fs/Makefile: Stupid typo breakage of exofs inclusion
[linux-btrfs-devel.git] / fs / sysfs / file.c
blobd4e6080b4b2053fae16fd451d01b6b20f813906f
1 /*
2 * fs/sysfs/file.c - sysfs regular (text) file implementation
4 * Copyright (c) 2001-3 Patrick Mochel
5 * Copyright (c) 2007 SUSE Linux Products GmbH
6 * Copyright (c) 2007 Tejun Heo <teheo@suse.de>
8 * This file is released under the GPLv2.
10 * Please see Documentation/filesystems/sysfs.txt for more information.
13 #include <linux/module.h>
14 #include <linux/kobject.h>
15 #include <linux/kallsyms.h>
16 #include <linux/slab.h>
17 #include <linux/fsnotify.h>
18 #include <linux/namei.h>
19 #include <linux/poll.h>
20 #include <linux/list.h>
21 #include <linux/mutex.h>
22 #include <linux/limits.h>
23 #include <asm/uaccess.h>
25 #include "sysfs.h"
28 * There's one sysfs_buffer for each open file and one
29 * sysfs_open_dirent for each sysfs_dirent with one or more open
30 * files.
32 * filp->private_data points to sysfs_buffer and
33 * sysfs_dirent->s_attr.open points to sysfs_open_dirent. s_attr.open
34 * is protected by sysfs_open_dirent_lock.
36 static DEFINE_SPINLOCK(sysfs_open_dirent_lock);
38 struct sysfs_open_dirent {
39 atomic_t refcnt;
40 atomic_t event;
41 wait_queue_head_t poll;
42 struct list_head buffers; /* goes through sysfs_buffer.list */
45 struct sysfs_buffer {
46 size_t count;
47 loff_t pos;
48 char * page;
49 const struct sysfs_ops * ops;
50 struct mutex mutex;
51 int needs_read_fill;
52 int event;
53 struct list_head list;
56 /**
57 * fill_read_buffer - allocate and fill buffer from object.
58 * @dentry: dentry pointer.
59 * @buffer: data buffer for file.
61 * Allocate @buffer->page, if it hasn't been already, then call the
62 * kobject's show() method to fill the buffer with this attribute's
63 * data.
64 * This is called only once, on the file's first read unless an error
65 * is returned.
67 static int fill_read_buffer(struct dentry * dentry, struct sysfs_buffer * buffer)
69 struct sysfs_dirent *attr_sd = dentry->d_fsdata;
70 struct kobject *kobj = attr_sd->s_parent->s_dir.kobj;
71 const struct sysfs_ops * ops = buffer->ops;
72 int ret = 0;
73 ssize_t count;
75 if (!buffer->page)
76 buffer->page = (char *) get_zeroed_page(GFP_KERNEL);
77 if (!buffer->page)
78 return -ENOMEM;
80 /* need attr_sd for attr and ops, its parent for kobj */
81 if (!sysfs_get_active(attr_sd))
82 return -ENODEV;
84 buffer->event = atomic_read(&attr_sd->s_attr.open->event);
85 count = ops->show(kobj, attr_sd->s_attr.attr, buffer->page);
87 sysfs_put_active(attr_sd);
90 * The code works fine with PAGE_SIZE return but it's likely to
91 * indicate truncated result or overflow in normal use cases.
93 if (count >= (ssize_t)PAGE_SIZE) {
94 print_symbol("fill_read_buffer: %s returned bad count\n",
95 (unsigned long)ops->show);
96 /* Try to struggle along */
97 count = PAGE_SIZE - 1;
99 if (count >= 0) {
100 buffer->needs_read_fill = 0;
101 buffer->count = count;
102 } else {
103 ret = count;
105 return ret;
109 * sysfs_read_file - read an attribute.
110 * @file: file pointer.
111 * @buf: buffer to fill.
112 * @count: number of bytes to read.
113 * @ppos: starting offset in file.
115 * Userspace wants to read an attribute file. The attribute descriptor
116 * is in the file's ->d_fsdata. The target object is in the directory's
117 * ->d_fsdata.
119 * We call fill_read_buffer() to allocate and fill the buffer from the
120 * object's show() method exactly once (if the read is happening from
121 * the beginning of the file). That should fill the entire buffer with
122 * all the data the object has to offer for that attribute.
123 * We then call flush_read_buffer() to copy the buffer to userspace
124 * in the increments specified.
127 static ssize_t
128 sysfs_read_file(struct file *file, char __user *buf, size_t count, loff_t *ppos)
130 struct sysfs_buffer * buffer = file->private_data;
131 ssize_t retval = 0;
133 mutex_lock(&buffer->mutex);
134 if (buffer->needs_read_fill || *ppos == 0) {
135 retval = fill_read_buffer(file->f_path.dentry,buffer);
136 if (retval)
137 goto out;
139 pr_debug("%s: count = %zd, ppos = %lld, buf = %s\n",
140 __func__, count, *ppos, buffer->page);
141 retval = simple_read_from_buffer(buf, count, ppos, buffer->page,
142 buffer->count);
143 out:
144 mutex_unlock(&buffer->mutex);
145 return retval;
149 * fill_write_buffer - copy buffer from userspace.
150 * @buffer: data buffer for file.
151 * @buf: data from user.
152 * @count: number of bytes in @userbuf.
154 * Allocate @buffer->page if it hasn't been already, then
155 * copy the user-supplied buffer into it.
158 static int
159 fill_write_buffer(struct sysfs_buffer * buffer, const char __user * buf, size_t count)
161 int error;
163 if (!buffer->page)
164 buffer->page = (char *)get_zeroed_page(GFP_KERNEL);
165 if (!buffer->page)
166 return -ENOMEM;
168 if (count >= PAGE_SIZE)
169 count = PAGE_SIZE - 1;
170 error = copy_from_user(buffer->page,buf,count);
171 buffer->needs_read_fill = 1;
172 /* if buf is assumed to contain a string, terminate it by \0,
173 so e.g. sscanf() can scan the string easily */
174 buffer->page[count] = 0;
175 return error ? -EFAULT : count;
180 * flush_write_buffer - push buffer to kobject.
181 * @dentry: dentry to the attribute
182 * @buffer: data buffer for file.
183 * @count: number of bytes
185 * Get the correct pointers for the kobject and the attribute we're
186 * dealing with, then call the store() method for the attribute,
187 * passing the buffer that we acquired in fill_write_buffer().
190 static int
191 flush_write_buffer(struct dentry * dentry, struct sysfs_buffer * buffer, size_t count)
193 struct sysfs_dirent *attr_sd = dentry->d_fsdata;
194 struct kobject *kobj = attr_sd->s_parent->s_dir.kobj;
195 const struct sysfs_ops * ops = buffer->ops;
196 int rc;
198 /* need attr_sd for attr and ops, its parent for kobj */
199 if (!sysfs_get_active(attr_sd))
200 return -ENODEV;
202 rc = ops->store(kobj, attr_sd->s_attr.attr, buffer->page, count);
204 sysfs_put_active(attr_sd);
206 return rc;
211 * sysfs_write_file - write an attribute.
212 * @file: file pointer
213 * @buf: data to write
214 * @count: number of bytes
215 * @ppos: starting offset
217 * Similar to sysfs_read_file(), though working in the opposite direction.
218 * We allocate and fill the data from the user in fill_write_buffer(),
219 * then push it to the kobject in flush_write_buffer().
220 * There is no easy way for us to know if userspace is only doing a partial
221 * write, so we don't support them. We expect the entire buffer to come
222 * on the first write.
223 * Hint: if you're writing a value, first read the file, modify only the
224 * the value you're changing, then write entire buffer back.
227 static ssize_t
228 sysfs_write_file(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
230 struct sysfs_buffer * buffer = file->private_data;
231 ssize_t len;
233 mutex_lock(&buffer->mutex);
234 len = fill_write_buffer(buffer, buf, count);
235 if (len > 0)
236 len = flush_write_buffer(file->f_path.dentry, buffer, len);
237 if (len > 0)
238 *ppos += len;
239 mutex_unlock(&buffer->mutex);
240 return len;
244 * sysfs_get_open_dirent - get or create sysfs_open_dirent
245 * @sd: target sysfs_dirent
246 * @buffer: sysfs_buffer for this instance of open
248 * If @sd->s_attr.open exists, increment its reference count;
249 * otherwise, create one. @buffer is chained to the buffers
250 * list.
252 * LOCKING:
253 * Kernel thread context (may sleep).
255 * RETURNS:
256 * 0 on success, -errno on failure.
258 static int sysfs_get_open_dirent(struct sysfs_dirent *sd,
259 struct sysfs_buffer *buffer)
261 struct sysfs_open_dirent *od, *new_od = NULL;
263 retry:
264 spin_lock_irq(&sysfs_open_dirent_lock);
266 if (!sd->s_attr.open && new_od) {
267 sd->s_attr.open = new_od;
268 new_od = NULL;
271 od = sd->s_attr.open;
272 if (od) {
273 atomic_inc(&od->refcnt);
274 list_add_tail(&buffer->list, &od->buffers);
277 spin_unlock_irq(&sysfs_open_dirent_lock);
279 if (od) {
280 kfree(new_od);
281 return 0;
284 /* not there, initialize a new one and retry */
285 new_od = kmalloc(sizeof(*new_od), GFP_KERNEL);
286 if (!new_od)
287 return -ENOMEM;
289 atomic_set(&new_od->refcnt, 0);
290 atomic_set(&new_od->event, 1);
291 init_waitqueue_head(&new_od->poll);
292 INIT_LIST_HEAD(&new_od->buffers);
293 goto retry;
297 * sysfs_put_open_dirent - put sysfs_open_dirent
298 * @sd: target sysfs_dirent
299 * @buffer: associated sysfs_buffer
301 * Put @sd->s_attr.open and unlink @buffer from the buffers list.
302 * If reference count reaches zero, disassociate and free it.
304 * LOCKING:
305 * None.
307 static void sysfs_put_open_dirent(struct sysfs_dirent *sd,
308 struct sysfs_buffer *buffer)
310 struct sysfs_open_dirent *od = sd->s_attr.open;
311 unsigned long flags;
313 spin_lock_irqsave(&sysfs_open_dirent_lock, flags);
315 list_del(&buffer->list);
316 if (atomic_dec_and_test(&od->refcnt))
317 sd->s_attr.open = NULL;
318 else
319 od = NULL;
321 spin_unlock_irqrestore(&sysfs_open_dirent_lock, flags);
323 kfree(od);
326 static int sysfs_open_file(struct inode *inode, struct file *file)
328 struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
329 struct kobject *kobj = attr_sd->s_parent->s_dir.kobj;
330 struct sysfs_buffer *buffer;
331 const struct sysfs_ops *ops;
332 int error = -EACCES;
334 /* need attr_sd for attr and ops, its parent for kobj */
335 if (!sysfs_get_active(attr_sd))
336 return -ENODEV;
338 /* every kobject with an attribute needs a ktype assigned */
339 if (kobj->ktype && kobj->ktype->sysfs_ops)
340 ops = kobj->ktype->sysfs_ops;
341 else {
342 WARN(1, KERN_ERR "missing sysfs attribute operations for "
343 "kobject: %s\n", kobject_name(kobj));
344 goto err_out;
347 /* File needs write support.
348 * The inode's perms must say it's ok,
349 * and we must have a store method.
351 if (file->f_mode & FMODE_WRITE) {
352 if (!(inode->i_mode & S_IWUGO) || !ops->store)
353 goto err_out;
356 /* File needs read support.
357 * The inode's perms must say it's ok, and we there
358 * must be a show method for it.
360 if (file->f_mode & FMODE_READ) {
361 if (!(inode->i_mode & S_IRUGO) || !ops->show)
362 goto err_out;
365 /* No error? Great, allocate a buffer for the file, and store it
366 * it in file->private_data for easy access.
368 error = -ENOMEM;
369 buffer = kzalloc(sizeof(struct sysfs_buffer), GFP_KERNEL);
370 if (!buffer)
371 goto err_out;
373 mutex_init(&buffer->mutex);
374 buffer->needs_read_fill = 1;
375 buffer->ops = ops;
376 file->private_data = buffer;
378 /* make sure we have open dirent struct */
379 error = sysfs_get_open_dirent(attr_sd, buffer);
380 if (error)
381 goto err_free;
383 /* open succeeded, put active references */
384 sysfs_put_active(attr_sd);
385 return 0;
387 err_free:
388 kfree(buffer);
389 err_out:
390 sysfs_put_active(attr_sd);
391 return error;
394 static int sysfs_release(struct inode *inode, struct file *filp)
396 struct sysfs_dirent *sd = filp->f_path.dentry->d_fsdata;
397 struct sysfs_buffer *buffer = filp->private_data;
399 sysfs_put_open_dirent(sd, buffer);
401 if (buffer->page)
402 free_page((unsigned long)buffer->page);
403 kfree(buffer);
405 return 0;
408 /* Sysfs attribute files are pollable. The idea is that you read
409 * the content and then you use 'poll' or 'select' to wait for
410 * the content to change. When the content changes (assuming the
411 * manager for the kobject supports notification), poll will
412 * return POLLERR|POLLPRI, and select will return the fd whether
413 * it is waiting for read, write, or exceptions.
414 * Once poll/select indicates that the value has changed, you
415 * need to close and re-open the file, or seek to 0 and read again.
416 * Reminder: this only works for attributes which actively support
417 * it, and it is not possible to test an attribute from userspace
418 * to see if it supports poll (Neither 'poll' nor 'select' return
419 * an appropriate error code). When in doubt, set a suitable timeout value.
421 static unsigned int sysfs_poll(struct file *filp, poll_table *wait)
423 struct sysfs_buffer * buffer = filp->private_data;
424 struct sysfs_dirent *attr_sd = filp->f_path.dentry->d_fsdata;
425 struct sysfs_open_dirent *od = attr_sd->s_attr.open;
427 /* need parent for the kobj, grab both */
428 if (!sysfs_get_active(attr_sd))
429 goto trigger;
431 poll_wait(filp, &od->poll, wait);
433 sysfs_put_active(attr_sd);
435 if (buffer->event != atomic_read(&od->event))
436 goto trigger;
438 return DEFAULT_POLLMASK;
440 trigger:
441 buffer->needs_read_fill = 1;
442 return DEFAULT_POLLMASK|POLLERR|POLLPRI;
445 void sysfs_notify_dirent(struct sysfs_dirent *sd)
447 struct sysfs_open_dirent *od;
448 unsigned long flags;
450 spin_lock_irqsave(&sysfs_open_dirent_lock, flags);
452 od = sd->s_attr.open;
453 if (od) {
454 atomic_inc(&od->event);
455 wake_up_interruptible(&od->poll);
458 spin_unlock_irqrestore(&sysfs_open_dirent_lock, flags);
460 EXPORT_SYMBOL_GPL(sysfs_notify_dirent);
462 void sysfs_notify(struct kobject *k, const char *dir, const char *attr)
464 struct sysfs_dirent *sd = k->sd;
466 mutex_lock(&sysfs_mutex);
468 if (sd && dir)
469 sd = sysfs_find_dirent(sd, NULL, dir);
470 if (sd && attr)
471 sd = sysfs_find_dirent(sd, NULL, attr);
472 if (sd)
473 sysfs_notify_dirent(sd);
475 mutex_unlock(&sysfs_mutex);
477 EXPORT_SYMBOL_GPL(sysfs_notify);
479 const struct file_operations sysfs_file_operations = {
480 .read = sysfs_read_file,
481 .write = sysfs_write_file,
482 .llseek = generic_file_llseek,
483 .open = sysfs_open_file,
484 .release = sysfs_release,
485 .poll = sysfs_poll,
488 int sysfs_attr_ns(struct kobject *kobj, const struct attribute *attr,
489 const void **pns)
491 struct sysfs_dirent *dir_sd = kobj->sd;
492 const struct sysfs_ops *ops;
493 const void *ns = NULL;
494 int err;
496 err = 0;
497 if (!sysfs_ns_type(dir_sd))
498 goto out;
500 err = -EINVAL;
501 if (!kobj->ktype)
502 goto out;
503 ops = kobj->ktype->sysfs_ops;
504 if (!ops)
505 goto out;
506 if (!ops->namespace)
507 goto out;
509 err = 0;
510 ns = ops->namespace(kobj, attr);
511 out:
512 if (err) {
513 WARN(1, KERN_ERR "missing sysfs namespace attribute operation for "
514 "kobject: %s\n", kobject_name(kobj));
516 *pns = ns;
517 return err;
520 int sysfs_add_file_mode(struct sysfs_dirent *dir_sd,
521 const struct attribute *attr, int type, mode_t amode)
523 umode_t mode = (amode & S_IALLUGO) | S_IFREG;
524 struct sysfs_addrm_cxt acxt;
525 struct sysfs_dirent *sd;
526 const void *ns;
527 int rc;
529 rc = sysfs_attr_ns(dir_sd->s_dir.kobj, attr, &ns);
530 if (rc)
531 return rc;
533 sd = sysfs_new_dirent(attr->name, mode, type);
534 if (!sd)
535 return -ENOMEM;
537 sd->s_ns = ns;
538 sd->s_attr.attr = (void *)attr;
539 sysfs_dirent_init_lockdep(sd);
541 sysfs_addrm_start(&acxt, dir_sd);
542 rc = sysfs_add_one(&acxt, sd);
543 sysfs_addrm_finish(&acxt);
545 if (rc)
546 sysfs_put(sd);
548 return rc;
552 int sysfs_add_file(struct sysfs_dirent *dir_sd, const struct attribute *attr,
553 int type)
555 return sysfs_add_file_mode(dir_sd, attr, type, attr->mode);
560 * sysfs_create_file - create an attribute file for an object.
561 * @kobj: object we're creating for.
562 * @attr: attribute descriptor.
565 int sysfs_create_file(struct kobject * kobj, const struct attribute * attr)
567 BUG_ON(!kobj || !kobj->sd || !attr);
569 return sysfs_add_file(kobj->sd, attr, SYSFS_KOBJ_ATTR);
573 int sysfs_create_files(struct kobject *kobj, const struct attribute **ptr)
575 int err = 0;
576 int i;
578 for (i = 0; ptr[i] && !err; i++)
579 err = sysfs_create_file(kobj, ptr[i]);
580 if (err)
581 while (--i >= 0)
582 sysfs_remove_file(kobj, ptr[i]);
583 return err;
587 * sysfs_add_file_to_group - add an attribute file to a pre-existing group.
588 * @kobj: object we're acting for.
589 * @attr: attribute descriptor.
590 * @group: group name.
592 int sysfs_add_file_to_group(struct kobject *kobj,
593 const struct attribute *attr, const char *group)
595 struct sysfs_dirent *dir_sd;
596 int error;
598 if (group)
599 dir_sd = sysfs_get_dirent(kobj->sd, NULL, group);
600 else
601 dir_sd = sysfs_get(kobj->sd);
603 if (!dir_sd)
604 return -ENOENT;
606 error = sysfs_add_file(dir_sd, attr, SYSFS_KOBJ_ATTR);
607 sysfs_put(dir_sd);
609 return error;
611 EXPORT_SYMBOL_GPL(sysfs_add_file_to_group);
614 * sysfs_chmod_file - update the modified mode value on an object attribute.
615 * @kobj: object we're acting for.
616 * @attr: attribute descriptor.
617 * @mode: file permissions.
620 int sysfs_chmod_file(struct kobject *kobj, const struct attribute *attr,
621 mode_t mode)
623 struct sysfs_dirent *sd;
624 struct iattr newattrs;
625 const void *ns;
626 int rc;
628 rc = sysfs_attr_ns(kobj, attr, &ns);
629 if (rc)
630 return rc;
632 mutex_lock(&sysfs_mutex);
634 rc = -ENOENT;
635 sd = sysfs_find_dirent(kobj->sd, ns, attr->name);
636 if (!sd)
637 goto out;
639 newattrs.ia_mode = (mode & S_IALLUGO) | (sd->s_mode & ~S_IALLUGO);
640 newattrs.ia_valid = ATTR_MODE;
641 rc = sysfs_sd_setattr(sd, &newattrs);
643 out:
644 mutex_unlock(&sysfs_mutex);
645 return rc;
647 EXPORT_SYMBOL_GPL(sysfs_chmod_file);
651 * sysfs_remove_file - remove an object attribute.
652 * @kobj: object we're acting for.
653 * @attr: attribute descriptor.
655 * Hash the attribute name and kill the victim.
658 void sysfs_remove_file(struct kobject * kobj, const struct attribute * attr)
660 const void *ns;
662 if (sysfs_attr_ns(kobj, attr, &ns))
663 return;
665 sysfs_hash_and_remove(kobj->sd, ns, attr->name);
668 void sysfs_remove_files(struct kobject * kobj, const struct attribute **ptr)
670 int i;
671 for (i = 0; ptr[i]; i++)
672 sysfs_remove_file(kobj, ptr[i]);
676 * sysfs_remove_file_from_group - remove an attribute file from a group.
677 * @kobj: object we're acting for.
678 * @attr: attribute descriptor.
679 * @group: group name.
681 void sysfs_remove_file_from_group(struct kobject *kobj,
682 const struct attribute *attr, const char *group)
684 struct sysfs_dirent *dir_sd;
686 if (group)
687 dir_sd = sysfs_get_dirent(kobj->sd, NULL, group);
688 else
689 dir_sd = sysfs_get(kobj->sd);
690 if (dir_sd) {
691 sysfs_hash_and_remove(dir_sd, NULL, attr->name);
692 sysfs_put(dir_sd);
695 EXPORT_SYMBOL_GPL(sysfs_remove_file_from_group);
697 struct sysfs_schedule_callback_struct {
698 struct list_head workq_list;
699 struct kobject *kobj;
700 void (*func)(void *);
701 void *data;
702 struct module *owner;
703 struct work_struct work;
706 static struct workqueue_struct *sysfs_workqueue;
707 static DEFINE_MUTEX(sysfs_workq_mutex);
708 static LIST_HEAD(sysfs_workq);
709 static void sysfs_schedule_callback_work(struct work_struct *work)
711 struct sysfs_schedule_callback_struct *ss = container_of(work,
712 struct sysfs_schedule_callback_struct, work);
714 (ss->func)(ss->data);
715 kobject_put(ss->kobj);
716 module_put(ss->owner);
717 mutex_lock(&sysfs_workq_mutex);
718 list_del(&ss->workq_list);
719 mutex_unlock(&sysfs_workq_mutex);
720 kfree(ss);
724 * sysfs_schedule_callback - helper to schedule a callback for a kobject
725 * @kobj: object we're acting for.
726 * @func: callback function to invoke later.
727 * @data: argument to pass to @func.
728 * @owner: module owning the callback code
730 * sysfs attribute methods must not unregister themselves or their parent
731 * kobject (which would amount to the same thing). Attempts to do so will
732 * deadlock, since unregistration is mutually exclusive with driver
733 * callbacks.
735 * Instead methods can call this routine, which will attempt to allocate
736 * and schedule a workqueue request to call back @func with @data as its
737 * argument in the workqueue's process context. @kobj will be pinned
738 * until @func returns.
740 * Returns 0 if the request was submitted, -ENOMEM if storage could not
741 * be allocated, -ENODEV if a reference to @owner isn't available,
742 * -EAGAIN if a callback has already been scheduled for @kobj.
744 int sysfs_schedule_callback(struct kobject *kobj, void (*func)(void *),
745 void *data, struct module *owner)
747 struct sysfs_schedule_callback_struct *ss, *tmp;
749 if (!try_module_get(owner))
750 return -ENODEV;
752 mutex_lock(&sysfs_workq_mutex);
753 list_for_each_entry_safe(ss, tmp, &sysfs_workq, workq_list)
754 if (ss->kobj == kobj) {
755 module_put(owner);
756 mutex_unlock(&sysfs_workq_mutex);
757 return -EAGAIN;
759 mutex_unlock(&sysfs_workq_mutex);
761 if (sysfs_workqueue == NULL) {
762 sysfs_workqueue = create_singlethread_workqueue("sysfsd");
763 if (sysfs_workqueue == NULL) {
764 module_put(owner);
765 return -ENOMEM;
769 ss = kmalloc(sizeof(*ss), GFP_KERNEL);
770 if (!ss) {
771 module_put(owner);
772 return -ENOMEM;
774 kobject_get(kobj);
775 ss->kobj = kobj;
776 ss->func = func;
777 ss->data = data;
778 ss->owner = owner;
779 INIT_WORK(&ss->work, sysfs_schedule_callback_work);
780 INIT_LIST_HEAD(&ss->workq_list);
781 mutex_lock(&sysfs_workq_mutex);
782 list_add_tail(&ss->workq_list, &sysfs_workq);
783 mutex_unlock(&sysfs_workq_mutex);
784 queue_work(sysfs_workqueue, &ss->work);
785 return 0;
787 EXPORT_SYMBOL_GPL(sysfs_schedule_callback);
790 EXPORT_SYMBOL_GPL(sysfs_create_file);
791 EXPORT_SYMBOL_GPL(sysfs_remove_file);
792 EXPORT_SYMBOL_GPL(sysfs_remove_files);
793 EXPORT_SYMBOL_GPL(sysfs_create_files);