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 spinlock_t sysfs_assoc_lock
= SPIN_LOCK_UNLOCKED
;
20 static spinlock_t sysfs_ino_lock
= SPIN_LOCK_UNLOCKED
;
21 static DEFINE_IDA(sysfs_ino_ida
);
24 * sysfs_link_sibling - link sysfs_dirent into sibling list
25 * @sd: sysfs_dirent of interest
27 * Link @sd into its sibling list which starts from
28 * sd->s_parent->s_children.
31 * mutex_lock(sysfs_mutex)
33 static void sysfs_link_sibling(struct sysfs_dirent
*sd
)
35 struct sysfs_dirent
*parent_sd
= sd
->s_parent
;
36 struct sysfs_dirent
**pos
;
38 BUG_ON(sd
->s_sibling
);
40 /* Store directory entries in order by ino. This allows
41 * readdir to properly restart without having to add a
42 * cursor into the s_children list.
44 for (pos
= &parent_sd
->s_children
; *pos
; pos
= &(*pos
)->s_sibling
) {
45 if (sd
->s_ino
< (*pos
)->s_ino
)
53 * sysfs_unlink_sibling - unlink sysfs_dirent from sibling list
54 * @sd: sysfs_dirent of interest
56 * Unlink @sd from its sibling list which starts from
57 * sd->s_parent->s_children.
60 * mutex_lock(sysfs_mutex)
62 static void sysfs_unlink_sibling(struct sysfs_dirent
*sd
)
64 struct sysfs_dirent
**pos
;
66 for (pos
= &sd
->s_parent
->s_children
; *pos
; pos
= &(*pos
)->s_sibling
) {
76 * sysfs_get_dentry - get dentry for the given sysfs_dirent
77 * @sd: sysfs_dirent of interest
79 * Get dentry for @sd. Dentry is looked up if currently not
80 * present. This function climbs sysfs_dirent tree till it
81 * reaches a sysfs_dirent with valid dentry attached and descends
82 * down from there looking up dentry for each step.
85 * Kernel thread context (may sleep)
88 * Pointer to found dentry on success, ERR_PTR() value on error.
90 struct dentry
*sysfs_get_dentry(struct sysfs_dirent
*sd
)
92 struct sysfs_dirent
*cur
;
93 struct dentry
*parent_dentry
, *dentry
;
96 /* Find the first parent which has valid s_dentry and get the
99 mutex_lock(&sysfs_mutex
);
101 spin_lock(&sysfs_assoc_lock
);
103 spin_lock(&dcache_lock
);
108 while (!cur
->s_dentry
|| !cur
->s_dentry
->d_inode
) {
109 if (cur
->s_flags
& SYSFS_FLAG_REMOVED
) {
110 dentry
= ERR_PTR(-ENOENT
);
118 dentry
= dget_locked(cur
->s_dentry
);
120 spin_unlock(&dcache_lock
);
121 spin_unlock(&sysfs_assoc_lock
);
123 /* from the found dentry, look up depth times */
125 /* find and get depth'th ancestor */
126 for (cur
= sd
, i
= 0; cur
&& i
< depth
; i
++)
129 /* This can happen if tree structure was modified due
130 * to move/rename. Restart.
139 mutex_unlock(&sysfs_mutex
);
142 parent_dentry
= dentry
;
143 mutex_lock(&parent_dentry
->d_inode
->i_mutex
);
144 dentry
= lookup_one_len_kern(cur
->s_name
, parent_dentry
,
145 strlen(cur
->s_name
));
146 mutex_unlock(&parent_dentry
->d_inode
->i_mutex
);
149 if (IS_ERR(dentry
)) {
154 mutex_lock(&sysfs_mutex
);
155 spin_lock(&sysfs_assoc_lock
);
157 /* This, again, can happen if tree structure has
158 * changed and we looked up the wrong thing. Restart.
160 if (cur
->s_dentry
!= dentry
) {
166 spin_unlock(&sysfs_assoc_lock
);
171 mutex_unlock(&sysfs_mutex
);
176 * sysfs_get_active - get an active reference to sysfs_dirent
177 * @sd: sysfs_dirent to get an active reference to
179 * Get an active reference of @sd. This function is noop if @sd
183 * Pointer to @sd on success, NULL on failure.
185 struct sysfs_dirent
*sysfs_get_active(struct sysfs_dirent
*sd
)
193 v
= atomic_read(&sd
->s_active
);
197 t
= atomic_cmpxchg(&sd
->s_active
, v
, v
+ 1);
208 * sysfs_put_active - put an active reference to sysfs_dirent
209 * @sd: sysfs_dirent to put an active reference to
211 * Put an active reference to @sd. This function is noop if @sd
214 void sysfs_put_active(struct sysfs_dirent
*sd
)
216 struct completion
*cmpl
;
222 v
= atomic_dec_return(&sd
->s_active
);
223 if (likely(v
!= SD_DEACTIVATED_BIAS
))
226 /* atomic_dec_return() is a mb(), we'll always see the updated
229 cmpl
= (void *)sd
->s_sibling
;
234 * sysfs_get_active_two - get active references to sysfs_dirent and parent
235 * @sd: sysfs_dirent of interest
237 * Get active reference to @sd and its parent. Parent's active
238 * reference is grabbed first. This function is noop if @sd is
242 * Pointer to @sd on success, NULL on failure.
244 struct sysfs_dirent
*sysfs_get_active_two(struct sysfs_dirent
*sd
)
247 if (sd
->s_parent
&& unlikely(!sysfs_get_active(sd
->s_parent
)))
249 if (unlikely(!sysfs_get_active(sd
))) {
250 sysfs_put_active(sd
->s_parent
);
258 * sysfs_put_active_two - put active references to sysfs_dirent and parent
259 * @sd: sysfs_dirent of interest
261 * Put active references to @sd and its parent. This function is
262 * noop if @sd is NULL.
264 void sysfs_put_active_two(struct sysfs_dirent
*sd
)
267 sysfs_put_active(sd
);
268 sysfs_put_active(sd
->s_parent
);
273 * sysfs_deactivate - deactivate sysfs_dirent
274 * @sd: sysfs_dirent to deactivate
276 * Deny new active references and drain existing ones.
278 static void sysfs_deactivate(struct sysfs_dirent
*sd
)
280 DECLARE_COMPLETION_ONSTACK(wait
);
283 BUG_ON(sd
->s_sibling
|| !(sd
->s_flags
& SYSFS_FLAG_REMOVED
));
284 sd
->s_sibling
= (void *)&wait
;
286 /* atomic_add_return() is a mb(), put_active() will always see
287 * the updated sd->s_sibling.
289 v
= atomic_add_return(SD_DEACTIVATED_BIAS
, &sd
->s_active
);
291 if (v
!= SD_DEACTIVATED_BIAS
)
292 wait_for_completion(&wait
);
294 sd
->s_sibling
= NULL
;
297 static int sysfs_alloc_ino(ino_t
*pino
)
302 spin_lock(&sysfs_ino_lock
);
303 rc
= ida_get_new_above(&sysfs_ino_ida
, 2, &ino
);
304 spin_unlock(&sysfs_ino_lock
);
307 if (ida_pre_get(&sysfs_ino_ida
, GFP_KERNEL
))
316 static void sysfs_free_ino(ino_t ino
)
318 spin_lock(&sysfs_ino_lock
);
319 ida_remove(&sysfs_ino_ida
, ino
);
320 spin_unlock(&sysfs_ino_lock
);
323 void release_sysfs_dirent(struct sysfs_dirent
* sd
)
325 struct sysfs_dirent
*parent_sd
;
328 /* Moving/renaming is always done while holding reference.
329 * sd->s_parent won't change beneath us.
331 parent_sd
= sd
->s_parent
;
333 if (sysfs_type(sd
) == SYSFS_KOBJ_LINK
)
334 sysfs_put(sd
->s_elem
.symlink
.target_sd
);
335 if (sysfs_type(sd
) & SYSFS_COPY_NAME
)
338 sysfs_free_ino(sd
->s_ino
);
339 kmem_cache_free(sysfs_dir_cachep
, sd
);
342 if (sd
&& atomic_dec_and_test(&sd
->s_count
))
346 static void sysfs_d_iput(struct dentry
* dentry
, struct inode
* inode
)
348 struct sysfs_dirent
* sd
= dentry
->d_fsdata
;
351 /* sd->s_dentry is protected with sysfs_assoc_lock.
352 * This allows sysfs_drop_dentry() to dereference it.
354 spin_lock(&sysfs_assoc_lock
);
356 /* The dentry might have been deleted or another
357 * lookup could have happened updating sd->s_dentry to
358 * point the new dentry. Ignore if it isn't pointing
361 if (sd
->s_dentry
== dentry
)
363 spin_unlock(&sysfs_assoc_lock
);
369 static struct dentry_operations sysfs_dentry_ops
= {
370 .d_iput
= sysfs_d_iput
,
373 struct sysfs_dirent
*sysfs_new_dirent(const char *name
, umode_t mode
, int type
)
375 char *dup_name
= NULL
;
376 struct sysfs_dirent
*sd
;
378 if (type
& SYSFS_COPY_NAME
) {
379 name
= dup_name
= kstrdup(name
, GFP_KERNEL
);
384 sd
= kmem_cache_zalloc(sysfs_dir_cachep
, GFP_KERNEL
);
388 if (sysfs_alloc_ino(&sd
->s_ino
))
391 atomic_set(&sd
->s_count
, 1);
392 atomic_set(&sd
->s_active
, 0);
393 atomic_set(&sd
->s_event
, 1);
402 kmem_cache_free(sysfs_dir_cachep
, sd
);
409 * sysfs_attach_dentry - associate sysfs_dirent with dentry
410 * @sd: target sysfs_dirent
411 * @dentry: dentry to associate
413 * Associate @sd with @dentry. This is protected by
414 * sysfs_assoc_lock to avoid race with sysfs_d_iput().
417 * mutex_lock(sysfs_mutex)
419 static void sysfs_attach_dentry(struct sysfs_dirent
*sd
, struct dentry
*dentry
)
421 dentry
->d_op
= &sysfs_dentry_ops
;
422 dentry
->d_fsdata
= sysfs_get(sd
);
424 /* protect sd->s_dentry against sysfs_d_iput */
425 spin_lock(&sysfs_assoc_lock
);
426 sd
->s_dentry
= dentry
;
427 spin_unlock(&sysfs_assoc_lock
);
432 static int sysfs_ilookup_test(struct inode
*inode
, void *arg
)
434 struct sysfs_dirent
*sd
= arg
;
435 return inode
->i_ino
== sd
->s_ino
;
439 * sysfs_addrm_start - prepare for sysfs_dirent add/remove
440 * @acxt: pointer to sysfs_addrm_cxt to be used
441 * @parent_sd: parent sysfs_dirent
443 * This function is called when the caller is about to add or
444 * remove sysfs_dirent under @parent_sd. This function acquires
445 * sysfs_mutex, grabs inode for @parent_sd if available and lock
446 * i_mutex of it. @acxt is used to keep and pass context to
447 * other addrm functions.
450 * Kernel thread context (may sleep). sysfs_mutex is locked on
451 * return. i_mutex of parent inode is locked on return if
454 void sysfs_addrm_start(struct sysfs_addrm_cxt
*acxt
,
455 struct sysfs_dirent
*parent_sd
)
459 memset(acxt
, 0, sizeof(*acxt
));
460 acxt
->parent_sd
= parent_sd
;
462 /* Lookup parent inode. inode initialization and I_NEW
463 * clearing are protected by sysfs_mutex. By grabbing it and
464 * looking up with _nowait variant, inode state can be
465 * determined reliably.
467 mutex_lock(&sysfs_mutex
);
469 inode
= ilookup5_nowait(sysfs_sb
, parent_sd
->s_ino
, sysfs_ilookup_test
,
472 if (inode
&& !(inode
->i_state
& I_NEW
)) {
473 /* parent inode available */
474 acxt
->parent_inode
= inode
;
476 /* sysfs_mutex is below i_mutex in lock hierarchy.
477 * First, trylock i_mutex. If fails, unlock
478 * sysfs_mutex and lock them in order.
480 if (!mutex_trylock(&inode
->i_mutex
)) {
481 mutex_unlock(&sysfs_mutex
);
482 mutex_lock(&inode
->i_mutex
);
483 mutex_lock(&sysfs_mutex
);
490 * sysfs_add_one - add sysfs_dirent to parent
491 * @acxt: addrm context to use
492 * @sd: sysfs_dirent to be added
494 * Get @acxt->parent_sd and set sd->s_parent to it and increment
495 * nlink of parent inode if @sd is a directory. @sd is NOT
496 * linked into the children list of the parent. The caller
497 * should invoke sysfs_link_sibling() after this function
498 * completes if @sd needs to be on the children list.
500 * This function should be called between calls to
501 * sysfs_addrm_start() and sysfs_addrm_finish() and should be
502 * passed the same @acxt as passed to sysfs_addrm_start().
505 * Determined by sysfs_addrm_start().
508 * 0 on success, -EEXIST if entry with the given name already
511 int sysfs_add_one(struct sysfs_addrm_cxt
*acxt
, struct sysfs_dirent
*sd
)
513 if (sysfs_find_dirent(acxt
->parent_sd
, sd
->s_name
))
516 sd
->s_parent
= sysfs_get(acxt
->parent_sd
);
518 if (sysfs_type(sd
) == SYSFS_DIR
&& acxt
->parent_inode
)
519 inc_nlink(acxt
->parent_inode
);
523 sysfs_link_sibling(sd
);
529 * sysfs_remove_one - remove sysfs_dirent from parent
530 * @acxt: addrm context to use
531 * @sd: sysfs_dirent to be added
533 * Mark @sd removed and drop nlink of parent inode if @sd is a
534 * directory. @sd is NOT unlinked from the children list of the
535 * parent. The caller is repsonsible for removing @sd from the
536 * children list before calling this function.
538 * This function should be called between calls to
539 * sysfs_addrm_start() and sysfs_addrm_finish() and should be
540 * passed the same @acxt as passed to sysfs_addrm_start().
543 * Determined by sysfs_addrm_start().
545 void sysfs_remove_one(struct sysfs_addrm_cxt
*acxt
, struct sysfs_dirent
*sd
)
547 BUG_ON(sd
->s_flags
& SYSFS_FLAG_REMOVED
);
549 sysfs_unlink_sibling(sd
);
551 sd
->s_flags
|= SYSFS_FLAG_REMOVED
;
552 sd
->s_sibling
= acxt
->removed
;
555 if (sysfs_type(sd
) == SYSFS_DIR
&& acxt
->parent_inode
)
556 drop_nlink(acxt
->parent_inode
);
562 * sysfs_drop_dentry - drop dentry for the specified sysfs_dirent
563 * @sd: target sysfs_dirent
565 * Drop dentry for @sd. @sd must have been unlinked from its
566 * parent on entry to this function such that it can't be looked
569 static void sysfs_drop_dentry(struct sysfs_dirent
*sd
)
572 struct dentry
*dentry
;
574 inode
= ilookup(sysfs_sb
, sd
->s_ino
);
578 /* Drop any existing dentries associated with sd.
580 * For the dentry to be properly freed we need to grab a
581 * reference to the dentry under the dcache lock, unhash it,
582 * and then put it. The playing with the dentry count allows
583 * dput to immediately free the dentry if it is not in use.
586 spin_lock(&dcache_lock
);
587 list_for_each_entry(dentry
, &inode
->i_dentry
, d_alias
) {
588 if (d_unhashed(dentry
))
591 spin_lock(&dentry
->d_lock
);
593 spin_unlock(&dentry
->d_lock
);
594 spin_unlock(&dcache_lock
);
598 spin_unlock(&dcache_lock
);
600 /* adjust nlink and update timestamp */
601 mutex_lock(&inode
->i_mutex
);
603 inode
->i_ctime
= CURRENT_TIME
;
605 if (sysfs_type(sd
) == SYSFS_DIR
)
608 mutex_unlock(&inode
->i_mutex
);
614 * sysfs_addrm_finish - finish up sysfs_dirent add/remove
615 * @acxt: addrm context to finish up
617 * Finish up sysfs_dirent add/remove. Resources acquired by
618 * sysfs_addrm_start() are released and removed sysfs_dirents are
619 * cleaned up. Timestamps on the parent inode are updated.
622 * All mutexes acquired by sysfs_addrm_start() are released.
624 void sysfs_addrm_finish(struct sysfs_addrm_cxt
*acxt
)
626 /* release resources acquired by sysfs_addrm_start() */
627 mutex_unlock(&sysfs_mutex
);
628 if (acxt
->parent_inode
) {
629 struct inode
*inode
= acxt
->parent_inode
;
631 /* if added/removed, update timestamps on the parent */
633 inode
->i_ctime
= inode
->i_mtime
= CURRENT_TIME
;
635 mutex_unlock(&inode
->i_mutex
);
639 /* kill removed sysfs_dirents */
640 while (acxt
->removed
) {
641 struct sysfs_dirent
*sd
= acxt
->removed
;
643 acxt
->removed
= sd
->s_sibling
;
644 sd
->s_sibling
= NULL
;
646 sysfs_drop_dentry(sd
);
647 sysfs_deactivate(sd
);
653 * sysfs_find_dirent - find sysfs_dirent with the given name
654 * @parent_sd: sysfs_dirent to search under
655 * @name: name to look for
657 * Look for sysfs_dirent with name @name under @parent_sd.
660 * mutex_lock(sysfs_mutex)
663 * Pointer to sysfs_dirent if found, NULL if not.
665 struct sysfs_dirent
*sysfs_find_dirent(struct sysfs_dirent
*parent_sd
,
666 const unsigned char *name
)
668 struct sysfs_dirent
*sd
;
670 for (sd
= parent_sd
->s_children
; sd
; sd
= sd
->s_sibling
)
671 if (!strcmp(sd
->s_name
, name
))
677 * sysfs_get_dirent - find and get sysfs_dirent with the given name
678 * @parent_sd: sysfs_dirent to search under
679 * @name: name to look for
681 * Look for sysfs_dirent with name @name under @parent_sd and get
685 * Kernel thread context (may sleep). Grabs sysfs_mutex.
688 * Pointer to sysfs_dirent if found, NULL if not.
690 struct sysfs_dirent
*sysfs_get_dirent(struct sysfs_dirent
*parent_sd
,
691 const unsigned char *name
)
693 struct sysfs_dirent
*sd
;
695 mutex_lock(&sysfs_mutex
);
696 sd
= sysfs_find_dirent(parent_sd
, name
);
698 mutex_unlock(&sysfs_mutex
);
703 static int create_dir(struct kobject
*kobj
, struct sysfs_dirent
*parent_sd
,
704 const char *name
, struct sysfs_dirent
**p_sd
)
706 umode_t mode
= S_IFDIR
| S_IRWXU
| S_IRUGO
| S_IXUGO
;
707 struct sysfs_addrm_cxt acxt
;
708 struct sysfs_dirent
*sd
;
712 sd
= sysfs_new_dirent(name
, mode
, SYSFS_DIR
);
715 sd
->s_elem
.dir
.kobj
= kobj
;
718 sysfs_addrm_start(&acxt
, parent_sd
);
719 rc
= sysfs_add_one(&acxt
, sd
);
720 sysfs_addrm_finish(&acxt
);
730 int sysfs_create_subdir(struct kobject
*kobj
, const char *name
,
731 struct sysfs_dirent
**p_sd
)
733 return create_dir(kobj
, kobj
->sd
, name
, p_sd
);
737 * sysfs_create_dir - create a directory for an object.
738 * @kobj: object we're creating directory for.
740 int sysfs_create_dir(struct kobject
* kobj
)
742 struct sysfs_dirent
*parent_sd
, *sd
;
748 parent_sd
= kobj
->parent
->sd
;
750 parent_sd
= &sysfs_root
;
752 error
= create_dir(kobj
, parent_sd
, kobject_name(kobj
), &sd
);
758 static struct dentry
* sysfs_lookup(struct inode
*dir
, struct dentry
*dentry
,
759 struct nameidata
*nd
)
761 struct dentry
*ret
= NULL
;
762 struct sysfs_dirent
*parent_sd
= dentry
->d_parent
->d_fsdata
;
763 struct sysfs_dirent
*sd
;
766 mutex_lock(&sysfs_mutex
);
768 sd
= sysfs_find_dirent(parent_sd
, dentry
->d_name
.name
);
774 /* attach dentry and inode */
775 inode
= sysfs_get_inode(sd
);
777 ret
= ERR_PTR(-ENOMEM
);
781 d_instantiate(dentry
, inode
);
782 sysfs_attach_dentry(sd
, dentry
);
785 mutex_unlock(&sysfs_mutex
);
789 const struct inode_operations sysfs_dir_inode_operations
= {
790 .lookup
= sysfs_lookup
,
791 .setattr
= sysfs_setattr
,
794 static void remove_dir(struct sysfs_dirent
*sd
)
796 struct sysfs_addrm_cxt acxt
;
798 sysfs_addrm_start(&acxt
, sd
->s_parent
);
799 sysfs_remove_one(&acxt
, sd
);
800 sysfs_addrm_finish(&acxt
);
803 void sysfs_remove_subdir(struct sysfs_dirent
*sd
)
809 static void __sysfs_remove_dir(struct sysfs_dirent
*dir_sd
)
811 struct sysfs_addrm_cxt acxt
;
812 struct sysfs_dirent
**pos
;
817 pr_debug("sysfs %s: removing dir\n", dir_sd
->s_name
);
818 sysfs_addrm_start(&acxt
, dir_sd
);
819 pos
= &dir_sd
->s_children
;
821 struct sysfs_dirent
*sd
= *pos
;
823 if (sysfs_type(sd
) != SYSFS_DIR
)
824 sysfs_remove_one(&acxt
, sd
);
826 pos
= &(*pos
)->s_sibling
;
828 sysfs_addrm_finish(&acxt
);
834 * sysfs_remove_dir - remove an object's directory.
837 * The only thing special about this is that we remove any files in
838 * the directory before we remove the directory, and we've inlined
839 * what used to be sysfs_rmdir() below, instead of calling separately.
842 void sysfs_remove_dir(struct kobject
* kobj
)
844 struct sysfs_dirent
*sd
= kobj
->sd
;
846 spin_lock(&sysfs_assoc_lock
);
848 spin_unlock(&sysfs_assoc_lock
);
850 __sysfs_remove_dir(sd
);
853 int sysfs_rename_dir(struct kobject
* kobj
, const char *new_name
)
855 struct sysfs_dirent
*sd
;
856 struct dentry
*parent
= NULL
;
857 struct dentry
*old_dentry
= NULL
, *new_dentry
= NULL
;
858 const char *dup_name
= NULL
;
861 /* get the original dentry */
863 old_dentry
= sysfs_get_dentry(sd
);
864 if (IS_ERR(old_dentry
)) {
865 error
= PTR_ERR(old_dentry
);
869 parent
= old_dentry
->d_parent
;
871 /* lock parent and get dentry for new name */
872 mutex_lock(&parent
->d_inode
->i_mutex
);
874 new_dentry
= lookup_one_len(new_name
, parent
, strlen(new_name
));
875 if (IS_ERR(new_dentry
)) {
876 error
= PTR_ERR(new_dentry
);
881 if (old_dentry
== new_dentry
)
885 if (new_dentry
->d_inode
)
888 /* rename kobject and sysfs_dirent */
890 new_name
= dup_name
= kstrdup(new_name
, GFP_KERNEL
);
894 error
= kobject_set_name(kobj
, "%s", new_name
);
898 mutex_lock(&sysfs_mutex
);
899 dup_name
= sd
->s_name
;
900 sd
->s_name
= new_name
;
901 mutex_unlock(&sysfs_mutex
);
904 d_add(new_dentry
, NULL
);
905 d_move(sd
->s_dentry
, new_dentry
);
913 mutex_unlock(&parent
->d_inode
->i_mutex
);
921 int sysfs_move_dir(struct kobject
*kobj
, struct kobject
*new_parent_kobj
)
923 struct sysfs_dirent
*sd
= kobj
->sd
;
924 struct sysfs_dirent
*new_parent_sd
;
925 struct dentry
*old_parent
, *new_parent
= NULL
;
926 struct dentry
*old_dentry
= NULL
, *new_dentry
= NULL
;
929 BUG_ON(!sd
->s_parent
);
930 new_parent_sd
= new_parent_kobj
->sd
? new_parent_kobj
->sd
: &sysfs_root
;
933 old_dentry
= sysfs_get_dentry(sd
);
934 if (IS_ERR(old_dentry
)) {
935 error
= PTR_ERR(old_dentry
);
938 old_parent
= sd
->s_parent
->s_dentry
;
940 new_parent
= sysfs_get_dentry(new_parent_sd
);
941 if (IS_ERR(new_parent
)) {
942 error
= PTR_ERR(new_parent
);
946 if (old_parent
->d_inode
== new_parent
->d_inode
) {
948 goto out_dput
; /* nothing to move */
951 mutex_lock(&old_parent
->d_inode
->i_mutex
);
952 if (!mutex_trylock(&new_parent
->d_inode
->i_mutex
)) {
953 mutex_unlock(&old_parent
->d_inode
->i_mutex
);
957 new_dentry
= lookup_one_len(kobject_name(kobj
), new_parent
, strlen(kobject_name(kobj
)));
958 if (IS_ERR(new_dentry
)) {
959 error
= PTR_ERR(new_dentry
);
963 d_add(new_dentry
, NULL
);
964 d_move(sd
->s_dentry
, new_dentry
);
967 /* Remove from old parent's list and insert into new parent's list. */
968 mutex_lock(&sysfs_mutex
);
970 sysfs_unlink_sibling(sd
);
971 sysfs_get(new_parent_sd
);
972 sysfs_put(sd
->s_parent
);
973 sd
->s_parent
= new_parent_sd
;
974 sysfs_link_sibling(sd
);
976 mutex_unlock(&sysfs_mutex
);
979 mutex_unlock(&new_parent
->d_inode
->i_mutex
);
980 mutex_unlock(&old_parent
->d_inode
->i_mutex
);
988 /* Relationship between s_mode and the DT_xxx types */
989 static inline unsigned char dt_type(struct sysfs_dirent
*sd
)
991 return (sd
->s_mode
>> 12) & 15;
994 static int sysfs_readdir(struct file
* filp
, void * dirent
, filldir_t filldir
)
996 struct dentry
*dentry
= filp
->f_path
.dentry
;
997 struct sysfs_dirent
* parent_sd
= dentry
->d_fsdata
;
998 struct sysfs_dirent
*pos
;
1001 if (filp
->f_pos
== 0) {
1002 ino
= parent_sd
->s_ino
;
1003 if (filldir(dirent
, ".", 1, filp
->f_pos
, ino
, DT_DIR
) == 0)
1006 if (filp
->f_pos
== 1) {
1007 if (parent_sd
->s_parent
)
1008 ino
= parent_sd
->s_parent
->s_ino
;
1010 ino
= parent_sd
->s_ino
;
1011 if (filldir(dirent
, "..", 2, filp
->f_pos
, ino
, DT_DIR
) == 0)
1014 if ((filp
->f_pos
> 1) && (filp
->f_pos
< INT_MAX
)) {
1015 mutex_lock(&sysfs_mutex
);
1017 /* Skip the dentries we have already reported */
1018 pos
= parent_sd
->s_children
;
1019 while (pos
&& (filp
->f_pos
> pos
->s_ino
))
1020 pos
= pos
->s_sibling
;
1022 for ( ; pos
; pos
= pos
->s_sibling
) {
1028 filp
->f_pos
= ino
= pos
->s_ino
;
1030 if (filldir(dirent
, name
, len
, filp
->f_pos
, ino
,
1035 filp
->f_pos
= INT_MAX
;
1036 mutex_unlock(&sysfs_mutex
);
1042 const struct file_operations sysfs_dir_operations
= {
1043 .read
= generic_read_dir
,
1044 .readdir
= sysfs_readdir
,