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 rb_to_kn(X) rb_entry((X), struct kernfs_node, 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 kernfs_node *kn)
50 if (hash != kn->s_hash)
51 return hash - kn->s_hash;
54 return strcmp(name, kn->s_name);
57 static int sysfs_sd_compare(const struct kernfs_node *left,
58 const struct kernfs_node *right)
60 return sysfs_name_compare(left->s_hash, left->s_name, left->s_ns,
65 * sysfs_link_sibling - link kernfs_node into sibling rbtree
66 * @kn: kernfs_node of interest
68 * Link @kn into its sibling rbtree which starts from
69 * @kn->s_parent->s_dir.children.
72 * mutex_lock(sysfs_mutex)
75 * 0 on susccess -EEXIST on failure.
77 static int sysfs_link_sibling(struct kernfs_node *kn)
79 struct rb_node **node = &kn->s_parent->s_dir.children.rb_node;
80 struct rb_node *parent = NULL;
82 if (sysfs_type(kn) == SYSFS_DIR)
83 kn->s_parent->s_dir.subdirs++;
86 struct kernfs_node *pos;
89 pos = rb_to_kn(*node);
91 result = sysfs_sd_compare(kn, 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(&kn->s_rb, parent, node);
101 rb_insert_color(&kn->s_rb, &kn->s_parent->s_dir.children);
106 * sysfs_unlink_sibling - unlink kernfs_node from sibling rbtree
107 * @kn: kernfs_node of interest
109 * Unlink @kn from its sibling rbtree which starts from
110 * kn->s_parent->s_dir.children.
113 * mutex_lock(sysfs_mutex)
115 static void sysfs_unlink_sibling(struct kernfs_node *kn)
117 if (sysfs_type(kn) == SYSFS_DIR)
118 kn->s_parent->s_dir.subdirs--;
120 rb_erase(&kn->s_rb, &kn->s_parent->s_dir.children);
124 * sysfs_get_active - get an active reference to kernfs_node
125 * @kn: kernfs_node to get an active reference to
127 * Get an active reference of @kn. This function is noop if @kn
131 * Pointer to @kn on success, NULL on failure.
133 struct kernfs_node *sysfs_get_active(struct kernfs_node *kn)
138 if (!atomic_inc_unless_negative(&kn->s_active))
141 if (kn->s_flags & SYSFS_FLAG_LOCKDEP)
142 rwsem_acquire_read(&kn->dep_map, 0, 1, _RET_IP_);
147 * sysfs_put_active - put an active reference to kernfs_node
148 * @kn: kernfs_node to put an active reference to
150 * Put an active reference to @kn. This function is noop if @kn
153 void sysfs_put_active(struct kernfs_node *kn)
160 if (kn->s_flags & SYSFS_FLAG_LOCKDEP)
161 rwsem_release(&kn->dep_map, 1, _RET_IP_);
162 v = atomic_dec_return(&kn->s_active);
163 if (likely(v != SD_DEACTIVATED_BIAS))
167 * atomic_dec_return() is a mb(), we'll always see the updated
170 complete(kn->u.completion);
174 * sysfs_deactivate - deactivate kernfs_node
175 * @kn: kernfs_node to deactivate
177 * Deny new active references and drain existing ones.
179 static void sysfs_deactivate(struct kernfs_node *kn)
181 DECLARE_COMPLETION_ONSTACK(wait);
184 BUG_ON(!(kn->s_flags & SYSFS_FLAG_REMOVED));
186 if (!(sysfs_type(kn) & SYSFS_ACTIVE_REF))
189 kn->u.completion = (void *)&wait;
191 rwsem_acquire(&kn->dep_map, 0, 0, _RET_IP_);
192 /* atomic_add_return() is a mb(), put_active() will always see
193 * the updated kn->u.completion.
195 v = atomic_add_return(SD_DEACTIVATED_BIAS, &kn->s_active);
197 if (v != SD_DEACTIVATED_BIAS) {
198 lock_contended(&kn->dep_map, _RET_IP_);
199 wait_for_completion(&wait);
202 lock_acquired(&kn->dep_map, _RET_IP_);
203 rwsem_release(&kn->dep_map, 1, _RET_IP_);
207 * kernfs_get - get a reference count on a kernfs_node
208 * @kn: the target kernfs_node
210 void kernfs_get(struct kernfs_node *kn)
213 WARN_ON(!atomic_read(&kn->s_count));
214 atomic_inc(&kn->s_count);
217 EXPORT_SYMBOL_GPL(kernfs_get);
220 * kernfs_put - put a reference count on a kernfs_node
221 * @kn: the target kernfs_node
223 * Put a reference count of @kn and destroy it if it reached zero.
225 void kernfs_put(struct kernfs_node *kn)
227 struct kernfs_node *parent;
228 struct kernfs_root *root;
230 if (!kn || !atomic_dec_and_test(&kn->s_count))
232 root = kernfs_root(kn);
234 /* Moving/renaming is always done while holding reference.
235 * kn->s_parent won't change beneath us.
237 parent = kn->s_parent;
239 WARN(!(kn->s_flags & SYSFS_FLAG_REMOVED),
240 "sysfs: free using entry: %s/%s\n",
241 parent ? parent->s_name : "", kn->s_name);
243 if (sysfs_type(kn) == SYSFS_KOBJ_LINK)
244 kernfs_put(kn->s_symlink.target_kn);
245 if (sysfs_type(kn) & SYSFS_COPY_NAME)
248 if (kn->s_iattr->ia_secdata)
249 security_release_secctx(kn->s_iattr->ia_secdata,
250 kn->s_iattr->ia_secdata_len);
251 simple_xattrs_free(&kn->s_iattr->xattrs);
254 ida_simple_remove(&root->ino_ida, kn->s_ino);
255 kmem_cache_free(sysfs_dir_cachep, kn);
259 if (atomic_dec_and_test(&kn->s_count))
262 /* just released the root kn, free @root too */
263 ida_destroy(&root->ino_ida);
267 EXPORT_SYMBOL_GPL(kernfs_put);
269 static int sysfs_dentry_delete(const struct dentry *dentry)
271 struct kernfs_node *kn = dentry->d_fsdata;
272 return !(kn && !(kn->s_flags & SYSFS_FLAG_REMOVED));
275 static int sysfs_dentry_revalidate(struct dentry *dentry, unsigned int flags)
277 struct kernfs_node *kn;
279 if (flags & LOOKUP_RCU)
282 kn = dentry->d_fsdata;
283 mutex_lock(&sysfs_mutex);
285 /* The sysfs dirent has been deleted */
286 if (kn->s_flags & SYSFS_FLAG_REMOVED)
289 /* The sysfs dirent has been moved? */
290 if (dentry->d_parent->d_fsdata != kn->s_parent)
293 /* The sysfs dirent has been renamed */
294 if (strcmp(dentry->d_name.name, kn->s_name) != 0)
297 /* The sysfs dirent has been moved to a different namespace */
298 if (kn->s_parent && kernfs_ns_enabled(kn->s_parent) &&
299 sysfs_info(dentry->d_sb)->ns != kn->s_ns)
302 mutex_unlock(&sysfs_mutex);
306 /* Remove the dentry from the dcache hashes.
307 * If this is a deleted dentry we use d_drop instead of d_delete
308 * so sysfs doesn't need to cope with negative dentries.
310 * If this is a dentry that has simply been renamed we
311 * use d_drop to remove it from the dcache lookup on its
312 * old parent. If this dentry persists later when a lookup
313 * is performed at its new name the dentry will be readded
314 * to the dcache hashes.
316 mutex_unlock(&sysfs_mutex);
318 /* If we have submounts we must allow the vfs caches
319 * to lie about the state of the filesystem to prevent
320 * leaks and other nasty things.
322 if (check_submounts_and_drop(dentry) != 0)
328 static void sysfs_dentry_release(struct dentry *dentry)
330 kernfs_put(dentry->d_fsdata);
333 const struct dentry_operations sysfs_dentry_ops = {
334 .d_revalidate = sysfs_dentry_revalidate,
335 .d_delete = sysfs_dentry_delete,
336 .d_release = sysfs_dentry_release,
339 struct kernfs_node *sysfs_new_dirent(struct kernfs_root *root,
340 const char *name, umode_t mode, int type)
342 char *dup_name = NULL;
343 struct kernfs_node *kn;
346 if (type & SYSFS_COPY_NAME) {
347 name = dup_name = kstrdup(name, GFP_KERNEL);
352 kn = kmem_cache_zalloc(sysfs_dir_cachep, GFP_KERNEL);
356 ret = ida_simple_get(&root->ino_ida, 1, 0, GFP_KERNEL);
361 atomic_set(&kn->s_count, 1);
362 atomic_set(&kn->s_active, 0);
366 kn->s_flags = type | SYSFS_FLAG_REMOVED;
371 kmem_cache_free(sysfs_dir_cachep, kn);
378 * sysfs_addrm_start - prepare for kernfs_node add/remove
379 * @acxt: pointer to sysfs_addrm_cxt to be used
381 * This function is called when the caller is about to add or remove
382 * kernfs_node. This function acquires sysfs_mutex. @acxt is used to
383 * keep and pass context to other addrm functions.
386 * Kernel thread context (may sleep). sysfs_mutex is locked on
389 void sysfs_addrm_start(struct sysfs_addrm_cxt *acxt)
390 __acquires(sysfs_mutex)
392 memset(acxt, 0, sizeof(*acxt));
394 mutex_lock(&sysfs_mutex);
398 * sysfs_add_one - add kernfs_node to parent without warning
399 * @acxt: addrm context to use
400 * @kn: kernfs_node to be added
401 * @parent: the parent kernfs_node to add @kn to
403 * Get @parent and set @kn->s_parent to it and increment nlink of
404 * the parent inode if @kn is a directory and link into the children
405 * list of the parent.
407 * This function should be called between calls to
408 * sysfs_addrm_start() and sysfs_addrm_finish() and should be
409 * passed the same @acxt as passed to sysfs_addrm_start().
412 * Determined by sysfs_addrm_start().
415 * 0 on success, -EEXIST if entry with the given name already
418 int sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct kernfs_node *kn,
419 struct kernfs_node *parent)
421 bool has_ns = kernfs_ns_enabled(parent);
422 struct sysfs_inode_attrs *ps_iattr;
425 if (has_ns != (bool)kn->s_ns) {
426 WARN(1, KERN_WARNING "sysfs: ns %s in '%s' for '%s'\n",
427 has_ns ? "required" : "invalid",
428 parent->s_name, kn->s_name);
432 if (sysfs_type(parent) != SYSFS_DIR)
435 kn->s_hash = sysfs_name_hash(kn->s_name, kn->s_ns);
436 kn->s_parent = parent;
439 ret = sysfs_link_sibling(kn);
443 /* Update timestamps on the parent */
444 ps_iattr = parent->s_iattr;
446 struct iattr *ps_iattrs = &ps_iattr->ia_iattr;
447 ps_iattrs->ia_ctime = ps_iattrs->ia_mtime = CURRENT_TIME;
450 /* Mark the entry added into directory tree */
451 kn->s_flags &= ~SYSFS_FLAG_REMOVED;
457 * sysfs_remove_one - remove kernfs_node from parent
458 * @acxt: addrm context to use
459 * @kn: kernfs_node to be removed
461 * Mark @kn removed and drop nlink of parent inode if @kn is a
462 * directory. @kn is unlinked from the children list.
464 * This function should be called between calls to
465 * sysfs_addrm_start() and sysfs_addrm_finish() and should be
466 * passed the same @acxt as passed to sysfs_addrm_start().
469 * Determined by sysfs_addrm_start().
471 static void sysfs_remove_one(struct sysfs_addrm_cxt *acxt,
472 struct kernfs_node *kn)
474 struct sysfs_inode_attrs *ps_iattr;
477 * Removal can be called multiple times on the same node. Only the
478 * first invocation is effective and puts the base ref.
480 if (kn->s_flags & SYSFS_FLAG_REMOVED)
484 sysfs_unlink_sibling(kn);
486 /* Update timestamps on the parent */
487 ps_iattr = kn->s_parent->s_iattr;
489 ps_iattr->ia_iattr.ia_ctime = CURRENT_TIME;
490 ps_iattr->ia_iattr.ia_mtime = CURRENT_TIME;
494 kn->s_flags |= SYSFS_FLAG_REMOVED;
495 kn->u.removed_list = acxt->removed;
500 * sysfs_addrm_finish - finish up kernfs_node add/remove
501 * @acxt: addrm context to finish up
503 * Finish up kernfs_node add/remove. Resources acquired by
504 * sysfs_addrm_start() are released and removed kernfs_nodes are
508 * sysfs_mutex is released.
510 void sysfs_addrm_finish(struct sysfs_addrm_cxt *acxt)
511 __releases(sysfs_mutex)
513 /* release resources acquired by sysfs_addrm_start() */
514 mutex_unlock(&sysfs_mutex);
516 /* kill removed kernfs_nodes */
517 while (acxt->removed) {
518 struct kernfs_node *kn = acxt->removed;
520 acxt->removed = kn->u.removed_list;
522 sysfs_deactivate(kn);
523 sysfs_unmap_bin_file(kn);
529 * kernfs_find_ns - find kernfs_node with the given name
530 * @parent: kernfs_node to search under
531 * @name: name to look for
532 * @ns: the namespace tag to use
534 * Look for kernfs_node with name @name under @parent. Returns pointer to
535 * the found kernfs_node on success, %NULL on failure.
537 static struct kernfs_node *kernfs_find_ns(struct kernfs_node *parent,
538 const unsigned char *name,
541 struct rb_node *node = parent->s_dir.children.rb_node;
542 bool has_ns = kernfs_ns_enabled(parent);
545 lockdep_assert_held(&sysfs_mutex);
547 if (has_ns != (bool)ns) {
548 WARN(1, KERN_WARNING "sysfs: ns %s in '%s' for '%s'\n",
549 has_ns ? "required" : "invalid",
550 parent->s_name, name);
554 hash = sysfs_name_hash(name, ns);
556 struct kernfs_node *kn;
560 result = sysfs_name_compare(hash, name, ns, kn);
562 node = node->rb_left;
564 node = node->rb_right;
572 * kernfs_find_and_get_ns - find and get kernfs_node with the given name
573 * @parent: kernfs_node to search under
574 * @name: name to look for
575 * @ns: the namespace tag to use
577 * Look for kernfs_node with name @name under @parent and get a reference
578 * if found. This function may sleep and returns pointer to the found
579 * kernfs_node on success, %NULL on failure.
581 struct kernfs_node *kernfs_find_and_get_ns(struct kernfs_node *parent,
582 const char *name, const void *ns)
584 struct kernfs_node *kn;
586 mutex_lock(&sysfs_mutex);
587 kn = kernfs_find_ns(parent, name, ns);
589 mutex_unlock(&sysfs_mutex);
593 EXPORT_SYMBOL_GPL(kernfs_find_and_get_ns);
596 * kernfs_create_root - create a new kernfs hierarchy
597 * @priv: opaque data associated with the new directory
599 * Returns the root of the new hierarchy on success, ERR_PTR() value on
602 struct kernfs_root *kernfs_create_root(void *priv)
604 struct kernfs_root *root;
605 struct kernfs_node *kn;
607 root = kzalloc(sizeof(*root), GFP_KERNEL);
609 return ERR_PTR(-ENOMEM);
611 ida_init(&root->ino_ida);
613 kn = sysfs_new_dirent(root, "", S_IFDIR | S_IRUGO | S_IXUGO, SYSFS_DIR);
615 ida_destroy(&root->ino_ida);
617 return ERR_PTR(-ENOMEM);
620 kn->s_flags &= ~SYSFS_FLAG_REMOVED;
622 kn->s_dir.root = root;
630 * kernfs_destroy_root - destroy a kernfs hierarchy
631 * @root: root of the hierarchy to destroy
633 * Destroy the hierarchy anchored at @root by removing all existing
634 * directories and destroying @root.
636 void kernfs_destroy_root(struct kernfs_root *root)
638 kernfs_remove(root->kn); /* will also free @root */
642 * kernfs_create_dir_ns - create a directory
643 * @parent: parent in which to create a new directory
644 * @name: name of the new directory
645 * @priv: opaque data associated with the new directory
646 * @ns: optional namespace tag of the directory
648 * Returns the created node on success, ERR_PTR() value on failure.
650 struct kernfs_node *kernfs_create_dir_ns(struct kernfs_node *parent,
651 const char *name, void *priv,
654 umode_t mode = S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO;
655 struct sysfs_addrm_cxt acxt;
656 struct kernfs_node *kn;
660 kn = sysfs_new_dirent(kernfs_root(parent), name, mode, SYSFS_DIR);
662 return ERR_PTR(-ENOMEM);
664 kn->s_dir.root = parent->s_dir.root;
669 sysfs_addrm_start(&acxt);
670 rc = sysfs_add_one(&acxt, kn, parent);
671 sysfs_addrm_finish(&acxt);
680 static struct dentry *sysfs_lookup(struct inode *dir, struct dentry *dentry,
683 struct dentry *ret = NULL;
684 struct kernfs_node *parent = dentry->d_parent->d_fsdata;
685 struct kernfs_node *kn;
687 const void *ns = NULL;
689 mutex_lock(&sysfs_mutex);
691 if (kernfs_ns_enabled(parent))
692 ns = sysfs_info(dir->i_sb)->ns;
694 kn = kernfs_find_ns(parent, dentry->d_name.name, ns);
698 ret = ERR_PTR(-ENOENT);
702 dentry->d_fsdata = kn;
704 /* attach dentry and inode */
705 inode = sysfs_get_inode(dir->i_sb, kn);
707 ret = ERR_PTR(-ENOMEM);
711 /* instantiate and hash dentry */
712 ret = d_materialise_unique(dentry, inode);
714 mutex_unlock(&sysfs_mutex);
718 const struct inode_operations sysfs_dir_inode_operations = {
719 .lookup = sysfs_lookup,
720 .permission = sysfs_permission,
721 .setattr = sysfs_setattr,
722 .getattr = sysfs_getattr,
723 .setxattr = sysfs_setxattr,
724 .removexattr = sysfs_removexattr,
725 .getxattr = sysfs_getxattr,
726 .listxattr = sysfs_listxattr,
729 static struct kernfs_node *sysfs_leftmost_descendant(struct kernfs_node *pos)
731 struct kernfs_node *last;
738 if (sysfs_type(pos) != SYSFS_DIR)
741 rbn = rb_first(&pos->s_dir.children);
752 * sysfs_next_descendant_post - find the next descendant for post-order walk
753 * @pos: the current position (%NULL to initiate traversal)
754 * @root: kernfs_node whose descendants to walk
756 * Find the next descendant to visit for post-order traversal of @root's
757 * descendants. @root is included in the iteration and the last node to be
760 static struct kernfs_node *sysfs_next_descendant_post(struct kernfs_node *pos,
761 struct kernfs_node *root)
765 lockdep_assert_held(&sysfs_mutex);
767 /* if first iteration, visit leftmost descendant which may be root */
769 return sysfs_leftmost_descendant(root);
771 /* if we visited @root, we're done */
775 /* if there's an unvisited sibling, visit its leftmost descendant */
776 rbn = rb_next(&pos->s_rb);
778 return sysfs_leftmost_descendant(rb_to_kn(rbn));
780 /* no sibling left, visit parent */
781 return pos->s_parent;
784 static void __kernfs_remove(struct sysfs_addrm_cxt *acxt,
785 struct kernfs_node *kn)
787 struct kernfs_node *pos, *next;
792 pr_debug("sysfs %s: removing\n", kn->s_name);
797 next = sysfs_next_descendant_post(pos, kn);
799 sysfs_remove_one(acxt, pos);
804 * kernfs_remove - remove a kernfs_node recursively
805 * @kn: the kernfs_node to remove
807 * Remove @kn along with all its subdirectories and files.
809 void kernfs_remove(struct kernfs_node *kn)
811 struct sysfs_addrm_cxt acxt;
813 sysfs_addrm_start(&acxt);
814 __kernfs_remove(&acxt, kn);
815 sysfs_addrm_finish(&acxt);
819 * kernfs_remove_by_name_ns - find a kernfs_node by name and remove it
820 * @parent: parent of the target
821 * @name: name of the kernfs_node to remove
822 * @ns: namespace tag of the kernfs_node to remove
824 * Look for the kernfs_node with @name and @ns under @parent and remove it.
825 * Returns 0 on success, -ENOENT if such entry doesn't exist.
827 int kernfs_remove_by_name_ns(struct kernfs_node *parent, const char *name,
830 struct sysfs_addrm_cxt acxt;
831 struct kernfs_node *kn;
834 WARN(1, KERN_WARNING "sysfs: can not remove '%s', no directory\n",
839 sysfs_addrm_start(&acxt);
841 kn = kernfs_find_ns(parent, name, ns);
843 __kernfs_remove(&acxt, kn);
845 sysfs_addrm_finish(&acxt);
854 * kernfs_rename_ns - move and rename a kernfs_node
856 * @new_parent: new parent to put @sd under
857 * @new_name: new name
858 * @new_ns: new namespace tag
860 int kernfs_rename_ns(struct kernfs_node *kn, struct kernfs_node *new_parent,
861 const char *new_name, const void *new_ns)
865 mutex_lock(&sysfs_mutex);
868 if ((kn->s_parent == new_parent) && (kn->s_ns == new_ns) &&
869 (strcmp(kn->s_name, new_name) == 0))
870 goto out; /* nothing to rename */
873 if (kernfs_find_ns(new_parent, new_name, new_ns))
876 /* rename kernfs_node */
877 if (strcmp(kn->s_name, new_name) != 0) {
879 new_name = kstrdup(new_name, GFP_KERNEL);
884 kn->s_name = new_name;
888 * Move to the appropriate place in the appropriate directories rbtree.
890 sysfs_unlink_sibling(kn);
891 kernfs_get(new_parent);
892 kernfs_put(kn->s_parent);
894 kn->s_hash = sysfs_name_hash(kn->s_name, kn->s_ns);
895 kn->s_parent = new_parent;
896 sysfs_link_sibling(kn);
900 mutex_unlock(&sysfs_mutex);
904 /* Relationship between s_mode and the DT_xxx types */
905 static inline unsigned char dt_type(struct kernfs_node *kn)
907 return (kn->s_mode >> 12) & 15;
910 static int sysfs_dir_release(struct inode *inode, struct file *filp)
912 kernfs_put(filp->private_data);
916 static struct kernfs_node *sysfs_dir_pos(const void *ns,
917 struct kernfs_node *parent, loff_t hash, struct kernfs_node *pos)
920 int valid = !(pos->s_flags & SYSFS_FLAG_REMOVED) &&
921 pos->s_parent == parent &&
927 if (!pos && (hash > 1) && (hash < INT_MAX)) {
928 struct rb_node *node = parent->s_dir.children.rb_node;
930 pos = rb_to_kn(node);
932 if (hash < pos->s_hash)
933 node = node->rb_left;
934 else if (hash > pos->s_hash)
935 node = node->rb_right;
940 /* Skip over entries in the wrong namespace */
941 while (pos && pos->s_ns != ns) {
942 struct rb_node *node = rb_next(&pos->s_rb);
946 pos = rb_to_kn(node);
951 static struct kernfs_node *sysfs_dir_next_pos(const void *ns,
952 struct kernfs_node *parent, ino_t ino, struct kernfs_node *pos)
954 pos = sysfs_dir_pos(ns, parent, ino, pos);
957 struct rb_node *node = rb_next(&pos->s_rb);
961 pos = rb_to_kn(node);
962 } while (pos && pos->s_ns != ns);
966 static int sysfs_readdir(struct file *file, struct dir_context *ctx)
968 struct dentry *dentry = file->f_path.dentry;
969 struct kernfs_node *parent = dentry->d_fsdata;
970 struct kernfs_node *pos = file->private_data;
971 const void *ns = NULL;
973 if (!dir_emit_dots(file, ctx))
975 mutex_lock(&sysfs_mutex);
977 if (kernfs_ns_enabled(parent))
978 ns = sysfs_info(dentry->d_sb)->ns;
980 for (pos = sysfs_dir_pos(ns, parent, ctx->pos, pos);
982 pos = sysfs_dir_next_pos(ns, parent, ctx->pos, pos)) {
983 const char *name = pos->s_name;
984 unsigned int type = dt_type(pos);
985 int len = strlen(name);
986 ino_t ino = pos->s_ino;
988 ctx->pos = pos->s_hash;
989 file->private_data = pos;
992 mutex_unlock(&sysfs_mutex);
993 if (!dir_emit(ctx, name, len, ino, type))
995 mutex_lock(&sysfs_mutex);
997 mutex_unlock(&sysfs_mutex);
998 file->private_data = NULL;
1003 static loff_t sysfs_dir_llseek(struct file *file, loff_t offset, int whence)
1005 struct inode *inode = file_inode(file);
1008 mutex_lock(&inode->i_mutex);
1009 ret = generic_file_llseek(file, offset, whence);
1010 mutex_unlock(&inode->i_mutex);
1015 const struct file_operations sysfs_dir_operations = {
1016 .read = generic_read_dir,
1017 .iterate = sysfs_readdir,
1018 .release = sysfs_dir_release,
1019 .llseek = sysfs_dir_llseek,