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 if (sysfs_type(sd) == SYSFS_DIR)
51 parent_sd->s_dir.subdirs++;
53 /* Store directory entries in order by ino. This allows
54 * readdir to properly restart without having to add a
55 * cursor into the s_dir.children list.
57 for (pos = &parent_sd->s_dir.children; *pos; pos = &(*pos)->s_sibling) {
58 if (sd->s_ino < (*pos)->s_ino)
66 * sysfs_unlink_sibling - unlink sysfs_dirent from sibling list
67 * @sd: sysfs_dirent of interest
69 * Unlink @sd from its sibling list which starts from
70 * sd->s_parent->s_dir.children.
73 * mutex_lock(sysfs_mutex)
75 static void sysfs_unlink_sibling(struct sysfs_dirent *sd)
77 struct sysfs_dirent **pos;
79 if (sysfs_type(sd) == SYSFS_DIR)
80 sd->s_parent->s_dir.subdirs--;
82 for (pos = &sd->s_parent->s_dir.children; *pos;
83 pos = &(*pos)->s_sibling) {
93 * sysfs_get_active - get an active reference to sysfs_dirent
94 * @sd: sysfs_dirent to get an active reference to
96 * Get an active reference of @sd. This function is noop if @sd
100 * Pointer to @sd on success, NULL on failure.
102 struct sysfs_dirent *sysfs_get_active(struct sysfs_dirent *sd)
110 v = atomic_read(&sd->s_active);
114 t = atomic_cmpxchg(&sd->s_active, v, v + 1);
115 if (likely(t == v)) {
116 rwsem_acquire_read(&sd->dep_map, 0, 1, _RET_IP_);
127 * sysfs_put_active - put an active reference to sysfs_dirent
128 * @sd: sysfs_dirent to put an active reference to
130 * Put an active reference to @sd. This function is noop if @sd
133 void sysfs_put_active(struct sysfs_dirent *sd)
135 struct completion *cmpl;
141 rwsem_release(&sd->dep_map, 1, _RET_IP_);
142 v = atomic_dec_return(&sd->s_active);
143 if (likely(v != SD_DEACTIVATED_BIAS))
146 /* atomic_dec_return() is a mb(), we'll always see the updated
149 cmpl = (void *)sd->s_sibling;
154 * sysfs_deactivate - deactivate sysfs_dirent
155 * @sd: sysfs_dirent to deactivate
157 * Deny new active references and drain existing ones.
159 static void sysfs_deactivate(struct sysfs_dirent *sd)
161 DECLARE_COMPLETION_ONSTACK(wait);
164 BUG_ON(sd->s_sibling || !(sd->s_flags & SYSFS_FLAG_REMOVED));
166 if (!(sysfs_type(sd) & SYSFS_ACTIVE_REF))
169 sd->s_sibling = (void *)&wait;
171 rwsem_acquire(&sd->dep_map, 0, 0, _RET_IP_);
172 /* atomic_add_return() is a mb(), put_active() will always see
173 * the updated sd->s_sibling.
175 v = atomic_add_return(SD_DEACTIVATED_BIAS, &sd->s_active);
177 if (v != SD_DEACTIVATED_BIAS) {
178 lock_contended(&sd->dep_map, _RET_IP_);
179 wait_for_completion(&wait);
182 sd->s_sibling = NULL;
184 lock_acquired(&sd->dep_map, _RET_IP_);
185 rwsem_release(&sd->dep_map, 1, _RET_IP_);
188 static int sysfs_alloc_ino(ino_t *pino)
193 spin_lock(&sysfs_ino_lock);
194 rc = ida_get_new_above(&sysfs_ino_ida, 2, &ino);
195 spin_unlock(&sysfs_ino_lock);
198 if (ida_pre_get(&sysfs_ino_ida, GFP_KERNEL))
207 static void sysfs_free_ino(ino_t ino)
209 spin_lock(&sysfs_ino_lock);
210 ida_remove(&sysfs_ino_ida, ino);
211 spin_unlock(&sysfs_ino_lock);
214 void release_sysfs_dirent(struct sysfs_dirent * sd)
216 struct sysfs_dirent *parent_sd;
219 /* Moving/renaming is always done while holding reference.
220 * sd->s_parent won't change beneath us.
222 parent_sd = sd->s_parent;
224 if (sysfs_type(sd) == SYSFS_KOBJ_LINK)
225 sysfs_put(sd->s_symlink.target_sd);
226 if (sysfs_type(sd) & SYSFS_COPY_NAME)
228 if (sd->s_iattr && sd->s_iattr->ia_secdata)
229 security_release_secctx(sd->s_iattr->ia_secdata,
230 sd->s_iattr->ia_secdata_len);
232 sysfs_free_ino(sd->s_ino);
233 kmem_cache_free(sysfs_dir_cachep, sd);
236 if (sd && atomic_dec_and_test(&sd->s_count))
240 static int sysfs_dentry_delete(const struct dentry *dentry)
242 struct sysfs_dirent *sd = dentry->d_fsdata;
243 return !!(sd->s_flags & SYSFS_FLAG_REMOVED);
246 static int sysfs_dentry_revalidate(struct dentry *dentry, struct nameidata *nd)
248 struct sysfs_dirent *sd;
251 if (nd->flags & LOOKUP_RCU)
254 sd = dentry->d_fsdata;
255 mutex_lock(&sysfs_mutex);
257 /* The sysfs dirent has been deleted */
258 if (sd->s_flags & SYSFS_FLAG_REMOVED)
261 /* The sysfs dirent has been moved? */
262 if (dentry->d_parent->d_fsdata != sd->s_parent)
265 /* The sysfs dirent has been renamed */
266 if (strcmp(dentry->d_name.name, sd->s_name) != 0)
269 mutex_unlock(&sysfs_mutex);
273 /* Remove the dentry from the dcache hashes.
274 * If this is a deleted dentry we use d_drop instead of d_delete
275 * so sysfs doesn't need to cope with negative dentries.
277 * If this is a dentry that has simply been renamed we
278 * use d_drop to remove it from the dcache lookup on its
279 * old parent. If this dentry persists later when a lookup
280 * is performed at its new name the dentry will be readded
281 * to the dcache hashes.
283 is_dir = (sysfs_type(sd) == SYSFS_DIR);
284 mutex_unlock(&sysfs_mutex);
286 /* If we have submounts we must allow the vfs caches
287 * to lie about the state of the filesystem to prevent
288 * leaks and other nasty things.
290 if (have_submounts(dentry))
292 shrink_dcache_parent(dentry);
298 static void sysfs_dentry_iput(struct dentry *dentry, struct inode *inode)
300 struct sysfs_dirent * sd = dentry->d_fsdata;
306 static const struct dentry_operations sysfs_dentry_ops = {
307 .d_revalidate = sysfs_dentry_revalidate,
308 .d_delete = sysfs_dentry_delete,
309 .d_iput = sysfs_dentry_iput,
312 struct sysfs_dirent *sysfs_new_dirent(const char *name, umode_t mode, int type)
314 char *dup_name = NULL;
315 struct sysfs_dirent *sd;
317 if (type & SYSFS_COPY_NAME) {
318 name = dup_name = kstrdup(name, GFP_KERNEL);
323 sd = kmem_cache_zalloc(sysfs_dir_cachep, GFP_KERNEL);
327 if (sysfs_alloc_ino(&sd->s_ino))
330 atomic_set(&sd->s_count, 1);
331 atomic_set(&sd->s_active, 0);
340 kmem_cache_free(sysfs_dir_cachep, sd);
347 * sysfs_addrm_start - prepare for sysfs_dirent add/remove
348 * @acxt: pointer to sysfs_addrm_cxt to be used
349 * @parent_sd: parent sysfs_dirent
351 * This function is called when the caller is about to add or
352 * remove sysfs_dirent under @parent_sd. This function acquires
353 * sysfs_mutex. @acxt is used to keep and pass context to
354 * other addrm functions.
357 * Kernel thread context (may sleep). sysfs_mutex is locked on
360 void sysfs_addrm_start(struct sysfs_addrm_cxt *acxt,
361 struct sysfs_dirent *parent_sd)
363 memset(acxt, 0, sizeof(*acxt));
364 acxt->parent_sd = parent_sd;
366 mutex_lock(&sysfs_mutex);
370 * __sysfs_add_one - add sysfs_dirent to parent without warning
371 * @acxt: addrm context to use
372 * @sd: sysfs_dirent to be added
374 * Get @acxt->parent_sd and set sd->s_parent to it and increment
375 * nlink of parent inode if @sd is a directory and link into the
376 * children list of the parent.
378 * This function should be called between calls to
379 * sysfs_addrm_start() and sysfs_addrm_finish() and should be
380 * passed the same @acxt as passed to sysfs_addrm_start().
383 * Determined by sysfs_addrm_start().
386 * 0 on success, -EEXIST if entry with the given name already
389 int __sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd)
391 struct sysfs_inode_attrs *ps_iattr;
393 if (sysfs_find_dirent(acxt->parent_sd, sd->s_ns, sd->s_name))
396 sd->s_parent = sysfs_get(acxt->parent_sd);
398 sysfs_link_sibling(sd);
400 /* Update timestamps on the parent */
401 ps_iattr = acxt->parent_sd->s_iattr;
403 struct iattr *ps_iattrs = &ps_iattr->ia_iattr;
404 ps_iattrs->ia_ctime = ps_iattrs->ia_mtime = CURRENT_TIME;
411 * sysfs_pathname - return full path to sysfs dirent
412 * @sd: sysfs_dirent whose path we want
413 * @path: caller allocated buffer
415 * Gives the name "/" to the sysfs_root entry; any path returned
416 * is relative to wherever sysfs is mounted.
418 * XXX: does no error checking on @path size
420 static char *sysfs_pathname(struct sysfs_dirent *sd, char *path)
423 sysfs_pathname(sd->s_parent, path);
426 strcat(path, sd->s_name);
431 * sysfs_add_one - add sysfs_dirent to parent
432 * @acxt: addrm context to use
433 * @sd: sysfs_dirent to be added
435 * Get @acxt->parent_sd and set sd->s_parent to it and increment
436 * nlink of parent inode if @sd is a directory and link into the
437 * children list of the parent.
439 * This function should be called between calls to
440 * sysfs_addrm_start() and sysfs_addrm_finish() and should be
441 * passed the same @acxt as passed to sysfs_addrm_start().
444 * Determined by sysfs_addrm_start().
447 * 0 on success, -EEXIST if entry with the given name already
450 int sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd)
454 ret = __sysfs_add_one(acxt, sd);
455 if (ret == -EEXIST) {
456 char *path = kzalloc(PATH_MAX, GFP_KERNEL);
458 "sysfs: cannot create duplicate filename '%s'\n",
459 (path == NULL) ? sd->s_name :
460 strcat(strcat(sysfs_pathname(acxt->parent_sd, path), "/"),
469 * sysfs_remove_one - remove sysfs_dirent from parent
470 * @acxt: addrm context to use
471 * @sd: sysfs_dirent to be removed
473 * Mark @sd removed and drop nlink of parent inode if @sd is a
474 * directory. @sd is unlinked from the children list.
476 * This function should be called between calls to
477 * sysfs_addrm_start() and sysfs_addrm_finish() and should be
478 * passed the same @acxt as passed to sysfs_addrm_start().
481 * Determined by sysfs_addrm_start().
483 void sysfs_remove_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd)
485 struct sysfs_inode_attrs *ps_iattr;
487 BUG_ON(sd->s_flags & SYSFS_FLAG_REMOVED);
489 sysfs_unlink_sibling(sd);
491 /* Update timestamps on the parent */
492 ps_iattr = acxt->parent_sd->s_iattr;
494 struct iattr *ps_iattrs = &ps_iattr->ia_iattr;
495 ps_iattrs->ia_ctime = ps_iattrs->ia_mtime = CURRENT_TIME;
498 sd->s_flags |= SYSFS_FLAG_REMOVED;
499 sd->s_sibling = acxt->removed;
504 * sysfs_addrm_finish - finish up sysfs_dirent add/remove
505 * @acxt: addrm context to finish up
507 * Finish up sysfs_dirent add/remove. Resources acquired by
508 * sysfs_addrm_start() are released and removed sysfs_dirents are
512 * sysfs_mutex is released.
514 void sysfs_addrm_finish(struct sysfs_addrm_cxt *acxt)
516 /* release resources acquired by sysfs_addrm_start() */
517 mutex_unlock(&sysfs_mutex);
519 /* kill removed sysfs_dirents */
520 while (acxt->removed) {
521 struct sysfs_dirent *sd = acxt->removed;
523 acxt->removed = sd->s_sibling;
524 sd->s_sibling = NULL;
526 sysfs_deactivate(sd);
533 * sysfs_find_dirent - find sysfs_dirent with the given name
534 * @parent_sd: sysfs_dirent to search under
535 * @name: name to look for
537 * Look for sysfs_dirent with name @name under @parent_sd.
540 * mutex_lock(sysfs_mutex)
543 * Pointer to sysfs_dirent if found, NULL if not.
545 struct sysfs_dirent *sysfs_find_dirent(struct sysfs_dirent *parent_sd,
547 const unsigned char *name)
549 struct sysfs_dirent *sd;
551 for (sd = parent_sd->s_dir.children; sd; sd = sd->s_sibling) {
552 if (ns && sd->s_ns && (sd->s_ns != ns))
554 if (!strcmp(sd->s_name, name))
561 * sysfs_get_dirent - find and get sysfs_dirent with the given name
562 * @parent_sd: sysfs_dirent to search under
563 * @name: name to look for
565 * Look for sysfs_dirent with name @name under @parent_sd and get
569 * Kernel thread context (may sleep). Grabs sysfs_mutex.
572 * Pointer to sysfs_dirent if found, NULL if not.
574 struct sysfs_dirent *sysfs_get_dirent(struct sysfs_dirent *parent_sd,
576 const unsigned char *name)
578 struct sysfs_dirent *sd;
580 mutex_lock(&sysfs_mutex);
581 sd = sysfs_find_dirent(parent_sd, ns, name);
583 mutex_unlock(&sysfs_mutex);
587 EXPORT_SYMBOL_GPL(sysfs_get_dirent);
589 static int create_dir(struct kobject *kobj, struct sysfs_dirent *parent_sd,
590 enum kobj_ns_type type, const void *ns, const char *name,
591 struct sysfs_dirent **p_sd)
593 umode_t mode = S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO;
594 struct sysfs_addrm_cxt acxt;
595 struct sysfs_dirent *sd;
599 sd = sysfs_new_dirent(name, mode, SYSFS_DIR);
603 sd->s_flags |= (type << SYSFS_NS_TYPE_SHIFT);
605 sd->s_dir.kobj = kobj;
608 sysfs_addrm_start(&acxt, parent_sd);
609 rc = sysfs_add_one(&acxt, sd);
610 sysfs_addrm_finish(&acxt);
620 int sysfs_create_subdir(struct kobject *kobj, const char *name,
621 struct sysfs_dirent **p_sd)
623 return create_dir(kobj, kobj->sd,
624 KOBJ_NS_TYPE_NONE, NULL, name, p_sd);
628 * sysfs_read_ns_type: return associated ns_type
629 * @kobj: the kobject being queried
631 * Each kobject can be tagged with exactly one namespace type
632 * (i.e. network or user). Return the ns_type associated with
635 static enum kobj_ns_type sysfs_read_ns_type(struct kobject *kobj)
637 const struct kobj_ns_type_operations *ops;
638 enum kobj_ns_type type;
640 ops = kobj_child_ns_ops(kobj);
642 return KOBJ_NS_TYPE_NONE;
645 BUG_ON(type <= KOBJ_NS_TYPE_NONE);
646 BUG_ON(type >= KOBJ_NS_TYPES);
647 BUG_ON(!kobj_ns_type_registered(type));
653 * sysfs_create_dir - create a directory for an object.
654 * @kobj: object we're creating directory for.
656 int sysfs_create_dir(struct kobject * kobj)
658 enum kobj_ns_type type;
659 struct sysfs_dirent *parent_sd, *sd;
660 const void *ns = NULL;
666 parent_sd = kobj->parent->sd;
668 parent_sd = &sysfs_root;
670 if (sysfs_ns_type(parent_sd))
671 ns = kobj->ktype->namespace(kobj);
672 type = sysfs_read_ns_type(kobj);
674 error = create_dir(kobj, parent_sd, type, ns, kobject_name(kobj), &sd);
680 static struct dentry * sysfs_lookup(struct inode *dir, struct dentry *dentry,
681 struct nameidata *nd)
683 struct dentry *ret = NULL;
684 struct dentry *parent = dentry->d_parent;
685 struct sysfs_dirent *parent_sd = parent->d_fsdata;
686 struct sysfs_dirent *sd;
688 enum kobj_ns_type type;
691 mutex_lock(&sysfs_mutex);
693 type = sysfs_ns_type(parent_sd);
694 ns = sysfs_info(dir->i_sb)->ns[type];
696 sd = sysfs_find_dirent(parent_sd, ns, dentry->d_name.name);
700 ret = ERR_PTR(-ENOENT);
704 /* attach dentry and inode */
705 inode = sysfs_get_inode(dir->i_sb, sd);
707 ret = ERR_PTR(-ENOMEM);
711 /* instantiate and hash dentry */
712 ret = d_find_alias(inode);
714 d_set_d_op(dentry, &sysfs_dentry_ops);
715 dentry->d_fsdata = sysfs_get(sd);
716 d_add(dentry, inode);
723 mutex_unlock(&sysfs_mutex);
727 const struct inode_operations sysfs_dir_inode_operations = {
728 .lookup = sysfs_lookup,
729 .permission = sysfs_permission,
730 .setattr = sysfs_setattr,
731 .getattr = sysfs_getattr,
732 .setxattr = sysfs_setxattr,
735 static void remove_dir(struct sysfs_dirent *sd)
737 struct sysfs_addrm_cxt acxt;
739 sysfs_addrm_start(&acxt, sd->s_parent);
740 sysfs_remove_one(&acxt, sd);
741 sysfs_addrm_finish(&acxt);
744 void sysfs_remove_subdir(struct sysfs_dirent *sd)
750 static void __sysfs_remove_dir(struct sysfs_dirent *dir_sd)
752 struct sysfs_addrm_cxt acxt;
753 struct sysfs_dirent **pos;
758 pr_debug("sysfs %s: removing dir\n", dir_sd->s_name);
759 sysfs_addrm_start(&acxt, dir_sd);
760 pos = &dir_sd->s_dir.children;
762 struct sysfs_dirent *sd = *pos;
764 if (sysfs_type(sd) != SYSFS_DIR)
765 sysfs_remove_one(&acxt, sd);
767 pos = &(*pos)->s_sibling;
769 sysfs_addrm_finish(&acxt);
775 * sysfs_remove_dir - remove an object's directory.
778 * The only thing special about this is that we remove any files in
779 * the directory before we remove the directory, and we've inlined
780 * what used to be sysfs_rmdir() below, instead of calling separately.
783 void sysfs_remove_dir(struct kobject * kobj)
785 struct sysfs_dirent *sd = kobj->sd;
787 spin_lock(&sysfs_assoc_lock);
789 spin_unlock(&sysfs_assoc_lock);
791 __sysfs_remove_dir(sd);
794 int sysfs_rename(struct sysfs_dirent *sd,
795 struct sysfs_dirent *new_parent_sd, const void *new_ns,
796 const char *new_name)
798 const char *dup_name = NULL;
801 mutex_lock(&sysfs_mutex);
804 if ((sd->s_parent == new_parent_sd) && (sd->s_ns == new_ns) &&
805 (strcmp(sd->s_name, new_name) == 0))
806 goto out; /* nothing to rename */
809 if (sysfs_find_dirent(new_parent_sd, new_ns, new_name))
812 /* rename sysfs_dirent */
813 if (strcmp(sd->s_name, new_name) != 0) {
815 new_name = dup_name = kstrdup(new_name, GFP_KERNEL);
819 dup_name = sd->s_name;
820 sd->s_name = new_name;
823 /* Remove from old parent's list and insert into new parent's list. */
824 if (sd->s_parent != new_parent_sd) {
825 sysfs_unlink_sibling(sd);
826 sysfs_get(new_parent_sd);
827 sysfs_put(sd->s_parent);
828 sd->s_parent = new_parent_sd;
829 sysfs_link_sibling(sd);
835 mutex_unlock(&sysfs_mutex);
840 int sysfs_rename_dir(struct kobject *kobj, const char *new_name)
842 struct sysfs_dirent *parent_sd = kobj->sd->s_parent;
843 const void *new_ns = NULL;
845 if (sysfs_ns_type(parent_sd))
846 new_ns = kobj->ktype->namespace(kobj);
848 return sysfs_rename(kobj->sd, parent_sd, new_ns, new_name);
851 int sysfs_move_dir(struct kobject *kobj, struct kobject *new_parent_kobj)
853 struct sysfs_dirent *sd = kobj->sd;
854 struct sysfs_dirent *new_parent_sd;
855 const void *new_ns = NULL;
857 BUG_ON(!sd->s_parent);
858 if (sysfs_ns_type(sd->s_parent))
859 new_ns = kobj->ktype->namespace(kobj);
860 new_parent_sd = new_parent_kobj && new_parent_kobj->sd ?
861 new_parent_kobj->sd : &sysfs_root;
863 return sysfs_rename(sd, new_parent_sd, new_ns, sd->s_name);
866 /* Relationship between s_mode and the DT_xxx types */
867 static inline unsigned char dt_type(struct sysfs_dirent *sd)
869 return (sd->s_mode >> 12) & 15;
872 static int sysfs_dir_release(struct inode *inode, struct file *filp)
874 sysfs_put(filp->private_data);
878 static struct sysfs_dirent *sysfs_dir_pos(const void *ns,
879 struct sysfs_dirent *parent_sd, ino_t ino, struct sysfs_dirent *pos)
882 int valid = !(pos->s_flags & SYSFS_FLAG_REMOVED) &&
883 pos->s_parent == parent_sd &&
889 if (!pos && (ino > 1) && (ino < INT_MAX)) {
890 pos = parent_sd->s_dir.children;
891 while (pos && (ino > pos->s_ino))
892 pos = pos->s_sibling;
894 while (pos && pos->s_ns && pos->s_ns != ns)
895 pos = pos->s_sibling;
899 static struct sysfs_dirent *sysfs_dir_next_pos(const void *ns,
900 struct sysfs_dirent *parent_sd, ino_t ino, struct sysfs_dirent *pos)
902 pos = sysfs_dir_pos(ns, parent_sd, ino, pos);
904 pos = pos->s_sibling;
905 while (pos && pos->s_ns && pos->s_ns != ns)
906 pos = pos->s_sibling;
910 static int sysfs_readdir(struct file * filp, void * dirent, filldir_t filldir)
912 struct dentry *dentry = filp->f_path.dentry;
913 struct sysfs_dirent * parent_sd = dentry->d_fsdata;
914 struct sysfs_dirent *pos = filp->private_data;
915 enum kobj_ns_type type;
919 type = sysfs_ns_type(parent_sd);
920 ns = sysfs_info(dentry->d_sb)->ns[type];
922 if (filp->f_pos == 0) {
923 ino = parent_sd->s_ino;
924 if (filldir(dirent, ".", 1, filp->f_pos, ino, DT_DIR) == 0)
927 if (filp->f_pos == 1) {
928 if (parent_sd->s_parent)
929 ino = parent_sd->s_parent->s_ino;
931 ino = parent_sd->s_ino;
932 if (filldir(dirent, "..", 2, filp->f_pos, ino, DT_DIR) == 0)
935 mutex_lock(&sysfs_mutex);
936 for (pos = sysfs_dir_pos(ns, parent_sd, filp->f_pos, pos);
938 pos = sysfs_dir_next_pos(ns, parent_sd, filp->f_pos, pos)) {
948 filp->private_data = sysfs_get(pos);
950 mutex_unlock(&sysfs_mutex);
951 ret = filldir(dirent, name, len, filp->f_pos, ino, type);
952 mutex_lock(&sysfs_mutex);
956 mutex_unlock(&sysfs_mutex);
957 if ((filp->f_pos > 1) && !pos) { /* EOF */
958 filp->f_pos = INT_MAX;
959 filp->private_data = NULL;
965 const struct file_operations sysfs_dir_operations = {
966 .read = generic_read_dir,
967 .readdir = sysfs_readdir,
968 .release = sysfs_dir_release,
969 .llseek = generic_file_llseek,