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 without warning
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_add_one - add sysfs_dirent to parent
439 * @acxt: addrm context to use
440 * @sd: sysfs_dirent to be added
442 * Get @acxt->parent_sd and set sd->s_parent to it and increment
443 * nlink of parent inode if @sd is a directory and link into the
444 * children list of the parent.
446 * This function should be called between calls to
447 * sysfs_addrm_start() and sysfs_addrm_finish() and should be
448 * passed the same @acxt as passed to sysfs_addrm_start().
451 * Determined by sysfs_addrm_start().
454 * 0 on success, -EEXIST if entry with the given name already
457 int sysfs_add_one(struct sysfs_addrm_cxt
*acxt
, struct sysfs_dirent
*sd
)
461 ret
= __sysfs_add_one(acxt
, sd
);
462 if (ret
== -EEXIST
) {
463 printk(KERN_WARNING
"sysfs: duplicate filename '%s' "
464 "can not be created\n", sd
->s_name
);
471 * sysfs_remove_one - remove sysfs_dirent from parent
472 * @acxt: addrm context to use
473 * @sd: sysfs_dirent to be removed
475 * Mark @sd removed and drop nlink of parent inode if @sd is a
476 * directory. @sd is unlinked from the children list.
478 * This function should be called between calls to
479 * sysfs_addrm_start() and sysfs_addrm_finish() and should be
480 * passed the same @acxt as passed to sysfs_addrm_start().
483 * Determined by sysfs_addrm_start().
485 void sysfs_remove_one(struct sysfs_addrm_cxt
*acxt
, struct sysfs_dirent
*sd
)
487 BUG_ON(sd
->s_flags
& SYSFS_FLAG_REMOVED
);
489 sysfs_unlink_sibling(sd
);
491 sd
->s_flags
|= SYSFS_FLAG_REMOVED
;
492 sd
->s_sibling
= acxt
->removed
;
495 if (sysfs_type(sd
) == SYSFS_DIR
&& acxt
->parent_inode
)
496 drop_nlink(acxt
->parent_inode
);
502 * sysfs_drop_dentry - drop dentry for the specified sysfs_dirent
503 * @sd: target sysfs_dirent
505 * Drop dentry for @sd. @sd must have been unlinked from its
506 * parent on entry to this function such that it can't be looked
509 static void sysfs_drop_dentry(struct sysfs_dirent
*sd
)
512 struct dentry
*dentry
;
514 inode
= ilookup(sysfs_sb
, sd
->s_ino
);
518 /* Drop any existing dentries associated with sd.
520 * For the dentry to be properly freed we need to grab a
521 * reference to the dentry under the dcache lock, unhash it,
522 * and then put it. The playing with the dentry count allows
523 * dput to immediately free the dentry if it is not in use.
526 spin_lock(&dcache_lock
);
527 list_for_each_entry(dentry
, &inode
->i_dentry
, d_alias
) {
528 if (d_unhashed(dentry
))
531 spin_lock(&dentry
->d_lock
);
533 spin_unlock(&dentry
->d_lock
);
534 spin_unlock(&dcache_lock
);
538 spin_unlock(&dcache_lock
);
540 /* adjust nlink and update timestamp */
541 mutex_lock(&inode
->i_mutex
);
543 inode
->i_ctime
= CURRENT_TIME
;
545 if (sysfs_type(sd
) == SYSFS_DIR
)
548 mutex_unlock(&inode
->i_mutex
);
554 * sysfs_addrm_finish - finish up sysfs_dirent add/remove
555 * @acxt: addrm context to finish up
557 * Finish up sysfs_dirent add/remove. Resources acquired by
558 * sysfs_addrm_start() are released and removed sysfs_dirents are
559 * cleaned up. Timestamps on the parent inode are updated.
562 * All mutexes acquired by sysfs_addrm_start() are released.
564 void sysfs_addrm_finish(struct sysfs_addrm_cxt
*acxt
)
566 /* release resources acquired by sysfs_addrm_start() */
567 mutex_unlock(&sysfs_mutex
);
568 if (acxt
->parent_inode
) {
569 struct inode
*inode
= acxt
->parent_inode
;
571 /* if added/removed, update timestamps on the parent */
573 inode
->i_ctime
= inode
->i_mtime
= CURRENT_TIME
;
575 mutex_unlock(&inode
->i_mutex
);
579 /* kill removed sysfs_dirents */
580 while (acxt
->removed
) {
581 struct sysfs_dirent
*sd
= acxt
->removed
;
583 acxt
->removed
= sd
->s_sibling
;
584 sd
->s_sibling
= NULL
;
586 sysfs_drop_dentry(sd
);
587 sysfs_deactivate(sd
);
593 * sysfs_find_dirent - find sysfs_dirent with the given name
594 * @parent_sd: sysfs_dirent to search under
595 * @name: name to look for
597 * Look for sysfs_dirent with name @name under @parent_sd.
600 * mutex_lock(sysfs_mutex)
603 * Pointer to sysfs_dirent if found, NULL if not.
605 struct sysfs_dirent
*sysfs_find_dirent(struct sysfs_dirent
*parent_sd
,
606 const unsigned char *name
)
608 struct sysfs_dirent
*sd
;
610 for (sd
= parent_sd
->s_dir
.children
; sd
; sd
= sd
->s_sibling
)
611 if (!strcmp(sd
->s_name
, name
))
617 * sysfs_get_dirent - find and get sysfs_dirent with the given name
618 * @parent_sd: sysfs_dirent to search under
619 * @name: name to look for
621 * Look for sysfs_dirent with name @name under @parent_sd and get
625 * Kernel thread context (may sleep). Grabs sysfs_mutex.
628 * Pointer to sysfs_dirent if found, NULL if not.
630 struct sysfs_dirent
*sysfs_get_dirent(struct sysfs_dirent
*parent_sd
,
631 const unsigned char *name
)
633 struct sysfs_dirent
*sd
;
635 mutex_lock(&sysfs_mutex
);
636 sd
= sysfs_find_dirent(parent_sd
, name
);
638 mutex_unlock(&sysfs_mutex
);
643 static int create_dir(struct kobject
*kobj
, struct sysfs_dirent
*parent_sd
,
644 const char *name
, struct sysfs_dirent
**p_sd
)
646 umode_t mode
= S_IFDIR
| S_IRWXU
| S_IRUGO
| S_IXUGO
;
647 struct sysfs_addrm_cxt acxt
;
648 struct sysfs_dirent
*sd
;
652 sd
= sysfs_new_dirent(name
, mode
, SYSFS_DIR
);
655 sd
->s_dir
.kobj
= kobj
;
658 sysfs_addrm_start(&acxt
, parent_sd
);
659 rc
= sysfs_add_one(&acxt
, sd
);
660 sysfs_addrm_finish(&acxt
);
670 int sysfs_create_subdir(struct kobject
*kobj
, const char *name
,
671 struct sysfs_dirent
**p_sd
)
673 return create_dir(kobj
, kobj
->sd
, name
, p_sd
);
677 * sysfs_create_dir - create a directory for an object.
678 * @kobj: object we're creating directory for.
680 int sysfs_create_dir(struct kobject
* kobj
)
682 struct sysfs_dirent
*parent_sd
, *sd
;
688 parent_sd
= kobj
->parent
->sd
;
690 parent_sd
= &sysfs_root
;
692 error
= create_dir(kobj
, parent_sd
, kobject_name(kobj
), &sd
);
698 static struct dentry
* sysfs_lookup(struct inode
*dir
, struct dentry
*dentry
,
699 struct nameidata
*nd
)
701 struct dentry
*ret
= NULL
;
702 struct sysfs_dirent
*parent_sd
= dentry
->d_parent
->d_fsdata
;
703 struct sysfs_dirent
*sd
;
706 mutex_lock(&sysfs_mutex
);
708 sd
= sysfs_find_dirent(parent_sd
, dentry
->d_name
.name
);
712 ret
= ERR_PTR(-ENOENT
);
716 /* attach dentry and inode */
717 inode
= sysfs_get_inode(sd
);
719 ret
= ERR_PTR(-ENOMEM
);
723 /* instantiate and hash dentry */
724 dentry
->d_op
= &sysfs_dentry_ops
;
725 dentry
->d_fsdata
= sysfs_get(sd
);
726 d_instantiate(dentry
, inode
);
730 mutex_unlock(&sysfs_mutex
);
734 const struct inode_operations sysfs_dir_inode_operations
= {
735 .lookup
= sysfs_lookup
,
736 .setattr
= sysfs_setattr
,
739 static void remove_dir(struct sysfs_dirent
*sd
)
741 struct sysfs_addrm_cxt acxt
;
743 sysfs_addrm_start(&acxt
, sd
->s_parent
);
744 sysfs_remove_one(&acxt
, sd
);
745 sysfs_addrm_finish(&acxt
);
748 void sysfs_remove_subdir(struct sysfs_dirent
*sd
)
754 static void __sysfs_remove_dir(struct sysfs_dirent
*dir_sd
)
756 struct sysfs_addrm_cxt acxt
;
757 struct sysfs_dirent
**pos
;
762 pr_debug("sysfs %s: removing dir\n", dir_sd
->s_name
);
763 sysfs_addrm_start(&acxt
, dir_sd
);
764 pos
= &dir_sd
->s_dir
.children
;
766 struct sysfs_dirent
*sd
= *pos
;
768 if (sysfs_type(sd
) != SYSFS_DIR
)
769 sysfs_remove_one(&acxt
, sd
);
771 pos
= &(*pos
)->s_sibling
;
773 sysfs_addrm_finish(&acxt
);
779 * sysfs_remove_dir - remove an object's directory.
782 * The only thing special about this is that we remove any files in
783 * the directory before we remove the directory, and we've inlined
784 * what used to be sysfs_rmdir() below, instead of calling separately.
787 void sysfs_remove_dir(struct kobject
* kobj
)
789 struct sysfs_dirent
*sd
= kobj
->sd
;
791 spin_lock(&sysfs_assoc_lock
);
793 spin_unlock(&sysfs_assoc_lock
);
795 __sysfs_remove_dir(sd
);
798 int sysfs_rename_dir(struct kobject
* kobj
, const char *new_name
)
800 struct sysfs_dirent
*sd
= kobj
->sd
;
801 struct dentry
*parent
= NULL
;
802 struct dentry
*old_dentry
= NULL
, *new_dentry
= NULL
;
803 const char *dup_name
= NULL
;
806 mutex_lock(&sysfs_rename_mutex
);
809 if (strcmp(sd
->s_name
, new_name
) == 0)
810 goto out
; /* nothing to rename */
812 /* get the original dentry */
813 old_dentry
= sysfs_get_dentry(sd
);
814 if (IS_ERR(old_dentry
)) {
815 error
= PTR_ERR(old_dentry
);
820 parent
= old_dentry
->d_parent
;
822 /* lock parent and get dentry for new name */
823 mutex_lock(&parent
->d_inode
->i_mutex
);
824 mutex_lock(&sysfs_mutex
);
827 if (sysfs_find_dirent(sd
->s_parent
, new_name
))
831 new_dentry
= d_alloc_name(parent
, new_name
);
835 /* rename kobject and sysfs_dirent */
837 new_name
= dup_name
= kstrdup(new_name
, GFP_KERNEL
);
841 error
= kobject_set_name(kobj
, "%s", new_name
);
845 dup_name
= sd
->s_name
;
846 sd
->s_name
= new_name
;
849 d_add(new_dentry
, NULL
);
850 d_move(old_dentry
, new_dentry
);
854 mutex_unlock(&sysfs_mutex
);
855 mutex_unlock(&parent
->d_inode
->i_mutex
);
860 mutex_unlock(&sysfs_rename_mutex
);
864 int sysfs_move_dir(struct kobject
*kobj
, struct kobject
*new_parent_kobj
)
866 struct sysfs_dirent
*sd
= kobj
->sd
;
867 struct sysfs_dirent
*new_parent_sd
;
868 struct dentry
*old_parent
, *new_parent
= NULL
;
869 struct dentry
*old_dentry
= NULL
, *new_dentry
= NULL
;
872 mutex_lock(&sysfs_rename_mutex
);
873 BUG_ON(!sd
->s_parent
);
874 new_parent_sd
= new_parent_kobj
->sd
? new_parent_kobj
->sd
: &sysfs_root
;
877 if (sd
->s_parent
== new_parent_sd
)
878 goto out
; /* nothing to move */
881 old_dentry
= sysfs_get_dentry(sd
);
882 if (IS_ERR(old_dentry
)) {
883 error
= PTR_ERR(old_dentry
);
887 old_parent
= old_dentry
->d_parent
;
889 new_parent
= sysfs_get_dentry(new_parent_sd
);
890 if (IS_ERR(new_parent
)) {
891 error
= PTR_ERR(new_parent
);
897 mutex_lock(&old_parent
->d_inode
->i_mutex
);
898 if (!mutex_trylock(&new_parent
->d_inode
->i_mutex
)) {
899 mutex_unlock(&old_parent
->d_inode
->i_mutex
);
902 mutex_lock(&sysfs_mutex
);
905 if (sysfs_find_dirent(new_parent_sd
, sd
->s_name
))
909 new_dentry
= d_alloc_name(new_parent
, sd
->s_name
);
914 d_add(new_dentry
, NULL
);
915 d_move(old_dentry
, new_dentry
);
917 /* Remove from old parent's list and insert into new parent's list. */
918 sysfs_unlink_sibling(sd
);
919 sysfs_get(new_parent_sd
);
920 sysfs_put(sd
->s_parent
);
921 sd
->s_parent
= new_parent_sd
;
922 sysfs_link_sibling(sd
);
925 mutex_unlock(&sysfs_mutex
);
926 mutex_unlock(&new_parent
->d_inode
->i_mutex
);
927 mutex_unlock(&old_parent
->d_inode
->i_mutex
);
932 mutex_unlock(&sysfs_rename_mutex
);
936 /* Relationship between s_mode and the DT_xxx types */
937 static inline unsigned char dt_type(struct sysfs_dirent
*sd
)
939 return (sd
->s_mode
>> 12) & 15;
942 static int sysfs_readdir(struct file
* filp
, void * dirent
, filldir_t filldir
)
944 struct dentry
*dentry
= filp
->f_path
.dentry
;
945 struct sysfs_dirent
* parent_sd
= dentry
->d_fsdata
;
946 struct sysfs_dirent
*pos
;
949 if (filp
->f_pos
== 0) {
950 ino
= parent_sd
->s_ino
;
951 if (filldir(dirent
, ".", 1, filp
->f_pos
, ino
, DT_DIR
) == 0)
954 if (filp
->f_pos
== 1) {
955 if (parent_sd
->s_parent
)
956 ino
= parent_sd
->s_parent
->s_ino
;
958 ino
= parent_sd
->s_ino
;
959 if (filldir(dirent
, "..", 2, filp
->f_pos
, ino
, DT_DIR
) == 0)
962 if ((filp
->f_pos
> 1) && (filp
->f_pos
< INT_MAX
)) {
963 mutex_lock(&sysfs_mutex
);
965 /* Skip the dentries we have already reported */
966 pos
= parent_sd
->s_dir
.children
;
967 while (pos
&& (filp
->f_pos
> pos
->s_ino
))
968 pos
= pos
->s_sibling
;
970 for ( ; pos
; pos
= pos
->s_sibling
) {
976 filp
->f_pos
= ino
= pos
->s_ino
;
978 if (filldir(dirent
, name
, len
, filp
->f_pos
, ino
,
983 filp
->f_pos
= INT_MAX
;
984 mutex_unlock(&sysfs_mutex
);
990 const struct file_operations sysfs_dir_operations
= {
991 .read
= generic_read_dir
,
992 .readdir
= sysfs_readdir
,