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>
24 #include <linux/security.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);
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;
49 struct rb_node *parent;
51 BUG_ON(sd->s_sibling);
53 if (sysfs_type(sd) == SYSFS_DIR)
54 parent_sd->s_dir.subdirs++;
56 /* Store directory entries in order by ino. This allows
57 * readdir to properly restart without having to add a
58 * cursor into the s_dir.children list.
60 for (pos = &parent_sd->s_dir.children; *pos; pos = &(*pos)->s_sibling) {
61 if (sd->s_ino < (*pos)->s_ino)
67 p = &parent_sd->s_dir.name_tree.rb_node;
72 #define node rb_entry(parent, struct sysfs_dirent, name_node)
73 c = strcmp(sd->s_name, node->s_name);
75 p = &node->name_node.rb_left;
77 p = &node->name_node.rb_right;
81 rb_link_node(&sd->name_node, parent, p);
82 rb_insert_color(&sd->name_node, &parent_sd->s_dir.name_tree);
86 * sysfs_unlink_sibling - unlink sysfs_dirent from sibling list
87 * @sd: sysfs_dirent of interest
89 * Unlink @sd from its sibling list which starts from
90 * sd->s_parent->s_dir.children.
93 * mutex_lock(sysfs_mutex)
95 static void sysfs_unlink_sibling(struct sysfs_dirent *sd)
97 struct sysfs_dirent **pos;
99 if (sysfs_type(sd) == SYSFS_DIR)
100 sd->s_parent->s_dir.subdirs--;
102 for (pos = &sd->s_parent->s_dir.children; *pos;
103 pos = &(*pos)->s_sibling) {
105 *pos = sd->s_sibling;
106 sd->s_sibling = NULL;
111 rb_erase(&sd->name_node, &sd->s_parent->s_dir.name_tree);
115 * sysfs_get_active - get an active reference to sysfs_dirent
116 * @sd: sysfs_dirent to get an active reference to
118 * Get an active reference of @sd. This function is noop if @sd
122 * Pointer to @sd on success, NULL on failure.
124 struct sysfs_dirent *sysfs_get_active(struct sysfs_dirent *sd)
132 v = atomic_read(&sd->s_active);
136 t = atomic_cmpxchg(&sd->s_active, v, v + 1);
137 if (likely(t == v)) {
138 rwsem_acquire_read(&sd->dep_map, 0, 1, _RET_IP_);
149 * sysfs_put_active - put an active reference to sysfs_dirent
150 * @sd: sysfs_dirent to put an active reference to
152 * Put an active reference to @sd. This function is noop if @sd
155 void sysfs_put_active(struct sysfs_dirent *sd)
162 rwsem_release(&sd->dep_map, 1, _RET_IP_);
163 v = atomic_dec_return(&sd->s_active);
164 if (likely(v != SD_DEACTIVATED_BIAS))
167 /* atomic_dec_return() is a mb(), we'll always see the updated
170 complete(sd->u.completion);
174 * sysfs_deactivate - deactivate sysfs_dirent
175 * @sd: sysfs_dirent to deactivate
177 * Deny new active references and drain existing ones.
179 static void sysfs_deactivate(struct sysfs_dirent *sd)
181 DECLARE_COMPLETION_ONSTACK(wait);
184 BUG_ON(!(sd->s_flags & SYSFS_FLAG_REMOVED));
186 if (!(sysfs_type(sd) & SYSFS_ACTIVE_REF))
189 sd->u.completion = (void *)&wait;
191 rwsem_acquire(&sd->dep_map, 0, 0, _RET_IP_);
192 /* atomic_add_return() is a mb(), put_active() will always see
193 * the updated sd->u.completion.
195 v = atomic_add_return(SD_DEACTIVATED_BIAS, &sd->s_active);
197 if (v != SD_DEACTIVATED_BIAS) {
198 lock_contended(&sd->dep_map, _RET_IP_);
199 wait_for_completion(&wait);
202 lock_acquired(&sd->dep_map, _RET_IP_);
203 rwsem_release(&sd->dep_map, 1, _RET_IP_);
206 static int sysfs_alloc_ino(ino_t *pino)
211 spin_lock(&sysfs_ino_lock);
212 rc = ida_get_new_above(&sysfs_ino_ida, 2, &ino);
213 spin_unlock(&sysfs_ino_lock);
216 if (ida_pre_get(&sysfs_ino_ida, GFP_KERNEL))
225 static void sysfs_free_ino(ino_t ino)
227 spin_lock(&sysfs_ino_lock);
228 ida_remove(&sysfs_ino_ida, ino);
229 spin_unlock(&sysfs_ino_lock);
232 void release_sysfs_dirent(struct sysfs_dirent * sd)
234 struct sysfs_dirent *parent_sd;
237 /* Moving/renaming is always done while holding reference.
238 * sd->s_parent won't change beneath us.
240 parent_sd = sd->s_parent;
242 if (sysfs_type(sd) == SYSFS_KOBJ_LINK)
243 sysfs_put(sd->s_symlink.target_sd);
244 if (sysfs_type(sd) & SYSFS_COPY_NAME)
246 if (sd->s_iattr && sd->s_iattr->ia_secdata)
247 security_release_secctx(sd->s_iattr->ia_secdata,
248 sd->s_iattr->ia_secdata_len);
250 sysfs_free_ino(sd->s_ino);
251 kmem_cache_free(sysfs_dir_cachep, sd);
254 if (sd && atomic_dec_and_test(&sd->s_count))
258 static int sysfs_dentry_delete(const struct dentry *dentry)
260 struct sysfs_dirent *sd = dentry->d_fsdata;
261 return !!(sd->s_flags & SYSFS_FLAG_REMOVED);
264 static int sysfs_dentry_revalidate(struct dentry *dentry, struct nameidata *nd)
266 struct sysfs_dirent *sd;
269 if (nd->flags & LOOKUP_RCU)
272 sd = dentry->d_fsdata;
273 mutex_lock(&sysfs_mutex);
275 /* The sysfs dirent has been deleted */
276 if (sd->s_flags & SYSFS_FLAG_REMOVED)
279 /* The sysfs dirent has been moved? */
280 if (dentry->d_parent->d_fsdata != sd->s_parent)
283 /* The sysfs dirent has been renamed */
284 if (strcmp(dentry->d_name.name, sd->s_name) != 0)
287 mutex_unlock(&sysfs_mutex);
291 /* Remove the dentry from the dcache hashes.
292 * If this is a deleted dentry we use d_drop instead of d_delete
293 * so sysfs doesn't need to cope with negative dentries.
295 * If this is a dentry that has simply been renamed we
296 * use d_drop to remove it from the dcache lookup on its
297 * old parent. If this dentry persists later when a lookup
298 * is performed at its new name the dentry will be readded
299 * to the dcache hashes.
301 is_dir = (sysfs_type(sd) == SYSFS_DIR);
302 mutex_unlock(&sysfs_mutex);
304 /* If we have submounts we must allow the vfs caches
305 * to lie about the state of the filesystem to prevent
306 * leaks and other nasty things.
308 if (have_submounts(dentry))
310 shrink_dcache_parent(dentry);
316 static void sysfs_dentry_iput(struct dentry *dentry, struct inode *inode)
318 struct sysfs_dirent * sd = dentry->d_fsdata;
324 static const struct dentry_operations sysfs_dentry_ops = {
325 .d_revalidate = sysfs_dentry_revalidate,
326 .d_delete = sysfs_dentry_delete,
327 .d_iput = sysfs_dentry_iput,
330 struct sysfs_dirent *sysfs_new_dirent(const char *name, umode_t mode, int type)
332 char *dup_name = NULL;
333 struct sysfs_dirent *sd;
335 if (type & SYSFS_COPY_NAME) {
336 name = dup_name = kstrdup(name, GFP_KERNEL);
341 sd = kmem_cache_zalloc(sysfs_dir_cachep, GFP_KERNEL);
345 if (sysfs_alloc_ino(&sd->s_ino))
348 atomic_set(&sd->s_count, 1);
349 atomic_set(&sd->s_active, 0);
358 kmem_cache_free(sysfs_dir_cachep, sd);
365 * sysfs_addrm_start - prepare for sysfs_dirent add/remove
366 * @acxt: pointer to sysfs_addrm_cxt to be used
367 * @parent_sd: parent sysfs_dirent
369 * This function is called when the caller is about to add or
370 * remove sysfs_dirent under @parent_sd. This function acquires
371 * sysfs_mutex. @acxt is used to keep and pass context to
372 * other addrm functions.
375 * Kernel thread context (may sleep). sysfs_mutex is locked on
378 void sysfs_addrm_start(struct sysfs_addrm_cxt *acxt,
379 struct sysfs_dirent *parent_sd)
381 memset(acxt, 0, sizeof(*acxt));
382 acxt->parent_sd = parent_sd;
384 mutex_lock(&sysfs_mutex);
388 * __sysfs_add_one - add sysfs_dirent to parent without warning
389 * @acxt: addrm context to use
390 * @sd: sysfs_dirent to be added
392 * Get @acxt->parent_sd and set sd->s_parent to it and increment
393 * nlink of parent inode if @sd is a directory and link into the
394 * children list of the parent.
396 * This function should be called between calls to
397 * sysfs_addrm_start() and sysfs_addrm_finish() and should be
398 * passed the same @acxt as passed to sysfs_addrm_start().
401 * Determined by sysfs_addrm_start().
404 * 0 on success, -EEXIST if entry with the given name already
407 int __sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd)
409 struct sysfs_inode_attrs *ps_iattr;
411 if (sysfs_find_dirent(acxt->parent_sd, sd->s_ns, sd->s_name))
414 sd->s_parent = sysfs_get(acxt->parent_sd);
416 sysfs_link_sibling(sd);
418 /* Update timestamps on the parent */
419 ps_iattr = acxt->parent_sd->s_iattr;
421 struct iattr *ps_iattrs = &ps_iattr->ia_iattr;
422 ps_iattrs->ia_ctime = ps_iattrs->ia_mtime = CURRENT_TIME;
429 * sysfs_pathname - return full path to sysfs dirent
430 * @sd: sysfs_dirent whose path we want
431 * @path: caller allocated buffer
433 * Gives the name "/" to the sysfs_root entry; any path returned
434 * is relative to wherever sysfs is mounted.
436 * XXX: does no error checking on @path size
438 static char *sysfs_pathname(struct sysfs_dirent *sd, char *path)
441 sysfs_pathname(sd->s_parent, path);
444 strcat(path, sd->s_name);
449 * sysfs_add_one - add sysfs_dirent to parent
450 * @acxt: addrm context to use
451 * @sd: sysfs_dirent to be added
453 * Get @acxt->parent_sd and set sd->s_parent to it and increment
454 * nlink of parent inode if @sd is a directory and link into the
455 * children list of the parent.
457 * This function should be called between calls to
458 * sysfs_addrm_start() and sysfs_addrm_finish() and should be
459 * passed the same @acxt as passed to sysfs_addrm_start().
462 * Determined by sysfs_addrm_start().
465 * 0 on success, -EEXIST if entry with the given name already
468 int sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd)
472 ret = __sysfs_add_one(acxt, sd);
473 if (ret == -EEXIST) {
474 char *path = kzalloc(PATH_MAX, GFP_KERNEL);
476 "sysfs: cannot create duplicate filename '%s'\n",
477 (path == NULL) ? sd->s_name :
478 strcat(strcat(sysfs_pathname(acxt->parent_sd, path), "/"),
487 * sysfs_remove_one - remove sysfs_dirent from parent
488 * @acxt: addrm context to use
489 * @sd: sysfs_dirent to be removed
491 * Mark @sd removed and drop nlink of parent inode if @sd is a
492 * directory. @sd is unlinked from the children list.
494 * This function should be called between calls to
495 * sysfs_addrm_start() and sysfs_addrm_finish() and should be
496 * passed the same @acxt as passed to sysfs_addrm_start().
499 * Determined by sysfs_addrm_start().
501 void sysfs_remove_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd)
503 struct sysfs_inode_attrs *ps_iattr;
505 BUG_ON(sd->s_flags & SYSFS_FLAG_REMOVED);
507 sysfs_unlink_sibling(sd);
509 /* Update timestamps on the parent */
510 ps_iattr = acxt->parent_sd->s_iattr;
512 struct iattr *ps_iattrs = &ps_iattr->ia_iattr;
513 ps_iattrs->ia_ctime = ps_iattrs->ia_mtime = CURRENT_TIME;
516 sd->s_flags |= SYSFS_FLAG_REMOVED;
517 sd->u.removed_list = acxt->removed;
522 * sysfs_addrm_finish - finish up sysfs_dirent add/remove
523 * @acxt: addrm context to finish up
525 * Finish up sysfs_dirent add/remove. Resources acquired by
526 * sysfs_addrm_start() are released and removed sysfs_dirents are
530 * sysfs_mutex is released.
532 void sysfs_addrm_finish(struct sysfs_addrm_cxt *acxt)
534 /* release resources acquired by sysfs_addrm_start() */
535 mutex_unlock(&sysfs_mutex);
537 /* kill removed sysfs_dirents */
538 while (acxt->removed) {
539 struct sysfs_dirent *sd = acxt->removed;
541 acxt->removed = sd->u.removed_list;
543 sysfs_deactivate(sd);
550 * sysfs_find_dirent - find sysfs_dirent with the given name
551 * @parent_sd: sysfs_dirent to search under
552 * @name: name to look for
554 * Look for sysfs_dirent with name @name under @parent_sd.
557 * mutex_lock(sysfs_mutex)
560 * Pointer to sysfs_dirent if found, NULL if not.
562 struct sysfs_dirent *sysfs_find_dirent(struct sysfs_dirent *parent_sd,
564 const unsigned char *name)
566 struct rb_node *p = parent_sd->s_dir.name_tree.rb_node;
567 struct sysfs_dirent *found = NULL;
571 #define node rb_entry(p, struct sysfs_dirent, name_node)
572 c = strcmp(name, node->s_name);
574 p = node->name_node.rb_left;
576 p = node->name_node.rb_right;
579 p = node->name_node.rb_left;
585 while (found->s_ns && found->s_ns != ns) {
586 p = rb_next(&found->name_node);
589 found = rb_entry(p, struct sysfs_dirent, name_node);
590 if (strcmp(name, found->s_name))
599 * sysfs_get_dirent - find and get sysfs_dirent with the given name
600 * @parent_sd: sysfs_dirent to search under
601 * @name: name to look for
603 * Look for sysfs_dirent with name @name under @parent_sd and get
607 * Kernel thread context (may sleep). Grabs sysfs_mutex.
610 * Pointer to sysfs_dirent if found, NULL if not.
612 struct sysfs_dirent *sysfs_get_dirent(struct sysfs_dirent *parent_sd,
614 const unsigned char *name)
616 struct sysfs_dirent *sd;
618 mutex_lock(&sysfs_mutex);
619 sd = sysfs_find_dirent(parent_sd, ns, name);
621 mutex_unlock(&sysfs_mutex);
625 EXPORT_SYMBOL_GPL(sysfs_get_dirent);
627 static int create_dir(struct kobject *kobj, struct sysfs_dirent *parent_sd,
628 enum kobj_ns_type type, const void *ns, const char *name,
629 struct sysfs_dirent **p_sd)
631 umode_t mode = S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO;
632 struct sysfs_addrm_cxt acxt;
633 struct sysfs_dirent *sd;
637 sd = sysfs_new_dirent(name, mode, SYSFS_DIR);
641 sd->s_flags |= (type << SYSFS_NS_TYPE_SHIFT);
643 sd->s_dir.kobj = kobj;
646 sysfs_addrm_start(&acxt, parent_sd);
647 rc = sysfs_add_one(&acxt, sd);
648 sysfs_addrm_finish(&acxt);
658 int sysfs_create_subdir(struct kobject *kobj, const char *name,
659 struct sysfs_dirent **p_sd)
661 return create_dir(kobj, kobj->sd,
662 KOBJ_NS_TYPE_NONE, NULL, name, p_sd);
666 * sysfs_read_ns_type: return associated ns_type
667 * @kobj: the kobject being queried
669 * Each kobject can be tagged with exactly one namespace type
670 * (i.e. network or user). Return the ns_type associated with
673 static enum kobj_ns_type sysfs_read_ns_type(struct kobject *kobj)
675 const struct kobj_ns_type_operations *ops;
676 enum kobj_ns_type type;
678 ops = kobj_child_ns_ops(kobj);
680 return KOBJ_NS_TYPE_NONE;
683 BUG_ON(type <= KOBJ_NS_TYPE_NONE);
684 BUG_ON(type >= KOBJ_NS_TYPES);
685 BUG_ON(!kobj_ns_type_registered(type));
691 * sysfs_create_dir - create a directory for an object.
692 * @kobj: object we're creating directory for.
694 int sysfs_create_dir(struct kobject * kobj)
696 enum kobj_ns_type type;
697 struct sysfs_dirent *parent_sd, *sd;
698 const void *ns = NULL;
704 parent_sd = kobj->parent->sd;
706 parent_sd = &sysfs_root;
708 if (sysfs_ns_type(parent_sd))
709 ns = kobj->ktype->namespace(kobj);
710 type = sysfs_read_ns_type(kobj);
712 error = create_dir(kobj, parent_sd, type, ns, kobject_name(kobj), &sd);
718 static struct dentry * sysfs_lookup(struct inode *dir, struct dentry *dentry,
719 struct nameidata *nd)
721 struct dentry *ret = NULL;
722 struct dentry *parent = dentry->d_parent;
723 struct sysfs_dirent *parent_sd = parent->d_fsdata;
724 struct sysfs_dirent *sd;
726 enum kobj_ns_type type;
729 mutex_lock(&sysfs_mutex);
731 type = sysfs_ns_type(parent_sd);
732 ns = sysfs_info(dir->i_sb)->ns[type];
734 sd = sysfs_find_dirent(parent_sd, ns, dentry->d_name.name);
738 ret = ERR_PTR(-ENOENT);
742 /* attach dentry and inode */
743 inode = sysfs_get_inode(dir->i_sb, sd);
745 ret = ERR_PTR(-ENOMEM);
749 /* instantiate and hash dentry */
750 ret = d_find_alias(inode);
752 d_set_d_op(dentry, &sysfs_dentry_ops);
753 dentry->d_fsdata = sysfs_get(sd);
754 d_add(dentry, inode);
761 mutex_unlock(&sysfs_mutex);
765 const struct inode_operations sysfs_dir_inode_operations = {
766 .lookup = sysfs_lookup,
767 .permission = sysfs_permission,
768 .setattr = sysfs_setattr,
769 .getattr = sysfs_getattr,
770 .setxattr = sysfs_setxattr,
773 static void remove_dir(struct sysfs_dirent *sd)
775 struct sysfs_addrm_cxt acxt;
777 sysfs_addrm_start(&acxt, sd->s_parent);
778 sysfs_remove_one(&acxt, sd);
779 sysfs_addrm_finish(&acxt);
782 void sysfs_remove_subdir(struct sysfs_dirent *sd)
788 static void __sysfs_remove_dir(struct sysfs_dirent *dir_sd)
790 struct sysfs_addrm_cxt acxt;
791 struct sysfs_dirent **pos;
796 pr_debug("sysfs %s: removing dir\n", dir_sd->s_name);
797 sysfs_addrm_start(&acxt, dir_sd);
798 pos = &dir_sd->s_dir.children;
800 struct sysfs_dirent *sd = *pos;
802 if (sysfs_type(sd) != SYSFS_DIR)
803 sysfs_remove_one(&acxt, sd);
805 pos = &(*pos)->s_sibling;
807 sysfs_addrm_finish(&acxt);
813 * sysfs_remove_dir - remove an object's directory.
816 * The only thing special about this is that we remove any files in
817 * the directory before we remove the directory, and we've inlined
818 * what used to be sysfs_rmdir() below, instead of calling separately.
821 void sysfs_remove_dir(struct kobject * kobj)
823 struct sysfs_dirent *sd = kobj->sd;
825 spin_lock(&sysfs_assoc_lock);
827 spin_unlock(&sysfs_assoc_lock);
829 __sysfs_remove_dir(sd);
832 int sysfs_rename(struct sysfs_dirent *sd,
833 struct sysfs_dirent *new_parent_sd, const void *new_ns,
834 const char *new_name)
836 const char *dup_name = NULL;
839 mutex_lock(&sysfs_mutex);
842 if ((sd->s_parent == new_parent_sd) && (sd->s_ns == new_ns) &&
843 (strcmp(sd->s_name, new_name) == 0))
844 goto out; /* nothing to rename */
847 if (sysfs_find_dirent(new_parent_sd, new_ns, new_name))
850 /* rename sysfs_dirent */
851 if (strcmp(sd->s_name, new_name) != 0) {
853 new_name = dup_name = kstrdup(new_name, GFP_KERNEL);
857 dup_name = sd->s_name;
858 sd->s_name = new_name;
861 /* Remove from old parent's list and insert into new parent's list. */
862 if (sd->s_parent != new_parent_sd) {
863 sysfs_unlink_sibling(sd);
864 sysfs_get(new_parent_sd);
865 sysfs_put(sd->s_parent);
866 sd->s_parent = new_parent_sd;
867 sysfs_link_sibling(sd);
873 mutex_unlock(&sysfs_mutex);
878 int sysfs_rename_dir(struct kobject *kobj, const char *new_name)
880 struct sysfs_dirent *parent_sd = kobj->sd->s_parent;
881 const void *new_ns = NULL;
883 if (sysfs_ns_type(parent_sd))
884 new_ns = kobj->ktype->namespace(kobj);
886 return sysfs_rename(kobj->sd, parent_sd, new_ns, new_name);
889 int sysfs_move_dir(struct kobject *kobj, struct kobject *new_parent_kobj)
891 struct sysfs_dirent *sd = kobj->sd;
892 struct sysfs_dirent *new_parent_sd;
893 const void *new_ns = NULL;
895 BUG_ON(!sd->s_parent);
896 if (sysfs_ns_type(sd->s_parent))
897 new_ns = kobj->ktype->namespace(kobj);
898 new_parent_sd = new_parent_kobj && new_parent_kobj->sd ?
899 new_parent_kobj->sd : &sysfs_root;
901 return sysfs_rename(sd, new_parent_sd, new_ns, sd->s_name);
904 /* Relationship between s_mode and the DT_xxx types */
905 static inline unsigned char dt_type(struct sysfs_dirent *sd)
907 return (sd->s_mode >> 12) & 15;
910 static int sysfs_dir_release(struct inode *inode, struct file *filp)
912 sysfs_put(filp->private_data);
916 static struct sysfs_dirent *sysfs_dir_pos(const void *ns,
917 struct sysfs_dirent *parent_sd, ino_t ino, struct sysfs_dirent *pos)
920 int valid = !(pos->s_flags & SYSFS_FLAG_REMOVED) &&
921 pos->s_parent == parent_sd &&
927 if (!pos && (ino > 1) && (ino < INT_MAX)) {
928 pos = parent_sd->s_dir.children;
929 while (pos && (ino > pos->s_ino))
930 pos = pos->s_sibling;
932 while (pos && pos->s_ns && pos->s_ns != ns)
933 pos = pos->s_sibling;
937 static struct sysfs_dirent *sysfs_dir_next_pos(const void *ns,
938 struct sysfs_dirent *parent_sd, ino_t ino, struct sysfs_dirent *pos)
940 pos = sysfs_dir_pos(ns, parent_sd, ino, pos);
942 pos = pos->s_sibling;
943 while (pos && pos->s_ns && pos->s_ns != ns)
944 pos = pos->s_sibling;
948 static int sysfs_readdir(struct file * filp, void * dirent, filldir_t filldir)
950 struct dentry *dentry = filp->f_path.dentry;
951 struct sysfs_dirent * parent_sd = dentry->d_fsdata;
952 struct sysfs_dirent *pos = filp->private_data;
953 enum kobj_ns_type type;
957 type = sysfs_ns_type(parent_sd);
958 ns = sysfs_info(dentry->d_sb)->ns[type];
960 if (filp->f_pos == 0) {
961 ino = parent_sd->s_ino;
962 if (filldir(dirent, ".", 1, filp->f_pos, ino, DT_DIR) == 0)
965 if (filp->f_pos == 1) {
966 if (parent_sd->s_parent)
967 ino = parent_sd->s_parent->s_ino;
969 ino = parent_sd->s_ino;
970 if (filldir(dirent, "..", 2, filp->f_pos, ino, DT_DIR) == 0)
973 mutex_lock(&sysfs_mutex);
974 for (pos = sysfs_dir_pos(ns, parent_sd, filp->f_pos, pos);
976 pos = sysfs_dir_next_pos(ns, parent_sd, filp->f_pos, pos)) {
986 filp->private_data = sysfs_get(pos);
988 mutex_unlock(&sysfs_mutex);
989 ret = filldir(dirent, name, len, filp->f_pos, ino, type);
990 mutex_lock(&sysfs_mutex);
994 mutex_unlock(&sysfs_mutex);
995 if ((filp->f_pos > 1) && !pos) { /* EOF */
996 filp->f_pos = INT_MAX;
997 filp->private_data = NULL;
1003 const struct file_operations sysfs_dir_operations = {
1004 .read = generic_read_dir,
1005 .readdir = sysfs_readdir,
1006 .release = sysfs_dir_release,
1007 .llseek = generic_file_llseek,