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12
13#undef DEBUG
14
15#include <linux/fs.h>
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>
25#include <linux/hash.h>
26#include "sysfs.h"
27
28DEFINE_MUTEX(sysfs_mutex);
29DEFINE_SPINLOCK(sysfs_assoc_lock);
30
31#define to_sysfs_dirent(X) rb_entry((X), struct sysfs_dirent, s_rb);
32
33static DEFINE_SPINLOCK(sysfs_ino_lock);
34static DEFINE_IDA(sysfs_ino_ida);
35
36
37
38
39
40
41
42
43static unsigned int sysfs_name_hash(const void *ns, const char *name)
44{
45 unsigned long hash = init_name_hash();
46 unsigned int len = strlen(name);
47 while (len--)
48 hash = partial_name_hash(*name++, hash);
49 hash = ( end_name_hash(hash) ^ hash_ptr( (void *)ns, 31 ) );
50 hash &= 0x7fffffffU;
51
52 if (hash < 1)
53 hash += 2;
54 if (hash >= INT_MAX)
55 hash = INT_MAX - 1;
56 return hash;
57}
58
59static int sysfs_name_compare(unsigned int hash, const void *ns,
60 const char *name, const struct sysfs_dirent *sd)
61{
62 if (hash != sd->s_hash)
63 return hash - sd->s_hash;
64 if (ns != sd->s_ns)
65 return ns - sd->s_ns;
66 return strcmp(name, sd->s_name);
67}
68
69static int sysfs_sd_compare(const struct sysfs_dirent *left,
70 const struct sysfs_dirent *right)
71{
72 return sysfs_name_compare(left->s_hash, left->s_ns, left->s_name,
73 right);
74}
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89static int sysfs_link_sibling(struct sysfs_dirent *sd)
90{
91 struct rb_node **node = &sd->s_parent->s_dir.children.rb_node;
92 struct rb_node *parent = NULL;
93
94 if (sysfs_type(sd) == SYSFS_DIR)
95 sd->s_parent->s_dir.subdirs++;
96
97 while (*node) {
98 struct sysfs_dirent *pos;
99 int result;
100
101 pos = to_sysfs_dirent(*node);
102 parent = *node;
103 result = sysfs_sd_compare(sd, pos);
104 if (result < 0)
105 node = &pos->s_rb.rb_left;
106 else if (result > 0)
107 node = &pos->s_rb.rb_right;
108 else
109 return -EEXIST;
110 }
111
112 rb_link_node(&sd->s_rb, parent, node);
113 rb_insert_color(&sd->s_rb, &sd->s_parent->s_dir.children);
114 return 0;
115}
116
117
118
119
120
121
122
123
124
125
126
127static void sysfs_unlink_sibling(struct sysfs_dirent *sd)
128{
129 if (sysfs_type(sd) == SYSFS_DIR)
130 sd->s_parent->s_dir.subdirs--;
131
132 rb_erase(&sd->s_rb, &sd->s_parent->s_dir.children);
133}
134
135#ifdef CONFIG_DEBUG_LOCK_ALLOC
136
137
138static bool ignore_lockdep(struct sysfs_dirent *sd)
139{
140 return sysfs_type(sd) == SYSFS_KOBJ_ATTR &&
141 sd->s_attr.attr->ignore_lockdep;
142}
143
144#else
145
146static inline bool ignore_lockdep(struct sysfs_dirent *sd)
147{
148 return true;
149}
150
151#endif
152
153
154
155
156
157
158
159
160
161
162
163struct sysfs_dirent *sysfs_get_active(struct sysfs_dirent *sd)
164{
165 if (unlikely(!sd))
166 return NULL;
167
168 while (1) {
169 int v, t;
170
171 v = atomic_read(&sd->s_active);
172 if (unlikely(v < 0))
173 return NULL;
174
175 t = atomic_cmpxchg(&sd->s_active, v, v + 1);
176 if (likely(t == v))
177 break;
178 if (t < 0)
179 return NULL;
180
181 cpu_relax();
182 }
183
184 if (likely(!ignore_lockdep(sd)))
185 rwsem_acquire_read(&sd->dep_map, 0, 1, _RET_IP_);
186 return sd;
187}
188
189
190
191
192
193
194
195
196void sysfs_put_active(struct sysfs_dirent *sd)
197{
198 int v;
199
200 if (unlikely(!sd))
201 return;
202
203 if (likely(!ignore_lockdep(sd)))
204 rwsem_release(&sd->dep_map, 1, _RET_IP_);
205 v = atomic_dec_return(&sd->s_active);
206 if (likely(v != SD_DEACTIVATED_BIAS))
207 return;
208
209
210
211
212 complete(sd->u.completion);
213}
214
215
216
217
218
219
220
221static void sysfs_deactivate(struct sysfs_dirent *sd)
222{
223 DECLARE_COMPLETION_ONSTACK(wait);
224 int v;
225
226 BUG_ON(!(sd->s_flags & SYSFS_FLAG_REMOVED));
227
228 if (!(sysfs_type(sd) & SYSFS_ACTIVE_REF))
229 return;
230
231 sd->u.completion = (void *)&wait;
232
233 rwsem_acquire(&sd->dep_map, 0, 0, _RET_IP_);
234
235
236
237 v = atomic_add_return(SD_DEACTIVATED_BIAS, &sd->s_active);
238
239 if (v != SD_DEACTIVATED_BIAS) {
240 lock_contended(&sd->dep_map, _RET_IP_);
241 wait_for_completion(&wait);
242 }
243
244 lock_acquired(&sd->dep_map, _RET_IP_);
245 rwsem_release(&sd->dep_map, 1, _RET_IP_);
246}
247
248static int sysfs_alloc_ino(unsigned int *pino)
249{
250 int ino, rc;
251
252 retry:
253 spin_lock(&sysfs_ino_lock);
254 rc = ida_get_new_above(&sysfs_ino_ida, 2, &ino);
255 spin_unlock(&sysfs_ino_lock);
256
257 if (rc == -EAGAIN) {
258 if (ida_pre_get(&sysfs_ino_ida, GFP_KERNEL))
259 goto retry;
260 rc = -ENOMEM;
261 }
262
263 *pino = ino;
264 return rc;
265}
266
267static void sysfs_free_ino(unsigned int ino)
268{
269 spin_lock(&sysfs_ino_lock);
270 ida_remove(&sysfs_ino_ida, ino);
271 spin_unlock(&sysfs_ino_lock);
272}
273
274void release_sysfs_dirent(struct sysfs_dirent * sd)
275{
276 struct sysfs_dirent *parent_sd;
277
278 repeat:
279
280
281
282 parent_sd = sd->s_parent;
283
284 if (sysfs_type(sd) == SYSFS_KOBJ_LINK)
285 sysfs_put(sd->s_symlink.target_sd);
286 if (sysfs_type(sd) & SYSFS_COPY_NAME)
287 kfree(sd->s_name);
288 if (sd->s_iattr && sd->s_iattr->ia_secdata)
289 security_release_secctx(sd->s_iattr->ia_secdata,
290 sd->s_iattr->ia_secdata_len);
291 kfree(sd->s_iattr);
292 sysfs_free_ino(sd->s_ino);
293 kmem_cache_free(sysfs_dir_cachep, sd);
294
295 sd = parent_sd;
296 if (sd && atomic_dec_and_test(&sd->s_count))
297 goto repeat;
298}
299
300static int sysfs_dentry_delete(const struct dentry *dentry)
301{
302 struct sysfs_dirent *sd = dentry->d_fsdata;
303 return !(sd && !(sd->s_flags & SYSFS_FLAG_REMOVED));
304}
305
306static int sysfs_dentry_revalidate(struct dentry *dentry, unsigned int flags)
307{
308 struct sysfs_dirent *sd;
309 int is_dir;
310 int type;
311
312 if (flags & LOOKUP_RCU)
313 return -ECHILD;
314
315 sd = dentry->d_fsdata;
316 mutex_lock(&sysfs_mutex);
317
318
319 if (sd->s_flags & SYSFS_FLAG_REMOVED)
320 goto out_bad;
321
322
323 if (dentry->d_parent->d_fsdata != sd->s_parent)
324 goto out_bad;
325
326
327 if (strcmp(dentry->d_name.name, sd->s_name) != 0)
328 goto out_bad;
329
330
331 type = KOBJ_NS_TYPE_NONE;
332 if (sd->s_parent) {
333 type = sysfs_ns_type(sd->s_parent);
334 if (type != KOBJ_NS_TYPE_NONE &&
335 sysfs_info(dentry->d_sb)->ns[type] != sd->s_ns)
336 goto out_bad;
337 }
338
339 mutex_unlock(&sysfs_mutex);
340out_valid:
341 return 1;
342out_bad:
343
344
345
346
347
348
349
350
351
352
353 is_dir = (sysfs_type(sd) == SYSFS_DIR);
354 mutex_unlock(&sysfs_mutex);
355 if (is_dir) {
356
357
358
359
360 if (have_submounts(dentry))
361 goto out_valid;
362 shrink_dcache_parent(dentry);
363 }
364 d_drop(dentry);
365 return 0;
366}
367
368static void sysfs_dentry_release(struct dentry *dentry)
369{
370 sysfs_put(dentry->d_fsdata);
371}
372
373const struct dentry_operations sysfs_dentry_ops = {
374 .d_revalidate = sysfs_dentry_revalidate,
375 .d_delete = sysfs_dentry_delete,
376 .d_release = sysfs_dentry_release,
377};
378
379struct sysfs_dirent *sysfs_new_dirent(const char *name, umode_t mode, int type)
380{
381 char *dup_name = NULL;
382 struct sysfs_dirent *sd;
383
384 if (type & SYSFS_COPY_NAME) {
385 name = dup_name = kstrdup(name, GFP_KERNEL);
386 if (!name)
387 return NULL;
388 }
389
390 sd = kmem_cache_zalloc(sysfs_dir_cachep, GFP_KERNEL);
391 if (!sd)
392 goto err_out1;
393
394 if (sysfs_alloc_ino(&sd->s_ino))
395 goto err_out2;
396
397 atomic_set(&sd->s_count, 1);
398 atomic_set(&sd->s_active, 0);
399
400 sd->s_name = name;
401 sd->s_mode = mode;
402 sd->s_flags = type;
403
404 return sd;
405
406 err_out2:
407 kmem_cache_free(sysfs_dir_cachep, sd);
408 err_out1:
409 kfree(dup_name);
410 return NULL;
411}
412
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425
426
427void sysfs_addrm_start(struct sysfs_addrm_cxt *acxt,
428 struct sysfs_dirent *parent_sd)
429{
430 memset(acxt, 0, sizeof(*acxt));
431 acxt->parent_sd = parent_sd;
432
433 mutex_lock(&sysfs_mutex);
434}
435
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455
456int __sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd)
457{
458 struct sysfs_inode_attrs *ps_iattr;
459 int ret;
460
461 if (!!sysfs_ns_type(acxt->parent_sd) != !!sd->s_ns) {
462 WARN(1, KERN_WARNING "sysfs: ns %s in '%s' for '%s'\n",
463 sysfs_ns_type(acxt->parent_sd)? "required": "invalid",
464 acxt->parent_sd->s_name, sd->s_name);
465 return -EINVAL;
466 }
467
468 sd->s_hash = sysfs_name_hash(sd->s_ns, sd->s_name);
469 sd->s_parent = sysfs_get(acxt->parent_sd);
470
471 ret = sysfs_link_sibling(sd);
472 if (ret)
473 return ret;
474
475
476 ps_iattr = acxt->parent_sd->s_iattr;
477 if (ps_iattr) {
478 struct iattr *ps_iattrs = &ps_iattr->ia_iattr;
479 ps_iattrs->ia_ctime = ps_iattrs->ia_mtime = CURRENT_TIME;
480 }
481
482 return 0;
483}
484
485
486
487
488
489
490
491
492
493static char *sysfs_pathname(struct sysfs_dirent *sd, char *path)
494{
495 if (sd->s_parent) {
496 sysfs_pathname(sd->s_parent, path);
497 strlcat(path, "/", PATH_MAX);
498 }
499 strlcat(path, sd->s_name, PATH_MAX);
500 return path;
501}
502
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521
522
523int sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd)
524{
525 int ret;
526
527 ret = __sysfs_add_one(acxt, sd);
528 if (ret == -EEXIST) {
529 char *path = kzalloc(PATH_MAX, GFP_KERNEL);
530 WARN(1, KERN_WARNING
531 "sysfs: cannot create duplicate filename '%s'\n",
532 (path == NULL) ? sd->s_name
533 : (sysfs_pathname(acxt->parent_sd, path),
534 strlcat(path, "/", PATH_MAX),
535 strlcat(path, sd->s_name, PATH_MAX),
536 path));
537 kfree(path);
538 }
539
540 return ret;
541}
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558void sysfs_remove_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd)
559{
560 struct sysfs_inode_attrs *ps_iattr;
561
562 BUG_ON(sd->s_flags & SYSFS_FLAG_REMOVED);
563
564 sysfs_unlink_sibling(sd);
565
566
567 ps_iattr = acxt->parent_sd->s_iattr;
568 if (ps_iattr) {
569 struct iattr *ps_iattrs = &ps_iattr->ia_iattr;
570 ps_iattrs->ia_ctime = ps_iattrs->ia_mtime = CURRENT_TIME;
571 }
572
573 sd->s_flags |= SYSFS_FLAG_REMOVED;
574 sd->u.removed_list = acxt->removed;
575 acxt->removed = sd;
576}
577
578
579
580
581
582
583
584
585
586
587
588
589void sysfs_addrm_finish(struct sysfs_addrm_cxt *acxt)
590{
591
592 mutex_unlock(&sysfs_mutex);
593
594
595 while (acxt->removed) {
596 struct sysfs_dirent *sd = acxt->removed;
597
598 acxt->removed = sd->u.removed_list;
599
600 sysfs_deactivate(sd);
601 unmap_bin_file(sd);
602 sysfs_put(sd);
603 }
604}
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619struct sysfs_dirent *sysfs_find_dirent(struct sysfs_dirent *parent_sd,
620 const void *ns,
621 const unsigned char *name)
622{
623 struct rb_node *node = parent_sd->s_dir.children.rb_node;
624 unsigned int hash;
625
626 if (!!sysfs_ns_type(parent_sd) != !!ns) {
627 WARN(1, KERN_WARNING "sysfs: ns %s in '%s' for '%s'\n",
628 sysfs_ns_type(parent_sd)? "required": "invalid",
629 parent_sd->s_name, name);
630 return NULL;
631 }
632
633 hash = sysfs_name_hash(ns, name);
634 while (node) {
635 struct sysfs_dirent *sd;
636 int result;
637
638 sd = to_sysfs_dirent(node);
639 result = sysfs_name_compare(hash, ns, name, sd);
640 if (result < 0)
641 node = node->rb_left;
642 else if (result > 0)
643 node = node->rb_right;
644 else
645 return sd;
646 }
647 return NULL;
648}
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664struct sysfs_dirent *sysfs_get_dirent(struct sysfs_dirent *parent_sd,
665 const void *ns,
666 const unsigned char *name)
667{
668 struct sysfs_dirent *sd;
669
670 mutex_lock(&sysfs_mutex);
671 sd = sysfs_find_dirent(parent_sd, ns, name);
672 sysfs_get(sd);
673 mutex_unlock(&sysfs_mutex);
674
675 return sd;
676}
677EXPORT_SYMBOL_GPL(sysfs_get_dirent);
678
679static int create_dir(struct kobject *kobj, struct sysfs_dirent *parent_sd,
680 enum kobj_ns_type type, const void *ns, const char *name,
681 struct sysfs_dirent **p_sd)
682{
683 umode_t mode = S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO;
684 struct sysfs_addrm_cxt acxt;
685 struct sysfs_dirent *sd;
686 int rc;
687
688
689 sd = sysfs_new_dirent(name, mode, SYSFS_DIR);
690 if (!sd)
691 return -ENOMEM;
692
693 sd->s_flags |= (type << SYSFS_NS_TYPE_SHIFT);
694 sd->s_ns = ns;
695 sd->s_dir.kobj = kobj;
696
697
698 sysfs_addrm_start(&acxt, parent_sd);
699 rc = sysfs_add_one(&acxt, sd);
700 sysfs_addrm_finish(&acxt);
701
702 if (rc == 0)
703 *p_sd = sd;
704 else
705 sysfs_put(sd);
706
707 return rc;
708}
709
710int sysfs_create_subdir(struct kobject *kobj, const char *name,
711 struct sysfs_dirent **p_sd)
712{
713 return create_dir(kobj, kobj->sd,
714 KOBJ_NS_TYPE_NONE, NULL, name, p_sd);
715}
716
717
718
719
720
721
722
723
724
725static enum kobj_ns_type sysfs_read_ns_type(struct kobject *kobj)
726{
727 const struct kobj_ns_type_operations *ops;
728 enum kobj_ns_type type;
729
730 ops = kobj_child_ns_ops(kobj);
731 if (!ops)
732 return KOBJ_NS_TYPE_NONE;
733
734 type = ops->type;
735 BUG_ON(type <= KOBJ_NS_TYPE_NONE);
736 BUG_ON(type >= KOBJ_NS_TYPES);
737 BUG_ON(!kobj_ns_type_registered(type));
738
739 return type;
740}
741
742
743
744
745
746int sysfs_create_dir(struct kobject * kobj)
747{
748 enum kobj_ns_type type;
749 struct sysfs_dirent *parent_sd, *sd;
750 const void *ns = NULL;
751 int error = 0;
752
753 BUG_ON(!kobj);
754
755 if (kobj->parent)
756 parent_sd = kobj->parent->sd;
757 else
758 parent_sd = &sysfs_root;
759
760 if (!parent_sd)
761 return -ENOENT;
762
763 if (sysfs_ns_type(parent_sd))
764 ns = kobj->ktype->namespace(kobj);
765 type = sysfs_read_ns_type(kobj);
766
767 error = create_dir(kobj, parent_sd, type, ns, kobject_name(kobj), &sd);
768 if (!error)
769 kobj->sd = sd;
770 return error;
771}
772
773static struct dentry * sysfs_lookup(struct inode *dir, struct dentry *dentry,
774 unsigned int flags)
775{
776 struct dentry *ret = NULL;
777 struct dentry *parent = dentry->d_parent;
778 struct sysfs_dirent *parent_sd = parent->d_fsdata;
779 struct sysfs_dirent *sd;
780 struct inode *inode;
781 enum kobj_ns_type type;
782 const void *ns;
783
784 mutex_lock(&sysfs_mutex);
785
786 type = sysfs_ns_type(parent_sd);
787 ns = sysfs_info(dir->i_sb)->ns[type];
788
789 sd = sysfs_find_dirent(parent_sd, ns, dentry->d_name.name);
790
791
792 if (!sd) {
793 ret = ERR_PTR(-ENOENT);
794 goto out_unlock;
795 }
796 dentry->d_fsdata = sysfs_get(sd);
797
798
799 inode = sysfs_get_inode(dir->i_sb, sd);
800 if (!inode) {
801 ret = ERR_PTR(-ENOMEM);
802 goto out_unlock;
803 }
804
805
806 ret = d_materialise_unique(dentry, inode);
807 out_unlock:
808 mutex_unlock(&sysfs_mutex);
809 return ret;
810}
811
812const struct inode_operations sysfs_dir_inode_operations = {
813 .lookup = sysfs_lookup,
814 .permission = sysfs_permission,
815 .setattr = sysfs_setattr,
816 .getattr = sysfs_getattr,
817 .setxattr = sysfs_setxattr,
818};
819
820static void remove_dir(struct sysfs_dirent *sd)
821{
822 struct sysfs_addrm_cxt acxt;
823
824 sysfs_addrm_start(&acxt, sd->s_parent);
825 sysfs_remove_one(&acxt, sd);
826 sysfs_addrm_finish(&acxt);
827}
828
829void sysfs_remove_subdir(struct sysfs_dirent *sd)
830{
831 remove_dir(sd);
832}
833
834
835static void __sysfs_remove_dir(struct sysfs_dirent *dir_sd)
836{
837 struct sysfs_addrm_cxt acxt;
838 struct rb_node *pos;
839
840 if (!dir_sd)
841 return;
842
843 pr_debug("sysfs %s: removing dir\n", dir_sd->s_name);
844 sysfs_addrm_start(&acxt, dir_sd);
845 pos = rb_first(&dir_sd->s_dir.children);
846 while (pos) {
847 struct sysfs_dirent *sd = to_sysfs_dirent(pos);
848 pos = rb_next(pos);
849 if (sysfs_type(sd) != SYSFS_DIR)
850 sysfs_remove_one(&acxt, sd);
851 }
852 sysfs_addrm_finish(&acxt);
853
854 remove_dir(dir_sd);
855}
856
857
858
859
860
861
862
863
864
865
866void sysfs_remove_dir(struct kobject * kobj)
867{
868 struct sysfs_dirent *sd = kobj->sd;
869
870 spin_lock(&sysfs_assoc_lock);
871 kobj->sd = NULL;
872 spin_unlock(&sysfs_assoc_lock);
873
874 __sysfs_remove_dir(sd);
875}
876
877int sysfs_rename(struct sysfs_dirent *sd,
878 struct sysfs_dirent *new_parent_sd, const void *new_ns,
879 const char *new_name)
880{
881 int error;
882
883 mutex_lock(&sysfs_mutex);
884
885 error = 0;
886 if ((sd->s_parent == new_parent_sd) && (sd->s_ns == new_ns) &&
887 (strcmp(sd->s_name, new_name) == 0))
888 goto out;
889
890 error = -EEXIST;
891 if (sysfs_find_dirent(new_parent_sd, new_ns, new_name))
892 goto out;
893
894
895 if (strcmp(sd->s_name, new_name) != 0) {
896 error = -ENOMEM;
897 new_name = kstrdup(new_name, GFP_KERNEL);
898 if (!new_name)
899 goto out;
900
901 kfree(sd->s_name);
902 sd->s_name = new_name;
903 }
904
905
906 sysfs_unlink_sibling(sd);
907 sysfs_get(new_parent_sd);
908 sysfs_put(sd->s_parent);
909 sd->s_ns = new_ns;
910 sd->s_hash = sysfs_name_hash(sd->s_ns, sd->s_name);
911 sd->s_parent = new_parent_sd;
912 sysfs_link_sibling(sd);
913
914 error = 0;
915 out:
916 mutex_unlock(&sysfs_mutex);
917 return error;
918}
919
920int sysfs_rename_dir(struct kobject *kobj, const char *new_name)
921{
922 struct sysfs_dirent *parent_sd = kobj->sd->s_parent;
923 const void *new_ns = NULL;
924
925 if (sysfs_ns_type(parent_sd))
926 new_ns = kobj->ktype->namespace(kobj);
927
928 return sysfs_rename(kobj->sd, parent_sd, new_ns, new_name);
929}
930
931int sysfs_move_dir(struct kobject *kobj, struct kobject *new_parent_kobj)
932{
933 struct sysfs_dirent *sd = kobj->sd;
934 struct sysfs_dirent *new_parent_sd;
935 const void *new_ns = NULL;
936
937 BUG_ON(!sd->s_parent);
938 if (sysfs_ns_type(sd->s_parent))
939 new_ns = kobj->ktype->namespace(kobj);
940 new_parent_sd = new_parent_kobj && new_parent_kobj->sd ?
941 new_parent_kobj->sd : &sysfs_root;
942
943 return sysfs_rename(sd, new_parent_sd, new_ns, sd->s_name);
944}
945
946
947static inline unsigned char dt_type(struct sysfs_dirent *sd)
948{
949 return (sd->s_mode >> 12) & 15;
950}
951
952static int sysfs_dir_release(struct inode *inode, struct file *filp)
953{
954 sysfs_put(filp->private_data);
955 return 0;
956}
957
958static struct sysfs_dirent *sysfs_dir_pos(const void *ns,
959 struct sysfs_dirent *parent_sd, loff_t hash, struct sysfs_dirent *pos)
960{
961 if (pos) {
962 int valid = !(pos->s_flags & SYSFS_FLAG_REMOVED) &&
963 pos->s_parent == parent_sd &&
964 hash == pos->s_hash;
965 sysfs_put(pos);
966 if (!valid)
967 pos = NULL;
968 }
969 if (!pos && (hash > 1) && (hash < INT_MAX)) {
970 struct rb_node *node = parent_sd->s_dir.children.rb_node;
971 while (node) {
972 pos = to_sysfs_dirent(node);
973
974 if (hash < pos->s_hash)
975 node = node->rb_left;
976 else if (hash > pos->s_hash)
977 node = node->rb_right;
978 else
979 break;
980 }
981 }
982
983 while (pos && pos->s_ns != ns) {
984 struct rb_node *node = rb_next(&pos->s_rb);
985 if (!node)
986 pos = NULL;
987 else
988 pos = to_sysfs_dirent(node);
989 }
990 return pos;
991}
992
993static struct sysfs_dirent *sysfs_dir_next_pos(const void *ns,
994 struct sysfs_dirent *parent_sd, ino_t ino, struct sysfs_dirent *pos)
995{
996 pos = sysfs_dir_pos(ns, parent_sd, ino, pos);
997 if (pos) do {
998 struct rb_node *node = rb_next(&pos->s_rb);
999 if (!node)
1000 pos = NULL;
1001 else
1002 pos = to_sysfs_dirent(node);
1003 } while (pos && pos->s_ns != ns);
1004 return pos;
1005}
1006
1007static int sysfs_readdir(struct file * filp, void * dirent, filldir_t filldir)
1008{
1009 struct dentry *dentry = filp->f_path.dentry;
1010 struct sysfs_dirent * parent_sd = dentry->d_fsdata;
1011 struct sysfs_dirent *pos = filp->private_data;
1012 enum kobj_ns_type type;
1013 const void *ns;
1014 ino_t ino;
1015
1016 type = sysfs_ns_type(parent_sd);
1017 ns = sysfs_info(dentry->d_sb)->ns[type];
1018
1019 if (filp->f_pos == 0) {
1020 ino = parent_sd->s_ino;
1021 if (filldir(dirent, ".", 1, filp->f_pos, ino, DT_DIR) == 0)
1022 filp->f_pos++;
1023 else
1024 return 0;
1025 }
1026 if (filp->f_pos == 1) {
1027 if (parent_sd->s_parent)
1028 ino = parent_sd->s_parent->s_ino;
1029 else
1030 ino = parent_sd->s_ino;
1031 if (filldir(dirent, "..", 2, filp->f_pos, ino, DT_DIR) == 0)
1032 filp->f_pos++;
1033 else
1034 return 0;
1035 }
1036 mutex_lock(&sysfs_mutex);
1037 for (pos = sysfs_dir_pos(ns, parent_sd, filp->f_pos, pos);
1038 pos;
1039 pos = sysfs_dir_next_pos(ns, parent_sd, filp->f_pos, pos)) {
1040 const char * name;
1041 unsigned int type;
1042 int len, ret;
1043
1044 name = pos->s_name;
1045 len = strlen(name);
1046 ino = pos->s_ino;
1047 type = dt_type(pos);
1048 filp->f_pos = pos->s_hash;
1049 filp->private_data = sysfs_get(pos);
1050
1051 mutex_unlock(&sysfs_mutex);
1052 ret = filldir(dirent, name, len, filp->f_pos, ino, type);
1053 mutex_lock(&sysfs_mutex);
1054 if (ret < 0)
1055 break;
1056 }
1057 mutex_unlock(&sysfs_mutex);
1058 if ((filp->f_pos > 1) && !pos) {
1059 filp->f_pos = INT_MAX;
1060 filp->private_data = NULL;
1061 }
1062 return 0;
1063}
1064
1065static loff_t sysfs_dir_llseek(struct file *file, loff_t offset, int whence)
1066{
1067 struct inode *inode = file_inode(file);
1068 loff_t ret;
1069
1070 mutex_lock(&inode->i_mutex);
1071 ret = generic_file_llseek(file, offset, whence);
1072 mutex_unlock(&inode->i_mutex);
1073
1074 return ret;
1075}
1076
1077const struct file_operations sysfs_dir_operations = {
1078 .read = generic_read_dir,
1079 .readdir = sysfs_readdir,
1080 .release = sysfs_dir_release,
1081 .llseek = sysfs_dir_llseek,
1082};
1083