2 * dir.c - Operations for sysfs directories.
8 #include <linux/mount.h>
9 #include <linux/module.h>
10 #include <linux/kobject.h>
11 #include <linux/namei.h>
12 #include <linux/idr.h>
13 #include <linux/completion.h>
14 #include <linux/mutex.h>
17 DEFINE_MUTEX(sysfs_mutex
);
18 DEFINE_MUTEX(sysfs_rename_mutex
);
19 spinlock_t sysfs_assoc_lock
= SPIN_LOCK_UNLOCKED
;
21 static spinlock_t sysfs_ino_lock
= SPIN_LOCK_UNLOCKED
;
22 static DEFINE_IDA(sysfs_ino_ida
);
25 * sysfs_link_sibling - link sysfs_dirent into sibling list
26 * @sd: sysfs_dirent of interest
28 * Link @sd into its sibling list which starts from
29 * sd->s_parent->s_children.
32 * mutex_lock(sysfs_mutex)
34 static void sysfs_link_sibling(struct sysfs_dirent
*sd
)
36 struct sysfs_dirent
*parent_sd
= sd
->s_parent
;
37 struct sysfs_dirent
**pos
;
39 BUG_ON(sd
->s_sibling
);
41 /* Store directory entries in order by ino. This allows
42 * readdir to properly restart without having to add a
43 * cursor into the s_children list.
45 for (pos
= &parent_sd
->s_children
; *pos
; pos
= &(*pos
)->s_sibling
) {
46 if (sd
->s_ino
< (*pos
)->s_ino
)
54 * sysfs_unlink_sibling - unlink sysfs_dirent from sibling list
55 * @sd: sysfs_dirent of interest
57 * Unlink @sd from its sibling list which starts from
58 * sd->s_parent->s_children.
61 * mutex_lock(sysfs_mutex)
63 static void sysfs_unlink_sibling(struct sysfs_dirent
*sd
)
65 struct sysfs_dirent
**pos
;
67 for (pos
= &sd
->s_parent
->s_children
; *pos
; pos
= &(*pos
)->s_sibling
) {
77 * sysfs_get_dentry - get dentry for the given sysfs_dirent
78 * @sd: sysfs_dirent of interest
80 * Get dentry for @sd. Dentry is looked up if currently not
81 * present. This function descends from the root looking up
82 * dentry for each step.
85 * mutex_lock(sysfs_rename_mutex)
88 * Pointer to found dentry on success, ERR_PTR() value on error.
90 struct dentry
*sysfs_get_dentry(struct sysfs_dirent
*sd
)
92 struct dentry
*dentry
= dget(sysfs_sb
->s_root
);
94 while (dentry
->d_fsdata
!= sd
) {
95 struct sysfs_dirent
*cur
;
96 struct dentry
*parent
;
98 /* find the first ancestor which hasn't been looked up */
100 while (cur
->s_parent
!= dentry
->d_fsdata
)
105 mutex_lock(&parent
->d_inode
->i_mutex
);
106 dentry
= lookup_one_len_kern(cur
->s_name
, parent
,
107 strlen(cur
->s_name
));
108 mutex_unlock(&parent
->d_inode
->i_mutex
);
118 * sysfs_get_active - get an active reference to sysfs_dirent
119 * @sd: sysfs_dirent to get an active reference to
121 * Get an active reference of @sd. This function is noop if @sd
125 * Pointer to @sd on success, NULL on failure.
127 struct sysfs_dirent
*sysfs_get_active(struct sysfs_dirent
*sd
)
135 v
= atomic_read(&sd
->s_active
);
139 t
= atomic_cmpxchg(&sd
->s_active
, v
, v
+ 1);
150 * sysfs_put_active - put an active reference to sysfs_dirent
151 * @sd: sysfs_dirent to put an active reference to
153 * Put an active reference to @sd. This function is noop if @sd
156 void sysfs_put_active(struct sysfs_dirent
*sd
)
158 struct completion
*cmpl
;
164 v
= atomic_dec_return(&sd
->s_active
);
165 if (likely(v
!= SD_DEACTIVATED_BIAS
))
168 /* atomic_dec_return() is a mb(), we'll always see the updated
171 cmpl
= (void *)sd
->s_sibling
;
176 * sysfs_get_active_two - get active references to sysfs_dirent and parent
177 * @sd: sysfs_dirent of interest
179 * Get active reference to @sd and its parent. Parent's active
180 * reference is grabbed first. This function is noop if @sd is
184 * Pointer to @sd on success, NULL on failure.
186 struct sysfs_dirent
*sysfs_get_active_two(struct sysfs_dirent
*sd
)
189 if (sd
->s_parent
&& unlikely(!sysfs_get_active(sd
->s_parent
)))
191 if (unlikely(!sysfs_get_active(sd
))) {
192 sysfs_put_active(sd
->s_parent
);
200 * sysfs_put_active_two - put active references to sysfs_dirent and parent
201 * @sd: sysfs_dirent of interest
203 * Put active references to @sd and its parent. This function is
204 * noop if @sd is NULL.
206 void sysfs_put_active_two(struct sysfs_dirent
*sd
)
209 sysfs_put_active(sd
);
210 sysfs_put_active(sd
->s_parent
);
215 * sysfs_deactivate - deactivate sysfs_dirent
216 * @sd: sysfs_dirent to deactivate
218 * Deny new active references and drain existing ones.
220 static void sysfs_deactivate(struct sysfs_dirent
*sd
)
222 DECLARE_COMPLETION_ONSTACK(wait
);
225 BUG_ON(sd
->s_sibling
|| !(sd
->s_flags
& SYSFS_FLAG_REMOVED
));
226 sd
->s_sibling
= (void *)&wait
;
228 /* atomic_add_return() is a mb(), put_active() will always see
229 * the updated sd->s_sibling.
231 v
= atomic_add_return(SD_DEACTIVATED_BIAS
, &sd
->s_active
);
233 if (v
!= SD_DEACTIVATED_BIAS
)
234 wait_for_completion(&wait
);
236 sd
->s_sibling
= NULL
;
239 static int sysfs_alloc_ino(ino_t
*pino
)
244 spin_lock(&sysfs_ino_lock
);
245 rc
= ida_get_new_above(&sysfs_ino_ida
, 2, &ino
);
246 spin_unlock(&sysfs_ino_lock
);
249 if (ida_pre_get(&sysfs_ino_ida
, GFP_KERNEL
))
258 static void sysfs_free_ino(ino_t ino
)
260 spin_lock(&sysfs_ino_lock
);
261 ida_remove(&sysfs_ino_ida
, ino
);
262 spin_unlock(&sysfs_ino_lock
);
265 void release_sysfs_dirent(struct sysfs_dirent
* sd
)
267 struct sysfs_dirent
*parent_sd
;
270 /* Moving/renaming is always done while holding reference.
271 * sd->s_parent won't change beneath us.
273 parent_sd
= sd
->s_parent
;
275 if (sysfs_type(sd
) == SYSFS_KOBJ_LINK
)
276 sysfs_put(sd
->s_elem
.symlink
.target_sd
);
277 if (sysfs_type(sd
) & SYSFS_COPY_NAME
)
280 sysfs_free_ino(sd
->s_ino
);
281 kmem_cache_free(sysfs_dir_cachep
, sd
);
284 if (sd
&& atomic_dec_and_test(&sd
->s_count
))
288 static void sysfs_d_iput(struct dentry
* dentry
, struct inode
* inode
)
290 struct sysfs_dirent
* sd
= dentry
->d_fsdata
;
296 static struct dentry_operations sysfs_dentry_ops
= {
297 .d_iput
= sysfs_d_iput
,
300 struct sysfs_dirent
*sysfs_new_dirent(const char *name
, umode_t mode
, int type
)
302 char *dup_name
= NULL
;
303 struct sysfs_dirent
*sd
;
305 if (type
& SYSFS_COPY_NAME
) {
306 name
= dup_name
= kstrdup(name
, GFP_KERNEL
);
311 sd
= kmem_cache_zalloc(sysfs_dir_cachep
, GFP_KERNEL
);
315 if (sysfs_alloc_ino(&sd
->s_ino
))
318 atomic_set(&sd
->s_count
, 1);
319 atomic_set(&sd
->s_active
, 0);
320 atomic_set(&sd
->s_event
, 1);
329 kmem_cache_free(sysfs_dir_cachep
, sd
);
336 * sysfs_attach_dentry - associate sysfs_dirent with dentry
337 * @sd: target sysfs_dirent
338 * @dentry: dentry to associate
341 * mutex_lock(sysfs_mutex)
343 static void sysfs_attach_dentry(struct sysfs_dirent
*sd
, struct dentry
*dentry
)
345 dentry
->d_op
= &sysfs_dentry_ops
;
346 dentry
->d_fsdata
= sysfs_get(sd
);
350 static int sysfs_ilookup_test(struct inode
*inode
, void *arg
)
352 struct sysfs_dirent
*sd
= arg
;
353 return inode
->i_ino
== sd
->s_ino
;
357 * sysfs_addrm_start - prepare for sysfs_dirent add/remove
358 * @acxt: pointer to sysfs_addrm_cxt to be used
359 * @parent_sd: parent sysfs_dirent
361 * This function is called when the caller is about to add or
362 * remove sysfs_dirent under @parent_sd. This function acquires
363 * sysfs_mutex, grabs inode for @parent_sd if available and lock
364 * i_mutex of it. @acxt is used to keep and pass context to
365 * other addrm functions.
368 * Kernel thread context (may sleep). sysfs_mutex is locked on
369 * return. i_mutex of parent inode is locked on return if
372 void sysfs_addrm_start(struct sysfs_addrm_cxt
*acxt
,
373 struct sysfs_dirent
*parent_sd
)
377 memset(acxt
, 0, sizeof(*acxt
));
378 acxt
->parent_sd
= parent_sd
;
380 /* Lookup parent inode. inode initialization and I_NEW
381 * clearing are protected by sysfs_mutex. By grabbing it and
382 * looking up with _nowait variant, inode state can be
383 * determined reliably.
385 mutex_lock(&sysfs_mutex
);
387 inode
= ilookup5_nowait(sysfs_sb
, parent_sd
->s_ino
, sysfs_ilookup_test
,
390 if (inode
&& !(inode
->i_state
& I_NEW
)) {
391 /* parent inode available */
392 acxt
->parent_inode
= inode
;
394 /* sysfs_mutex is below i_mutex in lock hierarchy.
395 * First, trylock i_mutex. If fails, unlock
396 * sysfs_mutex and lock them in order.
398 if (!mutex_trylock(&inode
->i_mutex
)) {
399 mutex_unlock(&sysfs_mutex
);
400 mutex_lock(&inode
->i_mutex
);
401 mutex_lock(&sysfs_mutex
);
408 * sysfs_add_one - add sysfs_dirent to parent
409 * @acxt: addrm context to use
410 * @sd: sysfs_dirent to be added
412 * Get @acxt->parent_sd and set sd->s_parent to it and increment
413 * nlink of parent inode if @sd is a directory. @sd is NOT
414 * linked into the children list of the parent. The caller
415 * should invoke sysfs_link_sibling() after this function
416 * completes if @sd needs to be on the children list.
418 * This function should be called between calls to
419 * sysfs_addrm_start() and sysfs_addrm_finish() and should be
420 * passed the same @acxt as passed to sysfs_addrm_start().
423 * Determined by sysfs_addrm_start().
426 * 0 on success, -EEXIST if entry with the given name already
429 int sysfs_add_one(struct sysfs_addrm_cxt
*acxt
, struct sysfs_dirent
*sd
)
431 if (sysfs_find_dirent(acxt
->parent_sd
, sd
->s_name
))
434 sd
->s_parent
= sysfs_get(acxt
->parent_sd
);
436 if (sysfs_type(sd
) == SYSFS_DIR
&& acxt
->parent_inode
)
437 inc_nlink(acxt
->parent_inode
);
441 sysfs_link_sibling(sd
);
447 * sysfs_remove_one - remove sysfs_dirent from parent
448 * @acxt: addrm context to use
449 * @sd: sysfs_dirent to be added
451 * Mark @sd removed and drop nlink of parent inode if @sd is a
452 * directory. @sd is NOT unlinked from the children list of the
453 * parent. The caller is repsonsible for removing @sd from the
454 * children list before calling this function.
456 * This function should be called between calls to
457 * sysfs_addrm_start() and sysfs_addrm_finish() and should be
458 * passed the same @acxt as passed to sysfs_addrm_start().
461 * Determined by sysfs_addrm_start().
463 void sysfs_remove_one(struct sysfs_addrm_cxt
*acxt
, struct sysfs_dirent
*sd
)
465 BUG_ON(sd
->s_flags
& SYSFS_FLAG_REMOVED
);
467 sysfs_unlink_sibling(sd
);
469 sd
->s_flags
|= SYSFS_FLAG_REMOVED
;
470 sd
->s_sibling
= acxt
->removed
;
473 if (sysfs_type(sd
) == SYSFS_DIR
&& acxt
->parent_inode
)
474 drop_nlink(acxt
->parent_inode
);
480 * sysfs_drop_dentry - drop dentry for the specified sysfs_dirent
481 * @sd: target sysfs_dirent
483 * Drop dentry for @sd. @sd must have been unlinked from its
484 * parent on entry to this function such that it can't be looked
487 static void sysfs_drop_dentry(struct sysfs_dirent
*sd
)
490 struct dentry
*dentry
;
492 inode
= ilookup(sysfs_sb
, sd
->s_ino
);
496 /* Drop any existing dentries associated with sd.
498 * For the dentry to be properly freed we need to grab a
499 * reference to the dentry under the dcache lock, unhash it,
500 * and then put it. The playing with the dentry count allows
501 * dput to immediately free the dentry if it is not in use.
504 spin_lock(&dcache_lock
);
505 list_for_each_entry(dentry
, &inode
->i_dentry
, d_alias
) {
506 if (d_unhashed(dentry
))
509 spin_lock(&dentry
->d_lock
);
511 spin_unlock(&dentry
->d_lock
);
512 spin_unlock(&dcache_lock
);
516 spin_unlock(&dcache_lock
);
518 /* adjust nlink and update timestamp */
519 mutex_lock(&inode
->i_mutex
);
521 inode
->i_ctime
= CURRENT_TIME
;
523 if (sysfs_type(sd
) == SYSFS_DIR
)
526 mutex_unlock(&inode
->i_mutex
);
532 * sysfs_addrm_finish - finish up sysfs_dirent add/remove
533 * @acxt: addrm context to finish up
535 * Finish up sysfs_dirent add/remove. Resources acquired by
536 * sysfs_addrm_start() are released and removed sysfs_dirents are
537 * cleaned up. Timestamps on the parent inode are updated.
540 * All mutexes acquired by sysfs_addrm_start() are released.
542 void sysfs_addrm_finish(struct sysfs_addrm_cxt
*acxt
)
544 /* release resources acquired by sysfs_addrm_start() */
545 mutex_unlock(&sysfs_mutex
);
546 if (acxt
->parent_inode
) {
547 struct inode
*inode
= acxt
->parent_inode
;
549 /* if added/removed, update timestamps on the parent */
551 inode
->i_ctime
= inode
->i_mtime
= CURRENT_TIME
;
553 mutex_unlock(&inode
->i_mutex
);
557 /* kill removed sysfs_dirents */
558 while (acxt
->removed
) {
559 struct sysfs_dirent
*sd
= acxt
->removed
;
561 acxt
->removed
= sd
->s_sibling
;
562 sd
->s_sibling
= NULL
;
564 sysfs_drop_dentry(sd
);
565 sysfs_deactivate(sd
);
571 * sysfs_find_dirent - find sysfs_dirent with the given name
572 * @parent_sd: sysfs_dirent to search under
573 * @name: name to look for
575 * Look for sysfs_dirent with name @name under @parent_sd.
578 * mutex_lock(sysfs_mutex)
581 * Pointer to sysfs_dirent if found, NULL if not.
583 struct sysfs_dirent
*sysfs_find_dirent(struct sysfs_dirent
*parent_sd
,
584 const unsigned char *name
)
586 struct sysfs_dirent
*sd
;
588 for (sd
= parent_sd
->s_children
; sd
; sd
= sd
->s_sibling
)
589 if (!strcmp(sd
->s_name
, name
))
595 * sysfs_get_dirent - find and get sysfs_dirent with the given name
596 * @parent_sd: sysfs_dirent to search under
597 * @name: name to look for
599 * Look for sysfs_dirent with name @name under @parent_sd and get
603 * Kernel thread context (may sleep). Grabs sysfs_mutex.
606 * Pointer to sysfs_dirent if found, NULL if not.
608 struct sysfs_dirent
*sysfs_get_dirent(struct sysfs_dirent
*parent_sd
,
609 const unsigned char *name
)
611 struct sysfs_dirent
*sd
;
613 mutex_lock(&sysfs_mutex
);
614 sd
= sysfs_find_dirent(parent_sd
, name
);
616 mutex_unlock(&sysfs_mutex
);
621 static int create_dir(struct kobject
*kobj
, struct sysfs_dirent
*parent_sd
,
622 const char *name
, struct sysfs_dirent
**p_sd
)
624 umode_t mode
= S_IFDIR
| S_IRWXU
| S_IRUGO
| S_IXUGO
;
625 struct sysfs_addrm_cxt acxt
;
626 struct sysfs_dirent
*sd
;
630 sd
= sysfs_new_dirent(name
, mode
, SYSFS_DIR
);
633 sd
->s_elem
.dir
.kobj
= kobj
;
636 sysfs_addrm_start(&acxt
, parent_sd
);
637 rc
= sysfs_add_one(&acxt
, sd
);
638 sysfs_addrm_finish(&acxt
);
648 int sysfs_create_subdir(struct kobject
*kobj
, const char *name
,
649 struct sysfs_dirent
**p_sd
)
651 return create_dir(kobj
, kobj
->sd
, name
, p_sd
);
655 * sysfs_create_dir - create a directory for an object.
656 * @kobj: object we're creating directory for.
658 int sysfs_create_dir(struct kobject
* kobj
)
660 struct sysfs_dirent
*parent_sd
, *sd
;
666 parent_sd
= kobj
->parent
->sd
;
668 parent_sd
= &sysfs_root
;
670 error
= create_dir(kobj
, parent_sd
, kobject_name(kobj
), &sd
);
676 static struct dentry
* sysfs_lookup(struct inode
*dir
, struct dentry
*dentry
,
677 struct nameidata
*nd
)
679 struct dentry
*ret
= NULL
;
680 struct sysfs_dirent
*parent_sd
= dentry
->d_parent
->d_fsdata
;
681 struct sysfs_dirent
*sd
;
684 mutex_lock(&sysfs_mutex
);
686 sd
= sysfs_find_dirent(parent_sd
, dentry
->d_name
.name
);
692 /* attach dentry and inode */
693 inode
= sysfs_get_inode(sd
);
695 ret
= ERR_PTR(-ENOMEM
);
699 d_instantiate(dentry
, inode
);
700 sysfs_attach_dentry(sd
, dentry
);
703 mutex_unlock(&sysfs_mutex
);
707 const struct inode_operations sysfs_dir_inode_operations
= {
708 .lookup
= sysfs_lookup
,
709 .setattr
= sysfs_setattr
,
712 static void remove_dir(struct sysfs_dirent
*sd
)
714 struct sysfs_addrm_cxt acxt
;
716 sysfs_addrm_start(&acxt
, sd
->s_parent
);
717 sysfs_remove_one(&acxt
, sd
);
718 sysfs_addrm_finish(&acxt
);
721 void sysfs_remove_subdir(struct sysfs_dirent
*sd
)
727 static void __sysfs_remove_dir(struct sysfs_dirent
*dir_sd
)
729 struct sysfs_addrm_cxt acxt
;
730 struct sysfs_dirent
**pos
;
735 pr_debug("sysfs %s: removing dir\n", dir_sd
->s_name
);
736 sysfs_addrm_start(&acxt
, dir_sd
);
737 pos
= &dir_sd
->s_children
;
739 struct sysfs_dirent
*sd
= *pos
;
741 if (sysfs_type(sd
) != SYSFS_DIR
)
742 sysfs_remove_one(&acxt
, sd
);
744 pos
= &(*pos
)->s_sibling
;
746 sysfs_addrm_finish(&acxt
);
752 * sysfs_remove_dir - remove an object's directory.
755 * The only thing special about this is that we remove any files in
756 * the directory before we remove the directory, and we've inlined
757 * what used to be sysfs_rmdir() below, instead of calling separately.
760 void sysfs_remove_dir(struct kobject
* kobj
)
762 struct sysfs_dirent
*sd
= kobj
->sd
;
764 spin_lock(&sysfs_assoc_lock
);
766 spin_unlock(&sysfs_assoc_lock
);
768 __sysfs_remove_dir(sd
);
771 int sysfs_rename_dir(struct kobject
* kobj
, const char *new_name
)
773 struct sysfs_dirent
*sd
;
774 struct dentry
*parent
= NULL
;
775 struct dentry
*old_dentry
= NULL
, *new_dentry
= NULL
;
776 const char *dup_name
= NULL
;
779 mutex_lock(&sysfs_rename_mutex
);
781 /* get the original dentry */
783 old_dentry
= sysfs_get_dentry(sd
);
784 if (IS_ERR(old_dentry
)) {
785 error
= PTR_ERR(old_dentry
);
789 parent
= old_dentry
->d_parent
;
791 /* lock parent and get dentry for new name */
792 mutex_lock(&parent
->d_inode
->i_mutex
);
794 new_dentry
= lookup_one_len(new_name
, parent
, strlen(new_name
));
795 if (IS_ERR(new_dentry
)) {
796 error
= PTR_ERR(new_dentry
);
801 if (old_dentry
== new_dentry
)
805 if (new_dentry
->d_inode
)
808 /* rename kobject and sysfs_dirent */
810 new_name
= dup_name
= kstrdup(new_name
, GFP_KERNEL
);
814 error
= kobject_set_name(kobj
, "%s", new_name
);
818 mutex_lock(&sysfs_mutex
);
819 dup_name
= sd
->s_name
;
820 sd
->s_name
= new_name
;
821 mutex_unlock(&sysfs_mutex
);
824 d_add(new_dentry
, NULL
);
825 d_move(old_dentry
, new_dentry
);
833 mutex_unlock(&parent
->d_inode
->i_mutex
);
838 mutex_unlock(&sysfs_rename_mutex
);
842 int sysfs_move_dir(struct kobject
*kobj
, struct kobject
*new_parent_kobj
)
844 struct sysfs_dirent
*sd
= kobj
->sd
;
845 struct sysfs_dirent
*new_parent_sd
;
846 struct dentry
*old_parent
, *new_parent
= NULL
;
847 struct dentry
*old_dentry
= NULL
, *new_dentry
= NULL
;
850 mutex_lock(&sysfs_rename_mutex
);
851 BUG_ON(!sd
->s_parent
);
852 new_parent_sd
= new_parent_kobj
->sd
? new_parent_kobj
->sd
: &sysfs_root
;
855 old_dentry
= sysfs_get_dentry(sd
);
856 if (IS_ERR(old_dentry
)) {
857 error
= PTR_ERR(old_dentry
);
860 old_parent
= old_dentry
->d_parent
;
862 new_parent
= sysfs_get_dentry(new_parent_sd
);
863 if (IS_ERR(new_parent
)) {
864 error
= PTR_ERR(new_parent
);
868 if (old_parent
->d_inode
== new_parent
->d_inode
) {
870 goto out_dput
; /* nothing to move */
873 mutex_lock(&old_parent
->d_inode
->i_mutex
);
874 if (!mutex_trylock(&new_parent
->d_inode
->i_mutex
)) {
875 mutex_unlock(&old_parent
->d_inode
->i_mutex
);
879 new_dentry
= lookup_one_len(kobject_name(kobj
), new_parent
, strlen(kobject_name(kobj
)));
880 if (IS_ERR(new_dentry
)) {
881 error
= PTR_ERR(new_dentry
);
885 d_add(new_dentry
, NULL
);
886 d_move(old_dentry
, new_dentry
);
889 /* Remove from old parent's list and insert into new parent's list. */
890 mutex_lock(&sysfs_mutex
);
892 sysfs_unlink_sibling(sd
);
893 sysfs_get(new_parent_sd
);
894 sysfs_put(sd
->s_parent
);
895 sd
->s_parent
= new_parent_sd
;
896 sysfs_link_sibling(sd
);
898 mutex_unlock(&sysfs_mutex
);
901 mutex_unlock(&new_parent
->d_inode
->i_mutex
);
902 mutex_unlock(&old_parent
->d_inode
->i_mutex
);
907 mutex_unlock(&sysfs_rename_mutex
);
911 /* Relationship between s_mode and the DT_xxx types */
912 static inline unsigned char dt_type(struct sysfs_dirent
*sd
)
914 return (sd
->s_mode
>> 12) & 15;
917 static int sysfs_readdir(struct file
* filp
, void * dirent
, filldir_t filldir
)
919 struct dentry
*dentry
= filp
->f_path
.dentry
;
920 struct sysfs_dirent
* parent_sd
= dentry
->d_fsdata
;
921 struct sysfs_dirent
*pos
;
924 if (filp
->f_pos
== 0) {
925 ino
= parent_sd
->s_ino
;
926 if (filldir(dirent
, ".", 1, filp
->f_pos
, ino
, DT_DIR
) == 0)
929 if (filp
->f_pos
== 1) {
930 if (parent_sd
->s_parent
)
931 ino
= parent_sd
->s_parent
->s_ino
;
933 ino
= parent_sd
->s_ino
;
934 if (filldir(dirent
, "..", 2, filp
->f_pos
, ino
, DT_DIR
) == 0)
937 if ((filp
->f_pos
> 1) && (filp
->f_pos
< INT_MAX
)) {
938 mutex_lock(&sysfs_mutex
);
940 /* Skip the dentries we have already reported */
941 pos
= parent_sd
->s_children
;
942 while (pos
&& (filp
->f_pos
> pos
->s_ino
))
943 pos
= pos
->s_sibling
;
945 for ( ; pos
; pos
= pos
->s_sibling
) {
951 filp
->f_pos
= ino
= pos
->s_ino
;
953 if (filldir(dirent
, name
, len
, filp
->f_pos
, ino
,
958 filp
->f_pos
= INT_MAX
;
959 mutex_unlock(&sysfs_mutex
);
965 const struct file_operations sysfs_dir_operations
= {
966 .read
= generic_read_dir
,
967 .readdir
= sysfs_readdir
,