2 * fs/kernfs/dir.c - kernfs directory implementation
4 * Copyright (c) 2001-3 Patrick Mochel
5 * Copyright (c) 2007 SUSE Linux Products GmbH
6 * Copyright (c) 2007, 2013 Tejun Heo <tj@kernel.org>
8 * This file is released under the GPLv2.
12 #include <linux/namei.h>
13 #include <linux/idr.h>
14 #include <linux/slab.h>
15 #include <linux/security.h>
16 #include <linux/hash.h>
18 #include "kernfs-internal.h"
20 DEFINE_MUTEX(sysfs_mutex);
22 #define to_sysfs_dirent(X) rb_entry((X), struct sysfs_dirent, s_rb)
26 * @name: Null terminated string to hash
27 * @ns: Namespace tag to hash
29 * Returns 31 bit hash of ns + name (so it fits in an off_t )
31 static unsigned int sysfs_name_hash(const char *name, const void *ns)
33 unsigned long hash = init_name_hash();
34 unsigned int len = strlen(name);
36 hash = partial_name_hash(*name++, hash);
37 hash = (end_name_hash(hash) ^ hash_ptr((void *)ns, 31));
39 /* Reserve hash numbers 0, 1 and INT_MAX for magic directory entries */
47 static int sysfs_name_compare(unsigned int hash, const char *name,
48 const void *ns, const struct sysfs_dirent *sd)
50 if (hash != sd->s_hash)
51 return hash - sd->s_hash;
54 return strcmp(name, sd->s_name);
57 static int sysfs_sd_compare(const struct sysfs_dirent *left,
58 const struct sysfs_dirent *right)
60 return sysfs_name_compare(left->s_hash, left->s_name, left->s_ns,
65 * sysfs_link_sibling - link sysfs_dirent into sibling rbtree
66 * @sd: sysfs_dirent of interest
68 * Link @sd into its sibling rbtree which starts from
69 * sd->s_parent->s_dir.children.
72 * mutex_lock(sysfs_mutex)
75 * 0 on susccess -EEXIST on failure.
77 static int sysfs_link_sibling(struct sysfs_dirent *sd)
79 struct rb_node **node = &sd->s_parent->s_dir.children.rb_node;
80 struct rb_node *parent = NULL;
82 if (sysfs_type(sd) == SYSFS_DIR)
83 sd->s_parent->s_dir.subdirs++;
86 struct sysfs_dirent *pos;
89 pos = to_sysfs_dirent(*node);
91 result = sysfs_sd_compare(sd, pos);
93 node = &pos->s_rb.rb_left;
95 node = &pos->s_rb.rb_right;
99 /* add new node and rebalance the tree */
100 rb_link_node(&sd->s_rb, parent, node);
101 rb_insert_color(&sd->s_rb, &sd->s_parent->s_dir.children);
106 * sysfs_unlink_sibling - unlink sysfs_dirent from sibling rbtree
107 * @sd: sysfs_dirent of interest
109 * Unlink @sd from its sibling rbtree which starts from
110 * sd->s_parent->s_dir.children.
113 * mutex_lock(sysfs_mutex)
115 static void sysfs_unlink_sibling(struct sysfs_dirent *sd)
117 if (sysfs_type(sd) == SYSFS_DIR)
118 sd->s_parent->s_dir.subdirs--;
120 rb_erase(&sd->s_rb, &sd->s_parent->s_dir.children);
124 * sysfs_get_active - get an active reference to sysfs_dirent
125 * @sd: sysfs_dirent to get an active reference to
127 * Get an active reference of @sd. This function is noop if @sd
131 * Pointer to @sd on success, NULL on failure.
133 struct sysfs_dirent *sysfs_get_active(struct sysfs_dirent *sd)
138 if (!atomic_inc_unless_negative(&sd->s_active))
141 if (sd->s_flags & SYSFS_FLAG_LOCKDEP)
142 rwsem_acquire_read(&sd->dep_map, 0, 1, _RET_IP_);
147 * sysfs_put_active - put an active reference to sysfs_dirent
148 * @sd: sysfs_dirent to put an active reference to
150 * Put an active reference to @sd. This function is noop if @sd
153 void sysfs_put_active(struct sysfs_dirent *sd)
160 if (sd->s_flags & SYSFS_FLAG_LOCKDEP)
161 rwsem_release(&sd->dep_map, 1, _RET_IP_);
162 v = atomic_dec_return(&sd->s_active);
163 if (likely(v != SD_DEACTIVATED_BIAS))
166 /* atomic_dec_return() is a mb(), we'll always see the updated
169 complete(sd->u.completion);
173 * sysfs_deactivate - deactivate sysfs_dirent
174 * @sd: sysfs_dirent to deactivate
176 * Deny new active references and drain existing ones.
178 static void sysfs_deactivate(struct sysfs_dirent *sd)
180 DECLARE_COMPLETION_ONSTACK(wait);
183 BUG_ON(!(sd->s_flags & SYSFS_FLAG_REMOVED));
185 if (!(sysfs_type(sd) & SYSFS_ACTIVE_REF))
188 sd->u.completion = (void *)&wait;
190 rwsem_acquire(&sd->dep_map, 0, 0, _RET_IP_);
191 /* atomic_add_return() is a mb(), put_active() will always see
192 * the updated sd->u.completion.
194 v = atomic_add_return(SD_DEACTIVATED_BIAS, &sd->s_active);
196 if (v != SD_DEACTIVATED_BIAS) {
197 lock_contended(&sd->dep_map, _RET_IP_);
198 wait_for_completion(&wait);
201 lock_acquired(&sd->dep_map, _RET_IP_);
202 rwsem_release(&sd->dep_map, 1, _RET_IP_);
206 * kernfs_get - get a reference count on a sysfs_dirent
207 * @sd: the target sysfs_dirent
209 void kernfs_get(struct sysfs_dirent *sd)
212 WARN_ON(!atomic_read(&sd->s_count));
213 atomic_inc(&sd->s_count);
216 EXPORT_SYMBOL_GPL(kernfs_get);
219 * kernfs_put - put a reference count on a sysfs_dirent
220 * @sd: the target sysfs_dirent
222 * Put a reference count of @sd and destroy it if it reached zero.
224 void kernfs_put(struct sysfs_dirent *sd)
226 struct sysfs_dirent *parent_sd;
227 struct kernfs_root *root;
229 if (!sd || !atomic_dec_and_test(&sd->s_count))
231 root = kernfs_root(sd);
233 /* Moving/renaming is always done while holding reference.
234 * sd->s_parent won't change beneath us.
236 parent_sd = sd->s_parent;
238 WARN(!(sd->s_flags & SYSFS_FLAG_REMOVED),
239 "sysfs: free using entry: %s/%s\n",
240 parent_sd ? parent_sd->s_name : "", sd->s_name);
242 if (sysfs_type(sd) == SYSFS_KOBJ_LINK)
243 kernfs_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 ida_simple_remove(&root->ino_ida, sd->s_ino);
251 kmem_cache_free(sysfs_dir_cachep, sd);
255 if (atomic_dec_and_test(&sd->s_count))
258 /* just released the root sd, free @root too */
259 ida_destroy(&root->ino_ida);
263 EXPORT_SYMBOL_GPL(kernfs_put);
265 static int sysfs_dentry_delete(const struct dentry *dentry)
267 struct sysfs_dirent *sd = dentry->d_fsdata;
268 return !(sd && !(sd->s_flags & SYSFS_FLAG_REMOVED));
271 static int sysfs_dentry_revalidate(struct dentry *dentry, unsigned int flags)
273 struct sysfs_dirent *sd;
275 if (flags & LOOKUP_RCU)
278 sd = dentry->d_fsdata;
279 mutex_lock(&sysfs_mutex);
281 /* The sysfs dirent has been deleted */
282 if (sd->s_flags & SYSFS_FLAG_REMOVED)
285 /* The sysfs dirent has been moved? */
286 if (dentry->d_parent->d_fsdata != sd->s_parent)
289 /* The sysfs dirent has been renamed */
290 if (strcmp(dentry->d_name.name, sd->s_name) != 0)
293 /* The sysfs dirent has been moved to a different namespace */
294 if (sd->s_parent && kernfs_ns_enabled(sd->s_parent) &&
295 sysfs_info(dentry->d_sb)->ns != sd->s_ns)
298 mutex_unlock(&sysfs_mutex);
302 /* Remove the dentry from the dcache hashes.
303 * If this is a deleted dentry we use d_drop instead of d_delete
304 * so sysfs doesn't need to cope with negative dentries.
306 * If this is a dentry that has simply been renamed we
307 * use d_drop to remove it from the dcache lookup on its
308 * old parent. If this dentry persists later when a lookup
309 * is performed at its new name the dentry will be readded
310 * to the dcache hashes.
312 mutex_unlock(&sysfs_mutex);
314 /* If we have submounts we must allow the vfs caches
315 * to lie about the state of the filesystem to prevent
316 * leaks and other nasty things.
318 if (check_submounts_and_drop(dentry) != 0)
324 static void sysfs_dentry_release(struct dentry *dentry)
326 kernfs_put(dentry->d_fsdata);
329 const struct dentry_operations sysfs_dentry_ops = {
330 .d_revalidate = sysfs_dentry_revalidate,
331 .d_delete = sysfs_dentry_delete,
332 .d_release = sysfs_dentry_release,
335 struct sysfs_dirent *sysfs_new_dirent(struct kernfs_root *root,
336 const char *name, umode_t mode, int type)
338 char *dup_name = NULL;
339 struct sysfs_dirent *sd;
342 if (type & SYSFS_COPY_NAME) {
343 name = dup_name = kstrdup(name, GFP_KERNEL);
348 sd = kmem_cache_zalloc(sysfs_dir_cachep, GFP_KERNEL);
352 ret = ida_simple_get(&root->ino_ida, 1, 0, GFP_KERNEL);
357 atomic_set(&sd->s_count, 1);
358 atomic_set(&sd->s_active, 0);
362 sd->s_flags = type | SYSFS_FLAG_REMOVED;
367 kmem_cache_free(sysfs_dir_cachep, sd);
374 * sysfs_addrm_start - prepare for sysfs_dirent add/remove
375 * @acxt: pointer to sysfs_addrm_cxt to be used
377 * This function is called when the caller is about to add or remove
378 * sysfs_dirent. This function acquires sysfs_mutex. @acxt is used
379 * to keep and pass context to other addrm functions.
382 * Kernel thread context (may sleep). sysfs_mutex is locked on
385 void sysfs_addrm_start(struct sysfs_addrm_cxt *acxt)
386 __acquires(sysfs_mutex)
388 memset(acxt, 0, sizeof(*acxt));
390 mutex_lock(&sysfs_mutex);
394 * sysfs_add_one - add sysfs_dirent to parent without warning
395 * @acxt: addrm context to use
396 * @sd: sysfs_dirent to be added
397 * @parent_sd: the parent sysfs_dirent to add @sd to
399 * Get @parent_sd and set @sd->s_parent to it and increment nlink of
400 * the parent inode if @sd is a directory and link into the children
401 * list of the parent.
403 * This function should be called between calls to
404 * sysfs_addrm_start() and sysfs_addrm_finish() and should be
405 * passed the same @acxt as passed to sysfs_addrm_start().
408 * Determined by sysfs_addrm_start().
411 * 0 on success, -EEXIST if entry with the given name already
414 int sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd,
415 struct sysfs_dirent *parent_sd)
417 bool has_ns = kernfs_ns_enabled(parent_sd);
418 struct sysfs_inode_attrs *ps_iattr;
421 if (has_ns != (bool)sd->s_ns) {
422 WARN(1, KERN_WARNING "sysfs: ns %s in '%s' for '%s'\n",
423 has_ns ? "required" : "invalid",
424 parent_sd->s_name, sd->s_name);
428 if (sysfs_type(parent_sd) != SYSFS_DIR)
431 sd->s_hash = sysfs_name_hash(sd->s_name, sd->s_ns);
432 sd->s_parent = parent_sd;
433 kernfs_get(parent_sd);
435 ret = sysfs_link_sibling(sd);
439 /* Update timestamps on the parent */
440 ps_iattr = parent_sd->s_iattr;
442 struct iattr *ps_iattrs = &ps_iattr->ia_iattr;
443 ps_iattrs->ia_ctime = ps_iattrs->ia_mtime = CURRENT_TIME;
446 /* Mark the entry added into directory tree */
447 sd->s_flags &= ~SYSFS_FLAG_REMOVED;
453 * sysfs_remove_one - remove sysfs_dirent from parent
454 * @acxt: addrm context to use
455 * @sd: sysfs_dirent to be removed
457 * Mark @sd removed and drop nlink of parent inode if @sd is a
458 * directory. @sd is unlinked from the children list.
460 * This function should be called between calls to
461 * sysfs_addrm_start() and sysfs_addrm_finish() and should be
462 * passed the same @acxt as passed to sysfs_addrm_start().
465 * Determined by sysfs_addrm_start().
467 static void sysfs_remove_one(struct sysfs_addrm_cxt *acxt,
468 struct sysfs_dirent *sd)
470 struct sysfs_inode_attrs *ps_iattr;
473 * Removal can be called multiple times on the same node. Only the
474 * first invocation is effective and puts the base ref.
476 if (sd->s_flags & SYSFS_FLAG_REMOVED)
480 sysfs_unlink_sibling(sd);
482 /* Update timestamps on the parent */
483 ps_iattr = sd->s_parent->s_iattr;
485 ps_iattr->ia_iattr.ia_ctime = CURRENT_TIME;
486 ps_iattr->ia_iattr.ia_mtime = CURRENT_TIME;
490 sd->s_flags |= SYSFS_FLAG_REMOVED;
491 sd->u.removed_list = acxt->removed;
496 * sysfs_addrm_finish - finish up sysfs_dirent add/remove
497 * @acxt: addrm context to finish up
499 * Finish up sysfs_dirent add/remove. Resources acquired by
500 * sysfs_addrm_start() are released and removed sysfs_dirents are
504 * sysfs_mutex is released.
506 void sysfs_addrm_finish(struct sysfs_addrm_cxt *acxt)
507 __releases(sysfs_mutex)
509 /* release resources acquired by sysfs_addrm_start() */
510 mutex_unlock(&sysfs_mutex);
512 /* kill removed sysfs_dirents */
513 while (acxt->removed) {
514 struct sysfs_dirent *sd = acxt->removed;
516 acxt->removed = sd->u.removed_list;
518 sysfs_deactivate(sd);
519 sysfs_unmap_bin_file(sd);
525 * kernfs_find_ns - find sysfs_dirent with the given name
526 * @parent: sysfs_dirent to search under
527 * @name: name to look for
528 * @ns: the namespace tag to use
530 * Look for sysfs_dirent with name @name under @parent. Returns pointer to
531 * the found sysfs_dirent on success, %NULL on failure.
533 static struct sysfs_dirent *kernfs_find_ns(struct sysfs_dirent *parent,
534 const unsigned char *name,
537 struct rb_node *node = parent->s_dir.children.rb_node;
538 bool has_ns = kernfs_ns_enabled(parent);
541 lockdep_assert_held(&sysfs_mutex);
543 if (has_ns != (bool)ns) {
544 WARN(1, KERN_WARNING "sysfs: ns %s in '%s' for '%s'\n",
545 has_ns ? "required" : "invalid",
546 parent->s_name, name);
550 hash = sysfs_name_hash(name, ns);
552 struct sysfs_dirent *sd;
555 sd = to_sysfs_dirent(node);
556 result = sysfs_name_compare(hash, name, ns, sd);
558 node = node->rb_left;
560 node = node->rb_right;
568 * kernfs_find_and_get_ns - find and get sysfs_dirent with the given name
569 * @parent: sysfs_dirent to search under
570 * @name: name to look for
571 * @ns: the namespace tag to use
573 * Look for sysfs_dirent with name @name under @parent and get a reference
574 * if found. This function may sleep and returns pointer to the found
575 * sysfs_dirent on success, %NULL on failure.
577 struct sysfs_dirent *kernfs_find_and_get_ns(struct sysfs_dirent *parent,
578 const char *name, const void *ns)
580 struct sysfs_dirent *sd;
582 mutex_lock(&sysfs_mutex);
583 sd = kernfs_find_ns(parent, name, ns);
585 mutex_unlock(&sysfs_mutex);
589 EXPORT_SYMBOL_GPL(kernfs_find_and_get_ns);
592 * kernfs_create_root - create a new kernfs hierarchy
593 * @priv: opaque data associated with the new directory
595 * Returns the root of the new hierarchy on success, ERR_PTR() value on
598 struct kernfs_root *kernfs_create_root(void *priv)
600 struct kernfs_root *root;
601 struct sysfs_dirent *sd;
603 root = kzalloc(sizeof(*root), GFP_KERNEL);
605 return ERR_PTR(-ENOMEM);
607 ida_init(&root->ino_ida);
609 sd = sysfs_new_dirent(root, "", S_IFDIR | S_IRUGO | S_IXUGO, SYSFS_DIR);
611 ida_destroy(&root->ino_ida);
613 return ERR_PTR(-ENOMEM);
616 sd->s_flags &= ~SYSFS_FLAG_REMOVED;
618 sd->s_dir.root = root;
626 * kernfs_destroy_root - destroy a kernfs hierarchy
627 * @root: root of the hierarchy to destroy
629 * Destroy the hierarchy anchored at @root by removing all existing
630 * directories and destroying @root.
632 void kernfs_destroy_root(struct kernfs_root *root)
634 kernfs_remove(root->sd); /* will also free @root */
638 * kernfs_create_dir_ns - create a directory
639 * @parent: parent in which to create a new directory
640 * @name: name of the new directory
641 * @priv: opaque data associated with the new directory
642 * @ns: optional namespace tag of the directory
644 * Returns the created node on success, ERR_PTR() value on failure.
646 struct sysfs_dirent *kernfs_create_dir_ns(struct sysfs_dirent *parent,
647 const char *name, void *priv,
650 umode_t mode = S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO;
651 struct sysfs_addrm_cxt acxt;
652 struct sysfs_dirent *sd;
656 sd = sysfs_new_dirent(kernfs_root(parent), name, mode, SYSFS_DIR);
658 return ERR_PTR(-ENOMEM);
660 sd->s_dir.root = parent->s_dir.root;
665 sysfs_addrm_start(&acxt);
666 rc = sysfs_add_one(&acxt, sd, parent);
667 sysfs_addrm_finish(&acxt);
676 static struct dentry *sysfs_lookup(struct inode *dir, struct dentry *dentry,
679 struct dentry *ret = NULL;
680 struct dentry *parent = dentry->d_parent;
681 struct sysfs_dirent *parent_sd = parent->d_fsdata;
682 struct sysfs_dirent *sd;
684 const void *ns = NULL;
686 mutex_lock(&sysfs_mutex);
688 if (kernfs_ns_enabled(parent_sd))
689 ns = sysfs_info(dir->i_sb)->ns;
691 sd = kernfs_find_ns(parent_sd, dentry->d_name.name, ns);
695 ret = ERR_PTR(-ENOENT);
699 dentry->d_fsdata = sd;
701 /* attach dentry and inode */
702 inode = sysfs_get_inode(dir->i_sb, sd);
704 ret = ERR_PTR(-ENOMEM);
708 /* instantiate and hash dentry */
709 ret = d_materialise_unique(dentry, inode);
711 mutex_unlock(&sysfs_mutex);
715 const struct inode_operations sysfs_dir_inode_operations = {
716 .lookup = sysfs_lookup,
717 .permission = sysfs_permission,
718 .setattr = sysfs_setattr,
719 .getattr = sysfs_getattr,
720 .setxattr = sysfs_setxattr,
723 static struct sysfs_dirent *sysfs_leftmost_descendant(struct sysfs_dirent *pos)
725 struct sysfs_dirent *last;
732 if (sysfs_type(pos) != SYSFS_DIR)
735 rbn = rb_first(&pos->s_dir.children);
739 pos = to_sysfs_dirent(rbn);
746 * sysfs_next_descendant_post - find the next descendant for post-order walk
747 * @pos: the current position (%NULL to initiate traversal)
748 * @root: sysfs_dirent whose descendants to walk
750 * Find the next descendant to visit for post-order traversal of @root's
751 * descendants. @root is included in the iteration and the last node to be
754 static struct sysfs_dirent *sysfs_next_descendant_post(struct sysfs_dirent *pos,
755 struct sysfs_dirent *root)
759 lockdep_assert_held(&sysfs_mutex);
761 /* if first iteration, visit leftmost descendant which may be root */
763 return sysfs_leftmost_descendant(root);
765 /* if we visited @root, we're done */
769 /* if there's an unvisited sibling, visit its leftmost descendant */
770 rbn = rb_next(&pos->s_rb);
772 return sysfs_leftmost_descendant(to_sysfs_dirent(rbn));
774 /* no sibling left, visit parent */
775 return pos->s_parent;
778 static void __kernfs_remove(struct sysfs_addrm_cxt *acxt,
779 struct sysfs_dirent *sd)
781 struct sysfs_dirent *pos, *next;
786 pr_debug("sysfs %s: removing\n", sd->s_name);
791 next = sysfs_next_descendant_post(pos, sd);
793 sysfs_remove_one(acxt, pos);
798 * kernfs_remove - remove a sysfs_dirent recursively
799 * @sd: the sysfs_dirent to remove
801 * Remove @sd along with all its subdirectories and files.
803 void kernfs_remove(struct sysfs_dirent *sd)
805 struct sysfs_addrm_cxt acxt;
807 sysfs_addrm_start(&acxt);
808 __kernfs_remove(&acxt, sd);
809 sysfs_addrm_finish(&acxt);
813 * kernfs_remove_by_name_ns - find a sysfs_dirent by name and remove it
814 * @dir_sd: parent of the target
815 * @name: name of the sysfs_dirent to remove
816 * @ns: namespace tag of the sysfs_dirent to remove
818 * Look for the sysfs_dirent with @name and @ns under @dir_sd and remove
819 * it. Returns 0 on success, -ENOENT if such entry doesn't exist.
821 int kernfs_remove_by_name_ns(struct sysfs_dirent *dir_sd, const char *name,
824 struct sysfs_addrm_cxt acxt;
825 struct sysfs_dirent *sd;
828 WARN(1, KERN_WARNING "sysfs: can not remove '%s', no directory\n",
833 sysfs_addrm_start(&acxt);
835 sd = kernfs_find_ns(dir_sd, name, ns);
837 __kernfs_remove(&acxt, sd);
839 sysfs_addrm_finish(&acxt);
848 * kernfs_rename_ns - move and rename a kernfs_node
850 * @new_parent: new parent to put @sd under
851 * @new_name: new name
852 * @new_ns: new namespace tag
854 int kernfs_rename_ns(struct sysfs_dirent *sd, struct sysfs_dirent *new_parent,
855 const char *new_name, const void *new_ns)
859 mutex_lock(&sysfs_mutex);
862 if ((sd->s_parent == new_parent) && (sd->s_ns == new_ns) &&
863 (strcmp(sd->s_name, new_name) == 0))
864 goto out; /* nothing to rename */
867 if (kernfs_find_ns(new_parent, new_name, new_ns))
870 /* rename sysfs_dirent */
871 if (strcmp(sd->s_name, new_name) != 0) {
873 new_name = kstrdup(new_name, GFP_KERNEL);
878 sd->s_name = new_name;
882 * Move to the appropriate place in the appropriate directories rbtree.
884 sysfs_unlink_sibling(sd);
885 kernfs_get(new_parent);
886 kernfs_put(sd->s_parent);
888 sd->s_hash = sysfs_name_hash(sd->s_name, sd->s_ns);
889 sd->s_parent = new_parent;
890 sysfs_link_sibling(sd);
894 mutex_unlock(&sysfs_mutex);
898 /* Relationship between s_mode and the DT_xxx types */
899 static inline unsigned char dt_type(struct sysfs_dirent *sd)
901 return (sd->s_mode >> 12) & 15;
904 static int sysfs_dir_release(struct inode *inode, struct file *filp)
906 kernfs_put(filp->private_data);
910 static struct sysfs_dirent *sysfs_dir_pos(const void *ns,
911 struct sysfs_dirent *parent_sd, loff_t hash, struct sysfs_dirent *pos)
914 int valid = !(pos->s_flags & SYSFS_FLAG_REMOVED) &&
915 pos->s_parent == parent_sd &&
921 if (!pos && (hash > 1) && (hash < INT_MAX)) {
922 struct rb_node *node = parent_sd->s_dir.children.rb_node;
924 pos = to_sysfs_dirent(node);
926 if (hash < pos->s_hash)
927 node = node->rb_left;
928 else if (hash > pos->s_hash)
929 node = node->rb_right;
934 /* Skip over entries in the wrong namespace */
935 while (pos && pos->s_ns != ns) {
936 struct rb_node *node = rb_next(&pos->s_rb);
940 pos = to_sysfs_dirent(node);
945 static struct sysfs_dirent *sysfs_dir_next_pos(const void *ns,
946 struct sysfs_dirent *parent_sd, ino_t ino, struct sysfs_dirent *pos)
948 pos = sysfs_dir_pos(ns, parent_sd, ino, pos);
951 struct rb_node *node = rb_next(&pos->s_rb);
955 pos = to_sysfs_dirent(node);
956 } while (pos && pos->s_ns != ns);
960 static int sysfs_readdir(struct file *file, struct dir_context *ctx)
962 struct dentry *dentry = file->f_path.dentry;
963 struct sysfs_dirent *parent_sd = dentry->d_fsdata;
964 struct sysfs_dirent *pos = file->private_data;
965 const void *ns = NULL;
967 if (!dir_emit_dots(file, ctx))
969 mutex_lock(&sysfs_mutex);
971 if (kernfs_ns_enabled(parent_sd))
972 ns = sysfs_info(dentry->d_sb)->ns;
974 for (pos = sysfs_dir_pos(ns, parent_sd, ctx->pos, pos);
976 pos = sysfs_dir_next_pos(ns, parent_sd, ctx->pos, pos)) {
977 const char *name = pos->s_name;
978 unsigned int type = dt_type(pos);
979 int len = strlen(name);
980 ino_t ino = pos->s_ino;
982 ctx->pos = pos->s_hash;
983 file->private_data = pos;
986 mutex_unlock(&sysfs_mutex);
987 if (!dir_emit(ctx, name, len, ino, type))
989 mutex_lock(&sysfs_mutex);
991 mutex_unlock(&sysfs_mutex);
992 file->private_data = NULL;
997 static loff_t sysfs_dir_llseek(struct file *file, loff_t offset, int whence)
999 struct inode *inode = file_inode(file);
1002 mutex_lock(&inode->i_mutex);
1003 ret = generic_file_llseek(file, offset, whence);
1004 mutex_unlock(&inode->i_mutex);
1009 const struct file_operations sysfs_dir_operations = {
1010 .read = generic_read_dir,
1011 .iterate = sysfs_readdir,
1012 .release = sysfs_dir_release,
1013 .llseek = sysfs_dir_llseek,