sysfs: Add lockdep annotations for the sysfs active reference
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / fs / sysfs / dir.c
blob699f371b9f12f0f9831f712101e63df948f66350
1 /*
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.
13 #undef DEBUG
15 #include <linux/fs.h>
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>
24 #include <linux/security.h>
25 #include "sysfs.h"
27 DEFINE_MUTEX(sysfs_mutex);
28 DEFINE_SPINLOCK(sysfs_assoc_lock);
30 static DEFINE_SPINLOCK(sysfs_ino_lock);
31 static DEFINE_IDA(sysfs_ino_ida);
33 /**
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.
40 * Locking:
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)
56 break;
58 sd->s_sibling = *pos;
59 *pos = sd;
62 /**
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.
69 * Locking:
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) {
78 if (*pos == sd) {
79 *pos = sd->s_sibling;
80 sd->s_sibling = NULL;
81 break;
86 /**
87 * sysfs_get_active - get an active reference to sysfs_dirent
88 * @sd: sysfs_dirent to get an active reference to
90 * Get an active reference of @sd. This function is noop if @sd
91 * is NULL.
93 * RETURNS:
94 * Pointer to @sd on success, NULL on failure.
96 static struct sysfs_dirent *sysfs_get_active(struct sysfs_dirent *sd)
98 if (unlikely(!sd))
99 return NULL;
101 while (1) {
102 int v, t;
104 v = atomic_read(&sd->s_active);
105 if (unlikely(v < 0))
106 return NULL;
108 t = atomic_cmpxchg(&sd->s_active, v, v + 1);
109 if (likely(t == v)) {
110 rwsem_acquire_read(&sd->dep_map, 0, 1, _RET_IP_);
111 return sd;
113 if (t < 0)
114 return NULL;
116 cpu_relax();
121 * sysfs_put_active - put an active reference to sysfs_dirent
122 * @sd: sysfs_dirent to put an active reference to
124 * Put an active reference to @sd. This function is noop if @sd
125 * is NULL.
127 static void sysfs_put_active(struct sysfs_dirent *sd)
129 struct completion *cmpl;
130 int v;
132 if (unlikely(!sd))
133 return;
135 rwsem_release(&sd->dep_map, 1, _RET_IP_);
136 v = atomic_dec_return(&sd->s_active);
137 if (likely(v != SD_DEACTIVATED_BIAS))
138 return;
140 /* atomic_dec_return() is a mb(), we'll always see the updated
141 * sd->s_sibling.
143 cmpl = (void *)sd->s_sibling;
144 complete(cmpl);
148 * sysfs_get_active_two - get active references to sysfs_dirent and parent
149 * @sd: sysfs_dirent of interest
151 * Get active reference to @sd and its parent. Parent's active
152 * reference is grabbed first. This function is noop if @sd is
153 * NULL.
155 * RETURNS:
156 * Pointer to @sd on success, NULL on failure.
158 struct sysfs_dirent *sysfs_get_active_two(struct sysfs_dirent *sd)
160 if (sd) {
161 if (sd->s_parent && unlikely(!sysfs_get_active(sd->s_parent)))
162 return NULL;
163 if (unlikely(!sysfs_get_active(sd))) {
164 sysfs_put_active(sd->s_parent);
165 return NULL;
168 return sd;
172 * sysfs_put_active_two - put active references to sysfs_dirent and parent
173 * @sd: sysfs_dirent of interest
175 * Put active references to @sd and its parent. This function is
176 * noop if @sd is NULL.
178 void sysfs_put_active_two(struct sysfs_dirent *sd)
180 if (sd) {
181 sysfs_put_active(sd);
182 sysfs_put_active(sd->s_parent);
187 * sysfs_deactivate - deactivate sysfs_dirent
188 * @sd: sysfs_dirent to deactivate
190 * Deny new active references and drain existing ones.
192 static void sysfs_deactivate(struct sysfs_dirent *sd)
194 DECLARE_COMPLETION_ONSTACK(wait);
195 int v;
197 BUG_ON(sd->s_sibling || !(sd->s_flags & SYSFS_FLAG_REMOVED));
198 sd->s_sibling = (void *)&wait;
200 rwsem_acquire(&sd->dep_map, 0, 0, _RET_IP_);
201 /* atomic_add_return() is a mb(), put_active() will always see
202 * the updated sd->s_sibling.
204 v = atomic_add_return(SD_DEACTIVATED_BIAS, &sd->s_active);
206 if (v != SD_DEACTIVATED_BIAS) {
207 lock_contended(&sd->dep_map, _RET_IP_);
208 wait_for_completion(&wait);
211 sd->s_sibling = NULL;
213 lock_acquired(&sd->dep_map, _RET_IP_);
214 rwsem_release(&sd->dep_map, 1, _RET_IP_);
217 static int sysfs_alloc_ino(ino_t *pino)
219 int ino, rc;
221 retry:
222 spin_lock(&sysfs_ino_lock);
223 rc = ida_get_new_above(&sysfs_ino_ida, 2, &ino);
224 spin_unlock(&sysfs_ino_lock);
226 if (rc == -EAGAIN) {
227 if (ida_pre_get(&sysfs_ino_ida, GFP_KERNEL))
228 goto retry;
229 rc = -ENOMEM;
232 *pino = ino;
233 return rc;
236 static void sysfs_free_ino(ino_t ino)
238 spin_lock(&sysfs_ino_lock);
239 ida_remove(&sysfs_ino_ida, ino);
240 spin_unlock(&sysfs_ino_lock);
243 void release_sysfs_dirent(struct sysfs_dirent * sd)
245 struct sysfs_dirent *parent_sd;
247 repeat:
248 /* Moving/renaming is always done while holding reference.
249 * sd->s_parent won't change beneath us.
251 parent_sd = sd->s_parent;
253 if (sysfs_type(sd) == SYSFS_KOBJ_LINK)
254 sysfs_put(sd->s_symlink.target_sd);
255 if (sysfs_type(sd) & SYSFS_COPY_NAME)
256 kfree(sd->s_name);
257 if (sd->s_iattr && sd->s_iattr->ia_secdata)
258 security_release_secctx(sd->s_iattr->ia_secdata,
259 sd->s_iattr->ia_secdata_len);
260 kfree(sd->s_iattr);
261 sysfs_free_ino(sd->s_ino);
262 kmem_cache_free(sysfs_dir_cachep, sd);
264 sd = parent_sd;
265 if (sd && atomic_dec_and_test(&sd->s_count))
266 goto repeat;
269 static int sysfs_dentry_delete(struct dentry *dentry)
271 struct sysfs_dirent *sd = dentry->d_fsdata;
272 return !!(sd->s_flags & SYSFS_FLAG_REMOVED);
275 static int sysfs_dentry_revalidate(struct dentry *dentry, struct nameidata *nd)
277 struct sysfs_dirent *sd = dentry->d_fsdata;
278 int is_dir;
280 mutex_lock(&sysfs_mutex);
282 /* The sysfs dirent has been deleted */
283 if (sd->s_flags & SYSFS_FLAG_REMOVED)
284 goto out_bad;
286 /* The sysfs dirent has been moved? */
287 if (dentry->d_parent->d_fsdata != sd->s_parent)
288 goto out_bad;
290 /* The sysfs dirent has been renamed */
291 if (strcmp(dentry->d_name.name, sd->s_name) != 0)
292 goto out_bad;
294 mutex_unlock(&sysfs_mutex);
295 out_valid:
296 return 1;
297 out_bad:
298 /* Remove the dentry from the dcache hashes.
299 * If this is a deleted dentry we use d_drop instead of d_delete
300 * so sysfs doesn't need to cope with negative dentries.
302 * If this is a dentry that has simply been renamed we
303 * use d_drop to remove it from the dcache lookup on its
304 * old parent. If this dentry persists later when a lookup
305 * is performed at its new name the dentry will be readded
306 * to the dcache hashes.
308 is_dir = (sysfs_type(sd) == SYSFS_DIR);
309 mutex_unlock(&sysfs_mutex);
310 if (is_dir) {
311 /* If we have submounts we must allow the vfs caches
312 * to lie about the state of the filesystem to prevent
313 * leaks and other nasty things.
315 if (have_submounts(dentry))
316 goto out_valid;
317 shrink_dcache_parent(dentry);
319 d_drop(dentry);
320 return 0;
323 static void sysfs_dentry_iput(struct dentry *dentry, struct inode *inode)
325 struct sysfs_dirent * sd = dentry->d_fsdata;
327 sysfs_put(sd);
328 iput(inode);
331 static const struct dentry_operations sysfs_dentry_ops = {
332 .d_revalidate = sysfs_dentry_revalidate,
333 .d_delete = sysfs_dentry_delete,
334 .d_iput = sysfs_dentry_iput,
337 struct sysfs_dirent *sysfs_new_dirent(const char *name, umode_t mode, int type)
339 char *dup_name = NULL;
340 struct sysfs_dirent *sd;
342 if (type & SYSFS_COPY_NAME) {
343 name = dup_name = kstrdup(name, GFP_KERNEL);
344 if (!name)
345 return NULL;
348 sd = kmem_cache_zalloc(sysfs_dir_cachep, GFP_KERNEL);
349 if (!sd)
350 goto err_out1;
352 if (sysfs_alloc_ino(&sd->s_ino))
353 goto err_out2;
355 atomic_set(&sd->s_count, 1);
356 atomic_set(&sd->s_active, 0);
357 sysfs_dirent_init_lockdep(sd);
359 sd->s_name = name;
360 sd->s_mode = mode;
361 sd->s_flags = type;
363 return sd;
365 err_out2:
366 kmem_cache_free(sysfs_dir_cachep, sd);
367 err_out1:
368 kfree(dup_name);
369 return NULL;
373 * sysfs_addrm_start - prepare for sysfs_dirent add/remove
374 * @acxt: pointer to sysfs_addrm_cxt to be used
375 * @parent_sd: parent sysfs_dirent
377 * This function is called when the caller is about to add or
378 * remove sysfs_dirent under @parent_sd. This function acquires
379 * sysfs_mutex. @acxt is used to keep and pass context to
380 * other addrm functions.
382 * LOCKING:
383 * Kernel thread context (may sleep). sysfs_mutex is locked on
384 * return.
386 void sysfs_addrm_start(struct sysfs_addrm_cxt *acxt,
387 struct sysfs_dirent *parent_sd)
389 memset(acxt, 0, sizeof(*acxt));
390 acxt->parent_sd = parent_sd;
392 mutex_lock(&sysfs_mutex);
396 * __sysfs_add_one - add sysfs_dirent to parent without warning
397 * @acxt: addrm context to use
398 * @sd: sysfs_dirent to be added
400 * Get @acxt->parent_sd and set sd->s_parent to it and increment
401 * nlink of parent inode if @sd is a directory and link into the
402 * children list of the parent.
404 * This function should be called between calls to
405 * sysfs_addrm_start() and sysfs_addrm_finish() and should be
406 * passed the same @acxt as passed to sysfs_addrm_start().
408 * LOCKING:
409 * Determined by sysfs_addrm_start().
411 * RETURNS:
412 * 0 on success, -EEXIST if entry with the given name already
413 * exists.
415 int __sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd)
417 struct sysfs_inode_attrs *ps_iattr;
419 if (sysfs_find_dirent(acxt->parent_sd, sd->s_name))
420 return -EEXIST;
422 sd->s_parent = sysfs_get(acxt->parent_sd);
424 sysfs_link_sibling(sd);
426 /* Update timestamps on the parent */
427 ps_iattr = acxt->parent_sd->s_iattr;
428 if (ps_iattr) {
429 struct iattr *ps_iattrs = &ps_iattr->ia_iattr;
430 ps_iattrs->ia_ctime = ps_iattrs->ia_mtime = CURRENT_TIME;
433 return 0;
437 * sysfs_pathname - return full path to sysfs dirent
438 * @sd: sysfs_dirent whose path we want
439 * @path: caller allocated buffer
441 * Gives the name "/" to the sysfs_root entry; any path returned
442 * is relative to wherever sysfs is mounted.
444 * XXX: does no error checking on @path size
446 static char *sysfs_pathname(struct sysfs_dirent *sd, char *path)
448 if (sd->s_parent) {
449 sysfs_pathname(sd->s_parent, path);
450 strcat(path, "/");
452 strcat(path, sd->s_name);
453 return path;
457 * sysfs_add_one - add sysfs_dirent to parent
458 * @acxt: addrm context to use
459 * @sd: sysfs_dirent to be added
461 * Get @acxt->parent_sd and set sd->s_parent to it and increment
462 * nlink of parent inode if @sd is a directory and link into the
463 * children list of the parent.
465 * This function should be called between calls to
466 * sysfs_addrm_start() and sysfs_addrm_finish() and should be
467 * passed the same @acxt as passed to sysfs_addrm_start().
469 * LOCKING:
470 * Determined by sysfs_addrm_start().
472 * RETURNS:
473 * 0 on success, -EEXIST if entry with the given name already
474 * exists.
476 int sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd)
478 int ret;
480 ret = __sysfs_add_one(acxt, sd);
481 if (ret == -EEXIST) {
482 char *path = kzalloc(PATH_MAX, GFP_KERNEL);
483 WARN(1, KERN_WARNING
484 "sysfs: cannot create duplicate filename '%s'\n",
485 (path == NULL) ? sd->s_name :
486 strcat(strcat(sysfs_pathname(acxt->parent_sd, path), "/"),
487 sd->s_name));
488 kfree(path);
491 return ret;
495 * sysfs_remove_one - remove sysfs_dirent from parent
496 * @acxt: addrm context to use
497 * @sd: sysfs_dirent to be removed
499 * Mark @sd removed and drop nlink of parent inode if @sd is a
500 * directory. @sd is unlinked from the children list.
502 * This function should be called between calls to
503 * sysfs_addrm_start() and sysfs_addrm_finish() and should be
504 * passed the same @acxt as passed to sysfs_addrm_start().
506 * LOCKING:
507 * Determined by sysfs_addrm_start().
509 void sysfs_remove_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd)
511 struct sysfs_inode_attrs *ps_iattr;
513 BUG_ON(sd->s_flags & SYSFS_FLAG_REMOVED);
515 sysfs_unlink_sibling(sd);
517 /* Update timestamps on the parent */
518 ps_iattr = acxt->parent_sd->s_iattr;
519 if (ps_iattr) {
520 struct iattr *ps_iattrs = &ps_iattr->ia_iattr;
521 ps_iattrs->ia_ctime = ps_iattrs->ia_mtime = CURRENT_TIME;
524 sd->s_flags |= SYSFS_FLAG_REMOVED;
525 sd->s_sibling = acxt->removed;
526 acxt->removed = sd;
530 * sysfs_addrm_finish - finish up sysfs_dirent add/remove
531 * @acxt: addrm context to finish up
533 * Finish up sysfs_dirent add/remove. Resources acquired by
534 * sysfs_addrm_start() are released and removed sysfs_dirents are
535 * cleaned up.
537 * LOCKING:
538 * sysfs_mutex is released.
540 void sysfs_addrm_finish(struct sysfs_addrm_cxt *acxt)
542 /* release resources acquired by sysfs_addrm_start() */
543 mutex_unlock(&sysfs_mutex);
545 /* kill removed sysfs_dirents */
546 while (acxt->removed) {
547 struct sysfs_dirent *sd = acxt->removed;
549 acxt->removed = sd->s_sibling;
550 sd->s_sibling = NULL;
552 sysfs_deactivate(sd);
553 unmap_bin_file(sd);
554 sysfs_put(sd);
559 * sysfs_find_dirent - find sysfs_dirent with the given name
560 * @parent_sd: sysfs_dirent to search under
561 * @name: name to look for
563 * Look for sysfs_dirent with name @name under @parent_sd.
565 * LOCKING:
566 * mutex_lock(sysfs_mutex)
568 * RETURNS:
569 * Pointer to sysfs_dirent if found, NULL if not.
571 struct sysfs_dirent *sysfs_find_dirent(struct sysfs_dirent *parent_sd,
572 const unsigned char *name)
574 struct sysfs_dirent *sd;
576 for (sd = parent_sd->s_dir.children; sd; sd = sd->s_sibling)
577 if (!strcmp(sd->s_name, name))
578 return sd;
579 return NULL;
583 * sysfs_get_dirent - find and get sysfs_dirent with the given name
584 * @parent_sd: sysfs_dirent to search under
585 * @name: name to look for
587 * Look for sysfs_dirent with name @name under @parent_sd and get
588 * it if found.
590 * LOCKING:
591 * Kernel thread context (may sleep). Grabs sysfs_mutex.
593 * RETURNS:
594 * Pointer to sysfs_dirent if found, NULL if not.
596 struct sysfs_dirent *sysfs_get_dirent(struct sysfs_dirent *parent_sd,
597 const unsigned char *name)
599 struct sysfs_dirent *sd;
601 mutex_lock(&sysfs_mutex);
602 sd = sysfs_find_dirent(parent_sd, name);
603 sysfs_get(sd);
604 mutex_unlock(&sysfs_mutex);
606 return sd;
608 EXPORT_SYMBOL_GPL(sysfs_get_dirent);
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;
616 int rc;
618 /* allocate */
619 sd = sysfs_new_dirent(name, mode, SYSFS_DIR);
620 if (!sd)
621 return -ENOMEM;
622 sd->s_dir.kobj = kobj;
624 /* link in */
625 sysfs_addrm_start(&acxt, parent_sd);
626 rc = sysfs_add_one(&acxt, sd);
627 sysfs_addrm_finish(&acxt);
629 if (rc == 0)
630 *p_sd = sd;
631 else
632 sysfs_put(sd);
634 return rc;
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;
650 int error = 0;
652 BUG_ON(!kobj);
654 if (kobj->parent)
655 parent_sd = kobj->parent->sd;
656 else
657 parent_sd = &sysfs_root;
659 error = create_dir(kobj, parent_sd, kobject_name(kobj), &sd);
660 if (!error)
661 kobj->sd = sd;
662 return error;
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;
671 struct inode *inode;
673 mutex_lock(&sysfs_mutex);
675 sd = sysfs_find_dirent(parent_sd, dentry->d_name.name);
677 /* no such entry */
678 if (!sd) {
679 ret = ERR_PTR(-ENOENT);
680 goto out_unlock;
683 /* attach dentry and inode */
684 inode = sysfs_get_inode(sd);
685 if (!inode) {
686 ret = ERR_PTR(-ENOMEM);
687 goto out_unlock;
690 /* instantiate and hash dentry */
691 ret = d_find_alias(inode);
692 if (!ret) {
693 dentry->d_op = &sysfs_dentry_ops;
694 dentry->d_fsdata = sysfs_get(sd);
695 d_add(dentry, inode);
696 } else {
697 d_move(ret, dentry);
698 iput(inode);
701 out_unlock:
702 mutex_unlock(&sysfs_mutex);
703 return ret;
706 const struct inode_operations sysfs_dir_inode_operations = {
707 .lookup = sysfs_lookup,
708 .permission = sysfs_permission,
709 .setattr = sysfs_setattr,
710 .getattr = sysfs_getattr,
711 .setxattr = sysfs_setxattr,
714 static void remove_dir(struct sysfs_dirent *sd)
716 struct sysfs_addrm_cxt acxt;
718 sysfs_addrm_start(&acxt, sd->s_parent);
719 sysfs_remove_one(&acxt, sd);
720 sysfs_addrm_finish(&acxt);
723 void sysfs_remove_subdir(struct sysfs_dirent *sd)
725 remove_dir(sd);
729 static void __sysfs_remove_dir(struct sysfs_dirent *dir_sd)
731 struct sysfs_addrm_cxt acxt;
732 struct sysfs_dirent **pos;
734 if (!dir_sd)
735 return;
737 pr_debug("sysfs %s: removing dir\n", dir_sd->s_name);
738 sysfs_addrm_start(&acxt, dir_sd);
739 pos = &dir_sd->s_dir.children;
740 while (*pos) {
741 struct sysfs_dirent *sd = *pos;
743 if (sysfs_type(sd) != SYSFS_DIR)
744 sysfs_remove_one(&acxt, sd);
745 else
746 pos = &(*pos)->s_sibling;
748 sysfs_addrm_finish(&acxt);
750 remove_dir(dir_sd);
754 * sysfs_remove_dir - remove an object's directory.
755 * @kobj: object.
757 * The only thing special about this is that we remove any files in
758 * the directory before we remove the directory, and we've inlined
759 * what used to be sysfs_rmdir() below, instead of calling separately.
762 void sysfs_remove_dir(struct kobject * kobj)
764 struct sysfs_dirent *sd = kobj->sd;
766 spin_lock(&sysfs_assoc_lock);
767 kobj->sd = NULL;
768 spin_unlock(&sysfs_assoc_lock);
770 __sysfs_remove_dir(sd);
773 int sysfs_rename(struct sysfs_dirent *sd,
774 struct sysfs_dirent *new_parent_sd, const char *new_name)
776 const char *dup_name = NULL;
777 int error;
779 mutex_lock(&sysfs_mutex);
781 error = 0;
782 if ((sd->s_parent == new_parent_sd) &&
783 (strcmp(sd->s_name, new_name) == 0))
784 goto out; /* nothing to rename */
786 error = -EEXIST;
787 if (sysfs_find_dirent(new_parent_sd, new_name))
788 goto out;
790 /* rename sysfs_dirent */
791 if (strcmp(sd->s_name, new_name) != 0) {
792 error = -ENOMEM;
793 new_name = dup_name = kstrdup(new_name, GFP_KERNEL);
794 if (!new_name)
795 goto out;
797 dup_name = sd->s_name;
798 sd->s_name = new_name;
801 /* Remove from old parent's list and insert into new parent's list. */
802 if (sd->s_parent != new_parent_sd) {
803 sysfs_unlink_sibling(sd);
804 sysfs_get(new_parent_sd);
805 sysfs_put(sd->s_parent);
806 sd->s_parent = new_parent_sd;
807 sysfs_link_sibling(sd);
810 error = 0;
811 out:
812 mutex_unlock(&sysfs_mutex);
813 kfree(dup_name);
814 return error;
817 int sysfs_rename_dir(struct kobject *kobj, const char *new_name)
819 return sysfs_rename(kobj->sd, kobj->sd->s_parent, new_name);
822 int sysfs_move_dir(struct kobject *kobj, struct kobject *new_parent_kobj)
824 struct sysfs_dirent *sd = kobj->sd;
825 struct sysfs_dirent *new_parent_sd;
827 BUG_ON(!sd->s_parent);
828 new_parent_sd = new_parent_kobj && new_parent_kobj->sd ?
829 new_parent_kobj->sd : &sysfs_root;
831 return sysfs_rename(sd, new_parent_sd, sd->s_name);
834 /* Relationship between s_mode and the DT_xxx types */
835 static inline unsigned char dt_type(struct sysfs_dirent *sd)
837 return (sd->s_mode >> 12) & 15;
840 static int sysfs_readdir(struct file * filp, void * dirent, filldir_t filldir)
842 struct dentry *dentry = filp->f_path.dentry;
843 struct sysfs_dirent * parent_sd = dentry->d_fsdata;
844 struct sysfs_dirent *pos;
845 ino_t ino;
847 if (filp->f_pos == 0) {
848 ino = parent_sd->s_ino;
849 if (filldir(dirent, ".", 1, filp->f_pos, ino, DT_DIR) == 0)
850 filp->f_pos++;
852 if (filp->f_pos == 1) {
853 if (parent_sd->s_parent)
854 ino = parent_sd->s_parent->s_ino;
855 else
856 ino = parent_sd->s_ino;
857 if (filldir(dirent, "..", 2, filp->f_pos, ino, DT_DIR) == 0)
858 filp->f_pos++;
860 if ((filp->f_pos > 1) && (filp->f_pos < INT_MAX)) {
861 mutex_lock(&sysfs_mutex);
863 /* Skip the dentries we have already reported */
864 pos = parent_sd->s_dir.children;
865 while (pos && (filp->f_pos > pos->s_ino))
866 pos = pos->s_sibling;
868 for ( ; pos; pos = pos->s_sibling) {
869 const char * name;
870 int len;
872 name = pos->s_name;
873 len = strlen(name);
874 filp->f_pos = ino = pos->s_ino;
876 if (filldir(dirent, name, len, filp->f_pos, ino,
877 dt_type(pos)) < 0)
878 break;
880 if (!pos)
881 filp->f_pos = INT_MAX;
882 mutex_unlock(&sysfs_mutex);
884 return 0;
888 const struct file_operations sysfs_dir_operations = {
889 .read = generic_read_dir,
890 .readdir = sysfs_readdir,
891 .llseek = generic_file_llseek,