kobj: object we're creating directory for. + */ + +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; +} + +/* 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; + } + + error = sysfs_create(dentry, (attr->mode & S_IALLUGO) | S_IFREG, init); + if (error) + 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; + dentry->d_fsdata = sysfs_get(sd); + sd->s_dentry = dentry; + d_rehash(dentry); + + return 0; +} + +static int sysfs_attach_link(struct sysfs_dirent * sd, struct dentry * dentry) +{ + int err = 0; + + err = sysfs_create(dentry, S_IFLNK|S_IRWXUGO, init_symlink); + if (!err) { + dentry->d_op = &sysfs_dentry_ops; + dentry->d_fsdata = sysfs_get(sd); + sd->s_dentry = dentry; + d_rehash(dentry); + } + 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, +}; + +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 an object's directory. + * @kobj: object. + * + * The only thing special about this is that we remove any files in + * the directory before we remove the directory, and we've inlined + * what used to be sysfs_rmdir() below, instead of calling separately. + */ + +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 = sysfs_get_dentry(parent, 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; +} + +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; +} + +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, +}; + +EXPORT_SYMBOL_GPL(sysfs_create_dir); +EXPORT_SYMBOL_GPL(sysfs_remove_dir); +EXPORT_SYMBOL_GPL(sysfs_rename_dir); + diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c new file mode 100644 index 00000000000..352f966a117 --- /dev/null +++ b/fs/sysfs/file.c @@ -0,0 +1,447 @@ +/* + * file.c - operations for regular (text) files. + */ + +#include <linux/module.h> +#include <linux/dnotify.h> +#include <linux/kobject.h> +#include <asm/uaccess.h> +#include <asm/semaphore.h> + +#include "sysfs.h" + +#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 = 0; + + 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 = 0; + + 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, +}; + + +struct sysfs_buffer { + size_t count; + loff_t pos; + char * page; + struct sysfs_ops * ops; + struct semaphore sem; + int needs_read_fill; +}; + + +/** + * fill_read_buffer - allocate and fill buffer from object. + * @dentry: dentry pointer. + * @buffer: data buffer for file. + * + * 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; +} + + +/** + * flush_read_buffer - push buffer to userspace. + * @buffer: data buffer for file. + * @userbuf: user-passed buffer. + * @count: number of bytes requested. + * @ppos: file position. + * + * 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; +} + +/** + * sysfs_read_file - read an attribute. + * @file: file pointer. + * @buf: buffer to fill. + * @count: number of bytes to read. + * @ppos: starting offset in file. + * + * 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; +} + + +/** + * fill_write_buffer - copy buffer from userspace. + * @buffer: data buffer for file. + * @userbuf: data from user. + * @count: number of bytes in @userbuf. + * + * 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 - 1; + error = copy_from_user(buffer->page,buf,count); + buffer->needs_read_fill = 1; + return error ? -EFAULT : count; +} + + +/** + * flush_write_buffer - push buffer to kobject. + * @file: file pointer. + * @buffer: data buffer for file. + * + * 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); +} + + +/** + * sysfs_write_file - write an attribute. + * @file: file pointer + * @buf: data to write + * @count: number of bytes + * @ppos: starting offset + * + * 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; + ssize_t len; + + down(&buffer->sem); + len = fill_write_buffer(buffer, buf, count); + if (len > 0) + len = flush_write_buffer(file->f_dentry, buffer, len); + if (len > 0) + *ppos += len; + up(&buffer->sem); + return len; +} + +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; +} + +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; +} + +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, +}; + + +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; +} + + +/** + * sysfs_create_file - create an attribute file for an object. + * @kobj: object we're creating for. + * @attr: atrribute descriptor. + */ + +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); + +} + + +/** + * sysfs_update_file - update the modified timestamp on an object attribute. + * @kobj: object we're acting for. + * @attr: attribute descriptor. + * + * Also call dnotify for the dentry, which lots of userspace programs + * use. + */ +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 = sysfs_get_dentry(dir, 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; + dnotify_parent(victim, DN_MODIFY); + + /** + * 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_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); +} + + +EXPORT_SYMBOL_GPL(sysfs_create_file); +EXPORT_SYMBOL_GPL(sysfs_remove_file); +EXPORT_SYMBOL_GPL(sysfs_update_file); + diff --git a/fs/sysfs/group.c b/fs/sysfs/group.c new file mode 100644 index 00000000000..f11ac5ea702 --- /dev/null +++ b/fs/sysfs/group.c @@ -0,0 +1,84 @@ +/* + * 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. + * + */ + +#include <linux/kobject.h> +#include <linux/module.h> +#include <linux/dcache.h> +#include <linux/err.h> +#include "sysfs.h" + + +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 = sysfs_get_dentry(kobj->dentry,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); +} + + +EXPORT_SYMBOL_GPL(sysfs_create_group); +EXPORT_SYMBOL_GPL(sysfs_remove_group); diff --git a/fs/sysfs/inode.c b/fs/sysfs/inode.c new file mode 100644 index 00000000000..aff7b2dfa8e --- /dev/null +++ b/fs/sysfs/inode.c @@ -0,0 +1,165 @@ +/* + * inode.c - basic inode and dentry operations. + * + * sysfs is Copyright (c) 2001-3 Patrick Mochel + * + * Please see Documentation/filesystems/sysfs.txt for more information. + */ + +#undef DEBUG + +#include <linux/pagemap.h> +#include <linux/namei.h> +#include <linux/backing-dev.h> +#include "sysfs.h" + +extern 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, +}; + +struct inode * sysfs_new_inode(mode_t mode) +{ + struct inode * inode = new_inode(sysfs_sb); + if (inode) { + inode->i_mode = mode; + inode->i_uid = 0; + inode->i_gid = 0; + inode->i_blksize = PAGE_CACHE_SIZE; + inode->i_blocks = 0; + inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; + inode->i_mapping->a_ops = &sysfs_aops; + inode->i_mapping->backing_dev_info = &sysfs_backing_dev_info; + } + return inode; +} + +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) { + if ((inode = sysfs_new_inode(mode))) { + 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)) + dget(dentry); /* pin only directory dentry in core */ + } else + iput(inode); + Done: + return error; +} + +struct dentry * sysfs_get_dentry(struct dentry * parent, const char * name) +{ + struct qstr qstr; + + qstr.name = name; + qstr.len = strlen(name); + qstr.hash = full_name_hash(name,qstr.len); + return lookup_hash(&qstr,parent); +} + +/* + * Get the name for corresponding element represented by the given sysfs_dirent + */ +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. + */ +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); + } + } +} + +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); +} + + diff --git a/fs/sysfs/mount.c b/fs/sysfs/mount.c new file mode 100644 index 00000000000..5c805bb1a4b --- /dev/null +++ b/fs/sysfs/mount.c @@ -0,0 +1,107 @@ +/* + * mount.c - operations for initializing and mounting sysfs. + */ + +#define DEBUG + +#include <linux/fs.h> +#include <linux/mount.h> +#include <linux/pagemap.h> +#include <linux/init.h> + +#include "sysfs.h" + +/* Random magic number */ +#define SYSFS_MAGIC 0x62656572 + +struct vfsmount *sysfs_mount; +struct super_block * sysfs_sb = NULL; +kmem_cache_t *sysfs_dir_cachep; + +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_element = NULL, + .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); + 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) { + 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; + } + } else + goto out_err; +out: + return err; +out_err: + kmem_cache_destroy(sysfs_dir_cachep); + sysfs_dir_cachep = NULL; + goto out; +} diff --git a/fs/sysfs/symlink.c b/fs/sysfs/symlink.c new file mode 100644 index 00000000000..dfdf7017435 --- /dev/null +++ b/fs/sysfs/symlink.c @@ -0,0 +1,180 @@ +/* + * symlink.c - operations for sysfs symlinks. + */ + +#include <linux/fs.h> +#include <linux/module.h> +#include <linux/kobject.h> +#include <linux/namei.h> + +#include "sysfs.h" + +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_add_link(struct dentry * parent, 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->target_kobj = 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; +} + +/** + * 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, 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; +} + + +/** + * sysfs_remove_link - remove symlink in object's directory. + * @kobj: object we're acting for. + * @name: name of the symlink to remove. + */ + +void sysfs_remove_link(struct kobject * kobj, char * name) +{ + sysfs_hash_and_remove(kobj->dentry,name); +} + +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; +} + +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; + + target_kobj = sysfs_get_kobject(dentry); + if (!target_kobj) { + kobject_put(kobj); + return -EINVAL; + } + + 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 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); +} + +struct inode_operations sysfs_symlink_inode_operations = { + .readlink = generic_readlink, + .follow_link = sysfs_follow_link, + .put_link = sysfs_put_link, +}; + + +EXPORT_SYMBOL_GPL(sysfs_create_link); +EXPORT_SYMBOL_GPL(sysfs_remove_link); + diff --git a/fs/sysfs/sysfs.h b/fs/sysfs/sysfs.h new file mode 100644 index 00000000000..a8a24a0c0b3 --- /dev/null +++ b/fs/sysfs/sysfs.h @@ -0,0 +1,95 @@ + +extern struct vfsmount * sysfs_mount; +extern kmem_cache_t *sysfs_dir_cachep; + +extern struct inode * sysfs_new_inode(mode_t mode); +extern int sysfs_create(struct dentry *, int mode, int (*init)(struct inode *)); + +extern int sysfs_make_dirent(struct sysfs_dirent *, struct dentry *, void *, + umode_t, int); +extern struct dentry * sysfs_get_dentry(struct dentry *, const char *); + +extern int sysfs_add_file(struct dentry *, const struct attribute *, int); +extern void sysfs_hash_and_remove(struct dentry * dir, const char * name); + +extern int sysfs_create_subdir(struct kobject *, const char *, struct dentry **); +extern void sysfs_remove_subdir(struct dentry *); + +extern const unsigned char * sysfs_get_name(struct sysfs_dirent *sd); +extern void sysfs_drop_dentry(struct sysfs_dirent *sd, struct dentry *parent); + +extern struct rw_semaphore sysfs_rename_sem; +extern struct super_block * sysfs_sb; +extern struct file_operations sysfs_dir_operations; +extern struct file_operations sysfs_file_operations; +extern struct file_operations bin_fops; +extern struct inode_operations sysfs_dir_inode_operations; +extern struct inode_operations sysfs_symlink_inode_operations; + +struct sysfs_symlink { + char * link_name; + struct kobject * target_kobj; +}; + +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 bin_attribute * to_bin_attr(struct dentry * dentry) +{ + struct sysfs_dirent * sd = dentry->d_fsdata; + return ((struct bin_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->target_kobj); + } else + kobj = kobject_get(sd->s_element); + } + spin_unlock(&dcache_lock); + + return kobj; +} + +static inline 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->target_kobj); + kfree(sl); + } + kmem_cache_free(sysfs_dir_cachep, sd); +} + +static inline 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 inline void sysfs_put(struct sysfs_dirent * sd) +{ + if (atomic_dec_and_test(&sd->s_count)) + release_sysfs_dirent(sd); +} + |