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>
25 #include <linux/hash.h>
28 DEFINE_MUTEX(sysfs_mutex);
29 DEFINE_SPINLOCK(sysfs_assoc_lock);
31 #define to_sysfs_dirent(X) rb_entry((X), struct sysfs_dirent, s_rb);
33 static DEFINE_SPINLOCK(sysfs_ino_lock);
34 static DEFINE_IDA(sysfs_ino_ida);
38 * @ns: Namespace tag to hash
39 * @name: Null terminated string to hash
41 * Returns 31 bit hash of ns + name (so it fits in an off_t )
43 static unsigned int sysfs_name_hash(const void *ns, const char *name)
45 unsigned long hash = init_name_hash();
46 unsigned int len = strlen(name);
48 hash = partial_name_hash(*name++, hash);
49 hash = ( end_name_hash(hash) ^ hash_ptr( (void *)ns, 31 ) );
51 /* Reserve hash numbers 0, 1 and INT_MAX for magic directory entries */
59 static int sysfs_name_compare(unsigned int hash, const void *ns,
60 const char *name, const struct sysfs_dirent *sd)
62 if (hash != sd->s_hash)
63 return hash - sd->s_hash;
66 return strcmp(name, sd->s_name);
69 static int sysfs_sd_compare(const struct sysfs_dirent *left,
70 const struct sysfs_dirent *right)
72 return sysfs_name_compare(left->s_hash, left->s_ns, left->s_name,
77 * sysfs_link_subling - link sysfs_dirent into sibling rbtree
78 * @sd: sysfs_dirent of interest
80 * Link @sd into its sibling rbtree which starts from
81 * sd->s_parent->s_dir.children.
84 * mutex_lock(sysfs_mutex)
87 * 0 on susccess -EEXIST on failure.
89 static int sysfs_link_sibling(struct sysfs_dirent *sd)
91 struct rb_node **node = &sd->s_parent->s_dir.children.rb_node;
92 struct rb_node *parent = NULL;
94 if (sysfs_type(sd) == SYSFS_DIR)
95 sd->s_parent->s_dir.subdirs++;
98 struct sysfs_dirent *pos;
101 pos = to_sysfs_dirent(*node);
103 result = sysfs_sd_compare(sd, pos);
105 node = &pos->s_rb.rb_left;
107 node = &pos->s_rb.rb_right;
111 /* add new node and rebalance the tree */
112 rb_link_node(&sd->s_rb, parent, node);
113 rb_insert_color(&sd->s_rb, &sd->s_parent->s_dir.children);
118 * sysfs_unlink_sibling - unlink sysfs_dirent from sibling rbtree
119 * @sd: sysfs_dirent of interest
121 * Unlink @sd from its sibling rbtree which starts from
122 * sd->s_parent->s_dir.children.
125 * mutex_lock(sysfs_mutex)
127 static void sysfs_unlink_sibling(struct sysfs_dirent *sd)
129 if (sysfs_type(sd) == SYSFS_DIR)
130 sd->s_parent->s_dir.subdirs--;
132 rb_erase(&sd->s_rb, &sd->s_parent->s_dir.children);
135 #ifdef CONFIG_DEBUG_LOCK_ALLOC
137 /* Test for attributes that want to ignore lockdep for read-locking */
138 static bool ignore_lockdep(struct sysfs_dirent *sd)
140 return sysfs_type(sd) == SYSFS_KOBJ_ATTR &&
141 sd->s_attr.attr->ignore_lockdep;
146 static inline bool ignore_lockdep(struct sysfs_dirent *sd)
154 * sysfs_get_active - get an active reference to sysfs_dirent
155 * @sd: sysfs_dirent to get an active reference to
157 * Get an active reference of @sd. This function is noop if @sd
161 * Pointer to @sd on success, NULL on failure.
163 struct sysfs_dirent *sysfs_get_active(struct sysfs_dirent *sd)
171 v = atomic_read(&sd->s_active);
175 t = atomic_cmpxchg(&sd->s_active, v, v + 1);
184 if (likely(!ignore_lockdep(sd)))
185 rwsem_acquire_read(&sd->dep_map, 0, 1, _RET_IP_);
190 * sysfs_put_active - put an active reference to sysfs_dirent
191 * @sd: sysfs_dirent to put an active reference to
193 * Put an active reference to @sd. This function is noop if @sd
196 void sysfs_put_active(struct sysfs_dirent *sd)
203 if (likely(!ignore_lockdep(sd)))
204 rwsem_release(&sd->dep_map, 1, _RET_IP_);
205 v = atomic_dec_return(&sd->s_active);
206 if (likely(v != SD_DEACTIVATED_BIAS))
209 /* atomic_dec_return() is a mb(), we'll always see the updated
212 complete(sd->u.completion);
216 * sysfs_deactivate - deactivate sysfs_dirent
217 * @sd: sysfs_dirent to deactivate
219 * Deny new active references and drain existing ones.
221 static void sysfs_deactivate(struct sysfs_dirent *sd)
223 DECLARE_COMPLETION_ONSTACK(wait);
226 BUG_ON(!(sd->s_flags & SYSFS_FLAG_REMOVED));
228 if (!(sysfs_type(sd) & SYSFS_ACTIVE_REF))
231 sd->u.completion = (void *)&wait;
233 rwsem_acquire(&sd->dep_map, 0, 0, _RET_IP_);
234 /* atomic_add_return() is a mb(), put_active() will always see
235 * the updated sd->u.completion.
237 v = atomic_add_return(SD_DEACTIVATED_BIAS, &sd->s_active);
239 if (v != SD_DEACTIVATED_BIAS) {
240 lock_contended(&sd->dep_map, _RET_IP_);
241 wait_for_completion(&wait);
244 lock_acquired(&sd->dep_map, _RET_IP_);
245 rwsem_release(&sd->dep_map, 1, _RET_IP_);
248 static int sysfs_alloc_ino(unsigned int *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(unsigned int 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)
288 if (sd->s_iattr && sd->s_iattr->ia_secdata)
289 security_release_secctx(sd->s_iattr->ia_secdata,
290 sd->s_iattr->ia_secdata_len);
292 sysfs_free_ino(sd->s_ino);
293 kmem_cache_free(sysfs_dir_cachep, sd);
296 if (sd && atomic_dec_and_test(&sd->s_count))
300 static int sysfs_dentry_delete(const struct dentry *dentry)
302 struct sysfs_dirent *sd = dentry->d_fsdata;
303 return !(sd && !(sd->s_flags & SYSFS_FLAG_REMOVED));
306 static int sysfs_dentry_revalidate(struct dentry *dentry, unsigned int flags)
308 struct sysfs_dirent *sd;
311 if (flags & LOOKUP_RCU)
314 sd = dentry->d_fsdata;
315 mutex_lock(&sysfs_mutex);
317 /* The sysfs dirent has been deleted */
318 if (sd->s_flags & SYSFS_FLAG_REMOVED)
321 /* The sysfs dirent has been moved? */
322 if (dentry->d_parent->d_fsdata != sd->s_parent)
325 /* The sysfs dirent has been renamed */
326 if (strcmp(dentry->d_name.name, sd->s_name) != 0)
329 mutex_unlock(&sysfs_mutex);
333 /* Remove the dentry from the dcache hashes.
334 * If this is a deleted dentry we use d_drop instead of d_delete
335 * so sysfs doesn't need to cope with negative dentries.
337 * If this is a dentry that has simply been renamed we
338 * use d_drop to remove it from the dcache lookup on its
339 * old parent. If this dentry persists later when a lookup
340 * is performed at its new name the dentry will be readded
341 * to the dcache hashes.
343 is_dir = (sysfs_type(sd) == SYSFS_DIR);
344 mutex_unlock(&sysfs_mutex);
346 /* If we have submounts we must allow the vfs caches
347 * to lie about the state of the filesystem to prevent
348 * leaks and other nasty things.
350 if (have_submounts(dentry))
352 shrink_dcache_parent(dentry);
358 static void sysfs_dentry_release(struct dentry *dentry)
360 sysfs_put(dentry->d_fsdata);
363 const struct dentry_operations sysfs_dentry_ops = {
364 .d_revalidate = sysfs_dentry_revalidate,
365 .d_delete = sysfs_dentry_delete,
366 .d_release = sysfs_dentry_release,
369 struct sysfs_dirent *sysfs_new_dirent(const char *name, umode_t mode, int type)
371 char *dup_name = NULL;
372 struct sysfs_dirent *sd;
374 if (type & SYSFS_COPY_NAME) {
375 name = dup_name = kstrdup(name, GFP_KERNEL);
380 sd = kmem_cache_zalloc(sysfs_dir_cachep, GFP_KERNEL);
384 if (sysfs_alloc_ino(&sd->s_ino))
387 atomic_set(&sd->s_count, 1);
388 atomic_set(&sd->s_active, 0);
397 kmem_cache_free(sysfs_dir_cachep, sd);
404 * sysfs_addrm_start - prepare for sysfs_dirent add/remove
405 * @acxt: pointer to sysfs_addrm_cxt to be used
406 * @parent_sd: parent sysfs_dirent
408 * This function is called when the caller is about to add or
409 * remove sysfs_dirent under @parent_sd. This function acquires
410 * sysfs_mutex. @acxt is used to keep and pass context to
411 * other addrm functions.
414 * Kernel thread context (may sleep). sysfs_mutex is locked on
417 void sysfs_addrm_start(struct sysfs_addrm_cxt *acxt,
418 struct sysfs_dirent *parent_sd)
420 memset(acxt, 0, sizeof(*acxt));
421 acxt->parent_sd = parent_sd;
423 mutex_lock(&sysfs_mutex);
427 * __sysfs_add_one - add sysfs_dirent to parent without warning
428 * @acxt: addrm context to use
429 * @sd: sysfs_dirent to be added
431 * Get @acxt->parent_sd and set sd->s_parent to it and increment
432 * nlink of parent inode if @sd is a directory and link into the
433 * children list of the parent.
435 * This function should be called between calls to
436 * sysfs_addrm_start() and sysfs_addrm_finish() and should be
437 * passed the same @acxt as passed to sysfs_addrm_start().
440 * Determined by sysfs_addrm_start().
443 * 0 on success, -EEXIST if entry with the given name already
446 int __sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd)
448 struct sysfs_inode_attrs *ps_iattr;
451 if (!!sysfs_ns_type(acxt->parent_sd) != !!sd->s_ns) {
452 WARN(1, KERN_WARNING "sysfs: ns %s in '%s' for '%s'\n",
453 sysfs_ns_type(acxt->parent_sd)? "required": "invalid",
454 acxt->parent_sd->s_name, sd->s_name);
458 sd->s_hash = sysfs_name_hash(sd->s_ns, sd->s_name);
459 sd->s_parent = sysfs_get(acxt->parent_sd);
461 ret = sysfs_link_sibling(sd);
465 /* Update timestamps on the parent */
466 ps_iattr = acxt->parent_sd->s_iattr;
468 struct iattr *ps_iattrs = &ps_iattr->ia_iattr;
469 ps_iattrs->ia_ctime = ps_iattrs->ia_mtime = CURRENT_TIME;
476 * sysfs_pathname - return full path to sysfs dirent
477 * @sd: sysfs_dirent whose path we want
478 * @path: caller allocated buffer
480 * Gives the name "/" to the sysfs_root entry; any path returned
481 * is relative to wherever sysfs is mounted.
483 * XXX: does no error checking on @path size
485 static char *sysfs_pathname(struct sysfs_dirent *sd, char *path)
488 sysfs_pathname(sd->s_parent, path);
491 strcat(path, sd->s_name);
496 * sysfs_add_one - add sysfs_dirent to parent
497 * @acxt: addrm context to use
498 * @sd: sysfs_dirent to be added
500 * Get @acxt->parent_sd and set sd->s_parent to it and increment
501 * nlink of parent inode if @sd is a directory and link into the
502 * children list of the parent.
504 * This function should be called between calls to
505 * sysfs_addrm_start() and sysfs_addrm_finish() and should be
506 * passed the same @acxt as passed to sysfs_addrm_start().
509 * Determined by sysfs_addrm_start().
512 * 0 on success, -EEXIST if entry with the given name already
515 int sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd)
519 ret = __sysfs_add_one(acxt, sd);
520 if (ret == -EEXIST) {
521 char *path = kzalloc(PATH_MAX, GFP_KERNEL);
523 "sysfs: cannot create duplicate filename '%s'\n",
524 (path == NULL) ? sd->s_name :
525 strcat(strcat(sysfs_pathname(acxt->parent_sd, path), "/"),
534 * sysfs_remove_one - remove sysfs_dirent from parent
535 * @acxt: addrm context to use
536 * @sd: sysfs_dirent to be removed
538 * Mark @sd removed and drop nlink of parent inode if @sd is a
539 * directory. @sd is unlinked from the children list.
541 * This function should be called between calls to
542 * sysfs_addrm_start() and sysfs_addrm_finish() and should be
543 * passed the same @acxt as passed to sysfs_addrm_start().
546 * Determined by sysfs_addrm_start().
548 void sysfs_remove_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd)
550 struct sysfs_inode_attrs *ps_iattr;
552 BUG_ON(sd->s_flags & SYSFS_FLAG_REMOVED);
554 sysfs_unlink_sibling(sd);
556 /* Update timestamps on the parent */
557 ps_iattr = acxt->parent_sd->s_iattr;
559 struct iattr *ps_iattrs = &ps_iattr->ia_iattr;
560 ps_iattrs->ia_ctime = ps_iattrs->ia_mtime = CURRENT_TIME;
563 sd->s_flags |= SYSFS_FLAG_REMOVED;
564 sd->u.removed_list = acxt->removed;
569 * sysfs_addrm_finish - finish up sysfs_dirent add/remove
570 * @acxt: addrm context to finish up
572 * Finish up sysfs_dirent add/remove. Resources acquired by
573 * sysfs_addrm_start() are released and removed sysfs_dirents are
577 * sysfs_mutex is released.
579 void sysfs_addrm_finish(struct sysfs_addrm_cxt *acxt)
581 /* release resources acquired by sysfs_addrm_start() */
582 mutex_unlock(&sysfs_mutex);
584 /* kill removed sysfs_dirents */
585 while (acxt->removed) {
586 struct sysfs_dirent *sd = acxt->removed;
588 acxt->removed = sd->u.removed_list;
590 sysfs_deactivate(sd);
597 * sysfs_find_dirent - find sysfs_dirent with the given name
598 * @parent_sd: sysfs_dirent to search under
599 * @name: name to look for
601 * Look for sysfs_dirent with name @name under @parent_sd.
604 * mutex_lock(sysfs_mutex)
607 * Pointer to sysfs_dirent if found, NULL if not.
609 struct sysfs_dirent *sysfs_find_dirent(struct sysfs_dirent *parent_sd,
611 const unsigned char *name)
613 struct rb_node *node = parent_sd->s_dir.children.rb_node;
616 if (!!sysfs_ns_type(parent_sd) != !!ns) {
617 WARN(1, KERN_WARNING "sysfs: ns %s in '%s' for '%s'\n",
618 sysfs_ns_type(parent_sd)? "required": "invalid",
619 parent_sd->s_name, name);
623 hash = sysfs_name_hash(ns, name);
625 struct sysfs_dirent *sd;
628 sd = to_sysfs_dirent(node);
629 result = sysfs_name_compare(hash, ns, name, sd);
631 node = node->rb_left;
633 node = node->rb_right;
641 * sysfs_get_dirent - find and get sysfs_dirent with the given name
642 * @parent_sd: sysfs_dirent to search under
643 * @name: name to look for
645 * Look for sysfs_dirent with name @name under @parent_sd and get
649 * Kernel thread context (may sleep). Grabs sysfs_mutex.
652 * Pointer to sysfs_dirent if found, NULL if not.
654 struct sysfs_dirent *sysfs_get_dirent(struct sysfs_dirent *parent_sd,
656 const unsigned char *name)
658 struct sysfs_dirent *sd;
660 mutex_lock(&sysfs_mutex);
661 sd = sysfs_find_dirent(parent_sd, ns, name);
663 mutex_unlock(&sysfs_mutex);
667 EXPORT_SYMBOL_GPL(sysfs_get_dirent);
669 static int create_dir(struct kobject *kobj, struct sysfs_dirent *parent_sd,
670 enum kobj_ns_type type, const void *ns, const char *name,
671 struct sysfs_dirent **p_sd)
673 umode_t mode = S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO;
674 struct sysfs_addrm_cxt acxt;
675 struct sysfs_dirent *sd;
679 sd = sysfs_new_dirent(name, mode, SYSFS_DIR);
683 sd->s_flags |= (type << SYSFS_NS_TYPE_SHIFT);
685 sd->s_dir.kobj = kobj;
688 sysfs_addrm_start(&acxt, parent_sd);
689 rc = sysfs_add_one(&acxt, sd);
690 sysfs_addrm_finish(&acxt);
700 int sysfs_create_subdir(struct kobject *kobj, const char *name,
701 struct sysfs_dirent **p_sd)
703 return create_dir(kobj, kobj->sd,
704 KOBJ_NS_TYPE_NONE, NULL, name, p_sd);
708 * sysfs_read_ns_type: return associated ns_type
709 * @kobj: the kobject being queried
711 * Each kobject can be tagged with exactly one namespace type
712 * (i.e. network or user). Return the ns_type associated with
715 static enum kobj_ns_type sysfs_read_ns_type(struct kobject *kobj)
717 const struct kobj_ns_type_operations *ops;
718 enum kobj_ns_type type;
720 ops = kobj_child_ns_ops(kobj);
722 return KOBJ_NS_TYPE_NONE;
725 BUG_ON(type <= KOBJ_NS_TYPE_NONE);
726 BUG_ON(type >= KOBJ_NS_TYPES);
727 BUG_ON(!kobj_ns_type_registered(type));
733 * sysfs_create_dir - create a directory for an object.
734 * @kobj: object we're creating directory for.
736 int sysfs_create_dir(struct kobject * kobj)
738 enum kobj_ns_type type;
739 struct sysfs_dirent *parent_sd, *sd;
740 const void *ns = NULL;
746 parent_sd = kobj->parent->sd;
748 parent_sd = &sysfs_root;
753 if (sysfs_ns_type(parent_sd))
754 ns = kobj->ktype->namespace(kobj);
755 type = sysfs_read_ns_type(kobj);
757 error = create_dir(kobj, parent_sd, type, ns, kobject_name(kobj), &sd);
763 static struct dentry * sysfs_lookup(struct inode *dir, struct dentry *dentry,
766 struct dentry *ret = NULL;
767 struct dentry *parent = dentry->d_parent;
768 struct sysfs_dirent *parent_sd = parent->d_fsdata;
769 struct sysfs_dirent *sd;
771 enum kobj_ns_type type;
774 mutex_lock(&sysfs_mutex);
776 type = sysfs_ns_type(parent_sd);
777 ns = sysfs_info(dir->i_sb)->ns[type];
779 sd = sysfs_find_dirent(parent_sd, ns, dentry->d_name.name);
783 ret = ERR_PTR(-ENOENT);
786 dentry->d_fsdata = sysfs_get(sd);
788 /* attach dentry and inode */
789 inode = sysfs_get_inode(dir->i_sb, sd);
791 ret = ERR_PTR(-ENOMEM);
795 /* instantiate and hash dentry */
796 ret = d_materialise_unique(dentry, inode);
798 mutex_unlock(&sysfs_mutex);
802 const struct inode_operations sysfs_dir_inode_operations = {
803 .lookup = sysfs_lookup,
804 .permission = sysfs_permission,
805 .setattr = sysfs_setattr,
806 .getattr = sysfs_getattr,
807 .setxattr = sysfs_setxattr,
810 static void remove_dir(struct sysfs_dirent *sd)
812 struct sysfs_addrm_cxt acxt;
814 sysfs_addrm_start(&acxt, sd->s_parent);
815 sysfs_remove_one(&acxt, sd);
816 sysfs_addrm_finish(&acxt);
819 void sysfs_remove_subdir(struct sysfs_dirent *sd)
825 static void __sysfs_remove_dir(struct sysfs_dirent *dir_sd)
827 struct sysfs_addrm_cxt acxt;
833 pr_debug("sysfs %s: removing dir\n", dir_sd->s_name);
834 sysfs_addrm_start(&acxt, dir_sd);
835 pos = rb_first(&dir_sd->s_dir.children);
837 struct sysfs_dirent *sd = to_sysfs_dirent(pos);
839 if (sysfs_type(sd) != SYSFS_DIR)
840 sysfs_remove_one(&acxt, sd);
842 sysfs_addrm_finish(&acxt);
848 * sysfs_remove_dir - remove an object's directory.
851 * The only thing special about this is that we remove any files in
852 * the directory before we remove the directory, and we've inlined
853 * what used to be sysfs_rmdir() below, instead of calling separately.
856 void sysfs_remove_dir(struct kobject * kobj)
858 struct sysfs_dirent *sd = kobj->sd;
860 spin_lock(&sysfs_assoc_lock);
862 spin_unlock(&sysfs_assoc_lock);
864 __sysfs_remove_dir(sd);
867 int sysfs_rename(struct sysfs_dirent *sd,
868 struct sysfs_dirent *new_parent_sd, const void *new_ns,
869 const char *new_name)
873 mutex_lock(&sysfs_mutex);
876 if ((sd->s_parent == new_parent_sd) && (sd->s_ns == new_ns) &&
877 (strcmp(sd->s_name, new_name) == 0))
878 goto out; /* nothing to rename */
881 if (sysfs_find_dirent(new_parent_sd, new_ns, new_name))
884 /* rename sysfs_dirent */
885 if (strcmp(sd->s_name, new_name) != 0) {
887 new_name = kstrdup(new_name, GFP_KERNEL);
892 sd->s_name = new_name;
895 /* Move to the appropriate place in the appropriate directories rbtree. */
896 sysfs_unlink_sibling(sd);
897 sysfs_get(new_parent_sd);
898 sysfs_put(sd->s_parent);
900 sd->s_hash = sysfs_name_hash(sd->s_ns, sd->s_name);
901 sd->s_parent = new_parent_sd;
902 sysfs_link_sibling(sd);
906 mutex_unlock(&sysfs_mutex);
910 int sysfs_rename_dir(struct kobject *kobj, const char *new_name)
912 struct sysfs_dirent *parent_sd = kobj->sd->s_parent;
913 const void *new_ns = NULL;
915 if (sysfs_ns_type(parent_sd))
916 new_ns = kobj->ktype->namespace(kobj);
918 return sysfs_rename(kobj->sd, parent_sd, new_ns, new_name);
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 const void *new_ns = NULL;
927 BUG_ON(!sd->s_parent);
928 if (sysfs_ns_type(sd->s_parent))
929 new_ns = kobj->ktype->namespace(kobj);
930 new_parent_sd = new_parent_kobj && new_parent_kobj->sd ?
931 new_parent_kobj->sd : &sysfs_root;
933 return sysfs_rename(sd, new_parent_sd, new_ns, sd->s_name);
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_dir_release(struct inode *inode, struct file *filp)
944 sysfs_put(filp->private_data);
948 static struct sysfs_dirent *sysfs_dir_pos(const void *ns,
949 struct sysfs_dirent *parent_sd, loff_t hash, struct sysfs_dirent *pos)
952 int valid = !(pos->s_flags & SYSFS_FLAG_REMOVED) &&
953 pos->s_parent == parent_sd &&
959 if (!pos && (hash > 1) && (hash < INT_MAX)) {
960 struct rb_node *node = parent_sd->s_dir.children.rb_node;
962 pos = to_sysfs_dirent(node);
964 if (hash < pos->s_hash)
965 node = node->rb_left;
966 else if (hash > pos->s_hash)
967 node = node->rb_right;
972 /* Skip over entries in the wrong namespace */
973 while (pos && pos->s_ns != ns) {
974 struct rb_node *node = rb_next(&pos->s_rb);
978 pos = to_sysfs_dirent(node);
983 static struct sysfs_dirent *sysfs_dir_next_pos(const void *ns,
984 struct sysfs_dirent *parent_sd, ino_t ino, struct sysfs_dirent *pos)
986 pos = sysfs_dir_pos(ns, parent_sd, ino, pos);
988 struct rb_node *node = rb_next(&pos->s_rb);
992 pos = to_sysfs_dirent(node);
993 } while (pos && pos->s_ns != ns);
997 static int sysfs_readdir(struct file * filp, void * dirent, filldir_t filldir)
999 struct dentry *dentry = filp->f_path.dentry;
1000 struct sysfs_dirent * parent_sd = dentry->d_fsdata;
1001 struct sysfs_dirent *pos = filp->private_data;
1002 enum kobj_ns_type type;
1006 type = sysfs_ns_type(parent_sd);
1007 ns = sysfs_info(dentry->d_sb)->ns[type];
1009 if (filp->f_pos == 0) {
1010 ino = parent_sd->s_ino;
1011 if (filldir(dirent, ".", 1, filp->f_pos, ino, DT_DIR) == 0)
1014 if (filp->f_pos == 1) {
1015 if (parent_sd->s_parent)
1016 ino = parent_sd->s_parent->s_ino;
1018 ino = parent_sd->s_ino;
1019 if (filldir(dirent, "..", 2, filp->f_pos, ino, DT_DIR) == 0)
1022 mutex_lock(&sysfs_mutex);
1023 for (pos = sysfs_dir_pos(ns, parent_sd, filp->f_pos, pos);
1025 pos = sysfs_dir_next_pos(ns, parent_sd, filp->f_pos, pos)) {
1033 type = dt_type(pos);
1034 filp->f_pos = pos->s_hash;
1035 filp->private_data = sysfs_get(pos);
1037 mutex_unlock(&sysfs_mutex);
1038 ret = filldir(dirent, name, len, filp->f_pos, ino, type);
1039 mutex_lock(&sysfs_mutex);
1043 mutex_unlock(&sysfs_mutex);
1044 if ((filp->f_pos > 1) && !pos) { /* EOF */
1045 filp->f_pos = INT_MAX;
1046 filp->private_data = NULL;
1052 const struct file_operations sysfs_dir_operations = {
1053 .read = generic_read_dir,
1054 .readdir = sysfs_readdir,
1055 .release = sysfs_dir_release,
1056 .llseek = generic_file_llseek,