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_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_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_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
))
483 rc
= battr
->mmap(file
, kobj
, battr
, vma
);
488 * PowerPC's pci_mmap of legacy_mem uses shmem_zero_setup()
489 * to satisfy versions of X which crash if the mmap fails: that
490 * substitutes a new vm_file, and we don't then want bin_vm_ops.
492 if (vma
->vm_file
!= file
)
496 if (of
->mmapped
&& of
->vm_ops
!= vma
->vm_ops
)
500 * It is not possible to successfully wrap close.
501 * So error if someone is trying to use close.
504 if (vma
->vm_ops
&& vma
->vm_ops
->close
)
509 of
->vm_ops
= vma
->vm_ops
;
510 vma
->vm_ops
= &sysfs_bin_vm_ops
;
512 sysfs_put_active(of
->sd
);
514 mutex_unlock(&of
->mutex
);
520 * sysfs_get_open_dirent - get or create sysfs_open_dirent
521 * @sd: target sysfs_dirent
522 * @of: sysfs_open_file for this instance of open
524 * If @sd->s_attr.open exists, increment its reference count;
525 * otherwise, create one. @of is chained to the files list.
528 * Kernel thread context (may sleep).
531 * 0 on success, -errno on failure.
533 static int sysfs_get_open_dirent(struct sysfs_dirent
*sd
,
534 struct sysfs_open_file
*of
)
536 struct sysfs_open_dirent
*od
, *new_od
= NULL
;
539 mutex_lock(&sysfs_open_file_mutex
);
540 spin_lock_irq(&sysfs_open_dirent_lock
);
542 if (!sd
->s_attr
.open
&& new_od
) {
543 sd
->s_attr
.open
= new_od
;
547 od
= sd
->s_attr
.open
;
549 atomic_inc(&od
->refcnt
);
550 list_add_tail(&of
->list
, &od
->files
);
553 spin_unlock_irq(&sysfs_open_dirent_lock
);
554 mutex_unlock(&sysfs_open_file_mutex
);
561 /* not there, initialize a new one and retry */
562 new_od
= kmalloc(sizeof(*new_od
), GFP_KERNEL
);
566 atomic_set(&new_od
->refcnt
, 0);
567 atomic_set(&new_od
->event
, 1);
568 init_waitqueue_head(&new_od
->poll
);
569 INIT_LIST_HEAD(&new_od
->files
);
574 * sysfs_put_open_dirent - put sysfs_open_dirent
575 * @sd: target sysfs_dirent
576 * @of: associated sysfs_open_file
578 * Put @sd->s_attr.open and unlink @of from the files list. If
579 * reference count reaches zero, disassociate and free it.
584 static void sysfs_put_open_dirent(struct sysfs_dirent
*sd
,
585 struct sysfs_open_file
*of
)
587 struct sysfs_open_dirent
*od
= sd
->s_attr
.open
;
590 mutex_lock(&sysfs_open_file_mutex
);
591 spin_lock_irqsave(&sysfs_open_dirent_lock
, flags
);
596 if (atomic_dec_and_test(&od
->refcnt
))
597 sd
->s_attr
.open
= NULL
;
601 spin_unlock_irqrestore(&sysfs_open_dirent_lock
, flags
);
602 mutex_unlock(&sysfs_open_file_mutex
);
607 static int sysfs_open_file(struct inode
*inode
, struct file
*file
)
609 struct sysfs_dirent
*attr_sd
= file
->f_path
.dentry
->d_fsdata
;
610 struct kobject
*kobj
= attr_sd
->s_parent
->s_dir
.kobj
;
611 struct sysfs_open_file
*of
;
612 bool has_read
, has_write
;
615 /* need attr_sd for attr and ops, its parent for kobj */
616 if (!sysfs_get_active(attr_sd
))
619 if (sysfs_is_bin(attr_sd
)) {
620 struct bin_attribute
*battr
= attr_sd
->s_attr
.bin_attr
;
622 has_read
= battr
->read
|| battr
->mmap
;
623 has_write
= battr
->write
|| battr
->mmap
;
625 const struct sysfs_ops
*ops
= sysfs_file_ops(attr_sd
);
627 /* every kobject with an attribute needs a ktype assigned */
628 if (WARN(!ops
, KERN_ERR
629 "missing sysfs attribute operations for kobject: %s\n",
633 has_read
= ops
->show
;
634 has_write
= ops
->store
;
637 /* check perms and supported operations */
638 if ((file
->f_mode
& FMODE_WRITE
) &&
639 (!(inode
->i_mode
& S_IWUGO
) || !has_write
))
642 if ((file
->f_mode
& FMODE_READ
) &&
643 (!(inode
->i_mode
& S_IRUGO
) || !has_read
))
646 /* allocate a sysfs_open_file for the file */
648 of
= kzalloc(sizeof(struct sysfs_open_file
), GFP_KERNEL
);
652 mutex_init(&of
->mutex
);
657 * Always instantiate seq_file even if read access doesn't use
658 * seq_file or is not requested. This unifies private data access
659 * and readable regular files are the vast majority anyway.
661 if (sysfs_is_bin(attr_sd
))
662 error
= single_open(file
, NULL
, of
);
664 error
= single_open(file
, sysfs_seq_show
, of
);
668 /* seq_file clears PWRITE unconditionally, restore it if WRITE */
669 if (file
->f_mode
& FMODE_WRITE
)
670 file
->f_mode
|= FMODE_PWRITE
;
672 /* make sure we have open dirent struct */
673 error
= sysfs_get_open_dirent(attr_sd
, of
);
677 /* open succeeded, put active references */
678 sysfs_put_active(attr_sd
);
682 single_release(inode
, file
);
686 sysfs_put_active(attr_sd
);
690 static int sysfs_release(struct inode
*inode
, struct file
*filp
)
692 struct sysfs_dirent
*sd
= filp
->f_path
.dentry
->d_fsdata
;
693 struct sysfs_open_file
*of
= sysfs_of(filp
);
695 sysfs_put_open_dirent(sd
, of
);
696 single_release(inode
, filp
);
702 void sysfs_unmap_bin_file(struct sysfs_dirent
*sd
)
704 struct sysfs_open_dirent
*od
;
705 struct sysfs_open_file
*of
;
707 if (!sysfs_is_bin(sd
))
710 spin_lock_irq(&sysfs_open_dirent_lock
);
711 od
= sd
->s_attr
.open
;
713 atomic_inc(&od
->refcnt
);
714 spin_unlock_irq(&sysfs_open_dirent_lock
);
718 mutex_lock(&sysfs_open_file_mutex
);
719 list_for_each_entry(of
, &od
->files
, list
) {
720 struct inode
*inode
= file_inode(of
->file
);
721 unmap_mapping_range(inode
->i_mapping
, 0, 0, 1);
723 mutex_unlock(&sysfs_open_file_mutex
);
725 sysfs_put_open_dirent(sd
, NULL
);
728 /* Sysfs attribute files are pollable. The idea is that you read
729 * the content and then you use 'poll' or 'select' to wait for
730 * the content to change. When the content changes (assuming the
731 * manager for the kobject supports notification), poll will
732 * return POLLERR|POLLPRI, and select will return the fd whether
733 * it is waiting for read, write, or exceptions.
734 * Once poll/select indicates that the value has changed, you
735 * need to close and re-open the file, or seek to 0 and read again.
736 * Reminder: this only works for attributes which actively support
737 * it, and it is not possible to test an attribute from userspace
738 * to see if it supports poll (Neither 'poll' nor 'select' return
739 * an appropriate error code). When in doubt, set a suitable timeout value.
741 static unsigned int sysfs_poll(struct file
*filp
, poll_table
*wait
)
743 struct sysfs_open_file
*of
= sysfs_of(filp
);
744 struct sysfs_dirent
*attr_sd
= filp
->f_path
.dentry
->d_fsdata
;
745 struct sysfs_open_dirent
*od
= attr_sd
->s_attr
.open
;
747 /* need parent for the kobj, grab both */
748 if (!sysfs_get_active(attr_sd
))
751 poll_wait(filp
, &od
->poll
, wait
);
753 sysfs_put_active(attr_sd
);
755 if (of
->event
!= atomic_read(&od
->event
))
758 return DEFAULT_POLLMASK
;
761 return DEFAULT_POLLMASK
|POLLERR
|POLLPRI
;
764 void sysfs_notify_dirent(struct sysfs_dirent
*sd
)
766 struct sysfs_open_dirent
*od
;
769 spin_lock_irqsave(&sysfs_open_dirent_lock
, flags
);
771 if (!WARN_ON(sysfs_type(sd
) != SYSFS_KOBJ_ATTR
)) {
772 od
= sd
->s_attr
.open
;
774 atomic_inc(&od
->event
);
775 wake_up_interruptible(&od
->poll
);
779 spin_unlock_irqrestore(&sysfs_open_dirent_lock
, flags
);
781 EXPORT_SYMBOL_GPL(sysfs_notify_dirent
);
783 void sysfs_notify(struct kobject
*k
, const char *dir
, const char *attr
)
785 struct sysfs_dirent
*sd
= k
->sd
;
787 mutex_lock(&sysfs_mutex
);
790 sd
= sysfs_find_dirent(sd
, dir
, NULL
);
792 sd
= sysfs_find_dirent(sd
, attr
, NULL
);
794 sysfs_notify_dirent(sd
);
796 mutex_unlock(&sysfs_mutex
);
798 EXPORT_SYMBOL_GPL(sysfs_notify
);
800 const struct file_operations sysfs_file_operations
= {
802 .write
= sysfs_write_file
,
803 .llseek
= generic_file_llseek
,
804 .open
= sysfs_open_file
,
805 .release
= sysfs_release
,
809 const struct file_operations sysfs_bin_operations
= {
810 .read
= sysfs_bin_read
,
811 .write
= sysfs_write_file
,
812 .llseek
= generic_file_llseek
,
813 .mmap
= sysfs_bin_mmap
,
814 .open
= sysfs_open_file
,
815 .release
= sysfs_release
,
819 int sysfs_add_file_mode_ns(struct sysfs_dirent
*dir_sd
,
820 const struct attribute
*attr
, int type
,
821 umode_t amode
, const void *ns
)
823 umode_t mode
= (amode
& S_IALLUGO
) | S_IFREG
;
824 struct sysfs_addrm_cxt acxt
;
825 struct sysfs_dirent
*sd
;
828 sd
= sysfs_new_dirent(attr
->name
, mode
, type
);
833 sd
->s_attr
.attr
= (void *)attr
;
834 sysfs_dirent_init_lockdep(sd
);
836 sysfs_addrm_start(&acxt
);
837 rc
= sysfs_add_one(&acxt
, sd
, dir_sd
);
838 sysfs_addrm_finish(&acxt
);
847 int sysfs_add_file(struct sysfs_dirent
*dir_sd
, const struct attribute
*attr
,
850 return sysfs_add_file_mode_ns(dir_sd
, attr
, type
, attr
->mode
, NULL
);
854 * sysfs_create_file_ns - create an attribute file for an object with custom ns
855 * @kobj: object we're creating for
856 * @attr: attribute descriptor
857 * @ns: namespace the new file should belong to
859 int sysfs_create_file_ns(struct kobject
*kobj
, const struct attribute
*attr
,
862 BUG_ON(!kobj
|| !kobj
->sd
|| !attr
);
864 return sysfs_add_file_mode_ns(kobj
->sd
, attr
, SYSFS_KOBJ_ATTR
,
868 EXPORT_SYMBOL_GPL(sysfs_create_file_ns
);
870 int sysfs_create_files(struct kobject
*kobj
, const struct attribute
**ptr
)
875 for (i
= 0; ptr
[i
] && !err
; i
++)
876 err
= sysfs_create_file(kobj
, ptr
[i
]);
879 sysfs_remove_file(kobj
, ptr
[i
]);
882 EXPORT_SYMBOL_GPL(sysfs_create_files
);
885 * sysfs_add_file_to_group - add an attribute file to a pre-existing group.
886 * @kobj: object we're acting for.
887 * @attr: attribute descriptor.
888 * @group: group name.
890 int sysfs_add_file_to_group(struct kobject
*kobj
,
891 const struct attribute
*attr
, const char *group
)
893 struct sysfs_dirent
*dir_sd
;
897 dir_sd
= sysfs_get_dirent(kobj
->sd
, group
);
899 dir_sd
= sysfs_get(kobj
->sd
);
904 error
= sysfs_add_file(dir_sd
, attr
, SYSFS_KOBJ_ATTR
);
909 EXPORT_SYMBOL_GPL(sysfs_add_file_to_group
);
912 * sysfs_chmod_file - update the modified mode value on an object attribute.
913 * @kobj: object we're acting for.
914 * @attr: attribute descriptor.
915 * @mode: file permissions.
918 int sysfs_chmod_file(struct kobject
*kobj
, const struct attribute
*attr
,
921 struct sysfs_dirent
*sd
;
922 struct iattr newattrs
;
925 mutex_lock(&sysfs_mutex
);
928 sd
= sysfs_find_dirent(kobj
->sd
, attr
->name
, NULL
);
932 newattrs
.ia_mode
= (mode
& S_IALLUGO
) | (sd
->s_mode
& ~S_IALLUGO
);
933 newattrs
.ia_valid
= ATTR_MODE
;
934 rc
= sysfs_sd_setattr(sd
, &newattrs
);
937 mutex_unlock(&sysfs_mutex
);
940 EXPORT_SYMBOL_GPL(sysfs_chmod_file
);
943 * sysfs_remove_file_ns - remove an object attribute with a custom ns tag
944 * @kobj: object we're acting for
945 * @attr: attribute descriptor
946 * @ns: namespace tag of the file to remove
948 * Hash the attribute name and namespace tag and kill the victim.
950 void sysfs_remove_file_ns(struct kobject
*kobj
, const struct attribute
*attr
,
953 struct sysfs_dirent
*dir_sd
= kobj
->sd
;
955 sysfs_hash_and_remove(dir_sd
, attr
->name
, ns
);
957 EXPORT_SYMBOL_GPL(sysfs_remove_file_ns
);
959 void sysfs_remove_files(struct kobject
*kobj
, const struct attribute
**ptr
)
962 for (i
= 0; ptr
[i
]; i
++)
963 sysfs_remove_file(kobj
, ptr
[i
]);
965 EXPORT_SYMBOL_GPL(sysfs_remove_files
);
968 * sysfs_remove_file_from_group - remove an attribute file from a group.
969 * @kobj: object we're acting for.
970 * @attr: attribute descriptor.
971 * @group: group name.
973 void sysfs_remove_file_from_group(struct kobject
*kobj
,
974 const struct attribute
*attr
, const char *group
)
976 struct sysfs_dirent
*dir_sd
;
979 dir_sd
= sysfs_get_dirent(kobj
->sd
, group
);
981 dir_sd
= sysfs_get(kobj
->sd
);
983 sysfs_hash_and_remove(dir_sd
, attr
->name
, NULL
);
987 EXPORT_SYMBOL_GPL(sysfs_remove_file_from_group
);
990 * sysfs_create_bin_file - create binary file for object.
992 * @attr: attribute descriptor.
994 int sysfs_create_bin_file(struct kobject
*kobj
,
995 const struct bin_attribute
*attr
)
997 BUG_ON(!kobj
|| !kobj
->sd
|| !attr
);
999 return sysfs_add_file(kobj
->sd
, &attr
->attr
, SYSFS_KOBJ_BIN_ATTR
);
1001 EXPORT_SYMBOL_GPL(sysfs_create_bin_file
);
1004 * sysfs_remove_bin_file - remove binary file for object.
1006 * @attr: attribute descriptor.
1008 void sysfs_remove_bin_file(struct kobject
*kobj
,
1009 const struct bin_attribute
*attr
)
1011 sysfs_hash_and_remove(kobj
->sd
, attr
->attr
.name
, NULL
);
1013 EXPORT_SYMBOL_GPL(sysfs_remove_bin_file
);
1015 struct sysfs_schedule_callback_struct
{
1016 struct list_head workq_list
;
1017 struct kobject
*kobj
;
1018 void (*func
)(void *);
1020 struct module
*owner
;
1021 struct work_struct work
;
1024 static struct workqueue_struct
*sysfs_workqueue
;
1025 static DEFINE_MUTEX(sysfs_workq_mutex
);
1026 static LIST_HEAD(sysfs_workq
);
1027 static void sysfs_schedule_callback_work(struct work_struct
*work
)
1029 struct sysfs_schedule_callback_struct
*ss
= container_of(work
,
1030 struct sysfs_schedule_callback_struct
, work
);
1032 (ss
->func
)(ss
->data
);
1033 kobject_put(ss
->kobj
);
1034 module_put(ss
->owner
);
1035 mutex_lock(&sysfs_workq_mutex
);
1036 list_del(&ss
->workq_list
);
1037 mutex_unlock(&sysfs_workq_mutex
);
1042 * sysfs_schedule_callback - helper to schedule a callback for a kobject
1043 * @kobj: object we're acting for.
1044 * @func: callback function to invoke later.
1045 * @data: argument to pass to @func.
1046 * @owner: module owning the callback code
1048 * sysfs attribute methods must not unregister themselves or their parent
1049 * kobject (which would amount to the same thing). Attempts to do so will
1050 * deadlock, since unregistration is mutually exclusive with driver
1053 * Instead methods can call this routine, which will attempt to allocate
1054 * and schedule a workqueue request to call back @func with @data as its
1055 * argument in the workqueue's process context. @kobj will be pinned
1056 * until @func returns.
1058 * Returns 0 if the request was submitted, -ENOMEM if storage could not
1059 * be allocated, -ENODEV if a reference to @owner isn't available,
1060 * -EAGAIN if a callback has already been scheduled for @kobj.
1062 int sysfs_schedule_callback(struct kobject
*kobj
, void (*func
)(void *),
1063 void *data
, struct module
*owner
)
1065 struct sysfs_schedule_callback_struct
*ss
, *tmp
;
1067 if (!try_module_get(owner
))
1070 mutex_lock(&sysfs_workq_mutex
);
1071 list_for_each_entry_safe(ss
, tmp
, &sysfs_workq
, workq_list
)
1072 if (ss
->kobj
== kobj
) {
1074 mutex_unlock(&sysfs_workq_mutex
);
1077 mutex_unlock(&sysfs_workq_mutex
);
1079 if (sysfs_workqueue
== NULL
) {
1080 sysfs_workqueue
= create_singlethread_workqueue("sysfsd");
1081 if (sysfs_workqueue
== NULL
) {
1087 ss
= kmalloc(sizeof(*ss
), GFP_KERNEL
);
1097 INIT_WORK(&ss
->work
, sysfs_schedule_callback_work
);
1098 INIT_LIST_HEAD(&ss
->workq_list
);
1099 mutex_lock(&sysfs_workq_mutex
);
1100 list_add_tail(&ss
->workq_list
, &sysfs_workq
);
1101 mutex_unlock(&sysfs_workq_mutex
);
1102 queue_work(sysfs_workqueue
, &ss
->work
);
1105 EXPORT_SYMBOL_GPL(sysfs_schedule_callback
);