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;
48 BUG_ON(sd->s_sibling);
50 /* Store directory entries in order by ino. This allows
51 * readdir to properly restart without having to add a
52 * cursor into the s_dir.children list.
54 for (pos = &parent_sd->s_dir.children; *pos; pos = &(*pos)->s_sibling) {
55 if (sd->s_ino < (*pos)->s_ino)
63 * sysfs_unlink_sibling - unlink sysfs_dirent from sibling list
64 * @sd: sysfs_dirent of interest
66 * Unlink @sd from its sibling list which starts from
67 * sd->s_parent->s_dir.children.
70 * mutex_lock(sysfs_mutex)
72 static void sysfs_unlink_sibling(struct sysfs_dirent *sd)
74 struct sysfs_dirent **pos;
76 for (pos = &sd->s_parent->s_dir.children; *pos;
77 pos = &(*pos)->s_sibling) {
87 * sysfs_get_active - get an active reference to sysfs_dirent
88 * @sd: sysfs_dirent to get an active reference to
90 * Get an active reference of @sd. This function is noop if @sd
94 * Pointer to @sd on success, NULL on failure.
96 struct sysfs_dirent *sysfs_get_active(struct sysfs_dirent *sd)
104 v = atomic_read(&sd->s_active);
108 t = atomic_cmpxchg(&sd->s_active, v, v + 1);
109 if (likely(t == v)) {
110 rwsem_acquire_read(&sd->dep_map, 0, 1, _RET_IP_);
121 * sysfs_put_active - put an active reference to sysfs_dirent
122 * @sd: sysfs_dirent to put an active reference to
124 * Put an active reference to @sd. This function is noop if @sd
127 void sysfs_put_active(struct sysfs_dirent *sd)
129 struct completion *cmpl;
135 rwsem_release(&sd->dep_map, 1, _RET_IP_);
136 v = atomic_dec_return(&sd->s_active);
137 if (likely(v != SD_DEACTIVATED_BIAS))
140 /* atomic_dec_return() is a mb(), we'll always see the updated
143 cmpl = (void *)sd->s_sibling;
148 * sysfs_deactivate - deactivate sysfs_dirent
149 * @sd: sysfs_dirent to deactivate
151 * Deny new active references and drain existing ones.
153 static void sysfs_deactivate(struct sysfs_dirent *sd)
155 DECLARE_COMPLETION_ONSTACK(wait);
158 BUG_ON(sd->s_sibling || !(sd->s_flags & SYSFS_FLAG_REMOVED));
160 if (!(sysfs_type(sd) & SYSFS_ACTIVE_REF))
163 sd->s_sibling = (void *)&wait;
165 rwsem_acquire(&sd->dep_map, 0, 0, _RET_IP_);
166 /* atomic_add_return() is a mb(), put_active() will always see
167 * the updated sd->s_sibling.
169 v = atomic_add_return(SD_DEACTIVATED_BIAS, &sd->s_active);
171 if (v != SD_DEACTIVATED_BIAS) {
172 lock_contended(&sd->dep_map, _RET_IP_);
173 wait_for_completion(&wait);
176 sd->s_sibling = NULL;
178 lock_acquired(&sd->dep_map, _RET_IP_);
179 rwsem_release(&sd->dep_map, 1, _RET_IP_);
182 static int sysfs_alloc_ino(ino_t *pino)
187 spin_lock(&sysfs_ino_lock);
188 rc = ida_get_new_above(&sysfs_ino_ida, 2, &ino);
189 spin_unlock(&sysfs_ino_lock);
192 if (ida_pre_get(&sysfs_ino_ida, GFP_KERNEL))
201 static void sysfs_free_ino(ino_t ino)
203 spin_lock(&sysfs_ino_lock);
204 ida_remove(&sysfs_ino_ida, ino);
205 spin_unlock(&sysfs_ino_lock);
208 void release_sysfs_dirent(struct sysfs_dirent * sd)
210 struct sysfs_dirent *parent_sd;
213 /* Moving/renaming is always done while holding reference.
214 * sd->s_parent won't change beneath us.
216 parent_sd = sd->s_parent;
218 if (sysfs_type(sd) == SYSFS_KOBJ_LINK)
219 sysfs_put(sd->s_symlink.target_sd);
220 if (sysfs_type(sd) & SYSFS_COPY_NAME)
222 if (sd->s_iattr && sd->s_iattr->ia_secdata)
223 security_release_secctx(sd->s_iattr->ia_secdata,
224 sd->s_iattr->ia_secdata_len);
226 sysfs_free_ino(sd->s_ino);
227 kmem_cache_free(sysfs_dir_cachep, sd);
230 if (sd && atomic_dec_and_test(&sd->s_count))
234 static int sysfs_dentry_delete(const struct dentry *dentry)
236 struct sysfs_dirent *sd = dentry->d_fsdata;
237 return !!(sd->s_flags & SYSFS_FLAG_REMOVED);
240 static int sysfs_dentry_revalidate(struct dentry *dentry, struct nameidata *nd)
242 struct sysfs_dirent *sd;
245 if (nd->flags & LOOKUP_RCU)
248 sd = dentry->d_fsdata;
249 mutex_lock(&sysfs_mutex);
251 /* The sysfs dirent has been deleted */
252 if (sd->s_flags & SYSFS_FLAG_REMOVED)
255 /* The sysfs dirent has been moved? */
256 if (dentry->d_parent->d_fsdata != sd->s_parent)
259 /* The sysfs dirent has been renamed */
260 if (strcmp(dentry->d_name.name, sd->s_name) != 0)
263 mutex_unlock(&sysfs_mutex);
267 /* Remove the dentry from the dcache hashes.
268 * If this is a deleted dentry we use d_drop instead of d_delete
269 * so sysfs doesn't need to cope with negative dentries.
271 * If this is a dentry that has simply been renamed we
272 * use d_drop to remove it from the dcache lookup on its
273 * old parent. If this dentry persists later when a lookup
274 * is performed at its new name the dentry will be readded
275 * to the dcache hashes.
277 is_dir = (sysfs_type(sd) == SYSFS_DIR);
278 mutex_unlock(&sysfs_mutex);
280 /* If we have submounts we must allow the vfs caches
281 * to lie about the state of the filesystem to prevent
282 * leaks and other nasty things.
284 if (have_submounts(dentry))
286 shrink_dcache_parent(dentry);
292 static void sysfs_dentry_iput(struct dentry *dentry, struct inode *inode)
294 struct sysfs_dirent * sd = dentry->d_fsdata;
300 static const struct dentry_operations sysfs_dentry_ops = {
301 .d_revalidate = sysfs_dentry_revalidate,
302 .d_delete = sysfs_dentry_delete,
303 .d_iput = sysfs_dentry_iput,
306 struct sysfs_dirent *sysfs_new_dirent(const char *name, umode_t mode, int type)
308 char *dup_name = NULL;
309 struct sysfs_dirent *sd;
311 if (type & SYSFS_COPY_NAME) {
312 name = dup_name = kstrdup(name, GFP_KERNEL);
317 sd = kmem_cache_zalloc(sysfs_dir_cachep, GFP_KERNEL);
321 if (sysfs_alloc_ino(&sd->s_ino))
324 atomic_set(&sd->s_count, 1);
325 atomic_set(&sd->s_active, 0);
334 kmem_cache_free(sysfs_dir_cachep, sd);
341 * sysfs_addrm_start - prepare for sysfs_dirent add/remove
342 * @acxt: pointer to sysfs_addrm_cxt to be used
343 * @parent_sd: parent sysfs_dirent
345 * This function is called when the caller is about to add or
346 * remove sysfs_dirent under @parent_sd. This function acquires
347 * sysfs_mutex. @acxt is used to keep and pass context to
348 * other addrm functions.
351 * Kernel thread context (may sleep). sysfs_mutex is locked on
354 void sysfs_addrm_start(struct sysfs_addrm_cxt *acxt,
355 struct sysfs_dirent *parent_sd)
357 memset(acxt, 0, sizeof(*acxt));
358 acxt->parent_sd = parent_sd;
360 mutex_lock(&sysfs_mutex);
364 * __sysfs_add_one - add sysfs_dirent to parent without warning
365 * @acxt: addrm context to use
366 * @sd: sysfs_dirent to be added
368 * Get @acxt->parent_sd and set sd->s_parent to it and increment
369 * nlink of parent inode if @sd is a directory and link into the
370 * children list of the parent.
372 * This function should be called between calls to
373 * sysfs_addrm_start() and sysfs_addrm_finish() and should be
374 * passed the same @acxt as passed to sysfs_addrm_start().
377 * Determined by sysfs_addrm_start().
380 * 0 on success, -EEXIST if entry with the given name already
383 int __sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd)
385 struct sysfs_inode_attrs *ps_iattr;
387 if (!!sysfs_ns_type(acxt->parent_sd) != !!sd->s_ns) {
388 WARN(1, KERN_WARNING "sysfs: ns %s in '%s' for '%s'\n",
389 sysfs_ns_type(acxt->parent_sd)? "required": "invalid",
390 acxt->parent_sd->s_name, sd->s_name);
394 if (sysfs_find_dirent(acxt->parent_sd, sd->s_ns, sd->s_name))
397 sd->s_parent = sysfs_get(acxt->parent_sd);
399 sysfs_link_sibling(sd);
401 /* Update timestamps on the parent */
402 ps_iattr = acxt->parent_sd->s_iattr;
404 struct iattr *ps_iattrs = &ps_iattr->ia_iattr;
405 ps_iattrs->ia_ctime = ps_iattrs->ia_mtime = CURRENT_TIME;
412 * sysfs_pathname - return full path to sysfs dirent
413 * @sd: sysfs_dirent whose path we want
414 * @path: caller allocated buffer
416 * Gives the name "/" to the sysfs_root entry; any path returned
417 * is relative to wherever sysfs is mounted.
419 * XXX: does no error checking on @path size
421 static char *sysfs_pathname(struct sysfs_dirent *sd, char *path)
424 sysfs_pathname(sd->s_parent, path);
427 strcat(path, sd->s_name);
432 * sysfs_add_one - add sysfs_dirent to parent
433 * @acxt: addrm context to use
434 * @sd: sysfs_dirent to be added
436 * Get @acxt->parent_sd and set sd->s_parent to it and increment
437 * nlink of parent inode if @sd is a directory and link into the
438 * children list of the parent.
440 * This function should be called between calls to
441 * sysfs_addrm_start() and sysfs_addrm_finish() and should be
442 * passed the same @acxt as passed to sysfs_addrm_start().
445 * Determined by sysfs_addrm_start().
448 * 0 on success, -EEXIST if entry with the given name already
451 int sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd)
455 ret = __sysfs_add_one(acxt, sd);
456 if (ret == -EEXIST) {
457 char *path = kzalloc(PATH_MAX, GFP_KERNEL);
459 "sysfs: cannot create duplicate filename '%s'\n",
460 (path == NULL) ? sd->s_name :
461 strcat(strcat(sysfs_pathname(acxt->parent_sd, path), "/"),
470 * sysfs_remove_one - remove sysfs_dirent from parent
471 * @acxt: addrm context to use
472 * @sd: sysfs_dirent to be removed
474 * Mark @sd removed and drop nlink of parent inode if @sd is a
475 * directory. @sd is unlinked from the children list.
477 * This function should be called between calls to
478 * sysfs_addrm_start() and sysfs_addrm_finish() and should be
479 * passed the same @acxt as passed to sysfs_addrm_start().
482 * Determined by sysfs_addrm_start().
484 void sysfs_remove_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd)
486 struct sysfs_inode_attrs *ps_iattr;
488 BUG_ON(sd->s_flags & SYSFS_FLAG_REMOVED);
490 sysfs_unlink_sibling(sd);
492 /* Update timestamps on the parent */
493 ps_iattr = acxt->parent_sd->s_iattr;
495 struct iattr *ps_iattrs = &ps_iattr->ia_iattr;
496 ps_iattrs->ia_ctime = ps_iattrs->ia_mtime = CURRENT_TIME;
499 sd->s_flags |= SYSFS_FLAG_REMOVED;
500 sd->s_sibling = acxt->removed;
505 * sysfs_addrm_finish - finish up sysfs_dirent add/remove
506 * @acxt: addrm context to finish up
508 * Finish up sysfs_dirent add/remove. Resources acquired by
509 * sysfs_addrm_start() are released and removed sysfs_dirents are
513 * sysfs_mutex is released.
515 void sysfs_addrm_finish(struct sysfs_addrm_cxt *acxt)
517 /* release resources acquired by sysfs_addrm_start() */
518 mutex_unlock(&sysfs_mutex);
520 /* kill removed sysfs_dirents */
521 while (acxt->removed) {
522 struct sysfs_dirent *sd = acxt->removed;
524 acxt->removed = sd->s_sibling;
525 sd->s_sibling = NULL;
527 sysfs_deactivate(sd);
534 * sysfs_find_dirent - find sysfs_dirent with the given name
535 * @parent_sd: sysfs_dirent to search under
536 * @name: name to look for
538 * Look for sysfs_dirent with name @name under @parent_sd.
541 * mutex_lock(sysfs_mutex)
544 * Pointer to sysfs_dirent if found, NULL if not.
546 struct sysfs_dirent *sysfs_find_dirent(struct sysfs_dirent *parent_sd,
548 const unsigned char *name)
550 struct sysfs_dirent *sd;
552 if (!!sysfs_ns_type(parent_sd) != !!ns) {
553 WARN(1, KERN_WARNING "sysfs: ns %s in '%s' for '%s'\n",
554 sysfs_ns_type(parent_sd)? "required": "invalid",
555 parent_sd->s_name, name);
559 for (sd = parent_sd->s_dir.children; sd; sd = sd->s_sibling) {
562 if (!strcmp(sd->s_name, name))
569 * sysfs_get_dirent - find and get sysfs_dirent with the given name
570 * @parent_sd: sysfs_dirent to search under
571 * @name: name to look for
573 * Look for sysfs_dirent with name @name under @parent_sd and get
577 * Kernel thread context (may sleep). Grabs sysfs_mutex.
580 * Pointer to sysfs_dirent if found, NULL if not.
582 struct sysfs_dirent *sysfs_get_dirent(struct sysfs_dirent *parent_sd,
584 const unsigned char *name)
586 struct sysfs_dirent *sd;
588 mutex_lock(&sysfs_mutex);
589 sd = sysfs_find_dirent(parent_sd, ns, name);
591 mutex_unlock(&sysfs_mutex);
595 EXPORT_SYMBOL_GPL(sysfs_get_dirent);
597 static int create_dir(struct kobject *kobj, struct sysfs_dirent *parent_sd,
598 enum kobj_ns_type type, const void *ns, const char *name,
599 struct sysfs_dirent **p_sd)
601 umode_t mode = S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO;
602 struct sysfs_addrm_cxt acxt;
603 struct sysfs_dirent *sd;
607 sd = sysfs_new_dirent(name, mode, SYSFS_DIR);
611 sd->s_flags |= (type << SYSFS_NS_TYPE_SHIFT);
613 sd->s_dir.kobj = kobj;
616 sysfs_addrm_start(&acxt, parent_sd);
617 rc = sysfs_add_one(&acxt, sd);
618 sysfs_addrm_finish(&acxt);
628 int sysfs_create_subdir(struct kobject *kobj, const char *name,
629 struct sysfs_dirent **p_sd)
631 return create_dir(kobj, kobj->sd,
632 KOBJ_NS_TYPE_NONE, NULL, name, p_sd);
636 * sysfs_read_ns_type: return associated ns_type
637 * @kobj: the kobject being queried
639 * Each kobject can be tagged with exactly one namespace type
640 * (i.e. network or user). Return the ns_type associated with
643 static enum kobj_ns_type sysfs_read_ns_type(struct kobject *kobj)
645 const struct kobj_ns_type_operations *ops;
646 enum kobj_ns_type type;
648 ops = kobj_child_ns_ops(kobj);
650 return KOBJ_NS_TYPE_NONE;
653 BUG_ON(type <= KOBJ_NS_TYPE_NONE);
654 BUG_ON(type >= KOBJ_NS_TYPES);
655 BUG_ON(!kobj_ns_type_registered(type));
661 * sysfs_create_dir - create a directory for an object.
662 * @kobj: object we're creating directory for.
664 int sysfs_create_dir(struct kobject * kobj)
666 enum kobj_ns_type type;
667 struct sysfs_dirent *parent_sd, *sd;
668 const void *ns = NULL;
674 parent_sd = kobj->parent->sd;
676 parent_sd = &sysfs_root;
678 if (sysfs_ns_type(parent_sd))
679 ns = kobj->ktype->namespace(kobj);
680 type = sysfs_read_ns_type(kobj);
682 error = create_dir(kobj, parent_sd, type, ns, kobject_name(kobj), &sd);
688 static struct dentry * sysfs_lookup(struct inode *dir, struct dentry *dentry,
689 struct nameidata *nd)
691 struct dentry *ret = NULL;
692 struct dentry *parent = dentry->d_parent;
693 struct sysfs_dirent *parent_sd = parent->d_fsdata;
694 struct sysfs_dirent *sd;
696 enum kobj_ns_type type;
699 mutex_lock(&sysfs_mutex);
701 type = sysfs_ns_type(parent_sd);
702 ns = sysfs_info(dir->i_sb)->ns[type];
704 sd = sysfs_find_dirent(parent_sd, ns, dentry->d_name.name);
708 ret = ERR_PTR(-ENOENT);
712 /* attach dentry and inode */
713 inode = sysfs_get_inode(dir->i_sb, sd);
715 ret = ERR_PTR(-ENOMEM);
719 /* instantiate and hash dentry */
720 ret = d_find_alias(inode);
722 d_set_d_op(dentry, &sysfs_dentry_ops);
723 dentry->d_fsdata = sysfs_get(sd);
724 d_add(dentry, inode);
731 mutex_unlock(&sysfs_mutex);
735 const struct inode_operations sysfs_dir_inode_operations = {
736 .lookup = sysfs_lookup,
737 .permission = sysfs_permission,
738 .setattr = sysfs_setattr,
739 .getattr = sysfs_getattr,
740 .setxattr = sysfs_setxattr,
743 static void remove_dir(struct sysfs_dirent *sd)
745 struct sysfs_addrm_cxt acxt;
747 sysfs_addrm_start(&acxt, sd->s_parent);
748 sysfs_remove_one(&acxt, sd);
749 sysfs_addrm_finish(&acxt);
752 void sysfs_remove_subdir(struct sysfs_dirent *sd)
758 static void __sysfs_remove_dir(struct sysfs_dirent *dir_sd)
760 struct sysfs_addrm_cxt acxt;
761 struct sysfs_dirent **pos;
766 pr_debug("sysfs %s: removing dir\n", dir_sd->s_name);
767 sysfs_addrm_start(&acxt, dir_sd);
768 pos = &dir_sd->s_dir.children;
770 struct sysfs_dirent *sd = *pos;
772 if (sysfs_type(sd) != SYSFS_DIR)
773 sysfs_remove_one(&acxt, sd);
775 pos = &(*pos)->s_sibling;
777 sysfs_addrm_finish(&acxt);
783 * sysfs_remove_dir - remove an object's directory.
786 * The only thing special about this is that we remove any files in
787 * the directory before we remove the directory, and we've inlined
788 * what used to be sysfs_rmdir() below, instead of calling separately.
791 void sysfs_remove_dir(struct kobject * kobj)
793 struct sysfs_dirent *sd = kobj->sd;
795 spin_lock(&sysfs_assoc_lock);
797 spin_unlock(&sysfs_assoc_lock);
799 __sysfs_remove_dir(sd);
802 int sysfs_rename(struct sysfs_dirent *sd,
803 struct sysfs_dirent *new_parent_sd, const void *new_ns,
804 const char *new_name)
806 const char *dup_name = NULL;
809 mutex_lock(&sysfs_mutex);
812 if ((sd->s_parent == new_parent_sd) && (sd->s_ns == new_ns) &&
813 (strcmp(sd->s_name, new_name) == 0))
814 goto out; /* nothing to rename */
817 if (sysfs_find_dirent(new_parent_sd, new_ns, new_name))
820 /* rename sysfs_dirent */
821 if (strcmp(sd->s_name, new_name) != 0) {
823 new_name = dup_name = kstrdup(new_name, GFP_KERNEL);
827 dup_name = sd->s_name;
828 sd->s_name = new_name;
831 /* Remove from old parent's list and insert into new parent's list. */
832 if (sd->s_parent != new_parent_sd) {
833 sysfs_unlink_sibling(sd);
834 sysfs_get(new_parent_sd);
835 sysfs_put(sd->s_parent);
836 sd->s_parent = new_parent_sd;
837 sysfs_link_sibling(sd);
843 mutex_unlock(&sysfs_mutex);
848 int sysfs_rename_dir(struct kobject *kobj, const char *new_name)
850 struct sysfs_dirent *parent_sd = kobj->sd->s_parent;
851 const void *new_ns = NULL;
853 if (sysfs_ns_type(parent_sd))
854 new_ns = kobj->ktype->namespace(kobj);
856 return sysfs_rename(kobj->sd, parent_sd, new_ns, new_name);
859 int sysfs_move_dir(struct kobject *kobj, struct kobject *new_parent_kobj)
861 struct sysfs_dirent *sd = kobj->sd;
862 struct sysfs_dirent *new_parent_sd;
863 const void *new_ns = NULL;
865 BUG_ON(!sd->s_parent);
866 if (sysfs_ns_type(sd->s_parent))
867 new_ns = kobj->ktype->namespace(kobj);
868 new_parent_sd = new_parent_kobj && new_parent_kobj->sd ?
869 new_parent_kobj->sd : &sysfs_root;
871 return sysfs_rename(sd, new_parent_sd, new_ns, sd->s_name);
874 /* Relationship between s_mode and the DT_xxx types */
875 static inline unsigned char dt_type(struct sysfs_dirent *sd)
877 return (sd->s_mode >> 12) & 15;
880 static int sysfs_dir_release(struct inode *inode, struct file *filp)
882 sysfs_put(filp->private_data);
886 static struct sysfs_dirent *sysfs_dir_pos(const void *ns,
887 struct sysfs_dirent *parent_sd, ino_t ino, struct sysfs_dirent *pos)
890 int valid = !(pos->s_flags & SYSFS_FLAG_REMOVED) &&
891 pos->s_parent == parent_sd &&
897 if (!pos && (ino > 1) && (ino < INT_MAX)) {
898 pos = parent_sd->s_dir.children;
899 while (pos && (ino > pos->s_ino))
900 pos = pos->s_sibling;
902 while (pos && pos->s_ns != ns)
903 pos = pos->s_sibling;
907 static struct sysfs_dirent *sysfs_dir_next_pos(const void *ns,
908 struct sysfs_dirent *parent_sd, ino_t ino, struct sysfs_dirent *pos)
910 pos = sysfs_dir_pos(ns, parent_sd, ino, pos);
912 pos = pos->s_sibling;
913 while (pos && pos->s_ns != ns)
914 pos = pos->s_sibling;
918 static int sysfs_readdir(struct file * filp, void * dirent, filldir_t filldir)
920 struct dentry *dentry = filp->f_path.dentry;
921 struct sysfs_dirent * parent_sd = dentry->d_fsdata;
922 struct sysfs_dirent *pos = filp->private_data;
923 enum kobj_ns_type type;
927 type = sysfs_ns_type(parent_sd);
928 ns = sysfs_info(dentry->d_sb)->ns[type];
930 if (filp->f_pos == 0) {
931 ino = parent_sd->s_ino;
932 if (filldir(dirent, ".", 1, filp->f_pos, ino, DT_DIR) == 0)
935 if (filp->f_pos == 1) {
936 if (parent_sd->s_parent)
937 ino = parent_sd->s_parent->s_ino;
939 ino = parent_sd->s_ino;
940 if (filldir(dirent, "..", 2, filp->f_pos, ino, DT_DIR) == 0)
943 mutex_lock(&sysfs_mutex);
944 for (pos = sysfs_dir_pos(ns, parent_sd, filp->f_pos, pos);
946 pos = sysfs_dir_next_pos(ns, parent_sd, filp->f_pos, pos)) {
956 filp->private_data = sysfs_get(pos);
958 mutex_unlock(&sysfs_mutex);
959 ret = filldir(dirent, name, len, filp->f_pos, ino, type);
960 mutex_lock(&sysfs_mutex);
964 mutex_unlock(&sysfs_mutex);
965 if ((filp->f_pos > 1) && !pos) { /* EOF */
966 filp->f_pos = INT_MAX;
967 filp->private_data = NULL;
973 const struct file_operations sysfs_dir_operations = {
974 .read = generic_read_dir,
975 .readdir = sysfs_readdir,
976 .release = sysfs_dir_release,
977 .llseek = generic_file_llseek,