2 * dir.c - Operations for sysfs directories.
8 #include <linux/mount.h>
9 #include <linux/module.h>
10 #include <linux/kobject.h>
11 #include <linux/namei.h>
12 #include <linux/idr.h>
13 #include <linux/completion.h>
14 #include <asm/semaphore.h>
17 DEFINE_MUTEX(sysfs_mutex);
18 spinlock_t sysfs_assoc_lock = SPIN_LOCK_UNLOCKED;
20 static spinlock_t sysfs_ino_lock = SPIN_LOCK_UNLOCKED;
21 static DEFINE_IDA(sysfs_ino_ida);
24 * sysfs_link_sibling - link sysfs_dirent into sibling list
25 * @sd: sysfs_dirent of interest
27 * Link @sd into its sibling list which starts from
28 * sd->s_parent->s_children.
31 * mutex_lock(sysfs_mutex)
33 void sysfs_link_sibling(struct sysfs_dirent *sd)
35 struct sysfs_dirent *parent_sd = sd->s_parent;
37 BUG_ON(sd->s_sibling);
38 sd->s_sibling = parent_sd->s_children;
39 parent_sd->s_children = sd;
43 * sysfs_unlink_sibling - unlink sysfs_dirent from sibling list
44 * @sd: sysfs_dirent of interest
46 * Unlink @sd from its sibling list which starts from
47 * sd->s_parent->s_children.
50 * mutex_lock(sysfs_mutex)
52 void sysfs_unlink_sibling(struct sysfs_dirent *sd)
54 struct sysfs_dirent **pos;
56 for (pos = &sd->s_parent->s_children; *pos; pos = &(*pos)->s_sibling) {
66 * sysfs_get_active - get an active reference to sysfs_dirent
67 * @sd: sysfs_dirent to get an active reference to
69 * Get an active reference of @sd. This function is noop if @sd
73 * Pointer to @sd on success, NULL on failure.
75 struct sysfs_dirent *sysfs_get_active(struct sysfs_dirent *sd)
83 v = atomic_read(&sd->s_active);
87 t = atomic_cmpxchg(&sd->s_active, v, v + 1);
98 * sysfs_put_active - put an active reference to sysfs_dirent
99 * @sd: sysfs_dirent to put an active reference to
101 * Put an active reference to @sd. This function is noop if @sd
104 void sysfs_put_active(struct sysfs_dirent *sd)
106 struct completion *cmpl;
112 v = atomic_dec_return(&sd->s_active);
113 if (likely(v != SD_DEACTIVATED_BIAS))
116 /* atomic_dec_return() is a mb(), we'll always see the updated
119 cmpl = (void *)sd->s_sibling;
124 * sysfs_get_active_two - get active references to sysfs_dirent and parent
125 * @sd: sysfs_dirent of interest
127 * Get active reference to @sd and its parent. Parent's active
128 * reference is grabbed first. This function is noop if @sd is
132 * Pointer to @sd on success, NULL on failure.
134 struct sysfs_dirent *sysfs_get_active_two(struct sysfs_dirent *sd)
137 if (sd->s_parent && unlikely(!sysfs_get_active(sd->s_parent)))
139 if (unlikely(!sysfs_get_active(sd))) {
140 sysfs_put_active(sd->s_parent);
148 * sysfs_put_active_two - put active references to sysfs_dirent and parent
149 * @sd: sysfs_dirent of interest
151 * Put active references to @sd and its parent. This function is
152 * noop if @sd is NULL.
154 void sysfs_put_active_two(struct sysfs_dirent *sd)
157 sysfs_put_active(sd);
158 sysfs_put_active(sd->s_parent);
163 * sysfs_deactivate - deactivate sysfs_dirent
164 * @sd: sysfs_dirent to deactivate
166 * Deny new active references and drain existing ones.
168 static void sysfs_deactivate(struct sysfs_dirent *sd)
170 DECLARE_COMPLETION_ONSTACK(wait);
173 BUG_ON(sd->s_sibling || !(sd->s_flags & SYSFS_FLAG_REMOVED));
174 sd->s_sibling = (void *)&wait;
176 /* atomic_add_return() is a mb(), put_active() will always see
177 * the updated sd->s_sibling.
179 v = atomic_add_return(SD_DEACTIVATED_BIAS, &sd->s_active);
181 if (v != SD_DEACTIVATED_BIAS)
182 wait_for_completion(&wait);
184 sd->s_sibling = NULL;
187 static int sysfs_alloc_ino(ino_t *pino)
192 spin_lock(&sysfs_ino_lock);
193 rc = ida_get_new_above(&sysfs_ino_ida, 2, &ino);
194 spin_unlock(&sysfs_ino_lock);
197 if (ida_pre_get(&sysfs_ino_ida, GFP_KERNEL))
206 static void sysfs_free_ino(ino_t ino)
208 spin_lock(&sysfs_ino_lock);
209 ida_remove(&sysfs_ino_ida, ino);
210 spin_unlock(&sysfs_ino_lock);
213 void release_sysfs_dirent(struct sysfs_dirent * sd)
215 struct sysfs_dirent *parent_sd;
218 /* Moving/renaming is always done while holding reference.
219 * sd->s_parent won't change beneath us.
221 parent_sd = sd->s_parent;
223 if (sysfs_type(sd) == SYSFS_KOBJ_LINK)
224 sysfs_put(sd->s_elem.symlink.target_sd);
225 if (sysfs_type(sd) & SYSFS_COPY_NAME)
228 sysfs_free_ino(sd->s_ino);
229 kmem_cache_free(sysfs_dir_cachep, sd);
232 if (sd && atomic_dec_and_test(&sd->s_count))
236 static void sysfs_d_iput(struct dentry * dentry, struct inode * inode)
238 struct sysfs_dirent * sd = dentry->d_fsdata;
241 /* sd->s_dentry is protected with sysfs_assoc_lock.
242 * This allows sysfs_drop_dentry() to dereference it.
244 spin_lock(&sysfs_assoc_lock);
246 /* The dentry might have been deleted or another
247 * lookup could have happened updating sd->s_dentry to
248 * point the new dentry. Ignore if it isn't pointing
251 if (sd->s_dentry == dentry)
253 spin_unlock(&sysfs_assoc_lock);
259 static struct dentry_operations sysfs_dentry_ops = {
260 .d_iput = sysfs_d_iput,
263 struct sysfs_dirent *sysfs_new_dirent(const char *name, umode_t mode, int type)
265 char *dup_name = NULL;
266 struct sysfs_dirent *sd = NULL;
268 if (type & SYSFS_COPY_NAME) {
269 name = dup_name = kstrdup(name, GFP_KERNEL);
274 sd = kmem_cache_zalloc(sysfs_dir_cachep, GFP_KERNEL);
278 if (sysfs_alloc_ino(&sd->s_ino))
281 atomic_set(&sd->s_count, 1);
282 atomic_set(&sd->s_active, 0);
283 atomic_set(&sd->s_event, 1);
293 kmem_cache_free(sysfs_dir_cachep, sd);
298 * sysfs_attach_dentry - associate sysfs_dirent with dentry
299 * @sd: target sysfs_dirent
300 * @dentry: dentry to associate
302 * Associate @sd with @dentry. This is protected by
303 * sysfs_assoc_lock to avoid race with sysfs_d_iput().
306 * mutex_lock(sysfs_mutex)
308 static void sysfs_attach_dentry(struct sysfs_dirent *sd, struct dentry *dentry)
310 dentry->d_op = &sysfs_dentry_ops;
311 dentry->d_fsdata = sysfs_get(sd);
313 /* protect sd->s_dentry against sysfs_d_iput */
314 spin_lock(&sysfs_assoc_lock);
315 sd->s_dentry = dentry;
316 spin_unlock(&sysfs_assoc_lock);
321 static int sysfs_ilookup_test(struct inode *inode, void *arg)
323 struct sysfs_dirent *sd = arg;
324 return inode->i_ino == sd->s_ino;
328 * sysfs_addrm_start - prepare for sysfs_dirent add/remove
329 * @acxt: pointer to sysfs_addrm_cxt to be used
330 * @parent_sd: parent sysfs_dirent
332 * This function is called when the caller is about to add or
333 * remove sysfs_dirent under @parent_sd. This function acquires
334 * sysfs_mutex, grabs inode for @parent_sd if available and lock
335 * i_mutex of it. @acxt is used to keep and pass context to
336 * other addrm functions.
339 * Kernel thread context (may sleep). sysfs_mutex is locked on
340 * return. i_mutex of parent inode is locked on return if
343 void sysfs_addrm_start(struct sysfs_addrm_cxt *acxt,
344 struct sysfs_dirent *parent_sd)
348 memset(acxt, 0, sizeof(*acxt));
349 acxt->parent_sd = parent_sd;
351 /* Lookup parent inode. inode initialization and I_NEW
352 * clearing are protected by sysfs_mutex. By grabbing it and
353 * looking up with _nowait variant, inode state can be
354 * determined reliably.
356 mutex_lock(&sysfs_mutex);
358 inode = ilookup5_nowait(sysfs_sb, parent_sd->s_ino, sysfs_ilookup_test,
361 if (inode && !(inode->i_state & I_NEW)) {
362 /* parent inode available */
363 acxt->parent_inode = inode;
365 /* sysfs_mutex is below i_mutex in lock hierarchy.
366 * First, trylock i_mutex. If fails, unlock
367 * sysfs_mutex and lock them in order.
369 if (!mutex_trylock(&inode->i_mutex)) {
370 mutex_unlock(&sysfs_mutex);
371 mutex_lock(&inode->i_mutex);
372 mutex_lock(&sysfs_mutex);
379 * sysfs_add_one - add sysfs_dirent to parent
380 * @acxt: addrm context to use
381 * @sd: sysfs_dirent to be added
383 * Get @acxt->parent_sd and set sd->s_parent to it and increment
384 * nlink of parent inode if @sd is a directory. @sd is NOT
385 * linked into the children list of the parent. The caller
386 * should invoke sysfs_link_sibling() after this function
387 * completes if @sd needs to be on the children list.
389 * This function should be called between calls to
390 * sysfs_addrm_start() and sysfs_addrm_finish() and should be
391 * passed the same @acxt as passed to sysfs_addrm_start().
394 * Determined by sysfs_addrm_start().
396 void sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd)
398 sd->s_parent = sysfs_get(acxt->parent_sd);
400 if (sysfs_type(sd) == SYSFS_DIR && acxt->parent_inode)
401 inc_nlink(acxt->parent_inode);
407 * sysfs_remove_one - remove sysfs_dirent from parent
408 * @acxt: addrm context to use
409 * @sd: sysfs_dirent to be added
411 * Mark @sd removed and drop nlink of parent inode if @sd is a
412 * directory. @sd is NOT unlinked from the children list of the
413 * parent. The caller is repsonsible for removing @sd from the
414 * children list before calling this function.
416 * This function should be called between calls to
417 * sysfs_addrm_start() and sysfs_addrm_finish() and should be
418 * passed the same @acxt as passed to sysfs_addrm_start().
421 * Determined by sysfs_addrm_start().
423 void sysfs_remove_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd)
425 BUG_ON(sd->s_sibling || (sd->s_flags & SYSFS_FLAG_REMOVED));
427 sd->s_flags |= SYSFS_FLAG_REMOVED;
428 sd->s_sibling = acxt->removed;
431 if (sysfs_type(sd) == SYSFS_DIR && acxt->parent_inode)
432 drop_nlink(acxt->parent_inode);
438 * sysfs_addrm_finish - finish up sysfs_dirent add/remove
439 * @acxt: addrm context to finish up
441 * Finish up sysfs_dirent add/remove. Resources acquired by
442 * sysfs_addrm_start() are released and removed sysfs_dirents are
443 * cleaned up. Timestamps on the parent inode are updated.
446 * All mutexes acquired by sysfs_addrm_start() are released.
449 * Number of added/removed sysfs_dirents since sysfs_addrm_start().
451 int sysfs_addrm_finish(struct sysfs_addrm_cxt *acxt)
453 /* release resources acquired by sysfs_addrm_start() */
454 mutex_unlock(&sysfs_mutex);
455 if (acxt->parent_inode) {
456 struct inode *inode = acxt->parent_inode;
458 /* if added/removed, update timestamps on the parent */
460 inode->i_ctime = inode->i_mtime = CURRENT_TIME;
462 mutex_unlock(&inode->i_mutex);
466 /* kill removed sysfs_dirents */
467 while (acxt->removed) {
468 struct sysfs_dirent *sd = acxt->removed;
470 acxt->removed = sd->s_sibling;
471 sd->s_sibling = NULL;
473 sysfs_drop_dentry(sd);
474 sysfs_deactivate(sd);
482 * sysfs_find_dirent - find sysfs_dirent with the given name
483 * @parent_sd: sysfs_dirent to search under
484 * @name: name to look for
486 * Look for sysfs_dirent with name @name under @parent_sd.
489 * mutex_lock(sysfs_mutex)
492 * Pointer to sysfs_dirent if found, NULL if not.
494 struct sysfs_dirent *sysfs_find_dirent(struct sysfs_dirent *parent_sd,
495 const unsigned char *name)
497 struct sysfs_dirent *sd;
499 for (sd = parent_sd->s_children; sd; sd = sd->s_sibling)
500 if (sysfs_type(sd) && !strcmp(sd->s_name, name))
506 * sysfs_get_dirent - find and get sysfs_dirent with the given name
507 * @parent_sd: sysfs_dirent to search under
508 * @name: name to look for
510 * Look for sysfs_dirent with name @name under @parent_sd and get
514 * Kernel thread context (may sleep). Grabs sysfs_mutex.
517 * Pointer to sysfs_dirent if found, NULL if not.
519 struct sysfs_dirent *sysfs_get_dirent(struct sysfs_dirent *parent_sd,
520 const unsigned char *name)
522 struct sysfs_dirent *sd;
524 mutex_lock(&sysfs_mutex);
525 sd = sysfs_find_dirent(parent_sd, name);
527 mutex_unlock(&sysfs_mutex);
532 static int create_dir(struct kobject *kobj, struct sysfs_dirent *parent_sd,
533 const char *name, struct sysfs_dirent **p_sd)
535 struct dentry *parent = parent_sd->s_dentry;
536 struct sysfs_addrm_cxt acxt;
538 umode_t mode = S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO;
539 struct dentry *dentry;
541 struct sysfs_dirent *sd;
543 sysfs_addrm_start(&acxt, parent_sd);
546 dentry = lookup_one_len(name, parent, strlen(name));
547 if (IS_ERR(dentry)) {
548 error = PTR_ERR(dentry);
557 sd = sysfs_new_dirent(name, mode, SYSFS_DIR);
560 sd->s_elem.dir.kobj = kobj;
562 inode = sysfs_get_inode(sd);
566 if (inode->i_state & I_NEW) {
567 inode->i_op = &sysfs_dir_inode_operations;
568 inode->i_fop = &sysfs_dir_operations;
569 /* directory inodes start off with i_nlink == 2 (for ".") */
575 if (sysfs_find_dirent(parent_sd, name))
578 sysfs_add_one(&acxt, sd);
579 sysfs_link_sibling(sd);
580 sysfs_instantiate(dentry, inode);
581 sysfs_attach_dentry(sd, dentry);
585 goto out_finish; /* pin directory dentry in core */
596 sysfs_addrm_finish(&acxt);
600 int sysfs_create_subdir(struct kobject *kobj, const char *name,
601 struct sysfs_dirent **p_sd)
603 return create_dir(kobj, kobj->sd, name, p_sd);
607 * sysfs_create_dir - create a directory for an object.
608 * @kobj: object we're creating directory for.
609 * @shadow_parent: parent object.
611 int sysfs_create_dir(struct kobject *kobj,
612 struct sysfs_dirent *shadow_parent_sd)
614 struct sysfs_dirent *parent_sd, *sd;
619 if (shadow_parent_sd)
620 parent_sd = shadow_parent_sd;
621 else if (kobj->parent)
622 parent_sd = kobj->parent->sd;
623 else if (sysfs_mount && sysfs_mount->mnt_sb)
624 parent_sd = sysfs_mount->mnt_sb->s_root->d_fsdata;
628 error = create_dir(kobj, parent_sd, kobject_name(kobj), &sd);
634 static struct dentry * sysfs_lookup(struct inode *dir, struct dentry *dentry,
635 struct nameidata *nd)
637 struct sysfs_dirent * parent_sd = dentry->d_parent->d_fsdata;
638 struct sysfs_dirent * sd;
639 struct bin_attribute *bin_attr;
643 for (sd = parent_sd->s_children; sd; sd = sd->s_sibling) {
644 if ((sysfs_type(sd) & SYSFS_NOT_PINNED) &&
645 !strcmp(sd->s_name, dentry->d_name.name)) {
655 /* attach dentry and inode */
656 inode = sysfs_get_inode(sd);
658 return ERR_PTR(-ENOMEM);
660 mutex_lock(&sysfs_mutex);
662 if (inode->i_state & I_NEW) {
663 /* initialize inode according to type */
664 switch (sysfs_type(sd)) {
665 case SYSFS_KOBJ_ATTR:
666 inode->i_size = PAGE_SIZE;
667 inode->i_fop = &sysfs_file_operations;
669 case SYSFS_KOBJ_BIN_ATTR:
670 bin_attr = sd->s_elem.bin_attr.bin_attr;
671 inode->i_size = bin_attr->size;
672 inode->i_fop = &bin_fops;
674 case SYSFS_KOBJ_LINK:
675 inode->i_op = &sysfs_symlink_inode_operations;
682 sysfs_instantiate(dentry, inode);
683 sysfs_attach_dentry(sd, dentry);
685 mutex_unlock(&sysfs_mutex);
690 const struct inode_operations sysfs_dir_inode_operations = {
691 .lookup = sysfs_lookup,
692 .setattr = sysfs_setattr,
695 static void remove_dir(struct sysfs_dirent *sd)
697 struct sysfs_addrm_cxt acxt;
699 sysfs_addrm_start(&acxt, sd->s_parent);
700 sysfs_unlink_sibling(sd);
701 sysfs_remove_one(&acxt, sd);
702 sysfs_addrm_finish(&acxt);
705 void sysfs_remove_subdir(struct sysfs_dirent *sd)
711 static void __sysfs_remove_dir(struct sysfs_dirent *dir_sd)
713 struct sysfs_addrm_cxt acxt;
714 struct sysfs_dirent **pos;
719 pr_debug("sysfs %s: removing dir\n", dir_sd->s_name);
720 sysfs_addrm_start(&acxt, dir_sd);
721 pos = &dir_sd->s_children;
723 struct sysfs_dirent *sd = *pos;
725 if (sysfs_type(sd) && (sysfs_type(sd) & SYSFS_NOT_PINNED)) {
726 *pos = sd->s_sibling;
727 sd->s_sibling = NULL;
728 sysfs_remove_one(&acxt, sd);
730 pos = &(*pos)->s_sibling;
732 sysfs_addrm_finish(&acxt);
738 * sysfs_remove_dir - remove an object's directory.
741 * The only thing special about this is that we remove any files in
742 * the directory before we remove the directory, and we've inlined
743 * what used to be sysfs_rmdir() below, instead of calling separately.
746 void sysfs_remove_dir(struct kobject * kobj)
748 struct sysfs_dirent *sd = kobj->sd;
750 spin_lock(&sysfs_assoc_lock);
752 spin_unlock(&sysfs_assoc_lock);
754 __sysfs_remove_dir(sd);
757 int sysfs_rename_dir(struct kobject *kobj, struct sysfs_dirent *new_parent_sd,
758 const char *new_name)
760 struct sysfs_dirent *sd = kobj->sd;
761 struct dentry *new_parent = new_parent_sd->s_dentry;
762 struct dentry *new_dentry;
769 mutex_lock(&new_parent->d_inode->i_mutex);
771 new_dentry = lookup_one_len(new_name, new_parent, strlen(new_name));
772 if (IS_ERR(new_dentry)) {
773 error = PTR_ERR(new_dentry);
777 /* By allowing two different directories with the same
778 * d_parent we allow this routine to move between different
779 * shadows of the same directory
782 if (sd->s_parent->s_dentry->d_inode != new_parent->d_inode ||
783 new_dentry->d_parent->d_inode != new_parent->d_inode ||
784 new_dentry == sd->s_dentry)
788 if (new_dentry->d_inode)
791 /* rename kobject and sysfs_dirent */
793 new_name = dup_name = kstrdup(new_name, GFP_KERNEL);
797 error = kobject_set_name(kobj, "%s", new_name);
802 sd->s_name = new_name;
804 /* move under the new parent */
805 d_add(new_dentry, NULL);
806 d_move(sd->s_dentry, new_dentry);
808 mutex_lock(&sysfs_mutex);
810 sysfs_unlink_sibling(sd);
811 sysfs_get(new_parent_sd);
812 sysfs_put(sd->s_parent);
813 sd->s_parent = new_parent_sd;
814 sysfs_link_sibling(sd);
816 mutex_unlock(&sysfs_mutex);
828 mutex_unlock(&new_parent->d_inode->i_mutex);
832 int sysfs_move_dir(struct kobject *kobj, struct kobject *new_parent)
834 struct dentry *old_parent_dentry, *new_parent_dentry, *new_dentry;
835 struct sysfs_dirent *new_parent_sd, *sd;
838 old_parent_dentry = kobj->parent ?
839 kobj->parent->sd->s_dentry : sysfs_mount->mnt_sb->s_root;
840 new_parent_dentry = new_parent ?
841 new_parent->sd->s_dentry : sysfs_mount->mnt_sb->s_root;
843 if (old_parent_dentry->d_inode == new_parent_dentry->d_inode)
844 return 0; /* nothing to move */
846 mutex_lock(&old_parent_dentry->d_inode->i_mutex);
847 if (!mutex_trylock(&new_parent_dentry->d_inode->i_mutex)) {
848 mutex_unlock(&old_parent_dentry->d_inode->i_mutex);
852 new_parent_sd = new_parent_dentry->d_fsdata;
855 new_dentry = lookup_one_len(kobj->name, new_parent_dentry,
857 if (IS_ERR(new_dentry)) {
858 error = PTR_ERR(new_dentry);
862 d_add(new_dentry, NULL);
863 d_move(sd->s_dentry, new_dentry);
866 /* Remove from old parent's list and insert into new parent's list. */
867 mutex_lock(&sysfs_mutex);
869 sysfs_unlink_sibling(sd);
870 sysfs_get(new_parent_sd);
871 sysfs_put(sd->s_parent);
872 sd->s_parent = new_parent_sd;
873 sysfs_link_sibling(sd);
875 mutex_unlock(&sysfs_mutex);
877 mutex_unlock(&new_parent_dentry->d_inode->i_mutex);
878 mutex_unlock(&old_parent_dentry->d_inode->i_mutex);
883 static int sysfs_dir_open(struct inode *inode, struct file *file)
885 struct dentry * dentry = file->f_path.dentry;
886 struct sysfs_dirent * parent_sd = dentry->d_fsdata;
887 struct sysfs_dirent * sd;
889 sd = sysfs_new_dirent("_DIR_", 0, 0);
891 mutex_lock(&sysfs_mutex);
892 sd->s_parent = sysfs_get(parent_sd);
893 sysfs_link_sibling(sd);
894 mutex_unlock(&sysfs_mutex);
897 file->private_data = sd;
898 return sd ? 0 : -ENOMEM;
901 static int sysfs_dir_close(struct inode *inode, struct file *file)
903 struct sysfs_dirent * cursor = file->private_data;
905 mutex_lock(&sysfs_mutex);
906 sysfs_unlink_sibling(cursor);
907 mutex_unlock(&sysfs_mutex);
909 release_sysfs_dirent(cursor);
914 /* Relationship between s_mode and the DT_xxx types */
915 static inline unsigned char dt_type(struct sysfs_dirent *sd)
917 return (sd->s_mode >> 12) & 15;
920 static int sysfs_readdir(struct file * filp, void * dirent, filldir_t filldir)
922 struct dentry *dentry = filp->f_path.dentry;
923 struct sysfs_dirent * parent_sd = dentry->d_fsdata;
924 struct sysfs_dirent *cursor = filp->private_data;
925 struct sysfs_dirent **pos;
931 ino = parent_sd->s_ino;
932 if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0)
938 if (parent_sd->s_parent)
939 ino = parent_sd->s_parent->s_ino;
941 ino = parent_sd->s_ino;
942 if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0)
948 mutex_lock(&sysfs_mutex);
950 pos = &parent_sd->s_children;
951 while (*pos != cursor)
952 pos = &(*pos)->s_sibling;
955 *pos = cursor->s_sibling;
957 if (filp->f_pos == 2)
958 pos = &parent_sd->s_children;
960 for ( ; *pos; pos = &(*pos)->s_sibling) {
961 struct sysfs_dirent *next = *pos;
965 if (!sysfs_type(next))
972 if (filldir(dirent, name, len, filp->f_pos, ino,
979 /* put cursor back in */
980 cursor->s_sibling = *pos;
983 mutex_unlock(&sysfs_mutex);
988 static loff_t sysfs_dir_lseek(struct file * file, loff_t offset, int origin)
990 struct dentry * dentry = file->f_path.dentry;
994 offset += file->f_pos;
1001 if (offset != file->f_pos) {
1002 mutex_lock(&sysfs_mutex);
1004 file->f_pos = offset;
1005 if (file->f_pos >= 2) {
1006 struct sysfs_dirent *sd = dentry->d_fsdata;
1007 struct sysfs_dirent *cursor = file->private_data;
1008 struct sysfs_dirent **pos;
1009 loff_t n = file->f_pos - 2;
1011 sysfs_unlink_sibling(cursor);
1013 pos = &sd->s_children;
1015 struct sysfs_dirent *next = *pos;
1016 if (sysfs_type(next))
1018 pos = &(*pos)->s_sibling;
1021 cursor->s_sibling = *pos;
1025 mutex_unlock(&sysfs_mutex);
1033 * sysfs_make_shadowed_dir - Setup so a directory can be shadowed
1034 * @kobj: object we're creating shadow of.
1037 int sysfs_make_shadowed_dir(struct kobject *kobj,
1038 void * (*follow_link)(struct dentry *, struct nameidata *))
1040 struct inode *inode;
1041 struct inode_operations *i_op;
1043 inode = kobj->sd->s_dentry->d_inode;
1044 if (inode->i_op != &sysfs_dir_inode_operations)
1047 i_op = kmalloc(sizeof(*i_op), GFP_KERNEL);
1051 memcpy(i_op, &sysfs_dir_inode_operations, sizeof(*i_op));
1052 i_op->follow_link = follow_link;
1054 /* Locking of inode->i_op?
1055 * Since setting i_op is a single word write and they
1056 * are atomic we should be ok here.
1063 * sysfs_create_shadow_dir - create a shadow directory for an object.
1064 * @kobj: object we're creating directory for.
1066 * sysfs_make_shadowed_dir must already have been called on this
1070 struct sysfs_dirent *sysfs_create_shadow_dir(struct kobject *kobj)
1072 struct dentry *dir = kobj->sd->s_dentry;
1073 struct inode *inode = dir->d_inode;
1074 struct dentry *parent = dir->d_parent;
1075 struct sysfs_dirent *parent_sd = parent->d_fsdata;
1076 struct dentry *shadow;
1077 struct sysfs_dirent *sd;
1078 struct sysfs_addrm_cxt acxt;
1080 sd = ERR_PTR(-EINVAL);
1081 if (!sysfs_is_shadowed_inode(inode))
1084 shadow = d_alloc(parent, &dir->d_name);
1088 sd = sysfs_new_dirent("_SHADOW_", inode->i_mode, SYSFS_DIR);
1091 sd->s_elem.dir.kobj = kobj;
1093 sysfs_addrm_start(&acxt, parent_sd);
1095 /* add but don't link into children list */
1096 sysfs_add_one(&acxt, sd);
1098 /* attach and instantiate dentry */
1099 sysfs_attach_dentry(sd, shadow);
1100 d_instantiate(shadow, igrab(inode));
1101 inc_nlink(inode); /* tj: synchronization? */
1103 sysfs_addrm_finish(&acxt);
1105 dget(shadow); /* Extra count - pin the dentry in core */
1111 sd = ERR_PTR(-ENOMEM);
1116 * sysfs_remove_shadow_dir - remove an object's directory.
1117 * @shadow_sd: sysfs_dirent of shadow directory
1119 * The only thing special about this is that we remove any files in
1120 * the directory before we remove the directory, and we've inlined
1121 * what used to be sysfs_rmdir() below, instead of calling separately.
1124 void sysfs_remove_shadow_dir(struct sysfs_dirent *shadow_sd)
1126 __sysfs_remove_dir(shadow_sd);
1129 const struct file_operations sysfs_dir_operations = {
1130 .open = sysfs_dir_open,
1131 .release = sysfs_dir_close,
1132 .llseek = sysfs_dir_lseek,
1133 .read = generic_read_dir,
1134 .readdir = sysfs_readdir,