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 <linux/uaccess.h>
24 #include <linux/seq_file.h>
30 * There's one sysfs_open_file for each open file and one sysfs_open_dirent
31 * for each sysfs_dirent with one or more open files.
33 * sysfs_dirent->s_attr.open points to sysfs_open_dirent. s_attr.open is
34 * protected by sysfs_open_dirent_lock.
36 * filp->private_data points to seq_file whose ->private points to
37 * sysfs_open_file. sysfs_open_files are chained at
38 * sysfs_open_dirent->files, which is protected by sysfs_open_file_mutex.
40 static DEFINE_SPINLOCK(sysfs_open_dirent_lock);
41 static DEFINE_MUTEX(sysfs_open_file_mutex);
43 struct sysfs_open_dirent {
46 wait_queue_head_t poll;
47 struct list_head files; /* goes through sysfs_open_file.list */
50 struct sysfs_open_file {
51 struct sysfs_dirent *sd;
55 struct list_head list;
58 const struct vm_operations_struct *vm_ops;
61 static bool sysfs_is_bin(struct sysfs_dirent *sd)
63 return sysfs_type(sd) == SYSFS_KOBJ_BIN_ATTR;
66 static struct sysfs_open_file *sysfs_of(struct file *file)
68 return ((struct seq_file *)file->private_data)->private;
72 * Determine ktype->sysfs_ops for the given sysfs_dirent. This function
73 * must be called while holding an active reference.
75 static const struct sysfs_ops *sysfs_file_ops(struct sysfs_dirent *sd)
77 struct kobject *kobj = sd->s_parent->s_dir.kobj;
79 if (!sysfs_ignore_lockdep(sd))
80 lockdep_assert_held(sd);
81 return kobj->ktype ? kobj->ktype->sysfs_ops : NULL;
85 * Reads on sysfs are handled through seq_file, which takes care of hairy
86 * details like buffering and seeking. The following function pipes
87 * sysfs_ops->show() result through seq_file.
89 static int sysfs_seq_show(struct seq_file *sf, void *v)
91 struct sysfs_open_file *of = sf->private;
92 struct kobject *kobj = of->sd->s_parent->s_dir.kobj;
93 const struct sysfs_ops *ops;
97 /* acquire buffer and ensure that it's >= PAGE_SIZE */
98 count = seq_get_buf(sf, &buf);
99 if (count < PAGE_SIZE) {
105 * Need @of->sd for attr and ops, its parent for kobj. @of->mutex
106 * nests outside active ref and is just to ensure that the ops
107 * aren't called concurrently for the same open file.
109 mutex_lock(&of->mutex);
110 if (!sysfs_get_active(of->sd)) {
111 mutex_unlock(&of->mutex);
115 of->event = atomic_read(&of->sd->s_attr.open->event);
118 * Lookup @ops and invoke show(). Control may reach here via seq
119 * file lseek even if @ops->show() isn't implemented.
121 ops = sysfs_file_ops(of->sd);
123 count = ops->show(kobj, of->sd->s_attr.attr, buf);
127 sysfs_put_active(of->sd);
128 mutex_unlock(&of->mutex);
134 * The code works fine with PAGE_SIZE return but it's likely to
135 * indicate truncated result or overflow in normal use cases.
137 if (count >= (ssize_t)PAGE_SIZE) {
138 print_symbol("fill_read_buffer: %s returned bad count\n",
139 (unsigned long)ops->show);
140 /* Try to struggle along */
141 count = PAGE_SIZE - 1;
143 seq_commit(sf, count);
148 * Read method for bin files. As reading a bin file can have side-effects,
149 * the exact offset and bytes specified in read(2) call should be passed to
150 * the read callback making it difficult to use seq_file. Implement
151 * simplistic custom buffering for bin files.
153 static ssize_t sysfs_bin_read(struct file *file, char __user *userbuf,
154 size_t bytes, loff_t *off)
156 struct sysfs_open_file *of = sysfs_of(file);
157 struct bin_attribute *battr = of->sd->s_bin_attr.bin_attr;
158 struct kobject *kobj = of->sd->s_parent->s_dir.kobj;
159 loff_t size = file_inode(file)->i_size;
160 int count = min_t(size_t, bytes, PAGE_SIZE);
170 if (offs + count > size)
174 buf = kmalloc(count, GFP_KERNEL);
178 /* need of->sd for battr, its parent for kobj */
179 mutex_lock(&of->mutex);
180 if (!sysfs_get_active(of->sd)) {
182 mutex_unlock(&of->mutex);
187 count = battr->read(file, kobj, battr, buf, offs, count);
191 sysfs_put_active(of->sd);
192 mutex_unlock(&of->mutex);
197 if (copy_to_user(userbuf, buf, count)) {
202 pr_debug("offs = %lld, *off = %lld, count = %d\n", offs, *off, count);
212 * flush_write_buffer - push buffer to kobject
214 * @buf: data buffer for file
215 * @off: file offset to write to
216 * @count: number of bytes
218 * Get the correct pointers for the kobject and the attribute we're dealing
219 * with, then call the store() method for it with @buf.
221 static int flush_write_buffer(struct sysfs_open_file *of, char *buf, loff_t off,
224 struct kobject *kobj = of->sd->s_parent->s_dir.kobj;
228 * Need @of->sd for attr and ops, its parent for kobj. @of->mutex
229 * nests outside active ref and is just to ensure that the ops
230 * aren't called concurrently for the same open file.
232 mutex_lock(&of->mutex);
233 if (!sysfs_get_active(of->sd)) {
234 mutex_unlock(&of->mutex);
238 if (sysfs_is_bin(of->sd)) {
239 struct bin_attribute *battr = of->sd->s_bin_attr.bin_attr;
243 rc = battr->write(of->file, kobj, battr, buf, off,
246 const struct sysfs_ops *ops = sysfs_file_ops(of->sd);
248 rc = ops->store(kobj, of->sd->s_attr.attr, buf, count);
251 sysfs_put_active(of->sd);
252 mutex_unlock(&of->mutex);
258 * sysfs_write_file - write an attribute
259 * @file: file pointer
260 * @user_buf: data to write
261 * @count: number of bytes
262 * @ppos: starting offset
264 * Copy data in from userland and pass it to the matching
265 * sysfs_ops->store() by invoking flush_write_buffer().
267 * There is no easy way for us to know if userspace is only doing a partial
268 * write, so we don't support them. We expect the entire buffer to come on
269 * the first write. Hint: if you're writing a value, first read the file,
270 * modify only the the value you're changing, then write entire buffer
273 static ssize_t sysfs_write_file(struct file *file, const char __user *user_buf,
274 size_t count, loff_t *ppos)
276 struct sysfs_open_file *of = sysfs_of(file);
277 ssize_t len = min_t(size_t, count, PAGE_SIZE);
278 loff_t size = file_inode(file)->i_size;
281 if (sysfs_is_bin(of->sd) && size) {
284 len = min_t(ssize_t, len, size - *ppos);
290 buf = kmalloc(len + 1, GFP_KERNEL);
294 if (copy_from_user(buf, user_buf, len)) {
298 buf[len] = '\0'; /* guarantee string termination */
300 len = flush_write_buffer(of, buf, *ppos, len);
308 static void sysfs_bin_vma_open(struct vm_area_struct *vma)
310 struct file *file = vma->vm_file;
311 struct sysfs_open_file *of = sysfs_of(file);
316 if (!sysfs_get_active(of->sd))
319 if (of->vm_ops->open)
320 of->vm_ops->open(vma);
322 sysfs_put_active(of->sd);
325 static int sysfs_bin_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
327 struct file *file = vma->vm_file;
328 struct sysfs_open_file *of = sysfs_of(file);
332 return VM_FAULT_SIGBUS;
334 if (!sysfs_get_active(of->sd))
335 return VM_FAULT_SIGBUS;
337 ret = VM_FAULT_SIGBUS;
338 if (of->vm_ops->fault)
339 ret = of->vm_ops->fault(vma, vmf);
341 sysfs_put_active(of->sd);
345 static int sysfs_bin_page_mkwrite(struct vm_area_struct *vma,
346 struct vm_fault *vmf)
348 struct file *file = vma->vm_file;
349 struct sysfs_open_file *of = sysfs_of(file);
353 return VM_FAULT_SIGBUS;
355 if (!sysfs_get_active(of->sd))
356 return VM_FAULT_SIGBUS;
359 if (of->vm_ops->page_mkwrite)
360 ret = of->vm_ops->page_mkwrite(vma, vmf);
362 file_update_time(file);
364 sysfs_put_active(of->sd);
368 static int sysfs_bin_access(struct vm_area_struct *vma, unsigned long addr,
369 void *buf, int len, int write)
371 struct file *file = vma->vm_file;
372 struct sysfs_open_file *of = sysfs_of(file);
378 if (!sysfs_get_active(of->sd))
382 if (of->vm_ops->access)
383 ret = of->vm_ops->access(vma, addr, buf, len, write);
385 sysfs_put_active(of->sd);
390 static int sysfs_bin_set_policy(struct vm_area_struct *vma,
391 struct mempolicy *new)
393 struct file *file = vma->vm_file;
394 struct sysfs_open_file *of = sysfs_of(file);
400 if (!sysfs_get_active(of->sd))
404 if (of->vm_ops->set_policy)
405 ret = of->vm_ops->set_policy(vma, new);
407 sysfs_put_active(of->sd);
411 static struct mempolicy *sysfs_bin_get_policy(struct vm_area_struct *vma,
414 struct file *file = vma->vm_file;
415 struct sysfs_open_file *of = sysfs_of(file);
416 struct mempolicy *pol;
419 return vma->vm_policy;
421 if (!sysfs_get_active(of->sd))
422 return vma->vm_policy;
424 pol = vma->vm_policy;
425 if (of->vm_ops->get_policy)
426 pol = of->vm_ops->get_policy(vma, addr);
428 sysfs_put_active(of->sd);
432 static int sysfs_bin_migrate(struct vm_area_struct *vma, const nodemask_t *from,
433 const nodemask_t *to, unsigned long flags)
435 struct file *file = vma->vm_file;
436 struct sysfs_open_file *of = sysfs_of(file);
442 if (!sysfs_get_active(of->sd))
446 if (of->vm_ops->migrate)
447 ret = of->vm_ops->migrate(vma, from, to, flags);
449 sysfs_put_active(of->sd);
454 static const struct vm_operations_struct sysfs_bin_vm_ops = {
455 .open = sysfs_bin_vma_open,
456 .fault = sysfs_bin_fault,
457 .page_mkwrite = sysfs_bin_page_mkwrite,
458 .access = sysfs_bin_access,
460 .set_policy = sysfs_bin_set_policy,
461 .get_policy = sysfs_bin_get_policy,
462 .migrate = sysfs_bin_migrate,
466 static int sysfs_bin_mmap(struct file *file, struct vm_area_struct *vma)
468 struct sysfs_open_file *of = sysfs_of(file);
469 struct bin_attribute *battr = of->sd->s_bin_attr.bin_attr;
470 struct kobject *kobj = of->sd->s_parent->s_dir.kobj;
473 mutex_lock(&of->mutex);
475 /* need of->sd for battr, its parent for kobj */
477 if (!sysfs_get_active(of->sd))
484 rc = battr->mmap(file, kobj, battr, vma);
489 * PowerPC's pci_mmap of legacy_mem uses shmem_zero_setup()
490 * to satisfy versions of X which crash if the mmap fails: that
491 * substitutes a new vm_file, and we don't then want bin_vm_ops.
493 if (vma->vm_file != file)
497 if (of->mmapped && of->vm_ops != vma->vm_ops)
501 * It is not possible to successfully wrap close.
502 * So error if someone is trying to use close.
505 if (vma->vm_ops && vma->vm_ops->close)
510 of->vm_ops = vma->vm_ops;
511 vma->vm_ops = &sysfs_bin_vm_ops;
513 sysfs_put_active(of->sd);
515 mutex_unlock(&of->mutex);
521 * sysfs_get_open_dirent - get or create sysfs_open_dirent
522 * @sd: target sysfs_dirent
523 * @of: sysfs_open_file for this instance of open
525 * If @sd->s_attr.open exists, increment its reference count;
526 * otherwise, create one. @of is chained to the files list.
529 * Kernel thread context (may sleep).
532 * 0 on success, -errno on failure.
534 static int sysfs_get_open_dirent(struct sysfs_dirent *sd,
535 struct sysfs_open_file *of)
537 struct sysfs_open_dirent *od, *new_od = NULL;
540 mutex_lock(&sysfs_open_file_mutex);
541 spin_lock_irq(&sysfs_open_dirent_lock);
543 if (!sd->s_attr.open && new_od) {
544 sd->s_attr.open = new_od;
548 od = sd->s_attr.open;
550 atomic_inc(&od->refcnt);
551 list_add_tail(&of->list, &od->files);
554 spin_unlock_irq(&sysfs_open_dirent_lock);
555 mutex_unlock(&sysfs_open_file_mutex);
562 /* not there, initialize a new one and retry */
563 new_od = kmalloc(sizeof(*new_od), GFP_KERNEL);
567 atomic_set(&new_od->refcnt, 0);
568 atomic_set(&new_od->event, 1);
569 init_waitqueue_head(&new_od->poll);
570 INIT_LIST_HEAD(&new_od->files);
575 * sysfs_put_open_dirent - put sysfs_open_dirent
576 * @sd: target sysfs_dirent
577 * @of: associated sysfs_open_file
579 * Put @sd->s_attr.open and unlink @of from the files list. If
580 * reference count reaches zero, disassociate and free it.
585 static void sysfs_put_open_dirent(struct sysfs_dirent *sd,
586 struct sysfs_open_file *of)
588 struct sysfs_open_dirent *od = sd->s_attr.open;
591 mutex_lock(&sysfs_open_file_mutex);
592 spin_lock_irqsave(&sysfs_open_dirent_lock, flags);
597 if (atomic_dec_and_test(&od->refcnt))
598 sd->s_attr.open = NULL;
602 spin_unlock_irqrestore(&sysfs_open_dirent_lock, flags);
603 mutex_unlock(&sysfs_open_file_mutex);
608 static int sysfs_open_file(struct inode *inode, struct file *file)
610 struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
611 struct kobject *kobj = attr_sd->s_parent->s_dir.kobj;
612 struct sysfs_open_file *of;
613 bool has_read, has_write;
616 /* need attr_sd for attr and ops, its parent for kobj */
617 if (!sysfs_get_active(attr_sd))
620 if (sysfs_is_bin(attr_sd)) {
621 struct bin_attribute *battr = attr_sd->s_bin_attr.bin_attr;
623 has_read = battr->read || battr->mmap;
624 has_write = battr->write || battr->mmap;
626 const struct sysfs_ops *ops = sysfs_file_ops(attr_sd);
628 /* every kobject with an attribute needs a ktype assigned */
629 if (WARN(!ops, KERN_ERR
630 "missing sysfs attribute operations for kobject: %s\n",
634 has_read = ops->show;
635 has_write = ops->store;
638 /* check perms and supported operations */
639 if ((file->f_mode & FMODE_WRITE) &&
640 (!(inode->i_mode & S_IWUGO) || !has_write))
643 if ((file->f_mode & FMODE_READ) &&
644 (!(inode->i_mode & S_IRUGO) || !has_read))
647 /* allocate a sysfs_open_file for the file */
649 of = kzalloc(sizeof(struct sysfs_open_file), GFP_KERNEL);
653 mutex_init(&of->mutex);
658 * Always instantiate seq_file even if read access doesn't use
659 * seq_file or is not requested. This unifies private data access
660 * and readable regular files are the vast majority anyway.
662 if (sysfs_is_bin(attr_sd))
663 error = single_open(file, NULL, of);
665 error = single_open(file, sysfs_seq_show, of);
669 /* seq_file clears PWRITE unconditionally, restore it if WRITE */
670 if (file->f_mode & FMODE_WRITE)
671 file->f_mode |= FMODE_PWRITE;
673 /* make sure we have open dirent struct */
674 error = sysfs_get_open_dirent(attr_sd, of);
678 /* open succeeded, put active references */
679 sysfs_put_active(attr_sd);
683 single_release(inode, file);
687 sysfs_put_active(attr_sd);
691 static int sysfs_release(struct inode *inode, struct file *filp)
693 struct sysfs_dirent *sd = filp->f_path.dentry->d_fsdata;
694 struct sysfs_open_file *of = sysfs_of(filp);
696 sysfs_put_open_dirent(sd, of);
697 single_release(inode, filp);
703 void sysfs_unmap_bin_file(struct sysfs_dirent *sd)
705 struct sysfs_open_dirent *od;
706 struct sysfs_open_file *of;
708 if (!sysfs_is_bin(sd))
711 spin_lock_irq(&sysfs_open_dirent_lock);
712 od = sd->s_attr.open;
714 atomic_inc(&od->refcnt);
715 spin_unlock_irq(&sysfs_open_dirent_lock);
719 mutex_lock(&sysfs_open_file_mutex);
720 list_for_each_entry(of, &od->files, list) {
721 struct inode *inode = file_inode(of->file);
722 unmap_mapping_range(inode->i_mapping, 0, 0, 1);
724 mutex_unlock(&sysfs_open_file_mutex);
726 sysfs_put_open_dirent(sd, NULL);
729 /* Sysfs attribute files are pollable. The idea is that you read
730 * the content and then you use 'poll' or 'select' to wait for
731 * the content to change. When the content changes (assuming the
732 * manager for the kobject supports notification), poll will
733 * return POLLERR|POLLPRI, and select will return the fd whether
734 * it is waiting for read, write, or exceptions.
735 * Once poll/select indicates that the value has changed, you
736 * need to close and re-open the file, or seek to 0 and read again.
737 * Reminder: this only works for attributes which actively support
738 * it, and it is not possible to test an attribute from userspace
739 * to see if it supports poll (Neither 'poll' nor 'select' return
740 * an appropriate error code). When in doubt, set a suitable timeout value.
742 static unsigned int sysfs_poll(struct file *filp, poll_table *wait)
744 struct sysfs_open_file *of = sysfs_of(filp);
745 struct sysfs_dirent *attr_sd = filp->f_path.dentry->d_fsdata;
746 struct sysfs_open_dirent *od = attr_sd->s_attr.open;
748 /* need parent for the kobj, grab both */
749 if (!sysfs_get_active(attr_sd))
752 poll_wait(filp, &od->poll, wait);
754 sysfs_put_active(attr_sd);
756 if (of->event != atomic_read(&od->event))
759 return DEFAULT_POLLMASK;
762 return DEFAULT_POLLMASK|POLLERR|POLLPRI;
765 void sysfs_notify_dirent(struct sysfs_dirent *sd)
767 struct sysfs_open_dirent *od;
770 spin_lock_irqsave(&sysfs_open_dirent_lock, flags);
772 if (!WARN_ON(sysfs_type(sd) != SYSFS_KOBJ_ATTR)) {
773 od = sd->s_attr.open;
775 atomic_inc(&od->event);
776 wake_up_interruptible(&od->poll);
780 spin_unlock_irqrestore(&sysfs_open_dirent_lock, flags);
782 EXPORT_SYMBOL_GPL(sysfs_notify_dirent);
784 void sysfs_notify(struct kobject *k, const char *dir, const char *attr)
786 struct sysfs_dirent *sd = k->sd;
788 mutex_lock(&sysfs_mutex);
791 sd = sysfs_find_dirent(sd, dir, NULL);
793 sd = sysfs_find_dirent(sd, attr, NULL);
795 sysfs_notify_dirent(sd);
797 mutex_unlock(&sysfs_mutex);
799 EXPORT_SYMBOL_GPL(sysfs_notify);
801 const struct file_operations sysfs_file_operations = {
803 .write = sysfs_write_file,
805 .open = sysfs_open_file,
806 .release = sysfs_release,
810 const struct file_operations sysfs_bin_operations = {
811 .read = sysfs_bin_read,
812 .write = sysfs_write_file,
813 .llseek = generic_file_llseek,
814 .mmap = sysfs_bin_mmap,
815 .open = sysfs_open_file,
816 .release = sysfs_release,
820 int sysfs_add_file_mode_ns(struct sysfs_dirent *dir_sd,
821 const struct attribute *attr, int type,
822 umode_t amode, const void *ns)
824 umode_t mode = (amode & S_IALLUGO) | S_IFREG;
825 struct sysfs_addrm_cxt acxt;
826 struct sysfs_dirent *sd;
829 sd = sysfs_new_dirent(attr->name, mode, type);
834 sd->s_attr.attr = (void *)attr;
835 sysfs_dirent_init_lockdep(sd);
837 sysfs_addrm_start(&acxt);
838 rc = sysfs_add_one(&acxt, sd, dir_sd);
839 sysfs_addrm_finish(&acxt);
848 int sysfs_add_file(struct sysfs_dirent *dir_sd, const struct attribute *attr,
851 return sysfs_add_file_mode_ns(dir_sd, attr, type, attr->mode, NULL);
855 * sysfs_create_file_ns - create an attribute file for an object with custom ns
856 * @kobj: object we're creating for
857 * @attr: attribute descriptor
858 * @ns: namespace the new file should belong to
860 int sysfs_create_file_ns(struct kobject *kobj, const struct attribute *attr,
863 BUG_ON(!kobj || !kobj->sd || !attr);
865 return sysfs_add_file_mode_ns(kobj->sd, attr, SYSFS_KOBJ_ATTR,
869 EXPORT_SYMBOL_GPL(sysfs_create_file_ns);
871 int sysfs_create_files(struct kobject *kobj, const struct attribute **ptr)
876 for (i = 0; ptr[i] && !err; i++)
877 err = sysfs_create_file(kobj, ptr[i]);
880 sysfs_remove_file(kobj, ptr[i]);
883 EXPORT_SYMBOL_GPL(sysfs_create_files);
886 * sysfs_add_file_to_group - add an attribute file to a pre-existing group.
887 * @kobj: object we're acting for.
888 * @attr: attribute descriptor.
889 * @group: group name.
891 int sysfs_add_file_to_group(struct kobject *kobj,
892 const struct attribute *attr, const char *group)
894 struct sysfs_dirent *dir_sd;
898 dir_sd = sysfs_get_dirent(kobj->sd, group);
900 dir_sd = sysfs_get(kobj->sd);
905 error = sysfs_add_file(dir_sd, attr, SYSFS_KOBJ_ATTR);
910 EXPORT_SYMBOL_GPL(sysfs_add_file_to_group);
913 * sysfs_chmod_file - update the modified mode value on an object attribute.
914 * @kobj: object we're acting for.
915 * @attr: attribute descriptor.
916 * @mode: file permissions.
919 int sysfs_chmod_file(struct kobject *kobj, const struct attribute *attr,
922 struct sysfs_dirent *sd;
923 struct iattr newattrs;
926 mutex_lock(&sysfs_mutex);
929 sd = sysfs_find_dirent(kobj->sd, attr->name, NULL);
933 newattrs.ia_mode = (mode & S_IALLUGO) | (sd->s_mode & ~S_IALLUGO);
934 newattrs.ia_valid = ATTR_MODE;
935 rc = sysfs_sd_setattr(sd, &newattrs);
938 mutex_unlock(&sysfs_mutex);
941 EXPORT_SYMBOL_GPL(sysfs_chmod_file);
944 * sysfs_remove_file_ns - remove an object attribute with a custom ns tag
945 * @kobj: object we're acting for
946 * @attr: attribute descriptor
947 * @ns: namespace tag of the file to remove
949 * Hash the attribute name and namespace tag and kill the victim.
951 void sysfs_remove_file_ns(struct kobject *kobj, const struct attribute *attr,
954 struct sysfs_dirent *dir_sd = kobj->sd;
956 sysfs_hash_and_remove(dir_sd, attr->name, ns);
958 EXPORT_SYMBOL_GPL(sysfs_remove_file_ns);
960 void sysfs_remove_files(struct kobject *kobj, const struct attribute **ptr)
963 for (i = 0; ptr[i]; i++)
964 sysfs_remove_file(kobj, ptr[i]);
966 EXPORT_SYMBOL_GPL(sysfs_remove_files);
969 * sysfs_remove_file_from_group - remove an attribute file from a group.
970 * @kobj: object we're acting for.
971 * @attr: attribute descriptor.
972 * @group: group name.
974 void sysfs_remove_file_from_group(struct kobject *kobj,
975 const struct attribute *attr, const char *group)
977 struct sysfs_dirent *dir_sd;
980 dir_sd = sysfs_get_dirent(kobj->sd, group);
982 dir_sd = sysfs_get(kobj->sd);
984 sysfs_hash_and_remove(dir_sd, attr->name, NULL);
988 EXPORT_SYMBOL_GPL(sysfs_remove_file_from_group);
991 * sysfs_create_bin_file - create binary file for object.
993 * @attr: attribute descriptor.
995 int sysfs_create_bin_file(struct kobject *kobj,
996 const struct bin_attribute *attr)
998 BUG_ON(!kobj || !kobj->sd || !attr);
1000 return sysfs_add_file(kobj->sd, &attr->attr, SYSFS_KOBJ_BIN_ATTR);
1002 EXPORT_SYMBOL_GPL(sysfs_create_bin_file);
1005 * sysfs_remove_bin_file - remove binary file for object.
1007 * @attr: attribute descriptor.
1009 void sysfs_remove_bin_file(struct kobject *kobj,
1010 const struct bin_attribute *attr)
1012 sysfs_hash_and_remove(kobj->sd, attr->attr.name, NULL);
1014 EXPORT_SYMBOL_GPL(sysfs_remove_bin_file);
1016 struct sysfs_schedule_callback_struct {
1017 struct list_head workq_list;
1018 struct kobject *kobj;
1019 void (*func)(void *);
1021 struct module *owner;
1022 struct work_struct work;
1025 static struct workqueue_struct *sysfs_workqueue;
1026 static DEFINE_MUTEX(sysfs_workq_mutex);
1027 static LIST_HEAD(sysfs_workq);
1028 static void sysfs_schedule_callback_work(struct work_struct *work)
1030 struct sysfs_schedule_callback_struct *ss = container_of(work,
1031 struct sysfs_schedule_callback_struct, work);
1033 (ss->func)(ss->data);
1034 kobject_put(ss->kobj);
1035 module_put(ss->owner);
1036 mutex_lock(&sysfs_workq_mutex);
1037 list_del(&ss->workq_list);
1038 mutex_unlock(&sysfs_workq_mutex);
1043 * sysfs_schedule_callback - helper to schedule a callback for a kobject
1044 * @kobj: object we're acting for.
1045 * @func: callback function to invoke later.
1046 * @data: argument to pass to @func.
1047 * @owner: module owning the callback code
1049 * sysfs attribute methods must not unregister themselves or their parent
1050 * kobject (which would amount to the same thing). Attempts to do so will
1051 * deadlock, since unregistration is mutually exclusive with driver
1054 * Instead methods can call this routine, which will attempt to allocate
1055 * and schedule a workqueue request to call back @func with @data as its
1056 * argument in the workqueue's process context. @kobj will be pinned
1057 * until @func returns.
1059 * Returns 0 if the request was submitted, -ENOMEM if storage could not
1060 * be allocated, -ENODEV if a reference to @owner isn't available,
1061 * -EAGAIN if a callback has already been scheduled for @kobj.
1063 int sysfs_schedule_callback(struct kobject *kobj, void (*func)(void *),
1064 void *data, struct module *owner)
1066 struct sysfs_schedule_callback_struct *ss, *tmp;
1068 if (!try_module_get(owner))
1071 mutex_lock(&sysfs_workq_mutex);
1072 list_for_each_entry_safe(ss, tmp, &sysfs_workq, workq_list)
1073 if (ss->kobj == kobj) {
1075 mutex_unlock(&sysfs_workq_mutex);
1078 mutex_unlock(&sysfs_workq_mutex);
1080 if (sysfs_workqueue == NULL) {
1081 sysfs_workqueue = create_singlethread_workqueue("sysfsd");
1082 if (sysfs_workqueue == NULL) {
1088 ss = kmalloc(sizeof(*ss), GFP_KERNEL);
1098 INIT_WORK(&ss->work, sysfs_schedule_callback_work);
1099 INIT_LIST_HEAD(&ss->workq_list);
1100 mutex_lock(&sysfs_workq_mutex);
1101 list_add_tail(&ss->workq_list, &sysfs_workq);
1102 mutex_unlock(&sysfs_workq_mutex);
1103 queue_work(sysfs_workqueue, &ss->work);
1106 EXPORT_SYMBOL_GPL(sysfs_schedule_callback);