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_sibling - 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);
115 /* if @sd has ns tag, mark the parent to enable ns filtering */
117 sd->s_parent->s_flags |= SYSFS_FLAG_HAS_NS;
123 * sysfs_unlink_sibling - unlink sysfs_dirent from sibling rbtree
124 * @sd: sysfs_dirent of interest
126 * Unlink @sd from its sibling rbtree which starts from
127 * sd->s_parent->s_dir.children.
130 * mutex_lock(sysfs_mutex)
132 static void sysfs_unlink_sibling(struct sysfs_dirent *sd)
134 if (sysfs_type(sd) == SYSFS_DIR)
135 sd->s_parent->s_dir.subdirs--;
137 rb_erase(&sd->s_rb, &sd->s_parent->s_dir.children);
140 * Either all or none of the children have tags. Clearing HAS_NS
141 * when there's no child left is enough to keep the flag synced.
143 if (RB_EMPTY_ROOT(&sd->s_parent->s_dir.children))
144 sd->s_parent->s_flags &= ~SYSFS_FLAG_HAS_NS;
147 #ifdef CONFIG_DEBUG_LOCK_ALLOC
149 /* Test for attributes that want to ignore lockdep for read-locking */
150 static bool ignore_lockdep(struct sysfs_dirent *sd)
152 return sysfs_type(sd) == SYSFS_KOBJ_ATTR &&
153 sd->s_attr.attr->ignore_lockdep;
158 static inline bool ignore_lockdep(struct sysfs_dirent *sd)
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)
180 if (!atomic_inc_unless_negative(&sd->s_active))
183 if (likely(!ignore_lockdep(sd)))
184 rwsem_acquire_read(&sd->dep_map, 0, 1, _RET_IP_);
189 * sysfs_put_active - put an active reference to sysfs_dirent
190 * @sd: sysfs_dirent to put an active reference to
192 * Put an active reference to @sd. This function is noop if @sd
195 void sysfs_put_active(struct sysfs_dirent *sd)
202 if (likely(!ignore_lockdep(sd)))
203 rwsem_release(&sd->dep_map, 1, _RET_IP_);
204 v = atomic_dec_return(&sd->s_active);
205 if (likely(v != SD_DEACTIVATED_BIAS))
208 /* atomic_dec_return() is a mb(), we'll always see the updated
211 complete(sd->u.completion);
215 * sysfs_deactivate - deactivate sysfs_dirent
216 * @sd: sysfs_dirent to deactivate
218 * Deny new active references and drain existing ones.
220 static void sysfs_deactivate(struct sysfs_dirent *sd)
222 DECLARE_COMPLETION_ONSTACK(wait);
225 BUG_ON(!(sd->s_flags & SYSFS_FLAG_REMOVED));
227 if (!(sysfs_type(sd) & SYSFS_ACTIVE_REF))
230 sd->u.completion = (void *)&wait;
232 rwsem_acquire(&sd->dep_map, 0, 0, _RET_IP_);
233 /* atomic_add_return() is a mb(), put_active() will always see
234 * the updated sd->u.completion.
236 v = atomic_add_return(SD_DEACTIVATED_BIAS, &sd->s_active);
238 if (v != SD_DEACTIVATED_BIAS) {
239 lock_contended(&sd->dep_map, _RET_IP_);
240 wait_for_completion(&wait);
243 lock_acquired(&sd->dep_map, _RET_IP_);
244 rwsem_release(&sd->dep_map, 1, _RET_IP_);
247 static int sysfs_alloc_ino(unsigned int *pino)
252 spin_lock(&sysfs_ino_lock);
253 rc = ida_get_new_above(&sysfs_ino_ida, 2, &ino);
254 spin_unlock(&sysfs_ino_lock);
257 if (ida_pre_get(&sysfs_ino_ida, GFP_KERNEL))
266 static void sysfs_free_ino(unsigned int ino)
268 spin_lock(&sysfs_ino_lock);
269 ida_remove(&sysfs_ino_ida, ino);
270 spin_unlock(&sysfs_ino_lock);
273 void release_sysfs_dirent(struct sysfs_dirent *sd)
275 struct sysfs_dirent *parent_sd;
278 /* Moving/renaming is always done while holding reference.
279 * sd->s_parent won't change beneath us.
281 parent_sd = sd->s_parent;
283 WARN(!(sd->s_flags & SYSFS_FLAG_REMOVED),
284 "sysfs: free using entry: %s/%s\n",
285 parent_sd ? parent_sd->s_name : "", sd->s_name);
287 if (sysfs_type(sd) == SYSFS_KOBJ_LINK)
288 sysfs_put(sd->s_symlink.target_sd);
289 if (sysfs_type(sd) & SYSFS_COPY_NAME)
291 if (sd->s_iattr && sd->s_iattr->ia_secdata)
292 security_release_secctx(sd->s_iattr->ia_secdata,
293 sd->s_iattr->ia_secdata_len);
295 sysfs_free_ino(sd->s_ino);
296 kmem_cache_free(sysfs_dir_cachep, sd);
299 if (sd && atomic_dec_and_test(&sd->s_count))
303 static int sysfs_dentry_delete(const struct dentry *dentry)
305 struct sysfs_dirent *sd = dentry->d_fsdata;
306 return !(sd && !(sd->s_flags & SYSFS_FLAG_REMOVED));
309 static int sysfs_dentry_revalidate(struct dentry *dentry, unsigned int flags)
311 struct sysfs_dirent *sd;
313 if (flags & LOOKUP_RCU)
316 sd = dentry->d_fsdata;
317 mutex_lock(&sysfs_mutex);
319 /* The sysfs dirent has been deleted */
320 if (sd->s_flags & SYSFS_FLAG_REMOVED)
323 /* The sysfs dirent has been moved? */
324 if (dentry->d_parent->d_fsdata != sd->s_parent)
327 /* The sysfs dirent has been renamed */
328 if (strcmp(dentry->d_name.name, sd->s_name) != 0)
331 /* The sysfs dirent has been moved to a different namespace */
332 if (sd->s_ns && sd->s_ns != sysfs_info(dentry->d_sb)->ns)
335 mutex_unlock(&sysfs_mutex);
339 /* Remove the dentry from the dcache hashes.
340 * If this is a deleted dentry we use d_drop instead of d_delete
341 * so sysfs doesn't need to cope with negative dentries.
343 * If this is a dentry that has simply been renamed we
344 * use d_drop to remove it from the dcache lookup on its
345 * old parent. If this dentry persists later when a lookup
346 * is performed at its new name the dentry will be readded
347 * to the dcache hashes.
349 mutex_unlock(&sysfs_mutex);
351 /* If we have submounts we must allow the vfs caches
352 * to lie about the state of the filesystem to prevent
353 * leaks and other nasty things.
355 if (check_submounts_and_drop(dentry) != 0)
361 static void sysfs_dentry_release(struct dentry *dentry)
363 sysfs_put(dentry->d_fsdata);
366 const struct dentry_operations sysfs_dentry_ops = {
367 .d_revalidate = sysfs_dentry_revalidate,
368 .d_delete = sysfs_dentry_delete,
369 .d_release = sysfs_dentry_release,
372 struct sysfs_dirent *sysfs_new_dirent(const char *name, umode_t mode, int type)
374 char *dup_name = NULL;
375 struct sysfs_dirent *sd;
377 if (type & SYSFS_COPY_NAME) {
378 name = dup_name = kstrdup(name, GFP_KERNEL);
383 sd = kmem_cache_zalloc(sysfs_dir_cachep, GFP_KERNEL);
387 if (sysfs_alloc_ino(&sd->s_ino))
390 atomic_set(&sd->s_count, 1);
391 atomic_set(&sd->s_active, 0);
395 sd->s_flags = type | SYSFS_FLAG_REMOVED;
400 kmem_cache_free(sysfs_dir_cachep, sd);
407 * sysfs_addrm_start - prepare for sysfs_dirent add/remove
408 * @acxt: pointer to sysfs_addrm_cxt to be used
409 * @parent_sd: parent sysfs_dirent
411 * This function is called when the caller is about to add or
412 * remove sysfs_dirent under @parent_sd. This function acquires
413 * sysfs_mutex. @acxt is used to keep and pass context to
414 * other addrm functions.
417 * Kernel thread context (may sleep). sysfs_mutex is locked on
420 void sysfs_addrm_start(struct sysfs_addrm_cxt *acxt,
421 struct sysfs_dirent *parent_sd)
423 memset(acxt, 0, sizeof(*acxt));
424 acxt->parent_sd = parent_sd;
426 mutex_lock(&sysfs_mutex);
430 * __sysfs_add_one - add sysfs_dirent to parent without warning
431 * @acxt: addrm context to use
432 * @sd: sysfs_dirent to be added
434 * Get @acxt->parent_sd and set sd->s_parent to it and increment
435 * nlink of parent inode if @sd is a directory and link into the
436 * children list of the parent.
438 * This function should be called between calls to
439 * sysfs_addrm_start() and sysfs_addrm_finish() and should be
440 * passed the same @acxt as passed to sysfs_addrm_start().
443 * Determined by sysfs_addrm_start().
446 * 0 on success, -EEXIST if entry with the given name already
449 int __sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd)
451 struct sysfs_inode_attrs *ps_iattr;
454 sd->s_hash = sysfs_name_hash(sd->s_ns, sd->s_name);
455 sd->s_parent = sysfs_get(acxt->parent_sd);
457 ret = sysfs_link_sibling(sd);
461 /* Update timestamps on the parent */
462 ps_iattr = acxt->parent_sd->s_iattr;
464 struct iattr *ps_iattrs = &ps_iattr->ia_iattr;
465 ps_iattrs->ia_ctime = ps_iattrs->ia_mtime = CURRENT_TIME;
468 /* Mark the entry added into directory tree */
469 sd->s_flags &= ~SYSFS_FLAG_REMOVED;
475 * sysfs_pathname - return full path to sysfs dirent
476 * @sd: sysfs_dirent whose path we want
477 * @path: caller allocated buffer of size PATH_MAX
479 * Gives the name "/" to the sysfs_root entry; any path returned
480 * is relative to wherever sysfs is mounted.
482 static char *sysfs_pathname(struct sysfs_dirent *sd, char *path)
485 sysfs_pathname(sd->s_parent, path);
486 strlcat(path, "/", PATH_MAX);
488 strlcat(path, sd->s_name, PATH_MAX);
493 * sysfs_add_one - add sysfs_dirent to parent
494 * @acxt: addrm context to use
495 * @sd: sysfs_dirent to be added
497 * Get @acxt->parent_sd and set sd->s_parent to it and increment
498 * nlink of parent inode if @sd is a directory and link into the
499 * children list of the parent.
501 * This function should be called between calls to
502 * sysfs_addrm_start() and sysfs_addrm_finish() and should be
503 * passed the same @acxt as passed to sysfs_addrm_start().
506 * Determined by sysfs_addrm_start().
509 * 0 on success, -EEXIST if entry with the given name already
512 int sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd)
516 ret = __sysfs_add_one(acxt, sd);
517 if (ret == -EEXIST) {
518 char *path = kzalloc(PATH_MAX, GFP_KERNEL);
520 "sysfs: cannot create duplicate filename '%s'\n",
521 (path == NULL) ? sd->s_name
522 : (sysfs_pathname(acxt->parent_sd, path),
523 strlcat(path, "/", PATH_MAX),
524 strlcat(path, sd->s_name, PATH_MAX),
533 * sysfs_remove_one - remove sysfs_dirent from parent
534 * @acxt: addrm context to use
535 * @sd: sysfs_dirent to be removed
537 * Mark @sd removed and drop nlink of parent inode if @sd is a
538 * directory. @sd is unlinked from the children list.
540 * This function should be called between calls to
541 * sysfs_addrm_start() and sysfs_addrm_finish() and should be
542 * passed the same @acxt as passed to sysfs_addrm_start().
545 * Determined by sysfs_addrm_start().
547 void sysfs_remove_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd)
549 struct sysfs_inode_attrs *ps_iattr;
551 BUG_ON(sd->s_flags & SYSFS_FLAG_REMOVED);
553 sysfs_unlink_sibling(sd);
555 /* Update timestamps on the parent */
556 ps_iattr = acxt->parent_sd->s_iattr;
558 struct iattr *ps_iattrs = &ps_iattr->ia_iattr;
559 ps_iattrs->ia_ctime = ps_iattrs->ia_mtime = CURRENT_TIME;
562 sd->s_flags |= SYSFS_FLAG_REMOVED;
563 sd->u.removed_list = acxt->removed;
568 * sysfs_addrm_finish - finish up sysfs_dirent add/remove
569 * @acxt: addrm context to finish up
571 * Finish up sysfs_dirent add/remove. Resources acquired by
572 * sysfs_addrm_start() are released and removed sysfs_dirents are
576 * sysfs_mutex is released.
578 void sysfs_addrm_finish(struct sysfs_addrm_cxt *acxt)
580 /* release resources acquired by sysfs_addrm_start() */
581 mutex_unlock(&sysfs_mutex);
583 /* kill removed sysfs_dirents */
584 while (acxt->removed) {
585 struct sysfs_dirent *sd = acxt->removed;
587 acxt->removed = sd->u.removed_list;
589 sysfs_deactivate(sd);
596 * sysfs_find_dirent - find sysfs_dirent with the given name
597 * @parent_sd: sysfs_dirent to search under
598 * @name: name to look for
600 * Look for sysfs_dirent with name @name under @parent_sd.
603 * mutex_lock(sysfs_mutex)
606 * Pointer to sysfs_dirent if found, NULL if not.
608 struct sysfs_dirent *sysfs_find_dirent(struct sysfs_dirent *parent_sd,
610 const unsigned char *name)
612 struct rb_node *node = parent_sd->s_dir.children.rb_node;
615 hash = sysfs_name_hash(ns, name);
617 struct sysfs_dirent *sd;
620 sd = to_sysfs_dirent(node);
621 result = sysfs_name_compare(hash, ns, name, sd);
623 node = node->rb_left;
625 node = node->rb_right;
633 * sysfs_get_dirent - find and get sysfs_dirent with the given name
634 * @parent_sd: sysfs_dirent to search under
635 * @name: name to look for
637 * Look for sysfs_dirent with name @name under @parent_sd and get
641 * Kernel thread context (may sleep). Grabs sysfs_mutex.
644 * Pointer to sysfs_dirent if found, NULL if not.
646 struct sysfs_dirent *sysfs_get_dirent(struct sysfs_dirent *parent_sd,
648 const unsigned char *name)
650 struct sysfs_dirent *sd;
652 mutex_lock(&sysfs_mutex);
653 sd = sysfs_find_dirent(parent_sd, ns, name);
655 mutex_unlock(&sysfs_mutex);
659 EXPORT_SYMBOL_GPL(sysfs_get_dirent);
661 static int create_dir(struct kobject *kobj, struct sysfs_dirent *parent_sd,
662 const void *ns, const char *name, struct sysfs_dirent **p_sd)
664 umode_t mode = S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO;
665 struct sysfs_addrm_cxt acxt;
666 struct sysfs_dirent *sd;
670 sd = sysfs_new_dirent(name, mode, SYSFS_DIR);
675 sd->s_dir.kobj = kobj;
678 sysfs_addrm_start(&acxt, parent_sd);
679 rc = sysfs_add_one(&acxt, sd);
680 sysfs_addrm_finish(&acxt);
690 int sysfs_create_subdir(struct kobject *kobj, const char *name,
691 struct sysfs_dirent **p_sd)
693 return create_dir(kobj, kobj->sd, NULL, name, p_sd);
697 * sysfs_create_dir_ns - create a directory for an object with a namespace tag
698 * @kobj: object we're creating directory for
699 * @ns: the namespace tag to use
701 int sysfs_create_dir_ns(struct kobject *kobj, const void *ns)
703 struct sysfs_dirent *parent_sd, *sd;
709 parent_sd = kobj->parent->sd;
711 parent_sd = &sysfs_root;
716 error = create_dir(kobj, parent_sd, ns, kobject_name(kobj), &sd);
722 static struct dentry *sysfs_lookup(struct inode *dir, struct dentry *dentry,
725 struct dentry *ret = NULL;
726 struct dentry *parent = dentry->d_parent;
727 struct sysfs_dirent *parent_sd = parent->d_fsdata;
728 struct sysfs_dirent *sd;
730 const void *ns = NULL;
732 mutex_lock(&sysfs_mutex);
734 if (parent_sd->s_flags & SYSFS_FLAG_HAS_NS)
735 ns = sysfs_info(dir->i_sb)->ns;
737 sd = sysfs_find_dirent(parent_sd, ns, dentry->d_name.name);
741 ret = ERR_PTR(-ENOENT);
744 dentry->d_fsdata = sysfs_get(sd);
746 /* attach dentry and inode */
747 inode = sysfs_get_inode(dir->i_sb, sd);
749 ret = ERR_PTR(-ENOMEM);
753 /* instantiate and hash dentry */
754 ret = d_materialise_unique(dentry, inode);
756 mutex_unlock(&sysfs_mutex);
760 const struct inode_operations sysfs_dir_inode_operations = {
761 .lookup = sysfs_lookup,
762 .permission = sysfs_permission,
763 .setattr = sysfs_setattr,
764 .getattr = sysfs_getattr,
765 .setxattr = sysfs_setxattr,
768 static void remove_dir(struct sysfs_dirent *sd)
770 struct sysfs_addrm_cxt acxt;
772 sysfs_addrm_start(&acxt, sd->s_parent);
773 sysfs_remove_one(&acxt, sd);
774 sysfs_addrm_finish(&acxt);
777 void sysfs_remove_subdir(struct sysfs_dirent *sd)
783 static void __sysfs_remove_dir(struct sysfs_dirent *dir_sd)
785 struct sysfs_addrm_cxt acxt;
791 pr_debug("sysfs %s: removing dir\n", dir_sd->s_name);
792 sysfs_addrm_start(&acxt, dir_sd);
793 pos = rb_first(&dir_sd->s_dir.children);
795 struct sysfs_dirent *sd = to_sysfs_dirent(pos);
797 if (sysfs_type(sd) != SYSFS_DIR)
798 sysfs_remove_one(&acxt, sd);
800 sysfs_addrm_finish(&acxt);
806 * sysfs_remove_dir - remove an object's directory.
809 * The only thing special about this is that we remove any files in
810 * the directory before we remove the directory, and we've inlined
811 * what used to be sysfs_rmdir() below, instead of calling separately.
814 void sysfs_remove_dir(struct kobject *kobj)
816 struct sysfs_dirent *sd = kobj->sd;
818 spin_lock(&sysfs_assoc_lock);
820 spin_unlock(&sysfs_assoc_lock);
822 __sysfs_remove_dir(sd);
825 int sysfs_rename(struct sysfs_dirent *sd,
826 struct sysfs_dirent *new_parent_sd, const void *new_ns,
827 const char *new_name)
831 mutex_lock(&sysfs_mutex);
834 if ((sd->s_parent == new_parent_sd) && (sd->s_ns == new_ns) &&
835 (strcmp(sd->s_name, new_name) == 0))
836 goto out; /* nothing to rename */
839 if (sysfs_find_dirent(new_parent_sd, new_ns, new_name))
842 /* rename sysfs_dirent */
843 if (strcmp(sd->s_name, new_name) != 0) {
845 new_name = kstrdup(new_name, GFP_KERNEL);
850 sd->s_name = new_name;
854 * Move to the appropriate place in the appropriate directories rbtree.
856 sysfs_unlink_sibling(sd);
857 sysfs_get(new_parent_sd);
858 sysfs_put(sd->s_parent);
860 sd->s_hash = sysfs_name_hash(sd->s_ns, sd->s_name);
861 sd->s_parent = new_parent_sd;
862 sysfs_link_sibling(sd);
866 mutex_unlock(&sysfs_mutex);
870 int sysfs_rename_dir_ns(struct kobject *kobj, const char *new_name,
873 struct sysfs_dirent *parent_sd = kobj->sd->s_parent;
875 return sysfs_rename(kobj->sd, parent_sd, new_ns, new_name);
878 int sysfs_move_dir_ns(struct kobject *kobj, struct kobject *new_parent_kobj,
881 struct sysfs_dirent *sd = kobj->sd;
882 struct sysfs_dirent *new_parent_sd;
884 BUG_ON(!sd->s_parent);
885 new_parent_sd = new_parent_kobj && new_parent_kobj->sd ?
886 new_parent_kobj->sd : &sysfs_root;
888 return sysfs_rename(sd, new_parent_sd, new_ns, sd->s_name);
891 /* Relationship between s_mode and the DT_xxx types */
892 static inline unsigned char dt_type(struct sysfs_dirent *sd)
894 return (sd->s_mode >> 12) & 15;
897 static int sysfs_dir_release(struct inode *inode, struct file *filp)
899 sysfs_put(filp->private_data);
903 static struct sysfs_dirent *sysfs_dir_pos(const void *ns,
904 struct sysfs_dirent *parent_sd, loff_t hash, struct sysfs_dirent *pos)
907 int valid = !(pos->s_flags & SYSFS_FLAG_REMOVED) &&
908 pos->s_parent == parent_sd &&
914 if (!pos && (hash > 1) && (hash < INT_MAX)) {
915 struct rb_node *node = parent_sd->s_dir.children.rb_node;
917 pos = to_sysfs_dirent(node);
919 if (hash < pos->s_hash)
920 node = node->rb_left;
921 else if (hash > pos->s_hash)
922 node = node->rb_right;
927 /* Skip over entries in the wrong namespace */
928 while (pos && pos->s_ns != ns) {
929 struct rb_node *node = rb_next(&pos->s_rb);
933 pos = to_sysfs_dirent(node);
938 static struct sysfs_dirent *sysfs_dir_next_pos(const void *ns,
939 struct sysfs_dirent *parent_sd, ino_t ino, struct sysfs_dirent *pos)
941 pos = sysfs_dir_pos(ns, parent_sd, ino, pos);
944 struct rb_node *node = rb_next(&pos->s_rb);
948 pos = to_sysfs_dirent(node);
949 } while (pos && pos->s_ns != ns);
953 static int sysfs_readdir(struct file *file, struct dir_context *ctx)
955 struct dentry *dentry = file->f_path.dentry;
956 struct sysfs_dirent *parent_sd = dentry->d_fsdata;
957 struct sysfs_dirent *pos = file->private_data;
958 const void *ns = NULL;
960 if (!dir_emit_dots(file, ctx))
962 mutex_lock(&sysfs_mutex);
964 if (parent_sd->s_flags & SYSFS_FLAG_HAS_NS)
965 ns = sysfs_info(dentry->d_sb)->ns;
967 for (pos = sysfs_dir_pos(ns, parent_sd, ctx->pos, pos);
969 pos = sysfs_dir_next_pos(ns, parent_sd, ctx->pos, pos)) {
970 const char *name = pos->s_name;
971 unsigned int type = dt_type(pos);
972 int len = strlen(name);
973 ino_t ino = pos->s_ino;
974 ctx->pos = pos->s_hash;
975 file->private_data = sysfs_get(pos);
977 mutex_unlock(&sysfs_mutex);
978 if (!dir_emit(ctx, name, len, ino, type))
980 mutex_lock(&sysfs_mutex);
982 mutex_unlock(&sysfs_mutex);
983 file->private_data = NULL;
988 static loff_t sysfs_dir_llseek(struct file *file, loff_t offset, int whence)
990 struct inode *inode = file_inode(file);
993 mutex_lock(&inode->i_mutex);
994 ret = generic_file_llseek(file, offset, whence);
995 mutex_unlock(&inode->i_mutex);
1000 const struct file_operations sysfs_dir_operations = {
1001 .read = generic_read_dir,
1002 .iterate = sysfs_readdir,
1003 .release = sysfs_dir_release,
1004 .llseek = sysfs_dir_llseek,