2 * fs/sysfs/dir.c - sysfs core and dir operation 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.
16 #include <linux/mount.h>
17 #include <linux/module.h>
18 #include <linux/kobject.h>
19 #include <linux/namei.h>
20 #include <linux/idr.h>
21 #include <linux/completion.h>
22 #include <linux/mutex.h>
23 #include <linux/slab.h>
26 DEFINE_MUTEX(sysfs_mutex
);
27 DEFINE_MUTEX(sysfs_rename_mutex
);
28 DEFINE_SPINLOCK(sysfs_assoc_lock
);
30 static DEFINE_SPINLOCK(sysfs_ino_lock
);
31 static DEFINE_IDA(sysfs_ino_ida
);
34 * sysfs_link_sibling - link sysfs_dirent into sibling list
35 * @sd: sysfs_dirent of interest
37 * Link @sd into its sibling list which starts from
38 * sd->s_parent->s_dir.children.
41 * mutex_lock(sysfs_mutex)
43 static void sysfs_link_sibling(struct sysfs_dirent
*sd
)
45 struct sysfs_dirent
*parent_sd
= sd
->s_parent
;
46 struct sysfs_dirent
**pos
;
48 BUG_ON(sd
->s_sibling
);
50 /* Store directory entries in order by ino. This allows
51 * readdir to properly restart without having to add a
52 * cursor into the s_dir.children list.
54 for (pos
= &parent_sd
->s_dir
.children
; *pos
; pos
= &(*pos
)->s_sibling
) {
55 if (sd
->s_ino
< (*pos
)->s_ino
)
63 * sysfs_unlink_sibling - unlink sysfs_dirent from sibling list
64 * @sd: sysfs_dirent of interest
66 * Unlink @sd from its sibling list which starts from
67 * sd->s_parent->s_dir.children.
70 * mutex_lock(sysfs_mutex)
72 static void sysfs_unlink_sibling(struct sysfs_dirent
*sd
)
74 struct sysfs_dirent
**pos
;
76 for (pos
= &sd
->s_parent
->s_dir
.children
; *pos
;
77 pos
= &(*pos
)->s_sibling
) {
87 * sysfs_get_dentry - get dentry for the given sysfs_dirent
88 * @sd: sysfs_dirent of interest
90 * Get dentry for @sd. Dentry is looked up if currently not
91 * present. This function descends from the root looking up
92 * dentry for each step.
95 * mutex_lock(sysfs_rename_mutex)
98 * Pointer to found dentry on success, ERR_PTR() value on error.
100 struct dentry
*sysfs_get_dentry(struct sysfs_dirent
*sd
)
102 struct dentry
*dentry
= dget(sysfs_sb
->s_root
);
104 while (dentry
->d_fsdata
!= sd
) {
105 struct sysfs_dirent
*cur
;
106 struct dentry
*parent
;
108 /* find the first ancestor which hasn't been looked up */
110 while (cur
->s_parent
!= dentry
->d_fsdata
)
115 mutex_lock(&parent
->d_inode
->i_mutex
);
116 dentry
= lookup_one_noperm(cur
->s_name
, parent
);
117 mutex_unlock(&parent
->d_inode
->i_mutex
);
127 * sysfs_get_active - get an active reference to sysfs_dirent
128 * @sd: sysfs_dirent to get an active reference to
130 * Get an active reference of @sd. This function is noop if @sd
134 * Pointer to @sd on success, NULL on failure.
136 static struct sysfs_dirent
*sysfs_get_active(struct sysfs_dirent
*sd
)
144 v
= atomic_read(&sd
->s_active
);
148 t
= atomic_cmpxchg(&sd
->s_active
, v
, v
+ 1);
159 * sysfs_put_active - put an active reference to sysfs_dirent
160 * @sd: sysfs_dirent to put an active reference to
162 * Put an active reference to @sd. This function is noop if @sd
165 static void sysfs_put_active(struct sysfs_dirent
*sd
)
167 struct completion
*cmpl
;
173 v
= atomic_dec_return(&sd
->s_active
);
174 if (likely(v
!= SD_DEACTIVATED_BIAS
))
177 /* atomic_dec_return() is a mb(), we'll always see the updated
180 cmpl
= (void *)sd
->s_sibling
;
185 * sysfs_get_active_two - get active references to sysfs_dirent and parent
186 * @sd: sysfs_dirent of interest
188 * Get active reference to @sd and its parent. Parent's active
189 * reference is grabbed first. This function is noop if @sd is
193 * Pointer to @sd on success, NULL on failure.
195 struct sysfs_dirent
*sysfs_get_active_two(struct sysfs_dirent
*sd
)
198 if (sd
->s_parent
&& unlikely(!sysfs_get_active(sd
->s_parent
)))
200 if (unlikely(!sysfs_get_active(sd
))) {
201 sysfs_put_active(sd
->s_parent
);
209 * sysfs_put_active_two - put active references to sysfs_dirent and parent
210 * @sd: sysfs_dirent of interest
212 * Put active references to @sd and its parent. This function is
213 * noop if @sd is NULL.
215 void sysfs_put_active_two(struct sysfs_dirent
*sd
)
218 sysfs_put_active(sd
);
219 sysfs_put_active(sd
->s_parent
);
224 * sysfs_deactivate - deactivate sysfs_dirent
225 * @sd: sysfs_dirent to deactivate
227 * Deny new active references and drain existing ones.
229 static void sysfs_deactivate(struct sysfs_dirent
*sd
)
231 DECLARE_COMPLETION_ONSTACK(wait
);
234 BUG_ON(sd
->s_sibling
|| !(sd
->s_flags
& SYSFS_FLAG_REMOVED
));
235 sd
->s_sibling
= (void *)&wait
;
237 /* atomic_add_return() is a mb(), put_active() will always see
238 * the updated sd->s_sibling.
240 v
= atomic_add_return(SD_DEACTIVATED_BIAS
, &sd
->s_active
);
242 if (v
!= SD_DEACTIVATED_BIAS
)
243 wait_for_completion(&wait
);
245 sd
->s_sibling
= NULL
;
248 static int sysfs_alloc_ino(ino_t
*pino
)
253 spin_lock(&sysfs_ino_lock
);
254 rc
= ida_get_new_above(&sysfs_ino_ida
, 2, &ino
);
255 spin_unlock(&sysfs_ino_lock
);
258 if (ida_pre_get(&sysfs_ino_ida
, GFP_KERNEL
))
267 static void sysfs_free_ino(ino_t ino
)
269 spin_lock(&sysfs_ino_lock
);
270 ida_remove(&sysfs_ino_ida
, ino
);
271 spin_unlock(&sysfs_ino_lock
);
274 void release_sysfs_dirent(struct sysfs_dirent
* sd
)
276 struct sysfs_dirent
*parent_sd
;
279 /* Moving/renaming is always done while holding reference.
280 * sd->s_parent won't change beneath us.
282 parent_sd
= sd
->s_parent
;
284 if (sysfs_type(sd
) == SYSFS_KOBJ_LINK
)
285 sysfs_put(sd
->s_symlink
.target_sd
);
286 if (sysfs_type(sd
) & SYSFS_COPY_NAME
)
289 sysfs_free_ino(sd
->s_ino
);
290 kmem_cache_free(sysfs_dir_cachep
, sd
);
293 if (sd
&& atomic_dec_and_test(&sd
->s_count
))
297 static void sysfs_d_iput(struct dentry
* dentry
, struct inode
* inode
)
299 struct sysfs_dirent
* sd
= dentry
->d_fsdata
;
305 static struct dentry_operations sysfs_dentry_ops
= {
306 .d_iput
= sysfs_d_iput
,
309 struct sysfs_dirent
*sysfs_new_dirent(const char *name
, umode_t mode
, int type
)
311 char *dup_name
= NULL
;
312 struct sysfs_dirent
*sd
;
314 if (type
& SYSFS_COPY_NAME
) {
315 name
= dup_name
= kstrdup(name
, GFP_KERNEL
);
320 sd
= kmem_cache_zalloc(sysfs_dir_cachep
, GFP_KERNEL
);
324 if (sysfs_alloc_ino(&sd
->s_ino
))
327 atomic_set(&sd
->s_count
, 1);
328 atomic_set(&sd
->s_active
, 0);
337 kmem_cache_free(sysfs_dir_cachep
, sd
);
343 static int sysfs_ilookup_test(struct inode
*inode
, void *arg
)
345 struct sysfs_dirent
*sd
= arg
;
346 return inode
->i_ino
== sd
->s_ino
;
350 * sysfs_addrm_start - prepare for sysfs_dirent add/remove
351 * @acxt: pointer to sysfs_addrm_cxt to be used
352 * @parent_sd: parent sysfs_dirent
354 * This function is called when the caller is about to add or
355 * remove sysfs_dirent under @parent_sd. This function acquires
356 * sysfs_mutex, grabs inode for @parent_sd if available and lock
357 * i_mutex of it. @acxt is used to keep and pass context to
358 * other addrm functions.
361 * Kernel thread context (may sleep). sysfs_mutex is locked on
362 * return. i_mutex of parent inode is locked on return if
365 void sysfs_addrm_start(struct sysfs_addrm_cxt
*acxt
,
366 struct sysfs_dirent
*parent_sd
)
370 memset(acxt
, 0, sizeof(*acxt
));
371 acxt
->parent_sd
= parent_sd
;
373 /* Lookup parent inode. inode initialization and I_NEW
374 * clearing are protected by sysfs_mutex. By grabbing it and
375 * looking up with _nowait variant, inode state can be
376 * determined reliably.
378 mutex_lock(&sysfs_mutex
);
380 inode
= ilookup5_nowait(sysfs_sb
, parent_sd
->s_ino
, sysfs_ilookup_test
,
383 if (inode
&& !(inode
->i_state
& I_NEW
)) {
384 /* parent inode available */
385 acxt
->parent_inode
= inode
;
387 /* sysfs_mutex is below i_mutex in lock hierarchy.
388 * First, trylock i_mutex. If fails, unlock
389 * sysfs_mutex and lock them in order.
391 if (!mutex_trylock(&inode
->i_mutex
)) {
392 mutex_unlock(&sysfs_mutex
);
393 mutex_lock(&inode
->i_mutex
);
394 mutex_lock(&sysfs_mutex
);
401 * sysfs_add_one - add sysfs_dirent to parent
402 * @acxt: addrm context to use
403 * @sd: sysfs_dirent to be added
405 * Get @acxt->parent_sd and set sd->s_parent to it and increment
406 * nlink of parent inode if @sd is a directory and link into the
407 * children list of the parent.
409 * This function should be called between calls to
410 * sysfs_addrm_start() and sysfs_addrm_finish() and should be
411 * passed the same @acxt as passed to sysfs_addrm_start().
414 * Determined by sysfs_addrm_start().
417 * 0 on success, -EEXIST if entry with the given name already
420 int sysfs_add_one(struct sysfs_addrm_cxt
*acxt
, struct sysfs_dirent
*sd
)
422 if (sysfs_find_dirent(acxt
->parent_sd
, sd
->s_name
))
425 sd
->s_parent
= sysfs_get(acxt
->parent_sd
);
427 if (sysfs_type(sd
) == SYSFS_DIR
&& acxt
->parent_inode
)
428 inc_nlink(acxt
->parent_inode
);
432 sysfs_link_sibling(sd
);
438 * sysfs_remove_one - remove sysfs_dirent from parent
439 * @acxt: addrm context to use
440 * @sd: sysfs_dirent to be removed
442 * Mark @sd removed and drop nlink of parent inode if @sd is a
443 * directory. @sd is unlinked from the children list.
445 * This function should be called between calls to
446 * sysfs_addrm_start() and sysfs_addrm_finish() and should be
447 * passed the same @acxt as passed to sysfs_addrm_start().
450 * Determined by sysfs_addrm_start().
452 void sysfs_remove_one(struct sysfs_addrm_cxt
*acxt
, struct sysfs_dirent
*sd
)
454 BUG_ON(sd
->s_flags
& SYSFS_FLAG_REMOVED
);
456 sysfs_unlink_sibling(sd
);
458 sd
->s_flags
|= SYSFS_FLAG_REMOVED
;
459 sd
->s_sibling
= acxt
->removed
;
462 if (sysfs_type(sd
) == SYSFS_DIR
&& acxt
->parent_inode
)
463 drop_nlink(acxt
->parent_inode
);
469 * sysfs_drop_dentry - drop dentry for the specified sysfs_dirent
470 * @sd: target sysfs_dirent
472 * Drop dentry for @sd. @sd must have been unlinked from its
473 * parent on entry to this function such that it can't be looked
476 static void sysfs_drop_dentry(struct sysfs_dirent
*sd
)
479 struct dentry
*dentry
;
481 inode
= ilookup(sysfs_sb
, sd
->s_ino
);
485 /* Drop any existing dentries associated with sd.
487 * For the dentry to be properly freed we need to grab a
488 * reference to the dentry under the dcache lock, unhash it,
489 * and then put it. The playing with the dentry count allows
490 * dput to immediately free the dentry if it is not in use.
493 spin_lock(&dcache_lock
);
494 list_for_each_entry(dentry
, &inode
->i_dentry
, d_alias
) {
495 if (d_unhashed(dentry
))
498 spin_lock(&dentry
->d_lock
);
500 spin_unlock(&dentry
->d_lock
);
501 spin_unlock(&dcache_lock
);
505 spin_unlock(&dcache_lock
);
507 /* adjust nlink and update timestamp */
508 mutex_lock(&inode
->i_mutex
);
510 inode
->i_ctime
= CURRENT_TIME
;
512 if (sysfs_type(sd
) == SYSFS_DIR
)
515 mutex_unlock(&inode
->i_mutex
);
521 * sysfs_addrm_finish - finish up sysfs_dirent add/remove
522 * @acxt: addrm context to finish up
524 * Finish up sysfs_dirent add/remove. Resources acquired by
525 * sysfs_addrm_start() are released and removed sysfs_dirents are
526 * cleaned up. Timestamps on the parent inode are updated.
529 * All mutexes acquired by sysfs_addrm_start() are released.
531 void sysfs_addrm_finish(struct sysfs_addrm_cxt
*acxt
)
533 /* release resources acquired by sysfs_addrm_start() */
534 mutex_unlock(&sysfs_mutex
);
535 if (acxt
->parent_inode
) {
536 struct inode
*inode
= acxt
->parent_inode
;
538 /* if added/removed, update timestamps on the parent */
540 inode
->i_ctime
= inode
->i_mtime
= CURRENT_TIME
;
542 mutex_unlock(&inode
->i_mutex
);
546 /* kill removed sysfs_dirents */
547 while (acxt
->removed
) {
548 struct sysfs_dirent
*sd
= acxt
->removed
;
550 acxt
->removed
= sd
->s_sibling
;
551 sd
->s_sibling
= NULL
;
553 sysfs_drop_dentry(sd
);
554 sysfs_deactivate(sd
);
560 * sysfs_find_dirent - find sysfs_dirent with the given name
561 * @parent_sd: sysfs_dirent to search under
562 * @name: name to look for
564 * Look for sysfs_dirent with name @name under @parent_sd.
567 * mutex_lock(sysfs_mutex)
570 * Pointer to sysfs_dirent if found, NULL if not.
572 struct sysfs_dirent
*sysfs_find_dirent(struct sysfs_dirent
*parent_sd
,
573 const unsigned char *name
)
575 struct sysfs_dirent
*sd
;
577 for (sd
= parent_sd
->s_dir
.children
; sd
; sd
= sd
->s_sibling
)
578 if (!strcmp(sd
->s_name
, name
))
584 * sysfs_get_dirent - find and get sysfs_dirent with the given name
585 * @parent_sd: sysfs_dirent to search under
586 * @name: name to look for
588 * Look for sysfs_dirent with name @name under @parent_sd and get
592 * Kernel thread context (may sleep). Grabs sysfs_mutex.
595 * Pointer to sysfs_dirent if found, NULL if not.
597 struct sysfs_dirent
*sysfs_get_dirent(struct sysfs_dirent
*parent_sd
,
598 const unsigned char *name
)
600 struct sysfs_dirent
*sd
;
602 mutex_lock(&sysfs_mutex
);
603 sd
= sysfs_find_dirent(parent_sd
, name
);
605 mutex_unlock(&sysfs_mutex
);
610 static int create_dir(struct kobject
*kobj
, struct sysfs_dirent
*parent_sd
,
611 const char *name
, struct sysfs_dirent
**p_sd
)
613 umode_t mode
= S_IFDIR
| S_IRWXU
| S_IRUGO
| S_IXUGO
;
614 struct sysfs_addrm_cxt acxt
;
615 struct sysfs_dirent
*sd
;
619 sd
= sysfs_new_dirent(name
, mode
, SYSFS_DIR
);
622 sd
->s_dir
.kobj
= kobj
;
625 sysfs_addrm_start(&acxt
, parent_sd
);
626 rc
= sysfs_add_one(&acxt
, sd
);
627 sysfs_addrm_finish(&acxt
);
637 int sysfs_create_subdir(struct kobject
*kobj
, const char *name
,
638 struct sysfs_dirent
**p_sd
)
640 return create_dir(kobj
, kobj
->sd
, name
, p_sd
);
644 * sysfs_create_dir - create a directory for an object.
645 * @kobj: object we're creating directory for.
647 int sysfs_create_dir(struct kobject
* kobj
)
649 struct sysfs_dirent
*parent_sd
, *sd
;
655 parent_sd
= kobj
->parent
->sd
;
657 parent_sd
= &sysfs_root
;
659 error
= create_dir(kobj
, parent_sd
, kobject_name(kobj
), &sd
);
665 static struct dentry
* sysfs_lookup(struct inode
*dir
, struct dentry
*dentry
,
666 struct nameidata
*nd
)
668 struct dentry
*ret
= NULL
;
669 struct sysfs_dirent
*parent_sd
= dentry
->d_parent
->d_fsdata
;
670 struct sysfs_dirent
*sd
;
673 mutex_lock(&sysfs_mutex
);
675 sd
= sysfs_find_dirent(parent_sd
, dentry
->d_name
.name
);
679 ret
= ERR_PTR(-ENOENT
);
683 /* attach dentry and inode */
684 inode
= sysfs_get_inode(sd
);
686 ret
= ERR_PTR(-ENOMEM
);
690 /* instantiate and hash dentry */
691 dentry
->d_op
= &sysfs_dentry_ops
;
692 dentry
->d_fsdata
= sysfs_get(sd
);
693 d_instantiate(dentry
, inode
);
697 mutex_unlock(&sysfs_mutex
);
701 const struct inode_operations sysfs_dir_inode_operations
= {
702 .lookup
= sysfs_lookup
,
703 .setattr
= sysfs_setattr
,
706 static void remove_dir(struct sysfs_dirent
*sd
)
708 struct sysfs_addrm_cxt acxt
;
710 sysfs_addrm_start(&acxt
, sd
->s_parent
);
711 sysfs_remove_one(&acxt
, sd
);
712 sysfs_addrm_finish(&acxt
);
715 void sysfs_remove_subdir(struct sysfs_dirent
*sd
)
721 static void __sysfs_remove_dir(struct sysfs_dirent
*dir_sd
)
723 struct sysfs_addrm_cxt acxt
;
724 struct sysfs_dirent
**pos
;
729 pr_debug("sysfs %s: removing dir\n", dir_sd
->s_name
);
730 sysfs_addrm_start(&acxt
, dir_sd
);
731 pos
= &dir_sd
->s_dir
.children
;
733 struct sysfs_dirent
*sd
= *pos
;
735 if (sysfs_type(sd
) != SYSFS_DIR
)
736 sysfs_remove_one(&acxt
, sd
);
738 pos
= &(*pos
)->s_sibling
;
740 sysfs_addrm_finish(&acxt
);
746 * sysfs_remove_dir - remove an object's directory.
749 * The only thing special about this is that we remove any files in
750 * the directory before we remove the directory, and we've inlined
751 * what used to be sysfs_rmdir() below, instead of calling separately.
754 void sysfs_remove_dir(struct kobject
* kobj
)
756 struct sysfs_dirent
*sd
= kobj
->sd
;
758 spin_lock(&sysfs_assoc_lock
);
760 spin_unlock(&sysfs_assoc_lock
);
762 __sysfs_remove_dir(sd
);
765 int sysfs_rename_dir(struct kobject
* kobj
, const char *new_name
)
767 struct sysfs_dirent
*sd
= kobj
->sd
;
768 struct dentry
*parent
= NULL
;
769 struct dentry
*old_dentry
= NULL
, *new_dentry
= NULL
;
770 const char *dup_name
= NULL
;
773 mutex_lock(&sysfs_rename_mutex
);
776 if (strcmp(sd
->s_name
, new_name
) == 0)
777 goto out
; /* nothing to rename */
779 /* get the original dentry */
780 old_dentry
= sysfs_get_dentry(sd
);
781 if (IS_ERR(old_dentry
)) {
782 error
= PTR_ERR(old_dentry
);
787 parent
= old_dentry
->d_parent
;
789 /* lock parent and get dentry for new name */
790 mutex_lock(&parent
->d_inode
->i_mutex
);
791 mutex_lock(&sysfs_mutex
);
794 if (sysfs_find_dirent(sd
->s_parent
, new_name
))
798 new_dentry
= d_alloc_name(parent
, new_name
);
802 /* rename kobject and sysfs_dirent */
804 new_name
= dup_name
= kstrdup(new_name
, GFP_KERNEL
);
808 error
= kobject_set_name(kobj
, "%s", new_name
);
812 dup_name
= sd
->s_name
;
813 sd
->s_name
= new_name
;
816 d_add(new_dentry
, NULL
);
817 d_move(old_dentry
, new_dentry
);
821 mutex_unlock(&sysfs_mutex
);
822 mutex_unlock(&parent
->d_inode
->i_mutex
);
827 mutex_unlock(&sysfs_rename_mutex
);
831 int sysfs_move_dir(struct kobject
*kobj
, struct kobject
*new_parent_kobj
)
833 struct sysfs_dirent
*sd
= kobj
->sd
;
834 struct sysfs_dirent
*new_parent_sd
;
835 struct dentry
*old_parent
, *new_parent
= NULL
;
836 struct dentry
*old_dentry
= NULL
, *new_dentry
= NULL
;
839 mutex_lock(&sysfs_rename_mutex
);
840 BUG_ON(!sd
->s_parent
);
841 new_parent_sd
= new_parent_kobj
->sd
? new_parent_kobj
->sd
: &sysfs_root
;
844 if (sd
->s_parent
== new_parent_sd
)
845 goto out
; /* nothing to move */
848 old_dentry
= sysfs_get_dentry(sd
);
849 if (IS_ERR(old_dentry
)) {
850 error
= PTR_ERR(old_dentry
);
854 old_parent
= old_dentry
->d_parent
;
856 new_parent
= sysfs_get_dentry(new_parent_sd
);
857 if (IS_ERR(new_parent
)) {
858 error
= PTR_ERR(new_parent
);
864 mutex_lock(&old_parent
->d_inode
->i_mutex
);
865 if (!mutex_trylock(&new_parent
->d_inode
->i_mutex
)) {
866 mutex_unlock(&old_parent
->d_inode
->i_mutex
);
869 mutex_lock(&sysfs_mutex
);
872 if (sysfs_find_dirent(new_parent_sd
, sd
->s_name
))
876 new_dentry
= d_alloc_name(new_parent
, sd
->s_name
);
881 d_add(new_dentry
, NULL
);
882 d_move(old_dentry
, new_dentry
);
884 /* Remove from old parent's list and insert into new parent's list. */
885 sysfs_unlink_sibling(sd
);
886 sysfs_get(new_parent_sd
);
887 sysfs_put(sd
->s_parent
);
888 sd
->s_parent
= new_parent_sd
;
889 sysfs_link_sibling(sd
);
892 mutex_unlock(&sysfs_mutex
);
893 mutex_unlock(&new_parent
->d_inode
->i_mutex
);
894 mutex_unlock(&old_parent
->d_inode
->i_mutex
);
899 mutex_unlock(&sysfs_rename_mutex
);
903 /* Relationship between s_mode and the DT_xxx types */
904 static inline unsigned char dt_type(struct sysfs_dirent
*sd
)
906 return (sd
->s_mode
>> 12) & 15;
909 static int sysfs_readdir(struct file
* filp
, void * dirent
, filldir_t filldir
)
911 struct dentry
*dentry
= filp
->f_path
.dentry
;
912 struct sysfs_dirent
* parent_sd
= dentry
->d_fsdata
;
913 struct sysfs_dirent
*pos
;
916 if (filp
->f_pos
== 0) {
917 ino
= parent_sd
->s_ino
;
918 if (filldir(dirent
, ".", 1, filp
->f_pos
, ino
, DT_DIR
) == 0)
921 if (filp
->f_pos
== 1) {
922 if (parent_sd
->s_parent
)
923 ino
= parent_sd
->s_parent
->s_ino
;
925 ino
= parent_sd
->s_ino
;
926 if (filldir(dirent
, "..", 2, filp
->f_pos
, ino
, DT_DIR
) == 0)
929 if ((filp
->f_pos
> 1) && (filp
->f_pos
< INT_MAX
)) {
930 mutex_lock(&sysfs_mutex
);
932 /* Skip the dentries we have already reported */
933 pos
= parent_sd
->s_dir
.children
;
934 while (pos
&& (filp
->f_pos
> pos
->s_ino
))
935 pos
= pos
->s_sibling
;
937 for ( ; pos
; pos
= pos
->s_sibling
) {
943 filp
->f_pos
= ino
= pos
->s_ino
;
945 if (filldir(dirent
, name
, len
, filp
->f_pos
, ino
,
950 filp
->f_pos
= INT_MAX
;
951 mutex_unlock(&sysfs_mutex
);
957 const struct file_operations sysfs_dir_operations
= {
958 .read
= generic_read_dir
,
959 .readdir
= sysfs_readdir
,