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[/] [test_project/] [trunk/] [linux_sd_driver/] [fs/] [sysfs/] [dir.c] - Blame information for rev 62

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1 62 marcus.erl
/*
2
 * fs/sysfs/dir.c - sysfs core and dir operation implementation
3
 *
4
 * Copyright (c) 2001-3 Patrick Mochel
5
 * Copyright (c) 2007 SUSE Linux Products GmbH
6
 * Copyright (c) 2007 Tejun Heo <teheo@suse.de>
7
 *
8
 * This file is released under the GPLv2.
9
 *
10
 * Please see Documentation/filesystems/sysfs.txt for more information.
11
 */
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 "sysfs.h"
24
 
25
DEFINE_MUTEX(sysfs_mutex);
26
DEFINE_MUTEX(sysfs_rename_mutex);
27
DEFINE_SPINLOCK(sysfs_assoc_lock);
28
 
29
static DEFINE_SPINLOCK(sysfs_ino_lock);
30
static DEFINE_IDA(sysfs_ino_ida);
31
 
32
/**
33
 *      sysfs_link_sibling - link sysfs_dirent into sibling list
34
 *      @sd: sysfs_dirent of interest
35
 *
36
 *      Link @sd into its sibling list which starts from
37
 *      sd->s_parent->s_dir.children.
38
 *
39
 *      Locking:
40
 *      mutex_lock(sysfs_mutex)
41
 */
42
static void sysfs_link_sibling(struct sysfs_dirent *sd)
43
{
44
        struct sysfs_dirent *parent_sd = sd->s_parent;
45
        struct sysfs_dirent **pos;
46
 
47
        BUG_ON(sd->s_sibling);
48
 
49
        /* Store directory entries in order by ino.  This allows
50
         * readdir to properly restart without having to add a
51
         * cursor into the s_dir.children list.
52
         */
53
        for (pos = &parent_sd->s_dir.children; *pos; pos = &(*pos)->s_sibling) {
54
                if (sd->s_ino < (*pos)->s_ino)
55
                        break;
56
        }
57
        sd->s_sibling = *pos;
58
        *pos = sd;
59
}
60
 
61
/**
62
 *      sysfs_unlink_sibling - unlink sysfs_dirent from sibling list
63
 *      @sd: sysfs_dirent of interest
64
 *
65
 *      Unlink @sd from its sibling list which starts from
66
 *      sd->s_parent->s_dir.children.
67
 *
68
 *      Locking:
69
 *      mutex_lock(sysfs_mutex)
70
 */
71
static void sysfs_unlink_sibling(struct sysfs_dirent *sd)
72
{
73
        struct sysfs_dirent **pos;
74
 
75
        for (pos = &sd->s_parent->s_dir.children; *pos;
76
             pos = &(*pos)->s_sibling) {
77
                if (*pos == sd) {
78
                        *pos = sd->s_sibling;
79
                        sd->s_sibling = NULL;
80
                        break;
81
                }
82
        }
83
}
84
 
85
/**
86
 *      sysfs_get_dentry - get dentry for the given sysfs_dirent
87
 *      @sd: sysfs_dirent of interest
88
 *
89
 *      Get dentry for @sd.  Dentry is looked up if currently not
90
 *      present.  This function descends from the root looking up
91
 *      dentry for each step.
92
 *
93
 *      LOCKING:
94
 *      mutex_lock(sysfs_rename_mutex)
95
 *
96
 *      RETURNS:
97
 *      Pointer to found dentry on success, ERR_PTR() value on error.
98
 */
99
struct dentry *sysfs_get_dentry(struct sysfs_dirent *sd)
100
{
101
        struct dentry *dentry = dget(sysfs_sb->s_root);
102
 
103
        while (dentry->d_fsdata != sd) {
104
                struct sysfs_dirent *cur;
105
                struct dentry *parent;
106
 
107
                /* find the first ancestor which hasn't been looked up */
108
                cur = sd;
109
                while (cur->s_parent != dentry->d_fsdata)
110
                        cur = cur->s_parent;
111
 
112
                /* look it up */
113
                parent = dentry;
114
                mutex_lock(&parent->d_inode->i_mutex);
115
                dentry = lookup_one_noperm(cur->s_name, parent);
116
                mutex_unlock(&parent->d_inode->i_mutex);
117
                dput(parent);
118
 
119
                if (IS_ERR(dentry))
120
                        break;
121
        }
122
        return dentry;
123
}
124
 
125
/**
126
 *      sysfs_get_active - get an active reference to sysfs_dirent
127
 *      @sd: sysfs_dirent to get an active reference to
128
 *
129
 *      Get an active reference of @sd.  This function is noop if @sd
130
 *      is NULL.
131
 *
132
 *      RETURNS:
133
 *      Pointer to @sd on success, NULL on failure.
134
 */
135
static struct sysfs_dirent *sysfs_get_active(struct sysfs_dirent *sd)
136
{
137
        if (unlikely(!sd))
138
                return NULL;
139
 
140
        while (1) {
141
                int v, t;
142
 
143
                v = atomic_read(&sd->s_active);
144
                if (unlikely(v < 0))
145
                        return NULL;
146
 
147
                t = atomic_cmpxchg(&sd->s_active, v, v + 1);
148
                if (likely(t == v))
149
                        return sd;
150
                if (t < 0)
151
                        return NULL;
152
 
153
                cpu_relax();
154
        }
155
}
156
 
157
/**
158
 *      sysfs_put_active - put an active reference to sysfs_dirent
159
 *      @sd: sysfs_dirent to put an active reference to
160
 *
161
 *      Put an active reference to @sd.  This function is noop if @sd
162
 *      is NULL.
163
 */
164
static void sysfs_put_active(struct sysfs_dirent *sd)
165
{
166
        struct completion *cmpl;
167
        int v;
168
 
169
        if (unlikely(!sd))
170
                return;
171
 
172
        v = atomic_dec_return(&sd->s_active);
173
        if (likely(v != SD_DEACTIVATED_BIAS))
174
                return;
175
 
176
        /* atomic_dec_return() is a mb(), we'll always see the updated
177
         * sd->s_sibling.
178
         */
179
        cmpl = (void *)sd->s_sibling;
180
        complete(cmpl);
181
}
182
 
183
/**
184
 *      sysfs_get_active_two - get active references to sysfs_dirent and parent
185
 *      @sd: sysfs_dirent of interest
186
 *
187
 *      Get active reference to @sd and its parent.  Parent's active
188
 *      reference is grabbed first.  This function is noop if @sd is
189
 *      NULL.
190
 *
191
 *      RETURNS:
192
 *      Pointer to @sd on success, NULL on failure.
193
 */
194
struct sysfs_dirent *sysfs_get_active_two(struct sysfs_dirent *sd)
195
{
196
        if (sd) {
197
                if (sd->s_parent && unlikely(!sysfs_get_active(sd->s_parent)))
198
                        return NULL;
199
                if (unlikely(!sysfs_get_active(sd))) {
200
                        sysfs_put_active(sd->s_parent);
201
                        return NULL;
202
                }
203
        }
204
        return sd;
205
}
206
 
207
/**
208
 *      sysfs_put_active_two - put active references to sysfs_dirent and parent
209
 *      @sd: sysfs_dirent of interest
210
 *
211
 *      Put active references to @sd and its parent.  This function is
212
 *      noop if @sd is NULL.
213
 */
214
void sysfs_put_active_two(struct sysfs_dirent *sd)
215
{
216
        if (sd) {
217
                sysfs_put_active(sd);
218
                sysfs_put_active(sd->s_parent);
219
        }
220
}
221
 
222
/**
223
 *      sysfs_deactivate - deactivate sysfs_dirent
224
 *      @sd: sysfs_dirent to deactivate
225
 *
226
 *      Deny new active references and drain existing ones.
227
 */
228
static void sysfs_deactivate(struct sysfs_dirent *sd)
229
{
230
        DECLARE_COMPLETION_ONSTACK(wait);
231
        int v;
232
 
233
        BUG_ON(sd->s_sibling || !(sd->s_flags & SYSFS_FLAG_REMOVED));
234
        sd->s_sibling = (void *)&wait;
235
 
236
        /* atomic_add_return() is a mb(), put_active() will always see
237
         * the updated sd->s_sibling.
238
         */
239
        v = atomic_add_return(SD_DEACTIVATED_BIAS, &sd->s_active);
240
 
241
        if (v != SD_DEACTIVATED_BIAS)
242
                wait_for_completion(&wait);
243
 
244
        sd->s_sibling = NULL;
245
}
246
 
247
static int sysfs_alloc_ino(ino_t *pino)
248
{
249
        int ino, rc;
250
 
251
 retry:
252
        spin_lock(&sysfs_ino_lock);
253
        rc = ida_get_new_above(&sysfs_ino_ida, 2, &ino);
254
        spin_unlock(&sysfs_ino_lock);
255
 
256
        if (rc == -EAGAIN) {
257
                if (ida_pre_get(&sysfs_ino_ida, GFP_KERNEL))
258
                        goto retry;
259
                rc = -ENOMEM;
260
        }
261
 
262
        *pino = ino;
263
        return rc;
264
}
265
 
266
static void sysfs_free_ino(ino_t ino)
267
{
268
        spin_lock(&sysfs_ino_lock);
269
        ida_remove(&sysfs_ino_ida, ino);
270
        spin_unlock(&sysfs_ino_lock);
271
}
272
 
273
void release_sysfs_dirent(struct sysfs_dirent * sd)
274
{
275
        struct sysfs_dirent *parent_sd;
276
 
277
 repeat:
278
        /* Moving/renaming is always done while holding reference.
279
         * sd->s_parent won't change beneath us.
280
         */
281
        parent_sd = sd->s_parent;
282
 
283
        if (sysfs_type(sd) == SYSFS_KOBJ_LINK)
284
                sysfs_put(sd->s_symlink.target_sd);
285
        if (sysfs_type(sd) & SYSFS_COPY_NAME)
286
                kfree(sd->s_name);
287
        kfree(sd->s_iattr);
288
        sysfs_free_ino(sd->s_ino);
289
        kmem_cache_free(sysfs_dir_cachep, sd);
290
 
291
        sd = parent_sd;
292
        if (sd && atomic_dec_and_test(&sd->s_count))
293
                goto repeat;
294
}
295
 
296
static void sysfs_d_iput(struct dentry * dentry, struct inode * inode)
297
{
298
        struct sysfs_dirent * sd = dentry->d_fsdata;
299
 
300
        sysfs_put(sd);
301
        iput(inode);
302
}
303
 
304
static struct dentry_operations sysfs_dentry_ops = {
305
        .d_iput         = sysfs_d_iput,
306
};
307
 
308
struct sysfs_dirent *sysfs_new_dirent(const char *name, umode_t mode, int type)
309
{
310
        char *dup_name = NULL;
311
        struct sysfs_dirent *sd;
312
 
313
        if (type & SYSFS_COPY_NAME) {
314
                name = dup_name = kstrdup(name, GFP_KERNEL);
315
                if (!name)
316
                        return NULL;
317
        }
318
 
319
        sd = kmem_cache_zalloc(sysfs_dir_cachep, GFP_KERNEL);
320
        if (!sd)
321
                goto err_out1;
322
 
323
        if (sysfs_alloc_ino(&sd->s_ino))
324
                goto err_out2;
325
 
326
        atomic_set(&sd->s_count, 1);
327
        atomic_set(&sd->s_active, 0);
328
 
329
        sd->s_name = name;
330
        sd->s_mode = mode;
331
        sd->s_flags = type;
332
 
333
        return sd;
334
 
335
 err_out2:
336
        kmem_cache_free(sysfs_dir_cachep, sd);
337
 err_out1:
338
        kfree(dup_name);
339
        return NULL;
340
}
341
 
342
static int sysfs_ilookup_test(struct inode *inode, void *arg)
343
{
344
        struct sysfs_dirent *sd = arg;
345
        return inode->i_ino == sd->s_ino;
346
}
347
 
348
/**
349
 *      sysfs_addrm_start - prepare for sysfs_dirent add/remove
350
 *      @acxt: pointer to sysfs_addrm_cxt to be used
351
 *      @parent_sd: parent sysfs_dirent
352
 *
353
 *      This function is called when the caller is about to add or
354
 *      remove sysfs_dirent under @parent_sd.  This function acquires
355
 *      sysfs_mutex, grabs inode for @parent_sd if available and lock
356
 *      i_mutex of it.  @acxt is used to keep and pass context to
357
 *      other addrm functions.
358
 *
359
 *      LOCKING:
360
 *      Kernel thread context (may sleep).  sysfs_mutex is locked on
361
 *      return.  i_mutex of parent inode is locked on return if
362
 *      available.
363
 */
364
void sysfs_addrm_start(struct sysfs_addrm_cxt *acxt,
365
                       struct sysfs_dirent *parent_sd)
366
{
367
        struct inode *inode;
368
 
369
        memset(acxt, 0, sizeof(*acxt));
370
        acxt->parent_sd = parent_sd;
371
 
372
        /* Lookup parent inode.  inode initialization and I_NEW
373
         * clearing are protected by sysfs_mutex.  By grabbing it and
374
         * looking up with _nowait variant, inode state can be
375
         * determined reliably.
376
         */
377
        mutex_lock(&sysfs_mutex);
378
 
379
        inode = ilookup5_nowait(sysfs_sb, parent_sd->s_ino, sysfs_ilookup_test,
380
                                parent_sd);
381
 
382
        if (inode && !(inode->i_state & I_NEW)) {
383
                /* parent inode available */
384
                acxt->parent_inode = inode;
385
 
386
                /* sysfs_mutex is below i_mutex in lock hierarchy.
387
                 * First, trylock i_mutex.  If fails, unlock
388
                 * sysfs_mutex and lock them in order.
389
                 */
390
                if (!mutex_trylock(&inode->i_mutex)) {
391
                        mutex_unlock(&sysfs_mutex);
392
                        mutex_lock(&inode->i_mutex);
393
                        mutex_lock(&sysfs_mutex);
394
                }
395
        } else
396
                iput(inode);
397
}
398
 
399
/**
400
 *      sysfs_add_one - add sysfs_dirent to parent
401
 *      @acxt: addrm context to use
402
 *      @sd: sysfs_dirent to be added
403
 *
404
 *      Get @acxt->parent_sd and set sd->s_parent to it and increment
405
 *      nlink of parent inode if @sd is a directory and link into the
406
 *      children list of the parent.
407
 *
408
 *      This function should be called between calls to
409
 *      sysfs_addrm_start() and sysfs_addrm_finish() and should be
410
 *      passed the same @acxt as passed to sysfs_addrm_start().
411
 *
412
 *      LOCKING:
413
 *      Determined by sysfs_addrm_start().
414
 *
415
 *      RETURNS:
416
 *      0 on success, -EEXIST if entry with the given name already
417
 *      exists.
418
 */
419
int sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd)
420
{
421
        if (sysfs_find_dirent(acxt->parent_sd, sd->s_name)) {
422
                printk(KERN_WARNING "sysfs: duplicate filename '%s' "
423
                       "can not be created\n", sd->s_name);
424
                WARN_ON(1);
425
                return -EEXIST;
426
        }
427
 
428
        sd->s_parent = sysfs_get(acxt->parent_sd);
429
 
430
        if (sysfs_type(sd) == SYSFS_DIR && acxt->parent_inode)
431
                inc_nlink(acxt->parent_inode);
432
 
433
        acxt->cnt++;
434
 
435
        sysfs_link_sibling(sd);
436
 
437
        return 0;
438
}
439
 
440
/**
441
 *      sysfs_remove_one - remove sysfs_dirent from parent
442
 *      @acxt: addrm context to use
443
 *      @sd: sysfs_dirent to be added
444
 *
445
 *      Mark @sd removed and drop nlink of parent inode if @sd is a
446
 *      directory.  @sd is unlinked from the children list.
447
 *
448
 *      This function should be called between calls to
449
 *      sysfs_addrm_start() and sysfs_addrm_finish() and should be
450
 *      passed the same @acxt as passed to sysfs_addrm_start().
451
 *
452
 *      LOCKING:
453
 *      Determined by sysfs_addrm_start().
454
 */
455
void sysfs_remove_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd)
456
{
457
        BUG_ON(sd->s_flags & SYSFS_FLAG_REMOVED);
458
 
459
        sysfs_unlink_sibling(sd);
460
 
461
        sd->s_flags |= SYSFS_FLAG_REMOVED;
462
        sd->s_sibling = acxt->removed;
463
        acxt->removed = sd;
464
 
465
        if (sysfs_type(sd) == SYSFS_DIR && acxt->parent_inode)
466
                drop_nlink(acxt->parent_inode);
467
 
468
        acxt->cnt++;
469
}
470
 
471
/**
472
 *      sysfs_drop_dentry - drop dentry for the specified sysfs_dirent
473
 *      @sd: target sysfs_dirent
474
 *
475
 *      Drop dentry for @sd.  @sd must have been unlinked from its
476
 *      parent on entry to this function such that it can't be looked
477
 *      up anymore.
478
 */
479
static void sysfs_drop_dentry(struct sysfs_dirent *sd)
480
{
481
        struct inode *inode;
482
        struct dentry *dentry;
483
 
484
        inode = ilookup(sysfs_sb, sd->s_ino);
485
        if (!inode)
486
                return;
487
 
488
        /* Drop any existing dentries associated with sd.
489
         *
490
         * For the dentry to be properly freed we need to grab a
491
         * reference to the dentry under the dcache lock,  unhash it,
492
         * and then put it.  The playing with the dentry count allows
493
         * dput to immediately free the dentry  if it is not in use.
494
         */
495
repeat:
496
        spin_lock(&dcache_lock);
497
        list_for_each_entry(dentry, &inode->i_dentry, d_alias) {
498
                if (d_unhashed(dentry))
499
                        continue;
500
                dget_locked(dentry);
501
                spin_lock(&dentry->d_lock);
502
                __d_drop(dentry);
503
                spin_unlock(&dentry->d_lock);
504
                spin_unlock(&dcache_lock);
505
                dput(dentry);
506
                goto repeat;
507
        }
508
        spin_unlock(&dcache_lock);
509
 
510
        /* adjust nlink and update timestamp */
511
        mutex_lock(&inode->i_mutex);
512
 
513
        inode->i_ctime = CURRENT_TIME;
514
        drop_nlink(inode);
515
        if (sysfs_type(sd) == SYSFS_DIR)
516
                drop_nlink(inode);
517
 
518
        mutex_unlock(&inode->i_mutex);
519
 
520
        iput(inode);
521
}
522
 
523
/**
524
 *      sysfs_addrm_finish - finish up sysfs_dirent add/remove
525
 *      @acxt: addrm context to finish up
526
 *
527
 *      Finish up sysfs_dirent add/remove.  Resources acquired by
528
 *      sysfs_addrm_start() are released and removed sysfs_dirents are
529
 *      cleaned up.  Timestamps on the parent inode are updated.
530
 *
531
 *      LOCKING:
532
 *      All mutexes acquired by sysfs_addrm_start() are released.
533
 */
534
void sysfs_addrm_finish(struct sysfs_addrm_cxt *acxt)
535
{
536
        /* release resources acquired by sysfs_addrm_start() */
537
        mutex_unlock(&sysfs_mutex);
538
        if (acxt->parent_inode) {
539
                struct inode *inode = acxt->parent_inode;
540
 
541
                /* if added/removed, update timestamps on the parent */
542
                if (acxt->cnt)
543
                        inode->i_ctime = inode->i_mtime = CURRENT_TIME;
544
 
545
                mutex_unlock(&inode->i_mutex);
546
                iput(inode);
547
        }
548
 
549
        /* kill removed sysfs_dirents */
550
        while (acxt->removed) {
551
                struct sysfs_dirent *sd = acxt->removed;
552
 
553
                acxt->removed = sd->s_sibling;
554
                sd->s_sibling = NULL;
555
 
556
                sysfs_drop_dentry(sd);
557
                sysfs_deactivate(sd);
558
                sysfs_put(sd);
559
        }
560
}
561
 
562
/**
563
 *      sysfs_find_dirent - find sysfs_dirent with the given name
564
 *      @parent_sd: sysfs_dirent to search under
565
 *      @name: name to look for
566
 *
567
 *      Look for sysfs_dirent with name @name under @parent_sd.
568
 *
569
 *      LOCKING:
570
 *      mutex_lock(sysfs_mutex)
571
 *
572
 *      RETURNS:
573
 *      Pointer to sysfs_dirent if found, NULL if not.
574
 */
575
struct sysfs_dirent *sysfs_find_dirent(struct sysfs_dirent *parent_sd,
576
                                       const unsigned char *name)
577
{
578
        struct sysfs_dirent *sd;
579
 
580
        for (sd = parent_sd->s_dir.children; sd; sd = sd->s_sibling)
581
                if (!strcmp(sd->s_name, name))
582
                        return sd;
583
        return NULL;
584
}
585
 
586
/**
587
 *      sysfs_get_dirent - find and get sysfs_dirent with the given name
588
 *      @parent_sd: sysfs_dirent to search under
589
 *      @name: name to look for
590
 *
591
 *      Look for sysfs_dirent with name @name under @parent_sd and get
592
 *      it if found.
593
 *
594
 *      LOCKING:
595
 *      Kernel thread context (may sleep).  Grabs sysfs_mutex.
596
 *
597
 *      RETURNS:
598
 *      Pointer to sysfs_dirent if found, NULL if not.
599
 */
600
struct sysfs_dirent *sysfs_get_dirent(struct sysfs_dirent *parent_sd,
601
                                      const unsigned char *name)
602
{
603
        struct sysfs_dirent *sd;
604
 
605
        mutex_lock(&sysfs_mutex);
606
        sd = sysfs_find_dirent(parent_sd, name);
607
        sysfs_get(sd);
608
        mutex_unlock(&sysfs_mutex);
609
 
610
        return sd;
611
}
612
 
613
static int create_dir(struct kobject *kobj, struct sysfs_dirent *parent_sd,
614
                      const char *name, struct sysfs_dirent **p_sd)
615
{
616
        umode_t mode = S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO;
617
        struct sysfs_addrm_cxt acxt;
618
        struct sysfs_dirent *sd;
619
        int rc;
620
 
621
        /* allocate */
622
        sd = sysfs_new_dirent(name, mode, SYSFS_DIR);
623
        if (!sd)
624
                return -ENOMEM;
625
        sd->s_dir.kobj = kobj;
626
 
627
        /* link in */
628
        sysfs_addrm_start(&acxt, parent_sd);
629
        rc = sysfs_add_one(&acxt, sd);
630
        sysfs_addrm_finish(&acxt);
631
 
632
        if (rc == 0)
633
                *p_sd = sd;
634
        else
635
                sysfs_put(sd);
636
 
637
        return rc;
638
}
639
 
640
int sysfs_create_subdir(struct kobject *kobj, const char *name,
641
                        struct sysfs_dirent **p_sd)
642
{
643
        return create_dir(kobj, kobj->sd, name, p_sd);
644
}
645
 
646
/**
647
 *      sysfs_create_dir - create a directory for an object.
648
 *      @kobj:          object we're creating directory for.
649
 */
650
int sysfs_create_dir(struct kobject * kobj)
651
{
652
        struct sysfs_dirent *parent_sd, *sd;
653
        int error = 0;
654
 
655
        BUG_ON(!kobj);
656
 
657
        if (kobj->parent)
658
                parent_sd = kobj->parent->sd;
659
        else
660
                parent_sd = &sysfs_root;
661
 
662
        error = create_dir(kobj, parent_sd, kobject_name(kobj), &sd);
663
        if (!error)
664
                kobj->sd = sd;
665
        return error;
666
}
667
 
668
static struct dentry * sysfs_lookup(struct inode *dir, struct dentry *dentry,
669
                                struct nameidata *nd)
670
{
671
        struct dentry *ret = NULL;
672
        struct sysfs_dirent *parent_sd = dentry->d_parent->d_fsdata;
673
        struct sysfs_dirent *sd;
674
        struct inode *inode;
675
 
676
        mutex_lock(&sysfs_mutex);
677
 
678
        sd = sysfs_find_dirent(parent_sd, dentry->d_name.name);
679
 
680
        /* no such entry */
681
        if (!sd) {
682
                ret = ERR_PTR(-ENOENT);
683
                goto out_unlock;
684
        }
685
 
686
        /* attach dentry and inode */
687
        inode = sysfs_get_inode(sd);
688
        if (!inode) {
689
                ret = ERR_PTR(-ENOMEM);
690
                goto out_unlock;
691
        }
692
 
693
        /* instantiate and hash dentry */
694
        dentry->d_op = &sysfs_dentry_ops;
695
        dentry->d_fsdata = sysfs_get(sd);
696
        d_instantiate(dentry, inode);
697
        d_rehash(dentry);
698
 
699
 out_unlock:
700
        mutex_unlock(&sysfs_mutex);
701
        return ret;
702
}
703
 
704
const struct inode_operations sysfs_dir_inode_operations = {
705
        .lookup         = sysfs_lookup,
706
        .setattr        = sysfs_setattr,
707
};
708
 
709
static void remove_dir(struct sysfs_dirent *sd)
710
{
711
        struct sysfs_addrm_cxt acxt;
712
 
713
        sysfs_addrm_start(&acxt, sd->s_parent);
714
        sysfs_remove_one(&acxt, sd);
715
        sysfs_addrm_finish(&acxt);
716
}
717
 
718
void sysfs_remove_subdir(struct sysfs_dirent *sd)
719
{
720
        remove_dir(sd);
721
}
722
 
723
 
724
static void __sysfs_remove_dir(struct sysfs_dirent *dir_sd)
725
{
726
        struct sysfs_addrm_cxt acxt;
727
        struct sysfs_dirent **pos;
728
 
729
        if (!dir_sd)
730
                return;
731
 
732
        pr_debug("sysfs %s: removing dir\n", dir_sd->s_name);
733
        sysfs_addrm_start(&acxt, dir_sd);
734
        pos = &dir_sd->s_dir.children;
735
        while (*pos) {
736
                struct sysfs_dirent *sd = *pos;
737
 
738
                if (sysfs_type(sd) != SYSFS_DIR)
739
                        sysfs_remove_one(&acxt, sd);
740
                else
741
                        pos = &(*pos)->s_sibling;
742
        }
743
        sysfs_addrm_finish(&acxt);
744
 
745
        remove_dir(dir_sd);
746
}
747
 
748
/**
749
 *      sysfs_remove_dir - remove an object's directory.
750
 *      @kobj:  object.
751
 *
752
 *      The only thing special about this is that we remove any files in
753
 *      the directory before we remove the directory, and we've inlined
754
 *      what used to be sysfs_rmdir() below, instead of calling separately.
755
 */
756
 
757
void sysfs_remove_dir(struct kobject * kobj)
758
{
759
        struct sysfs_dirent *sd = kobj->sd;
760
 
761
        spin_lock(&sysfs_assoc_lock);
762
        kobj->sd = NULL;
763
        spin_unlock(&sysfs_assoc_lock);
764
 
765
        __sysfs_remove_dir(sd);
766
}
767
 
768
int sysfs_rename_dir(struct kobject * kobj, const char *new_name)
769
{
770
        struct sysfs_dirent *sd = kobj->sd;
771
        struct dentry *parent = NULL;
772
        struct dentry *old_dentry = NULL, *new_dentry = NULL;
773
        const char *dup_name = NULL;
774
        int error;
775
 
776
        mutex_lock(&sysfs_rename_mutex);
777
 
778
        error = 0;
779
        if (strcmp(sd->s_name, new_name) == 0)
780
                goto out;       /* nothing to rename */
781
 
782
        /* get the original dentry */
783
        old_dentry = sysfs_get_dentry(sd);
784
        if (IS_ERR(old_dentry)) {
785
                error = PTR_ERR(old_dentry);
786
                old_dentry = NULL;
787
                goto out;
788
        }
789
 
790
        parent = old_dentry->d_parent;
791
 
792
        /* lock parent and get dentry for new name */
793
        mutex_lock(&parent->d_inode->i_mutex);
794
        mutex_lock(&sysfs_mutex);
795
 
796
        error = -EEXIST;
797
        if (sysfs_find_dirent(sd->s_parent, new_name))
798
                goto out_unlock;
799
 
800
        error = -ENOMEM;
801
        new_dentry = d_alloc_name(parent, new_name);
802
        if (!new_dentry)
803
                goto out_unlock;
804
 
805
        /* rename kobject and sysfs_dirent */
806
        error = -ENOMEM;
807
        new_name = dup_name = kstrdup(new_name, GFP_KERNEL);
808
        if (!new_name)
809
                goto out_unlock;
810
 
811
        error = kobject_set_name(kobj, "%s", new_name);
812
        if (error)
813
                goto out_unlock;
814
 
815
        dup_name = sd->s_name;
816
        sd->s_name = new_name;
817
 
818
        /* rename */
819
        d_add(new_dentry, NULL);
820
        d_move(old_dentry, new_dentry);
821
 
822
        error = 0;
823
 out_unlock:
824
        mutex_unlock(&sysfs_mutex);
825
        mutex_unlock(&parent->d_inode->i_mutex);
826
        kfree(dup_name);
827
        dput(old_dentry);
828
        dput(new_dentry);
829
 out:
830
        mutex_unlock(&sysfs_rename_mutex);
831
        return error;
832
}
833
 
834
int sysfs_move_dir(struct kobject *kobj, struct kobject *new_parent_kobj)
835
{
836
        struct sysfs_dirent *sd = kobj->sd;
837
        struct sysfs_dirent *new_parent_sd;
838
        struct dentry *old_parent, *new_parent = NULL;
839
        struct dentry *old_dentry = NULL, *new_dentry = NULL;
840
        int error;
841
 
842
        mutex_lock(&sysfs_rename_mutex);
843
        BUG_ON(!sd->s_parent);
844
        new_parent_sd = new_parent_kobj->sd ? new_parent_kobj->sd : &sysfs_root;
845
 
846
        error = 0;
847
        if (sd->s_parent == new_parent_sd)
848
                goto out;       /* nothing to move */
849
 
850
        /* get dentries */
851
        old_dentry = sysfs_get_dentry(sd);
852
        if (IS_ERR(old_dentry)) {
853
                error = PTR_ERR(old_dentry);
854
                old_dentry = NULL;
855
                goto out;
856
        }
857
        old_parent = old_dentry->d_parent;
858
 
859
        new_parent = sysfs_get_dentry(new_parent_sd);
860
        if (IS_ERR(new_parent)) {
861
                error = PTR_ERR(new_parent);
862
                new_parent = NULL;
863
                goto out;
864
        }
865
 
866
again:
867
        mutex_lock(&old_parent->d_inode->i_mutex);
868
        if (!mutex_trylock(&new_parent->d_inode->i_mutex)) {
869
                mutex_unlock(&old_parent->d_inode->i_mutex);
870
                goto again;
871
        }
872
        mutex_lock(&sysfs_mutex);
873
 
874
        error = -EEXIST;
875
        if (sysfs_find_dirent(new_parent_sd, sd->s_name))
876
                goto out_unlock;
877
 
878
        error = -ENOMEM;
879
        new_dentry = d_alloc_name(new_parent, sd->s_name);
880
        if (!new_dentry)
881
                goto out_unlock;
882
 
883
        error = 0;
884
        d_add(new_dentry, NULL);
885
        d_move(old_dentry, new_dentry);
886
 
887
        /* Remove from old parent's list and insert into new parent's list. */
888
        sysfs_unlink_sibling(sd);
889
        sysfs_get(new_parent_sd);
890
        sysfs_put(sd->s_parent);
891
        sd->s_parent = new_parent_sd;
892
        sysfs_link_sibling(sd);
893
 
894
 out_unlock:
895
        mutex_unlock(&sysfs_mutex);
896
        mutex_unlock(&new_parent->d_inode->i_mutex);
897
        mutex_unlock(&old_parent->d_inode->i_mutex);
898
 out:
899
        dput(new_parent);
900
        dput(old_dentry);
901
        dput(new_dentry);
902
        mutex_unlock(&sysfs_rename_mutex);
903
        return error;
904
}
905
 
906
/* Relationship between s_mode and the DT_xxx types */
907
static inline unsigned char dt_type(struct sysfs_dirent *sd)
908
{
909
        return (sd->s_mode >> 12) & 15;
910
}
911
 
912
static int sysfs_readdir(struct file * filp, void * dirent, filldir_t filldir)
913
{
914
        struct dentry *dentry = filp->f_path.dentry;
915
        struct sysfs_dirent * parent_sd = dentry->d_fsdata;
916
        struct sysfs_dirent *pos;
917
        ino_t ino;
918
 
919
        if (filp->f_pos == 0) {
920
                ino = parent_sd->s_ino;
921
                if (filldir(dirent, ".", 1, filp->f_pos, ino, DT_DIR) == 0)
922
                        filp->f_pos++;
923
        }
924
        if (filp->f_pos == 1) {
925
                if (parent_sd->s_parent)
926
                        ino = parent_sd->s_parent->s_ino;
927
                else
928
                        ino = parent_sd->s_ino;
929
                if (filldir(dirent, "..", 2, filp->f_pos, ino, DT_DIR) == 0)
930
                        filp->f_pos++;
931
        }
932
        if ((filp->f_pos > 1) && (filp->f_pos < INT_MAX)) {
933
                mutex_lock(&sysfs_mutex);
934
 
935
                /* Skip the dentries we have already reported */
936
                pos = parent_sd->s_dir.children;
937
                while (pos && (filp->f_pos > pos->s_ino))
938
                        pos = pos->s_sibling;
939
 
940
                for ( ; pos; pos = pos->s_sibling) {
941
                        const char * name;
942
                        int len;
943
 
944
                        name = pos->s_name;
945
                        len = strlen(name);
946
                        filp->f_pos = ino = pos->s_ino;
947
 
948
                        if (filldir(dirent, name, len, filp->f_pos, ino,
949
                                         dt_type(pos)) < 0)
950
                                break;
951
                }
952
                if (!pos)
953
                        filp->f_pos = INT_MAX;
954
                mutex_unlock(&sysfs_mutex);
955
        }
956
        return 0;
957
}
958
 
959
 
960
const struct file_operations sysfs_dir_operations = {
961
        .read           = generic_read_dir,
962
        .readdir        = sysfs_readdir,
963
};

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