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
;
37 BUG_ON(sd
->s_sibling
);
38 sd
->s_sibling
= parent_sd
->s_children
;
39 parent_sd
->s_children
= sd
;
43 * sysfs_unlink_sibling - unlink sysfs_dirent from sibling list
44 * @sd: sysfs_dirent of interest
46 * Unlink @sd from its sibling list which starts from
47 * sd->s_parent->s_children.
50 * mutex_lock(sysfs_mutex)
52 static void sysfs_unlink_sibling(struct sysfs_dirent
*sd
)
54 struct sysfs_dirent
**pos
;
56 for (pos
= &sd
->s_parent
->s_children
; *pos
; pos
= &(*pos
)->s_sibling
) {
66 * sysfs_get_dentry - get dentry for the given sysfs_dirent
67 * @sd: sysfs_dirent of interest
69 * Get dentry for @sd. Dentry is looked up if currently not
70 * present. This function climbs sysfs_dirent tree till it
71 * reaches a sysfs_dirent with valid dentry attached and descends
72 * down from there looking up dentry for each step.
75 * Kernel thread context (may sleep)
78 * Pointer to found dentry on success, ERR_PTR() value on error.
80 struct dentry
*sysfs_get_dentry(struct sysfs_dirent
*sd
)
82 struct sysfs_dirent
*cur
;
83 struct dentry
*parent_dentry
, *dentry
;
86 /* Find the first parent which has valid s_dentry and get the
89 mutex_lock(&sysfs_mutex
);
91 spin_lock(&sysfs_assoc_lock
);
93 spin_lock(&dcache_lock
);
98 while (!cur
->s_dentry
|| !cur
->s_dentry
->d_inode
) {
99 if (cur
->s_flags
& SYSFS_FLAG_REMOVED
) {
100 dentry
= ERR_PTR(-ENOENT
);
108 dentry
= dget_locked(cur
->s_dentry
);
110 spin_unlock(&dcache_lock
);
111 spin_unlock(&sysfs_assoc_lock
);
113 /* from the found dentry, look up depth times */
115 /* find and get depth'th ancestor */
116 for (cur
= sd
, i
= 0; cur
&& i
< depth
; i
++)
119 /* This can happen if tree structure was modified due
120 * to move/rename. Restart.
129 mutex_unlock(&sysfs_mutex
);
132 parent_dentry
= dentry
;
133 mutex_lock(&parent_dentry
->d_inode
->i_mutex
);
134 dentry
= lookup_one_len_kern(cur
->s_name
, parent_dentry
,
135 strlen(cur
->s_name
));
136 mutex_unlock(&parent_dentry
->d_inode
->i_mutex
);
139 if (IS_ERR(dentry
)) {
144 mutex_lock(&sysfs_mutex
);
145 spin_lock(&sysfs_assoc_lock
);
147 /* This, again, can happen if tree structure has
148 * changed and we looked up the wrong thing. Restart.
150 if (cur
->s_dentry
!= dentry
) {
156 spin_unlock(&sysfs_assoc_lock
);
161 mutex_unlock(&sysfs_mutex
);
166 * sysfs_get_active - get an active reference to sysfs_dirent
167 * @sd: sysfs_dirent to get an active reference to
169 * Get an active reference of @sd. This function is noop if @sd
173 * Pointer to @sd on success, NULL on failure.
175 struct sysfs_dirent
*sysfs_get_active(struct sysfs_dirent
*sd
)
183 v
= atomic_read(&sd
->s_active
);
187 t
= atomic_cmpxchg(&sd
->s_active
, v
, v
+ 1);
198 * sysfs_put_active - put an active reference to sysfs_dirent
199 * @sd: sysfs_dirent to put an active reference to
201 * Put an active reference to @sd. This function is noop if @sd
204 void sysfs_put_active(struct sysfs_dirent
*sd
)
206 struct completion
*cmpl
;
212 v
= atomic_dec_return(&sd
->s_active
);
213 if (likely(v
!= SD_DEACTIVATED_BIAS
))
216 /* atomic_dec_return() is a mb(), we'll always see the updated
219 cmpl
= (void *)sd
->s_sibling
;
224 * sysfs_get_active_two - get active references to sysfs_dirent and parent
225 * @sd: sysfs_dirent of interest
227 * Get active reference to @sd and its parent. Parent's active
228 * reference is grabbed first. This function is noop if @sd is
232 * Pointer to @sd on success, NULL on failure.
234 struct sysfs_dirent
*sysfs_get_active_two(struct sysfs_dirent
*sd
)
237 if (sd
->s_parent
&& unlikely(!sysfs_get_active(sd
->s_parent
)))
239 if (unlikely(!sysfs_get_active(sd
))) {
240 sysfs_put_active(sd
->s_parent
);
248 * sysfs_put_active_two - put active references to sysfs_dirent and parent
249 * @sd: sysfs_dirent of interest
251 * Put active references to @sd and its parent. This function is
252 * noop if @sd is NULL.
254 void sysfs_put_active_two(struct sysfs_dirent
*sd
)
257 sysfs_put_active(sd
);
258 sysfs_put_active(sd
->s_parent
);
263 * sysfs_deactivate - deactivate sysfs_dirent
264 * @sd: sysfs_dirent to deactivate
266 * Deny new active references and drain existing ones.
268 static void sysfs_deactivate(struct sysfs_dirent
*sd
)
270 DECLARE_COMPLETION_ONSTACK(wait
);
273 BUG_ON(sd
->s_sibling
|| !(sd
->s_flags
& SYSFS_FLAG_REMOVED
));
274 sd
->s_sibling
= (void *)&wait
;
276 /* atomic_add_return() is a mb(), put_active() will always see
277 * the updated sd->s_sibling.
279 v
= atomic_add_return(SD_DEACTIVATED_BIAS
, &sd
->s_active
);
281 if (v
!= SD_DEACTIVATED_BIAS
)
282 wait_for_completion(&wait
);
284 sd
->s_sibling
= NULL
;
287 static int sysfs_alloc_ino(ino_t
*pino
)
292 spin_lock(&sysfs_ino_lock
);
293 rc
= ida_get_new_above(&sysfs_ino_ida
, 2, &ino
);
294 spin_unlock(&sysfs_ino_lock
);
297 if (ida_pre_get(&sysfs_ino_ida
, GFP_KERNEL
))
306 static void sysfs_free_ino(ino_t ino
)
308 spin_lock(&sysfs_ino_lock
);
309 ida_remove(&sysfs_ino_ida
, ino
);
310 spin_unlock(&sysfs_ino_lock
);
313 void release_sysfs_dirent(struct sysfs_dirent
* sd
)
315 struct sysfs_dirent
*parent_sd
;
318 /* Moving/renaming is always done while holding reference.
319 * sd->s_parent won't change beneath us.
321 parent_sd
= sd
->s_parent
;
323 if (sysfs_type(sd
) == SYSFS_KOBJ_LINK
)
324 sysfs_put(sd
->s_elem
.symlink
.target_sd
);
325 if (sysfs_type(sd
) & SYSFS_COPY_NAME
)
328 sysfs_free_ino(sd
->s_ino
);
329 kmem_cache_free(sysfs_dir_cachep
, sd
);
332 if (sd
&& atomic_dec_and_test(&sd
->s_count
))
336 static void sysfs_d_iput(struct dentry
* dentry
, struct inode
* inode
)
338 struct sysfs_dirent
* sd
= dentry
->d_fsdata
;
341 /* sd->s_dentry is protected with sysfs_assoc_lock.
342 * This allows sysfs_drop_dentry() to dereference it.
344 spin_lock(&sysfs_assoc_lock
);
346 /* The dentry might have been deleted or another
347 * lookup could have happened updating sd->s_dentry to
348 * point the new dentry. Ignore if it isn't pointing
351 if (sd
->s_dentry
== dentry
)
353 spin_unlock(&sysfs_assoc_lock
);
359 static struct dentry_operations sysfs_dentry_ops
= {
360 .d_iput
= sysfs_d_iput
,
363 struct sysfs_dirent
*sysfs_new_dirent(const char *name
, umode_t mode
, int type
)
365 char *dup_name
= NULL
;
366 struct sysfs_dirent
*sd
;
368 if (type
& SYSFS_COPY_NAME
) {
369 name
= dup_name
= kstrdup(name
, GFP_KERNEL
);
374 sd
= kmem_cache_zalloc(sysfs_dir_cachep
, GFP_KERNEL
);
378 if (sysfs_alloc_ino(&sd
->s_ino
))
381 atomic_set(&sd
->s_count
, 1);
382 atomic_set(&sd
->s_active
, 0);
383 atomic_set(&sd
->s_event
, 1);
392 kmem_cache_free(sysfs_dir_cachep
, sd
);
399 * sysfs_attach_dentry - associate sysfs_dirent with dentry
400 * @sd: target sysfs_dirent
401 * @dentry: dentry to associate
403 * Associate @sd with @dentry. This is protected by
404 * sysfs_assoc_lock to avoid race with sysfs_d_iput().
407 * mutex_lock(sysfs_mutex)
409 static void sysfs_attach_dentry(struct sysfs_dirent
*sd
, struct dentry
*dentry
)
411 dentry
->d_op
= &sysfs_dentry_ops
;
412 dentry
->d_fsdata
= sysfs_get(sd
);
414 /* protect sd->s_dentry against sysfs_d_iput */
415 spin_lock(&sysfs_assoc_lock
);
416 sd
->s_dentry
= dentry
;
417 spin_unlock(&sysfs_assoc_lock
);
422 static int sysfs_ilookup_test(struct inode
*inode
, void *arg
)
424 struct sysfs_dirent
*sd
= arg
;
425 return inode
->i_ino
== sd
->s_ino
;
429 * sysfs_addrm_start - prepare for sysfs_dirent add/remove
430 * @acxt: pointer to sysfs_addrm_cxt to be used
431 * @parent_sd: parent sysfs_dirent
433 * This function is called when the caller is about to add or
434 * remove sysfs_dirent under @parent_sd. This function acquires
435 * sysfs_mutex, grabs inode for @parent_sd if available and lock
436 * i_mutex of it. @acxt is used to keep and pass context to
437 * other addrm functions.
440 * Kernel thread context (may sleep). sysfs_mutex is locked on
441 * return. i_mutex of parent inode is locked on return if
444 void sysfs_addrm_start(struct sysfs_addrm_cxt
*acxt
,
445 struct sysfs_dirent
*parent_sd
)
449 memset(acxt
, 0, sizeof(*acxt
));
450 acxt
->parent_sd
= parent_sd
;
452 /* Lookup parent inode. inode initialization and I_NEW
453 * clearing are protected by sysfs_mutex. By grabbing it and
454 * looking up with _nowait variant, inode state can be
455 * determined reliably.
457 mutex_lock(&sysfs_mutex
);
459 inode
= ilookup5_nowait(sysfs_sb
, parent_sd
->s_ino
, sysfs_ilookup_test
,
462 if (inode
&& !(inode
->i_state
& I_NEW
)) {
463 /* parent inode available */
464 acxt
->parent_inode
= inode
;
466 /* sysfs_mutex is below i_mutex in lock hierarchy.
467 * First, trylock i_mutex. If fails, unlock
468 * sysfs_mutex and lock them in order.
470 if (!mutex_trylock(&inode
->i_mutex
)) {
471 mutex_unlock(&sysfs_mutex
);
472 mutex_lock(&inode
->i_mutex
);
473 mutex_lock(&sysfs_mutex
);
480 * sysfs_add_one - add sysfs_dirent to parent
481 * @acxt: addrm context to use
482 * @sd: sysfs_dirent to be added
484 * Get @acxt->parent_sd and set sd->s_parent to it and increment
485 * nlink of parent inode if @sd is a directory. @sd is NOT
486 * linked into the children list of the parent. The caller
487 * should invoke sysfs_link_sibling() after this function
488 * completes if @sd needs to be on the children list.
490 * This function should be called between calls to
491 * sysfs_addrm_start() and sysfs_addrm_finish() and should be
492 * passed the same @acxt as passed to sysfs_addrm_start().
495 * Determined by sysfs_addrm_start().
498 * 0 on success, -EEXIST if entry with the given name already
501 int sysfs_add_one(struct sysfs_addrm_cxt
*acxt
, struct sysfs_dirent
*sd
)
503 if (sysfs_find_dirent(acxt
->parent_sd
, sd
->s_name
))
506 sd
->s_parent
= sysfs_get(acxt
->parent_sd
);
508 if (sysfs_type(sd
) == SYSFS_DIR
&& acxt
->parent_inode
)
509 inc_nlink(acxt
->parent_inode
);
513 sysfs_link_sibling(sd
);
519 * sysfs_remove_one - remove sysfs_dirent from parent
520 * @acxt: addrm context to use
521 * @sd: sysfs_dirent to be added
523 * Mark @sd removed and drop nlink of parent inode if @sd is a
524 * directory. @sd is NOT unlinked from the children list of the
525 * parent. The caller is repsonsible for removing @sd from the
526 * children list before calling this function.
528 * This function should be called between calls to
529 * sysfs_addrm_start() and sysfs_addrm_finish() and should be
530 * passed the same @acxt as passed to sysfs_addrm_start().
533 * Determined by sysfs_addrm_start().
535 void sysfs_remove_one(struct sysfs_addrm_cxt
*acxt
, struct sysfs_dirent
*sd
)
537 BUG_ON(sd
->s_flags
& SYSFS_FLAG_REMOVED
);
539 sysfs_unlink_sibling(sd
);
541 sd
->s_flags
|= SYSFS_FLAG_REMOVED
;
542 sd
->s_sibling
= acxt
->removed
;
545 if (sysfs_type(sd
) == SYSFS_DIR
&& acxt
->parent_inode
)
546 drop_nlink(acxt
->parent_inode
);
552 * sysfs_drop_dentry - drop dentry for the specified sysfs_dirent
553 * @sd: target sysfs_dirent
555 * Drop dentry for @sd. @sd must have been unlinked from its
556 * parent on entry to this function such that it can't be looked
559 * @sd->s_dentry which is protected with sysfs_assoc_lock points
560 * to the currently associated dentry but we're not holding a
561 * reference to it and racing with dput(). Grab dcache_lock and
562 * verify dentry before dropping it. If @sd->s_dentry is NULL or
563 * dput() beats us, no need to bother.
565 static void sysfs_drop_dentry(struct sysfs_dirent
*sd
)
567 struct dentry
*dentry
= NULL
;
570 /* We're not holding a reference to ->s_dentry dentry but the
571 * field will stay valid as long as sysfs_assoc_lock is held.
573 spin_lock(&sysfs_assoc_lock
);
574 spin_lock(&dcache_lock
);
576 /* drop dentry if it's there and dput() didn't kill it yet */
577 if (sd
->s_dentry
&& sd
->s_dentry
->d_inode
) {
578 dentry
= dget_locked(sd
->s_dentry
);
579 spin_lock(&dentry
->d_lock
);
581 spin_unlock(&dentry
->d_lock
);
584 spin_unlock(&dcache_lock
);
585 spin_unlock(&sysfs_assoc_lock
);
589 /* adjust nlink and update timestamp */
590 inode
= ilookup(sysfs_sb
, sd
->s_ino
);
592 mutex_lock(&inode
->i_mutex
);
594 inode
->i_ctime
= CURRENT_TIME
;
596 if (sysfs_type(sd
) == SYSFS_DIR
)
599 mutex_unlock(&inode
->i_mutex
);
605 * sysfs_addrm_finish - finish up sysfs_dirent add/remove
606 * @acxt: addrm context to finish up
608 * Finish up sysfs_dirent add/remove. Resources acquired by
609 * sysfs_addrm_start() are released and removed sysfs_dirents are
610 * cleaned up. Timestamps on the parent inode are updated.
613 * All mutexes acquired by sysfs_addrm_start() are released.
615 void sysfs_addrm_finish(struct sysfs_addrm_cxt
*acxt
)
617 /* release resources acquired by sysfs_addrm_start() */
618 mutex_unlock(&sysfs_mutex
);
619 if (acxt
->parent_inode
) {
620 struct inode
*inode
= acxt
->parent_inode
;
622 /* if added/removed, update timestamps on the parent */
624 inode
->i_ctime
= inode
->i_mtime
= CURRENT_TIME
;
626 mutex_unlock(&inode
->i_mutex
);
630 /* kill removed sysfs_dirents */
631 while (acxt
->removed
) {
632 struct sysfs_dirent
*sd
= acxt
->removed
;
634 acxt
->removed
= sd
->s_sibling
;
635 sd
->s_sibling
= NULL
;
637 sysfs_drop_dentry(sd
);
638 sysfs_deactivate(sd
);
644 * sysfs_find_dirent - find sysfs_dirent with the given name
645 * @parent_sd: sysfs_dirent to search under
646 * @name: name to look for
648 * Look for sysfs_dirent with name @name under @parent_sd.
651 * mutex_lock(sysfs_mutex)
654 * Pointer to sysfs_dirent if found, NULL if not.
656 struct sysfs_dirent
*sysfs_find_dirent(struct sysfs_dirent
*parent_sd
,
657 const unsigned char *name
)
659 struct sysfs_dirent
*sd
;
661 for (sd
= parent_sd
->s_children
; sd
; sd
= sd
->s_sibling
)
662 if (sysfs_type(sd
) && !strcmp(sd
->s_name
, name
))
668 * sysfs_get_dirent - find and get sysfs_dirent with the given name
669 * @parent_sd: sysfs_dirent to search under
670 * @name: name to look for
672 * Look for sysfs_dirent with name @name under @parent_sd and get
676 * Kernel thread context (may sleep). Grabs sysfs_mutex.
679 * Pointer to sysfs_dirent if found, NULL if not.
681 struct sysfs_dirent
*sysfs_get_dirent(struct sysfs_dirent
*parent_sd
,
682 const unsigned char *name
)
684 struct sysfs_dirent
*sd
;
686 mutex_lock(&sysfs_mutex
);
687 sd
= sysfs_find_dirent(parent_sd
, name
);
689 mutex_unlock(&sysfs_mutex
);
694 static int create_dir(struct kobject
*kobj
, struct sysfs_dirent
*parent_sd
,
695 const char *name
, struct sysfs_dirent
**p_sd
)
697 umode_t mode
= S_IFDIR
| S_IRWXU
| S_IRUGO
| S_IXUGO
;
698 struct sysfs_addrm_cxt acxt
;
699 struct sysfs_dirent
*sd
;
703 sd
= sysfs_new_dirent(name
, mode
, SYSFS_DIR
);
706 sd
->s_elem
.dir
.kobj
= kobj
;
709 sysfs_addrm_start(&acxt
, parent_sd
);
710 rc
= sysfs_add_one(&acxt
, sd
);
711 sysfs_addrm_finish(&acxt
);
721 int sysfs_create_subdir(struct kobject
*kobj
, const char *name
,
722 struct sysfs_dirent
**p_sd
)
724 return create_dir(kobj
, kobj
->sd
, name
, p_sd
);
728 * sysfs_create_dir - create a directory for an object.
729 * @kobj: object we're creating directory for.
731 int sysfs_create_dir(struct kobject
* kobj
)
733 struct sysfs_dirent
*parent_sd
, *sd
;
739 parent_sd
= kobj
->parent
->sd
;
740 else if (sysfs_mount
&& sysfs_mount
->mnt_sb
)
741 parent_sd
= sysfs_mount
->mnt_sb
->s_root
->d_fsdata
;
745 error
= create_dir(kobj
, parent_sd
, kobject_name(kobj
), &sd
);
751 static struct dentry
* sysfs_lookup(struct inode
*dir
, struct dentry
*dentry
,
752 struct nameidata
*nd
)
754 struct dentry
*ret
= NULL
;
755 struct sysfs_dirent
*parent_sd
= dentry
->d_parent
->d_fsdata
;
756 struct sysfs_dirent
*sd
;
759 mutex_lock(&sysfs_mutex
);
761 for (sd
= parent_sd
->s_children
; sd
; sd
= sd
->s_sibling
)
762 if (sysfs_type(sd
) && !strcmp(sd
->s_name
, dentry
->d_name
.name
))
769 /* attach dentry and inode */
770 inode
= sysfs_get_inode(sd
);
772 ret
= ERR_PTR(-ENOMEM
);
776 d_instantiate(dentry
, inode
);
777 sysfs_attach_dentry(sd
, dentry
);
780 mutex_unlock(&sysfs_mutex
);
784 const struct inode_operations sysfs_dir_inode_operations
= {
785 .lookup
= sysfs_lookup
,
786 .setattr
= sysfs_setattr
,
789 static void remove_dir(struct sysfs_dirent
*sd
)
791 struct sysfs_addrm_cxt acxt
;
793 sysfs_addrm_start(&acxt
, sd
->s_parent
);
794 sysfs_remove_one(&acxt
, sd
);
795 sysfs_addrm_finish(&acxt
);
798 void sysfs_remove_subdir(struct sysfs_dirent
*sd
)
804 static void __sysfs_remove_dir(struct sysfs_dirent
*dir_sd
)
806 struct sysfs_addrm_cxt acxt
;
807 struct sysfs_dirent
**pos
;
812 pr_debug("sysfs %s: removing dir\n", dir_sd
->s_name
);
813 sysfs_addrm_start(&acxt
, dir_sd
);
814 pos
= &dir_sd
->s_children
;
816 struct sysfs_dirent
*sd
= *pos
;
818 if (sysfs_type(sd
) && sysfs_type(sd
) != SYSFS_DIR
)
819 sysfs_remove_one(&acxt
, sd
);
821 pos
= &(*pos
)->s_sibling
;
823 sysfs_addrm_finish(&acxt
);
829 * sysfs_remove_dir - remove an object's directory.
832 * The only thing special about this is that we remove any files in
833 * the directory before we remove the directory, and we've inlined
834 * what used to be sysfs_rmdir() below, instead of calling separately.
837 void sysfs_remove_dir(struct kobject
* kobj
)
839 struct sysfs_dirent
*sd
= kobj
->sd
;
841 spin_lock(&sysfs_assoc_lock
);
843 spin_unlock(&sysfs_assoc_lock
);
845 __sysfs_remove_dir(sd
);
848 int sysfs_rename_dir(struct kobject
* kobj
, const char *new_name
)
850 struct sysfs_dirent
*sd
;
851 struct dentry
*parent
= NULL
;
852 struct dentry
*old_dentry
= NULL
, *new_dentry
= NULL
;
853 const char *dup_name
= NULL
;
856 /* get the original dentry */
858 old_dentry
= sysfs_get_dentry(sd
);
859 if (IS_ERR(old_dentry
)) {
860 error
= PTR_ERR(old_dentry
);
864 parent
= old_dentry
->d_parent
;
866 /* lock parent and get dentry for new name */
867 mutex_lock(&parent
->d_inode
->i_mutex
);
869 new_dentry
= lookup_one_len(new_name
, parent
, strlen(new_name
));
870 if (IS_ERR(new_dentry
)) {
871 error
= PTR_ERR(new_dentry
);
876 if (old_dentry
== new_dentry
)
880 if (new_dentry
->d_inode
)
883 /* rename kobject and sysfs_dirent */
885 new_name
= dup_name
= kstrdup(new_name
, GFP_KERNEL
);
889 error
= kobject_set_name(kobj
, "%s", new_name
);
893 mutex_lock(&sysfs_mutex
);
894 dup_name
= sd
->s_name
;
895 sd
->s_name
= new_name
;
896 mutex_unlock(&sysfs_mutex
);
899 d_add(new_dentry
, NULL
);
900 d_move(sd
->s_dentry
, new_dentry
);
908 mutex_unlock(&parent
->d_inode
->i_mutex
);
916 int sysfs_move_dir(struct kobject
*kobj
, struct kobject
*new_parent_kobj
)
918 struct sysfs_dirent
*sd
= kobj
->sd
;
919 struct sysfs_dirent
*new_parent_sd
;
920 struct dentry
*old_parent
, *new_parent
= NULL
;
921 struct dentry
*old_dentry
= NULL
, *new_dentry
= NULL
;
924 BUG_ON(!sd
->s_parent
);
925 new_parent_sd
= new_parent_kobj
->sd
? new_parent_kobj
->sd
: &sysfs_root
;
928 old_dentry
= sysfs_get_dentry(sd
);
929 if (IS_ERR(old_dentry
)) {
930 error
= PTR_ERR(old_dentry
);
933 old_parent
= sd
->s_parent
->s_dentry
;
935 new_parent
= sysfs_get_dentry(new_parent_sd
);
936 if (IS_ERR(new_parent
)) {
937 error
= PTR_ERR(new_parent
);
941 if (old_parent
->d_inode
== new_parent
->d_inode
) {
943 goto out_dput
; /* nothing to move */
946 mutex_lock(&old_parent
->d_inode
->i_mutex
);
947 if (!mutex_trylock(&new_parent
->d_inode
->i_mutex
)) {
948 mutex_unlock(&old_parent
->d_inode
->i_mutex
);
952 new_dentry
= lookup_one_len(kobject_name(kobj
), new_parent
, strlen(kobject_name(kobj
)));
953 if (IS_ERR(new_dentry
)) {
954 error
= PTR_ERR(new_dentry
);
958 d_add(new_dentry
, NULL
);
959 d_move(sd
->s_dentry
, new_dentry
);
962 /* Remove from old parent's list and insert into new parent's list. */
963 mutex_lock(&sysfs_mutex
);
965 sysfs_unlink_sibling(sd
);
966 sysfs_get(new_parent_sd
);
967 sysfs_put(sd
->s_parent
);
968 sd
->s_parent
= new_parent_sd
;
969 sysfs_link_sibling(sd
);
971 mutex_unlock(&sysfs_mutex
);
974 mutex_unlock(&new_parent
->d_inode
->i_mutex
);
975 mutex_unlock(&old_parent
->d_inode
->i_mutex
);
983 static int sysfs_dir_open(struct inode
*inode
, struct file
*file
)
985 struct dentry
* dentry
= file
->f_path
.dentry
;
986 struct sysfs_dirent
* parent_sd
= dentry
->d_fsdata
;
987 struct sysfs_dirent
* sd
;
989 sd
= sysfs_new_dirent("_DIR_", 0, 0);
991 mutex_lock(&sysfs_mutex
);
992 sd
->s_parent
= sysfs_get(parent_sd
);
993 sysfs_link_sibling(sd
);
994 mutex_unlock(&sysfs_mutex
);
997 file
->private_data
= sd
;
998 return sd
? 0 : -ENOMEM
;
1001 static int sysfs_dir_close(struct inode
*inode
, struct file
*file
)
1003 struct sysfs_dirent
* cursor
= file
->private_data
;
1005 mutex_lock(&sysfs_mutex
);
1006 sysfs_unlink_sibling(cursor
);
1007 mutex_unlock(&sysfs_mutex
);
1009 release_sysfs_dirent(cursor
);
1014 /* Relationship between s_mode and the DT_xxx types */
1015 static inline unsigned char dt_type(struct sysfs_dirent
*sd
)
1017 return (sd
->s_mode
>> 12) & 15;
1020 static int sysfs_readdir(struct file
* filp
, void * dirent
, filldir_t filldir
)
1022 struct dentry
*dentry
= filp
->f_path
.dentry
;
1023 struct sysfs_dirent
* parent_sd
= dentry
->d_fsdata
;
1024 struct sysfs_dirent
*cursor
= filp
->private_data
;
1025 struct sysfs_dirent
**pos
;
1027 int i
= filp
->f_pos
;
1031 ino
= parent_sd
->s_ino
;
1032 if (filldir(dirent
, ".", 1, i
, ino
, DT_DIR
) < 0)
1038 if (parent_sd
->s_parent
)
1039 ino
= parent_sd
->s_parent
->s_ino
;
1041 ino
= parent_sd
->s_ino
;
1042 if (filldir(dirent
, "..", 2, i
, ino
, DT_DIR
) < 0)
1048 mutex_lock(&sysfs_mutex
);
1050 pos
= &parent_sd
->s_children
;
1051 while (*pos
!= cursor
)
1052 pos
= &(*pos
)->s_sibling
;
1055 *pos
= cursor
->s_sibling
;
1057 if (filp
->f_pos
== 2)
1058 pos
= &parent_sd
->s_children
;
1060 for ( ; *pos
; pos
= &(*pos
)->s_sibling
) {
1061 struct sysfs_dirent
*next
= *pos
;
1065 if (!sysfs_type(next
))
1068 name
= next
->s_name
;
1072 if (filldir(dirent
, name
, len
, filp
->f_pos
, ino
,
1079 /* put cursor back in */
1080 cursor
->s_sibling
= *pos
;
1083 mutex_unlock(&sysfs_mutex
);
1088 static loff_t
sysfs_dir_lseek(struct file
* file
, loff_t offset
, int origin
)
1090 struct dentry
* dentry
= file
->f_path
.dentry
;
1094 offset
+= file
->f_pos
;
1101 if (offset
!= file
->f_pos
) {
1102 mutex_lock(&sysfs_mutex
);
1104 file
->f_pos
= offset
;
1105 if (file
->f_pos
>= 2) {
1106 struct sysfs_dirent
*sd
= dentry
->d_fsdata
;
1107 struct sysfs_dirent
*cursor
= file
->private_data
;
1108 struct sysfs_dirent
**pos
;
1109 loff_t n
= file
->f_pos
- 2;
1111 sysfs_unlink_sibling(cursor
);
1113 pos
= &sd
->s_children
;
1115 struct sysfs_dirent
*next
= *pos
;
1116 if (sysfs_type(next
))
1118 pos
= &(*pos
)->s_sibling
;
1121 cursor
->s_sibling
= *pos
;
1125 mutex_unlock(&sysfs_mutex
);
1131 const struct file_operations sysfs_dir_operations
= {
1132 .open
= sysfs_dir_open
,
1133 .release
= sysfs_dir_close
,
1134 .llseek
= sysfs_dir_lseek
,
1135 .read
= generic_read_dir
,
1136 .readdir
= sysfs_readdir
,