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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * dir.c - Operations for sysfs directories. | |
3 | */ | |
4 | ||
5 | #undef DEBUG | |
6 | ||
7 | #include <linux/fs.h> | |
8 | #include <linux/mount.h> | |
9 | #include <linux/module.h> | |
10 | #include <linux/kobject.h> | |
5f45f1a7 | 11 | #include <linux/namei.h> |
2b611bb7 | 12 | #include <linux/idr.h> |
8619f979 | 13 | #include <linux/completion.h> |
869512ab | 14 | #include <linux/mutex.h> |
1da177e4 LT |
15 | #include "sysfs.h" |
16 | ||
3007e997 | 17 | DEFINE_MUTEX(sysfs_mutex); |
5f995323 | 18 | spinlock_t sysfs_assoc_lock = SPIN_LOCK_UNLOCKED; |
1da177e4 | 19 | |
2b611bb7 TH |
20 | static spinlock_t sysfs_ino_lock = SPIN_LOCK_UNLOCKED; |
21 | static DEFINE_IDA(sysfs_ino_ida); | |
22 | ||
0c73f18b TH |
23 | /** |
24 | * sysfs_link_sibling - link sysfs_dirent into sibling list | |
25 | * @sd: sysfs_dirent of interest | |
26 | * | |
27 | * Link @sd into its sibling list which starts from | |
28 | * sd->s_parent->s_children. | |
29 | * | |
30 | * Locking: | |
3007e997 | 31 | * mutex_lock(sysfs_mutex) |
0c73f18b | 32 | */ |
41fc1c27 | 33 | static void sysfs_link_sibling(struct sysfs_dirent *sd) |
0c73f18b TH |
34 | { |
35 | struct sysfs_dirent *parent_sd = sd->s_parent; | |
36 | ||
37 | BUG_ON(sd->s_sibling); | |
38 | sd->s_sibling = parent_sd->s_children; | |
39 | parent_sd->s_children = sd; | |
40 | } | |
41 | ||
42 | /** | |
43 | * sysfs_unlink_sibling - unlink sysfs_dirent from sibling list | |
44 | * @sd: sysfs_dirent of interest | |
45 | * | |
46 | * Unlink @sd from its sibling list which starts from | |
47 | * sd->s_parent->s_children. | |
48 | * | |
49 | * Locking: | |
3007e997 | 50 | * mutex_lock(sysfs_mutex) |
0c73f18b | 51 | */ |
41fc1c27 | 52 | static void sysfs_unlink_sibling(struct sysfs_dirent *sd) |
0c73f18b TH |
53 | { |
54 | struct sysfs_dirent **pos; | |
55 | ||
56 | for (pos = &sd->s_parent->s_children; *pos; pos = &(*pos)->s_sibling) { | |
57 | if (*pos == sd) { | |
58 | *pos = sd->s_sibling; | |
59 | sd->s_sibling = NULL; | |
60 | break; | |
61 | } | |
62 | } | |
63 | } | |
64 | ||
53e0ae92 TH |
65 | /** |
66 | * sysfs_get_dentry - get dentry for the given sysfs_dirent | |
67 | * @sd: sysfs_dirent of interest | |
68 | * | |
69 | * Get dentry for @sd. Dentry is looked up if currently not | |
70 | * present. This function climbs sysfs_dirent tree till it | |
71 | * reaches a sysfs_dirent with valid dentry attached and descends | |
72 | * down from there looking up dentry for each step. | |
73 | * | |
74 | * LOCKING: | |
75 | * Kernel thread context (may sleep) | |
76 | * | |
77 | * RETURNS: | |
78 | * Pointer to found dentry on success, ERR_PTR() value on error. | |
79 | */ | |
80 | struct dentry *sysfs_get_dentry(struct sysfs_dirent *sd) | |
81 | { | |
82 | struct sysfs_dirent *cur; | |
83 | struct dentry *parent_dentry, *dentry; | |
84 | int i, depth; | |
85 | ||
86 | /* Find the first parent which has valid s_dentry and get the | |
87 | * dentry. | |
88 | */ | |
89 | mutex_lock(&sysfs_mutex); | |
90 | restart0: | |
91 | spin_lock(&sysfs_assoc_lock); | |
92 | restart1: | |
93 | spin_lock(&dcache_lock); | |
94 | ||
95 | dentry = NULL; | |
96 | depth = 0; | |
97 | cur = sd; | |
98 | while (!cur->s_dentry || !cur->s_dentry->d_inode) { | |
99 | if (cur->s_flags & SYSFS_FLAG_REMOVED) { | |
100 | dentry = ERR_PTR(-ENOENT); | |
101 | depth = 0; | |
102 | break; | |
103 | } | |
104 | cur = cur->s_parent; | |
105 | depth++; | |
106 | } | |
107 | if (!IS_ERR(dentry)) | |
108 | dentry = dget_locked(cur->s_dentry); | |
109 | ||
110 | spin_unlock(&dcache_lock); | |
111 | spin_unlock(&sysfs_assoc_lock); | |
112 | ||
113 | /* from the found dentry, look up depth times */ | |
114 | while (depth--) { | |
115 | /* find and get depth'th ancestor */ | |
116 | for (cur = sd, i = 0; cur && i < depth; i++) | |
117 | cur = cur->s_parent; | |
118 | ||
119 | /* This can happen if tree structure was modified due | |
120 | * to move/rename. Restart. | |
121 | */ | |
122 | if (i != depth) { | |
123 | dput(dentry); | |
124 | goto restart0; | |
125 | } | |
126 | ||
127 | sysfs_get(cur); | |
128 | ||
129 | mutex_unlock(&sysfs_mutex); | |
130 | ||
131 | /* look it up */ | |
132 | parent_dentry = dentry; | |
25328026 | 133 | mutex_lock(&parent_dentry->d_inode->i_mutex); |
53e0ae92 TH |
134 | dentry = lookup_one_len_kern(cur->s_name, parent_dentry, |
135 | strlen(cur->s_name)); | |
25328026 | 136 | mutex_unlock(&parent_dentry->d_inode->i_mutex); |
53e0ae92 TH |
137 | dput(parent_dentry); |
138 | ||
139 | if (IS_ERR(dentry)) { | |
140 | sysfs_put(cur); | |
141 | return dentry; | |
142 | } | |
143 | ||
144 | mutex_lock(&sysfs_mutex); | |
145 | spin_lock(&sysfs_assoc_lock); | |
146 | ||
147 | /* This, again, can happen if tree structure has | |
148 | * changed and we looked up the wrong thing. Restart. | |
149 | */ | |
150 | if (cur->s_dentry != dentry) { | |
151 | dput(dentry); | |
152 | sysfs_put(cur); | |
153 | goto restart1; | |
154 | } | |
155 | ||
156 | spin_unlock(&sysfs_assoc_lock); | |
157 | ||
158 | sysfs_put(cur); | |
159 | } | |
160 | ||
161 | mutex_unlock(&sysfs_mutex); | |
162 | return dentry; | |
163 | } | |
164 | ||
b6b4a439 TH |
165 | /** |
166 | * sysfs_get_active - get an active reference to sysfs_dirent | |
167 | * @sd: sysfs_dirent to get an active reference to | |
168 | * | |
169 | * Get an active reference of @sd. This function is noop if @sd | |
170 | * is NULL. | |
171 | * | |
172 | * RETURNS: | |
173 | * Pointer to @sd on success, NULL on failure. | |
174 | */ | |
175 | struct sysfs_dirent *sysfs_get_active(struct sysfs_dirent *sd) | |
176 | { | |
8619f979 TH |
177 | if (unlikely(!sd)) |
178 | return NULL; | |
179 | ||
180 | while (1) { | |
181 | int v, t; | |
182 | ||
183 | v = atomic_read(&sd->s_active); | |
184 | if (unlikely(v < 0)) | |
185 | return NULL; | |
186 | ||
187 | t = atomic_cmpxchg(&sd->s_active, v, v + 1); | |
188 | if (likely(t == v)) | |
189 | return sd; | |
190 | if (t < 0) | |
191 | return NULL; | |
192 | ||
193 | cpu_relax(); | |
b6b4a439 | 194 | } |
b6b4a439 TH |
195 | } |
196 | ||
197 | /** | |
198 | * sysfs_put_active - put an active reference to sysfs_dirent | |
199 | * @sd: sysfs_dirent to put an active reference to | |
200 | * | |
201 | * Put an active reference to @sd. This function is noop if @sd | |
202 | * is NULL. | |
203 | */ | |
204 | void sysfs_put_active(struct sysfs_dirent *sd) | |
205 | { | |
8619f979 TH |
206 | struct completion *cmpl; |
207 | int v; | |
208 | ||
209 | if (unlikely(!sd)) | |
210 | return; | |
211 | ||
212 | v = atomic_dec_return(&sd->s_active); | |
213 | if (likely(v != SD_DEACTIVATED_BIAS)) | |
214 | return; | |
215 | ||
216 | /* atomic_dec_return() is a mb(), we'll always see the updated | |
0c73f18b | 217 | * sd->s_sibling. |
8619f979 | 218 | */ |
0c73f18b | 219 | cmpl = (void *)sd->s_sibling; |
8619f979 | 220 | complete(cmpl); |
b6b4a439 TH |
221 | } |
222 | ||
223 | /** | |
224 | * sysfs_get_active_two - get active references to sysfs_dirent and parent | |
225 | * @sd: sysfs_dirent of interest | |
226 | * | |
227 | * Get active reference to @sd and its parent. Parent's active | |
228 | * reference is grabbed first. This function is noop if @sd is | |
229 | * NULL. | |
230 | * | |
231 | * RETURNS: | |
232 | * Pointer to @sd on success, NULL on failure. | |
233 | */ | |
234 | struct sysfs_dirent *sysfs_get_active_two(struct sysfs_dirent *sd) | |
235 | { | |
236 | if (sd) { | |
237 | if (sd->s_parent && unlikely(!sysfs_get_active(sd->s_parent))) | |
238 | return NULL; | |
239 | if (unlikely(!sysfs_get_active(sd))) { | |
240 | sysfs_put_active(sd->s_parent); | |
241 | return NULL; | |
242 | } | |
243 | } | |
244 | return sd; | |
245 | } | |
246 | ||
247 | /** | |
248 | * sysfs_put_active_two - put active references to sysfs_dirent and parent | |
249 | * @sd: sysfs_dirent of interest | |
250 | * | |
251 | * Put active references to @sd and its parent. This function is | |
252 | * noop if @sd is NULL. | |
253 | */ | |
254 | void sysfs_put_active_two(struct sysfs_dirent *sd) | |
255 | { | |
256 | if (sd) { | |
257 | sysfs_put_active(sd); | |
258 | sysfs_put_active(sd->s_parent); | |
259 | } | |
260 | } | |
261 | ||
262 | /** | |
263 | * sysfs_deactivate - deactivate sysfs_dirent | |
264 | * @sd: sysfs_dirent to deactivate | |
265 | * | |
8619f979 | 266 | * Deny new active references and drain existing ones. |
b6b4a439 | 267 | */ |
fb6896da | 268 | static void sysfs_deactivate(struct sysfs_dirent *sd) |
b6b4a439 | 269 | { |
8619f979 TH |
270 | DECLARE_COMPLETION_ONSTACK(wait); |
271 | int v; | |
b6b4a439 | 272 | |
380e6fbb | 273 | BUG_ON(sd->s_sibling || !(sd->s_flags & SYSFS_FLAG_REMOVED)); |
0c73f18b | 274 | sd->s_sibling = (void *)&wait; |
8619f979 TH |
275 | |
276 | /* atomic_add_return() is a mb(), put_active() will always see | |
0c73f18b | 277 | * the updated sd->s_sibling. |
b6b4a439 | 278 | */ |
8619f979 TH |
279 | v = atomic_add_return(SD_DEACTIVATED_BIAS, &sd->s_active); |
280 | ||
281 | if (v != SD_DEACTIVATED_BIAS) | |
282 | wait_for_completion(&wait); | |
283 | ||
0c73f18b | 284 | sd->s_sibling = NULL; |
b6b4a439 TH |
285 | } |
286 | ||
42b37df6 | 287 | static int sysfs_alloc_ino(ino_t *pino) |
2b611bb7 TH |
288 | { |
289 | int ino, rc; | |
290 | ||
291 | retry: | |
292 | spin_lock(&sysfs_ino_lock); | |
293 | rc = ida_get_new_above(&sysfs_ino_ida, 2, &ino); | |
294 | spin_unlock(&sysfs_ino_lock); | |
295 | ||
296 | if (rc == -EAGAIN) { | |
297 | if (ida_pre_get(&sysfs_ino_ida, GFP_KERNEL)) | |
298 | goto retry; | |
299 | rc = -ENOMEM; | |
300 | } | |
301 | ||
302 | *pino = ino; | |
303 | return rc; | |
304 | } | |
305 | ||
306 | static void sysfs_free_ino(ino_t ino) | |
307 | { | |
308 | spin_lock(&sysfs_ino_lock); | |
309 | ida_remove(&sysfs_ino_ida, ino); | |
310 | spin_unlock(&sysfs_ino_lock); | |
311 | } | |
312 | ||
fa7f912a TH |
313 | void release_sysfs_dirent(struct sysfs_dirent * sd) |
314 | { | |
13b3086d TH |
315 | struct sysfs_dirent *parent_sd; |
316 | ||
317 | repeat: | |
3007e997 TH |
318 | /* Moving/renaming is always done while holding reference. |
319 | * sd->s_parent won't change beneath us. | |
320 | */ | |
13b3086d TH |
321 | parent_sd = sd->s_parent; |
322 | ||
b402d72c | 323 | if (sysfs_type(sd) == SYSFS_KOBJ_LINK) |
2b29ac25 | 324 | sysfs_put(sd->s_elem.symlink.target_sd); |
b402d72c | 325 | if (sysfs_type(sd) & SYSFS_COPY_NAME) |
0c096b50 | 326 | kfree(sd->s_name); |
fa7f912a | 327 | kfree(sd->s_iattr); |
2b611bb7 | 328 | sysfs_free_ino(sd->s_ino); |
fa7f912a | 329 | kmem_cache_free(sysfs_dir_cachep, sd); |
13b3086d TH |
330 | |
331 | sd = parent_sd; | |
332 | if (sd && atomic_dec_and_test(&sd->s_count)) | |
333 | goto repeat; | |
fa7f912a TH |
334 | } |
335 | ||
1da177e4 LT |
336 | static void sysfs_d_iput(struct dentry * dentry, struct inode * inode) |
337 | { | |
338 | struct sysfs_dirent * sd = dentry->d_fsdata; | |
339 | ||
340 | if (sd) { | |
5f995323 TH |
341 | /* sd->s_dentry is protected with sysfs_assoc_lock. |
342 | * This allows sysfs_drop_dentry() to dereference it. | |
dd14cbc9 | 343 | */ |
5f995323 | 344 | spin_lock(&sysfs_assoc_lock); |
dd14cbc9 TH |
345 | |
346 | /* The dentry might have been deleted or another | |
347 | * lookup could have happened updating sd->s_dentry to | |
348 | * point the new dentry. Ignore if it isn't pointing | |
349 | * to this dentry. | |
350 | */ | |
351 | if (sd->s_dentry == dentry) | |
352 | sd->s_dentry = NULL; | |
5f995323 | 353 | spin_unlock(&sysfs_assoc_lock); |
1da177e4 LT |
354 | sysfs_put(sd); |
355 | } | |
356 | iput(inode); | |
357 | } | |
358 | ||
359 | static struct dentry_operations sysfs_dentry_ops = { | |
360 | .d_iput = sysfs_d_iput, | |
361 | }; | |
362 | ||
3e519038 | 363 | struct sysfs_dirent *sysfs_new_dirent(const char *name, umode_t mode, int type) |
1da177e4 | 364 | { |
0c096b50 | 365 | char *dup_name = NULL; |
01da2425 | 366 | struct sysfs_dirent *sd; |
0c096b50 TH |
367 | |
368 | if (type & SYSFS_COPY_NAME) { | |
369 | name = dup_name = kstrdup(name, GFP_KERNEL); | |
370 | if (!name) | |
01da2425 | 371 | return NULL; |
0c096b50 | 372 | } |
1da177e4 | 373 | |
c3762229 | 374 | sd = kmem_cache_zalloc(sysfs_dir_cachep, GFP_KERNEL); |
1da177e4 | 375 | if (!sd) |
01da2425 | 376 | goto err_out1; |
1da177e4 | 377 | |
0c096b50 | 378 | if (sysfs_alloc_ino(&sd->s_ino)) |
01da2425 | 379 | goto err_out2; |
2b611bb7 | 380 | |
1da177e4 | 381 | atomic_set(&sd->s_count, 1); |
8619f979 | 382 | atomic_set(&sd->s_active, 0); |
eea3f891 | 383 | atomic_set(&sd->s_event, 1); |
a26cd722 | 384 | |
0c096b50 | 385 | sd->s_name = name; |
a26cd722 | 386 | sd->s_mode = mode; |
b402d72c | 387 | sd->s_flags = type; |
1da177e4 LT |
388 | |
389 | return sd; | |
0c096b50 | 390 | |
01da2425 | 391 | err_out2: |
0c096b50 | 392 | kmem_cache_free(sysfs_dir_cachep, sd); |
01da2425 AM |
393 | err_out1: |
394 | kfree(dup_name); | |
0c096b50 | 395 | return NULL; |
1da177e4 LT |
396 | } |
397 | ||
3007e997 TH |
398 | /** |
399 | * sysfs_attach_dentry - associate sysfs_dirent with dentry | |
400 | * @sd: target sysfs_dirent | |
401 | * @dentry: dentry to associate | |
402 | * | |
403 | * Associate @sd with @dentry. This is protected by | |
404 | * sysfs_assoc_lock to avoid race with sysfs_d_iput(). | |
405 | * | |
406 | * LOCKING: | |
407 | * mutex_lock(sysfs_mutex) | |
408 | */ | |
198a2a84 TH |
409 | static void sysfs_attach_dentry(struct sysfs_dirent *sd, struct dentry *dentry) |
410 | { | |
411 | dentry->d_op = &sysfs_dentry_ops; | |
412 | dentry->d_fsdata = sysfs_get(sd); | |
413 | ||
414 | /* protect sd->s_dentry against sysfs_d_iput */ | |
5f995323 | 415 | spin_lock(&sysfs_assoc_lock); |
198a2a84 | 416 | sd->s_dentry = dentry; |
5f995323 | 417 | spin_unlock(&sysfs_assoc_lock); |
198a2a84 TH |
418 | |
419 | d_rehash(dentry); | |
420 | } | |
421 | ||
fb6896da TH |
422 | static int sysfs_ilookup_test(struct inode *inode, void *arg) |
423 | { | |
424 | struct sysfs_dirent *sd = arg; | |
425 | return inode->i_ino == sd->s_ino; | |
426 | } | |
427 | ||
3007e997 | 428 | /** |
fb6896da TH |
429 | * sysfs_addrm_start - prepare for sysfs_dirent add/remove |
430 | * @acxt: pointer to sysfs_addrm_cxt to be used | |
431 | * @parent_sd: parent sysfs_dirent | |
3007e997 | 432 | * |
fb6896da TH |
433 | * This function is called when the caller is about to add or |
434 | * remove sysfs_dirent under @parent_sd. This function acquires | |
435 | * sysfs_mutex, grabs inode for @parent_sd if available and lock | |
436 | * i_mutex of it. @acxt is used to keep and pass context to | |
437 | * other addrm functions. | |
3007e997 TH |
438 | * |
439 | * LOCKING: | |
fb6896da TH |
440 | * Kernel thread context (may sleep). sysfs_mutex is locked on |
441 | * return. i_mutex of parent inode is locked on return if | |
442 | * available. | |
3007e997 | 443 | */ |
fb6896da TH |
444 | void sysfs_addrm_start(struct sysfs_addrm_cxt *acxt, |
445 | struct sysfs_dirent *parent_sd) | |
b592fcfe | 446 | { |
fb6896da | 447 | struct inode *inode; |
b592fcfe | 448 | |
fb6896da TH |
449 | memset(acxt, 0, sizeof(*acxt)); |
450 | acxt->parent_sd = parent_sd; | |
451 | ||
452 | /* Lookup parent inode. inode initialization and I_NEW | |
453 | * clearing are protected by sysfs_mutex. By grabbing it and | |
454 | * looking up with _nowait variant, inode state can be | |
455 | * determined reliably. | |
456 | */ | |
457 | mutex_lock(&sysfs_mutex); | |
458 | ||
459 | inode = ilookup5_nowait(sysfs_sb, parent_sd->s_ino, sysfs_ilookup_test, | |
460 | parent_sd); | |
461 | ||
462 | if (inode && !(inode->i_state & I_NEW)) { | |
463 | /* parent inode available */ | |
464 | acxt->parent_inode = inode; | |
465 | ||
466 | /* sysfs_mutex is below i_mutex in lock hierarchy. | |
467 | * First, trylock i_mutex. If fails, unlock | |
468 | * sysfs_mutex and lock them in order. | |
469 | */ | |
470 | if (!mutex_trylock(&inode->i_mutex)) { | |
471 | mutex_unlock(&sysfs_mutex); | |
472 | mutex_lock(&inode->i_mutex); | |
473 | mutex_lock(&sysfs_mutex); | |
474 | } | |
475 | } else | |
476 | iput(inode); | |
477 | } | |
478 | ||
479 | /** | |
480 | * sysfs_add_one - add sysfs_dirent to parent | |
481 | * @acxt: addrm context to use | |
482 | * @sd: sysfs_dirent to be added | |
483 | * | |
484 | * Get @acxt->parent_sd and set sd->s_parent to it and increment | |
485 | * nlink of parent inode if @sd is a directory. @sd is NOT | |
486 | * linked into the children list of the parent. The caller | |
487 | * should invoke sysfs_link_sibling() after this function | |
488 | * completes if @sd needs to be on the children list. | |
489 | * | |
490 | * This function should be called between calls to | |
491 | * sysfs_addrm_start() and sysfs_addrm_finish() and should be | |
492 | * passed the same @acxt as passed to sysfs_addrm_start(). | |
493 | * | |
494 | * LOCKING: | |
495 | * Determined by sysfs_addrm_start(). | |
23dc2799 TH |
496 | * |
497 | * RETURNS: | |
498 | * 0 on success, -EEXIST if entry with the given name already | |
499 | * exists. | |
fb6896da | 500 | */ |
23dc2799 | 501 | int sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd) |
fb6896da | 502 | { |
23dc2799 TH |
503 | if (sysfs_find_dirent(acxt->parent_sd, sd->s_name)) |
504 | return -EEXIST; | |
505 | ||
fb6896da TH |
506 | sd->s_parent = sysfs_get(acxt->parent_sd); |
507 | ||
508 | if (sysfs_type(sd) == SYSFS_DIR && acxt->parent_inode) | |
509 | inc_nlink(acxt->parent_inode); | |
510 | ||
511 | acxt->cnt++; | |
41fc1c27 TH |
512 | |
513 | sysfs_link_sibling(sd); | |
23dc2799 TH |
514 | |
515 | return 0; | |
fb6896da TH |
516 | } |
517 | ||
518 | /** | |
519 | * sysfs_remove_one - remove sysfs_dirent from parent | |
520 | * @acxt: addrm context to use | |
521 | * @sd: sysfs_dirent to be added | |
522 | * | |
523 | * Mark @sd removed and drop nlink of parent inode if @sd is a | |
524 | * directory. @sd is NOT unlinked from the children list of the | |
525 | * parent. The caller is repsonsible for removing @sd from the | |
526 | * children list before calling this function. | |
527 | * | |
528 | * This function should be called between calls to | |
529 | * sysfs_addrm_start() and sysfs_addrm_finish() and should be | |
530 | * passed the same @acxt as passed to sysfs_addrm_start(). | |
531 | * | |
532 | * LOCKING: | |
533 | * Determined by sysfs_addrm_start(). | |
534 | */ | |
535 | void sysfs_remove_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd) | |
536 | { | |
41fc1c27 TH |
537 | BUG_ON(sd->s_flags & SYSFS_FLAG_REMOVED); |
538 | ||
539 | sysfs_unlink_sibling(sd); | |
fb6896da TH |
540 | |
541 | sd->s_flags |= SYSFS_FLAG_REMOVED; | |
542 | sd->s_sibling = acxt->removed; | |
543 | acxt->removed = sd; | |
544 | ||
545 | if (sysfs_type(sd) == SYSFS_DIR && acxt->parent_inode) | |
546 | drop_nlink(acxt->parent_inode); | |
547 | ||
548 | acxt->cnt++; | |
549 | } | |
550 | ||
a0edd7c8 TH |
551 | /** |
552 | * sysfs_drop_dentry - drop dentry for the specified sysfs_dirent | |
553 | * @sd: target sysfs_dirent | |
554 | * | |
555 | * Drop dentry for @sd. @sd must have been unlinked from its | |
556 | * parent on entry to this function such that it can't be looked | |
557 | * up anymore. | |
558 | * | |
559 | * @sd->s_dentry which is protected with sysfs_assoc_lock points | |
560 | * to the currently associated dentry but we're not holding a | |
561 | * reference to it and racing with dput(). Grab dcache_lock and | |
562 | * verify dentry before dropping it. If @sd->s_dentry is NULL or | |
563 | * dput() beats us, no need to bother. | |
564 | */ | |
565 | static void sysfs_drop_dentry(struct sysfs_dirent *sd) | |
566 | { | |
567 | struct dentry *dentry = NULL; | |
568 | struct inode *inode; | |
569 | ||
570 | /* We're not holding a reference to ->s_dentry dentry but the | |
571 | * field will stay valid as long as sysfs_assoc_lock is held. | |
572 | */ | |
573 | spin_lock(&sysfs_assoc_lock); | |
574 | spin_lock(&dcache_lock); | |
575 | ||
576 | /* drop dentry if it's there and dput() didn't kill it yet */ | |
577 | if (sd->s_dentry && sd->s_dentry->d_inode) { | |
578 | dentry = dget_locked(sd->s_dentry); | |
579 | spin_lock(&dentry->d_lock); | |
580 | __d_drop(dentry); | |
581 | spin_unlock(&dentry->d_lock); | |
582 | } | |
583 | ||
584 | spin_unlock(&dcache_lock); | |
585 | spin_unlock(&sysfs_assoc_lock); | |
586 | ||
51225039 | 587 | dput(dentry); |
a0edd7c8 TH |
588 | |
589 | /* adjust nlink and update timestamp */ | |
590 | inode = ilookup(sysfs_sb, sd->s_ino); | |
591 | if (inode) { | |
592 | mutex_lock(&inode->i_mutex); | |
593 | ||
594 | inode->i_ctime = CURRENT_TIME; | |
595 | drop_nlink(inode); | |
596 | if (sysfs_type(sd) == SYSFS_DIR) | |
597 | drop_nlink(inode); | |
598 | ||
599 | mutex_unlock(&inode->i_mutex); | |
600 | iput(inode); | |
601 | } | |
602 | } | |
603 | ||
fb6896da TH |
604 | /** |
605 | * sysfs_addrm_finish - finish up sysfs_dirent add/remove | |
606 | * @acxt: addrm context to finish up | |
607 | * | |
608 | * Finish up sysfs_dirent add/remove. Resources acquired by | |
609 | * sysfs_addrm_start() are released and removed sysfs_dirents are | |
610 | * cleaned up. Timestamps on the parent inode are updated. | |
611 | * | |
612 | * LOCKING: | |
613 | * All mutexes acquired by sysfs_addrm_start() are released. | |
fb6896da | 614 | */ |
990e53f8 | 615 | void sysfs_addrm_finish(struct sysfs_addrm_cxt *acxt) |
fb6896da TH |
616 | { |
617 | /* release resources acquired by sysfs_addrm_start() */ | |
618 | mutex_unlock(&sysfs_mutex); | |
619 | if (acxt->parent_inode) { | |
620 | struct inode *inode = acxt->parent_inode; | |
621 | ||
622 | /* if added/removed, update timestamps on the parent */ | |
623 | if (acxt->cnt) | |
624 | inode->i_ctime = inode->i_mtime = CURRENT_TIME; | |
625 | ||
626 | mutex_unlock(&inode->i_mutex); | |
627 | iput(inode); | |
628 | } | |
629 | ||
630 | /* kill removed sysfs_dirents */ | |
631 | while (acxt->removed) { | |
632 | struct sysfs_dirent *sd = acxt->removed; | |
633 | ||
634 | acxt->removed = sd->s_sibling; | |
635 | sd->s_sibling = NULL; | |
636 | ||
637 | sysfs_drop_dentry(sd); | |
638 | sysfs_deactivate(sd); | |
639 | sysfs_put(sd); | |
13b3086d | 640 | } |
b592fcfe EB |
641 | } |
642 | ||
f0b0af47 TH |
643 | /** |
644 | * sysfs_find_dirent - find sysfs_dirent with the given name | |
645 | * @parent_sd: sysfs_dirent to search under | |
646 | * @name: name to look for | |
647 | * | |
648 | * Look for sysfs_dirent with name @name under @parent_sd. | |
c516865c | 649 | * |
f0b0af47 | 650 | * LOCKING: |
3007e997 | 651 | * mutex_lock(sysfs_mutex) |
c516865c | 652 | * |
f0b0af47 TH |
653 | * RETURNS: |
654 | * Pointer to sysfs_dirent if found, NULL if not. | |
c516865c | 655 | */ |
f0b0af47 TH |
656 | struct sysfs_dirent *sysfs_find_dirent(struct sysfs_dirent *parent_sd, |
657 | const unsigned char *name) | |
c516865c | 658 | { |
f0b0af47 TH |
659 | struct sysfs_dirent *sd; |
660 | ||
661 | for (sd = parent_sd->s_children; sd; sd = sd->s_sibling) | |
662 | if (sysfs_type(sd) && !strcmp(sd->s_name, name)) | |
663 | return sd; | |
664 | return NULL; | |
665 | } | |
c516865c | 666 | |
f0b0af47 TH |
667 | /** |
668 | * sysfs_get_dirent - find and get sysfs_dirent with the given name | |
669 | * @parent_sd: sysfs_dirent to search under | |
670 | * @name: name to look for | |
671 | * | |
672 | * Look for sysfs_dirent with name @name under @parent_sd and get | |
673 | * it if found. | |
674 | * | |
675 | * LOCKING: | |
3007e997 | 676 | * Kernel thread context (may sleep). Grabs sysfs_mutex. |
f0b0af47 TH |
677 | * |
678 | * RETURNS: | |
679 | * Pointer to sysfs_dirent if found, NULL if not. | |
680 | */ | |
681 | struct sysfs_dirent *sysfs_get_dirent(struct sysfs_dirent *parent_sd, | |
682 | const unsigned char *name) | |
683 | { | |
684 | struct sysfs_dirent *sd; | |
685 | ||
3007e997 | 686 | mutex_lock(&sysfs_mutex); |
f0b0af47 TH |
687 | sd = sysfs_find_dirent(parent_sd, name); |
688 | sysfs_get(sd); | |
3007e997 | 689 | mutex_unlock(&sysfs_mutex); |
f0b0af47 TH |
690 | |
691 | return sd; | |
c516865c MS |
692 | } |
693 | ||
608e266a TH |
694 | static int create_dir(struct kobject *kobj, struct sysfs_dirent *parent_sd, |
695 | const char *name, struct sysfs_dirent **p_sd) | |
1da177e4 | 696 | { |
1da177e4 | 697 | umode_t mode = S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO; |
51225039 | 698 | struct sysfs_addrm_cxt acxt; |
dfeb9fb0 | 699 | struct sysfs_dirent *sd; |
23dc2799 | 700 | int rc; |
1da177e4 | 701 | |
fc9f54b9 | 702 | /* allocate */ |
3e519038 | 703 | sd = sysfs_new_dirent(name, mode, SYSFS_DIR); |
a26cd722 | 704 | if (!sd) |
51225039 | 705 | return -ENOMEM; |
3e519038 | 706 | sd->s_elem.dir.kobj = kobj; |
dfeb9fb0 | 707 | |
fc9f54b9 | 708 | /* link in */ |
51225039 | 709 | sysfs_addrm_start(&acxt, parent_sd); |
23dc2799 TH |
710 | rc = sysfs_add_one(&acxt, sd); |
711 | sysfs_addrm_finish(&acxt); | |
967e35dc | 712 | |
23dc2799 TH |
713 | if (rc == 0) |
714 | *p_sd = sd; | |
715 | else | |
967e35dc | 716 | sysfs_put(sd); |
dfeb9fb0 | 717 | |
23dc2799 | 718 | return rc; |
1da177e4 LT |
719 | } |
720 | ||
608e266a TH |
721 | int sysfs_create_subdir(struct kobject *kobj, const char *name, |
722 | struct sysfs_dirent **p_sd) | |
1da177e4 | 723 | { |
608e266a | 724 | return create_dir(kobj, kobj->sd, name, p_sd); |
1da177e4 LT |
725 | } |
726 | ||
727 | /** | |
728 | * sysfs_create_dir - create a directory for an object. | |
1da177e4 LT |
729 | * @kobj: object we're creating directory for. |
730 | */ | |
90bc6135 | 731 | int sysfs_create_dir(struct kobject * kobj) |
1da177e4 | 732 | { |
608e266a | 733 | struct sysfs_dirent *parent_sd, *sd; |
1da177e4 LT |
734 | int error = 0; |
735 | ||
736 | BUG_ON(!kobj); | |
737 | ||
90bc6135 | 738 | if (kobj->parent) |
608e266a | 739 | parent_sd = kobj->parent->sd; |
1da177e4 | 740 | else |
7d0c7d67 | 741 | parent_sd = &sysfs_root; |
1da177e4 | 742 | |
608e266a | 743 | error = create_dir(kobj, parent_sd, kobject_name(kobj), &sd); |
1da177e4 | 744 | if (!error) |
608e266a | 745 | kobj->sd = sd; |
1da177e4 LT |
746 | return error; |
747 | } | |
748 | ||
1da177e4 LT |
749 | static struct dentry * sysfs_lookup(struct inode *dir, struct dentry *dentry, |
750 | struct nameidata *nd) | |
751 | { | |
6cb52147 | 752 | struct dentry *ret = NULL; |
a7a04754 TH |
753 | struct sysfs_dirent *parent_sd = dentry->d_parent->d_fsdata; |
754 | struct sysfs_dirent *sd; | |
fc9f54b9 | 755 | struct inode *inode; |
1da177e4 | 756 | |
6cb52147 TH |
757 | mutex_lock(&sysfs_mutex); |
758 | ||
a7a04754 TH |
759 | for (sd = parent_sd->s_children; sd; sd = sd->s_sibling) |
760 | if (sysfs_type(sd) && !strcmp(sd->s_name, dentry->d_name.name)) | |
1da177e4 | 761 | break; |
1da177e4 | 762 | |
fc9f54b9 | 763 | /* no such entry */ |
a7a04754 | 764 | if (!sd) |
6cb52147 | 765 | goto out_unlock; |
fc9f54b9 TH |
766 | |
767 | /* attach dentry and inode */ | |
8312a8d7 | 768 | inode = sysfs_get_inode(sd); |
6cb52147 TH |
769 | if (!inode) { |
770 | ret = ERR_PTR(-ENOMEM); | |
771 | goto out_unlock; | |
772 | } | |
3007e997 | 773 | |
119dd52b | 774 | d_instantiate(dentry, inode); |
fc9f54b9 TH |
775 | sysfs_attach_dentry(sd, dentry); |
776 | ||
6cb52147 | 777 | out_unlock: |
3007e997 | 778 | mutex_unlock(&sysfs_mutex); |
6cb52147 | 779 | return ret; |
1da177e4 LT |
780 | } |
781 | ||
c5ef1c42 | 782 | const struct inode_operations sysfs_dir_inode_operations = { |
1da177e4 | 783 | .lookup = sysfs_lookup, |
988d186d | 784 | .setattr = sysfs_setattr, |
1da177e4 LT |
785 | }; |
786 | ||
608e266a | 787 | static void remove_dir(struct sysfs_dirent *sd) |
1da177e4 | 788 | { |
fb6896da | 789 | struct sysfs_addrm_cxt acxt; |
1da177e4 | 790 | |
fb6896da | 791 | sysfs_addrm_start(&acxt, sd->s_parent); |
fb6896da TH |
792 | sysfs_remove_one(&acxt, sd); |
793 | sysfs_addrm_finish(&acxt); | |
1da177e4 LT |
794 | } |
795 | ||
608e266a | 796 | void sysfs_remove_subdir(struct sysfs_dirent *sd) |
1da177e4 | 797 | { |
608e266a | 798 | remove_dir(sd); |
1da177e4 LT |
799 | } |
800 | ||
801 | ||
608e266a | 802 | static void __sysfs_remove_dir(struct sysfs_dirent *dir_sd) |
1da177e4 | 803 | { |
fb6896da | 804 | struct sysfs_addrm_cxt acxt; |
0c73f18b | 805 | struct sysfs_dirent **pos; |
1da177e4 | 806 | |
608e266a | 807 | if (!dir_sd) |
1da177e4 LT |
808 | return; |
809 | ||
608e266a | 810 | pr_debug("sysfs %s: removing dir\n", dir_sd->s_name); |
fb6896da | 811 | sysfs_addrm_start(&acxt, dir_sd); |
608e266a | 812 | pos = &dir_sd->s_children; |
0c73f18b TH |
813 | while (*pos) { |
814 | struct sysfs_dirent *sd = *pos; | |
815 | ||
41fc1c27 | 816 | if (sysfs_type(sd) && sysfs_type(sd) != SYSFS_DIR) |
fb6896da | 817 | sysfs_remove_one(&acxt, sd); |
41fc1c27 | 818 | else |
0c73f18b | 819 | pos = &(*pos)->s_sibling; |
1da177e4 | 820 | } |
fb6896da | 821 | sysfs_addrm_finish(&acxt); |
0ab66088 | 822 | |
608e266a | 823 | remove_dir(dir_sd); |
b592fcfe EB |
824 | } |
825 | ||
826 | /** | |
827 | * sysfs_remove_dir - remove an object's directory. | |
828 | * @kobj: object. | |
829 | * | |
830 | * The only thing special about this is that we remove any files in | |
831 | * the directory before we remove the directory, and we've inlined | |
832 | * what used to be sysfs_rmdir() below, instead of calling separately. | |
833 | */ | |
834 | ||
835 | void sysfs_remove_dir(struct kobject * kobj) | |
836 | { | |
608e266a | 837 | struct sysfs_dirent *sd = kobj->sd; |
aecdceda | 838 | |
5f995323 | 839 | spin_lock(&sysfs_assoc_lock); |
608e266a | 840 | kobj->sd = NULL; |
5f995323 | 841 | spin_unlock(&sysfs_assoc_lock); |
aecdceda | 842 | |
608e266a | 843 | __sysfs_remove_dir(sd); |
1da177e4 LT |
844 | } |
845 | ||
90bc6135 | 846 | int sysfs_rename_dir(struct kobject * kobj, const char *new_name) |
1da177e4 | 847 | { |
90bc6135 EB |
848 | struct sysfs_dirent *sd; |
849 | struct dentry *parent = NULL; | |
51225039 TH |
850 | struct dentry *old_dentry = NULL, *new_dentry = NULL; |
851 | const char *dup_name = NULL; | |
996b7376 | 852 | int error; |
1da177e4 | 853 | |
ff869de7 | 854 | /* get the original dentry */ |
90bc6135 | 855 | sd = kobj->sd; |
51225039 TH |
856 | old_dentry = sysfs_get_dentry(sd); |
857 | if (IS_ERR(old_dentry)) { | |
858 | error = PTR_ERR(old_dentry); | |
859 | goto out_dput; | |
860 | } | |
861 | ||
ff869de7 | 862 | parent = old_dentry->d_parent; |
1da177e4 | 863 | |
90bc6135 EB |
864 | /* lock parent and get dentry for new name */ |
865 | mutex_lock(&parent->d_inode->i_mutex); | |
1da177e4 | 866 | |
90bc6135 | 867 | new_dentry = lookup_one_len(new_name, parent, strlen(new_name)); |
996b7376 TH |
868 | if (IS_ERR(new_dentry)) { |
869 | error = PTR_ERR(new_dentry); | |
870 | goto out_unlock; | |
1da177e4 | 871 | } |
996b7376 | 872 | |
996b7376 | 873 | error = -EINVAL; |
90bc6135 | 874 | if (old_dentry == new_dentry) |
51225039 | 875 | goto out_unlock; |
996b7376 TH |
876 | |
877 | error = -EEXIST; | |
878 | if (new_dentry->d_inode) | |
51225039 | 879 | goto out_unlock; |
996b7376 | 880 | |
0c096b50 TH |
881 | /* rename kobject and sysfs_dirent */ |
882 | error = -ENOMEM; | |
883 | new_name = dup_name = kstrdup(new_name, GFP_KERNEL); | |
884 | if (!new_name) | |
885 | goto out_drop; | |
886 | ||
996b7376 TH |
887 | error = kobject_set_name(kobj, "%s", new_name); |
888 | if (error) | |
51225039 | 889 | goto out_drop; |
996b7376 | 890 | |
6cb52147 | 891 | mutex_lock(&sysfs_mutex); |
51225039 | 892 | dup_name = sd->s_name; |
0c096b50 | 893 | sd->s_name = new_name; |
ff869de7 | 894 | mutex_unlock(&sysfs_mutex); |
0c096b50 | 895 | |
ff869de7 | 896 | /* rename */ |
996b7376 | 897 | d_add(new_dentry, NULL); |
608e266a | 898 | d_move(sd->s_dentry, new_dentry); |
996b7376 | 899 | |
996b7376 TH |
900 | error = 0; |
901 | goto out_unlock; | |
902 | ||
903 | out_drop: | |
904 | d_drop(new_dentry); | |
996b7376 | 905 | out_unlock: |
90bc6135 | 906 | mutex_unlock(&parent->d_inode->i_mutex); |
51225039 TH |
907 | out_dput: |
908 | kfree(dup_name); | |
51225039 TH |
909 | dput(old_dentry); |
910 | dput(new_dentry); | |
1da177e4 LT |
911 | return error; |
912 | } | |
913 | ||
51225039 | 914 | int sysfs_move_dir(struct kobject *kobj, struct kobject *new_parent_kobj) |
8a82472f | 915 | { |
51225039 TH |
916 | struct sysfs_dirent *sd = kobj->sd; |
917 | struct sysfs_dirent *new_parent_sd; | |
918 | struct dentry *old_parent, *new_parent = NULL; | |
919 | struct dentry *old_dentry = NULL, *new_dentry = NULL; | |
8a82472f CH |
920 | int error; |
921 | ||
51225039 TH |
922 | BUG_ON(!sd->s_parent); |
923 | new_parent_sd = new_parent_kobj->sd ? new_parent_kobj->sd : &sysfs_root; | |
924 | ||
925 | /* get dentries */ | |
926 | old_dentry = sysfs_get_dentry(sd); | |
927 | if (IS_ERR(old_dentry)) { | |
928 | error = PTR_ERR(old_dentry); | |
929 | goto out_dput; | |
930 | } | |
931 | old_parent = sd->s_parent->s_dentry; | |
932 | ||
933 | new_parent = sysfs_get_dentry(new_parent_sd); | |
934 | if (IS_ERR(new_parent)) { | |
935 | error = PTR_ERR(new_parent); | |
936 | goto out_dput; | |
937 | } | |
8a82472f | 938 | |
51225039 TH |
939 | if (old_parent->d_inode == new_parent->d_inode) { |
940 | error = 0; | |
941 | goto out_dput; /* nothing to move */ | |
942 | } | |
8a82472f | 943 | again: |
51225039 TH |
944 | mutex_lock(&old_parent->d_inode->i_mutex); |
945 | if (!mutex_trylock(&new_parent->d_inode->i_mutex)) { | |
946 | mutex_unlock(&old_parent->d_inode->i_mutex); | |
8a82472f CH |
947 | goto again; |
948 | } | |
949 | ||
19c38de8 | 950 | new_dentry = lookup_one_len(kobject_name(kobj), new_parent, strlen(kobject_name(kobj))); |
8a82472f CH |
951 | if (IS_ERR(new_dentry)) { |
952 | error = PTR_ERR(new_dentry); | |
51225039 | 953 | goto out_unlock; |
8a82472f CH |
954 | } else |
955 | error = 0; | |
956 | d_add(new_dentry, NULL); | |
608e266a | 957 | d_move(sd->s_dentry, new_dentry); |
8a82472f CH |
958 | dput(new_dentry); |
959 | ||
960 | /* Remove from old parent's list and insert into new parent's list. */ | |
3007e997 TH |
961 | mutex_lock(&sysfs_mutex); |
962 | ||
0c73f18b | 963 | sysfs_unlink_sibling(sd); |
7f7cfffe TH |
964 | sysfs_get(new_parent_sd); |
965 | sysfs_put(sd->s_parent); | |
966 | sd->s_parent = new_parent_sd; | |
0c73f18b | 967 | sysfs_link_sibling(sd); |
8a82472f | 968 | |
3007e997 | 969 | mutex_unlock(&sysfs_mutex); |
8a82472f | 970 | |
51225039 TH |
971 | out_unlock: |
972 | mutex_unlock(&new_parent->d_inode->i_mutex); | |
973 | mutex_unlock(&old_parent->d_inode->i_mutex); | |
974 | out_dput: | |
975 | dput(new_parent); | |
976 | dput(old_dentry); | |
977 | dput(new_dentry); | |
8a82472f CH |
978 | return error; |
979 | } | |
980 | ||
1da177e4 LT |
981 | static int sysfs_dir_open(struct inode *inode, struct file *file) |
982 | { | |
f427f5d5 | 983 | struct dentry * dentry = file->f_path.dentry; |
1da177e4 | 984 | struct sysfs_dirent * parent_sd = dentry->d_fsdata; |
a26cd722 | 985 | struct sysfs_dirent * sd; |
1da177e4 | 986 | |
3e519038 | 987 | sd = sysfs_new_dirent("_DIR_", 0, 0); |
3007e997 TH |
988 | if (sd) { |
989 | mutex_lock(&sysfs_mutex); | |
fb6896da TH |
990 | sd->s_parent = sysfs_get(parent_sd); |
991 | sysfs_link_sibling(sd); | |
3007e997 TH |
992 | mutex_unlock(&sysfs_mutex); |
993 | } | |
1da177e4 | 994 | |
a26cd722 TH |
995 | file->private_data = sd; |
996 | return sd ? 0 : -ENOMEM; | |
1da177e4 LT |
997 | } |
998 | ||
999 | static int sysfs_dir_close(struct inode *inode, struct file *file) | |
1000 | { | |
1da177e4 LT |
1001 | struct sysfs_dirent * cursor = file->private_data; |
1002 | ||
3007e997 | 1003 | mutex_lock(&sysfs_mutex); |
0c73f18b | 1004 | sysfs_unlink_sibling(cursor); |
3007e997 | 1005 | mutex_unlock(&sysfs_mutex); |
1da177e4 LT |
1006 | |
1007 | release_sysfs_dirent(cursor); | |
1008 | ||
1009 | return 0; | |
1010 | } | |
1011 | ||
1012 | /* Relationship between s_mode and the DT_xxx types */ | |
1013 | static inline unsigned char dt_type(struct sysfs_dirent *sd) | |
1014 | { | |
1015 | return (sd->s_mode >> 12) & 15; | |
1016 | } | |
1017 | ||
1018 | static int sysfs_readdir(struct file * filp, void * dirent, filldir_t filldir) | |
1019 | { | |
f427f5d5 | 1020 | struct dentry *dentry = filp->f_path.dentry; |
1da177e4 LT |
1021 | struct sysfs_dirent * parent_sd = dentry->d_fsdata; |
1022 | struct sysfs_dirent *cursor = filp->private_data; | |
0c73f18b | 1023 | struct sysfs_dirent **pos; |
1da177e4 LT |
1024 | ino_t ino; |
1025 | int i = filp->f_pos; | |
1026 | ||
1027 | switch (i) { | |
1028 | case 0: | |
dc351252 | 1029 | ino = parent_sd->s_ino; |
1da177e4 LT |
1030 | if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0) |
1031 | break; | |
1032 | filp->f_pos++; | |
1033 | i++; | |
1034 | /* fallthrough */ | |
1035 | case 1: | |
13b3086d TH |
1036 | if (parent_sd->s_parent) |
1037 | ino = parent_sd->s_parent->s_ino; | |
1038 | else | |
1039 | ino = parent_sd->s_ino; | |
1da177e4 LT |
1040 | if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0) |
1041 | break; | |
1042 | filp->f_pos++; | |
1043 | i++; | |
1044 | /* fallthrough */ | |
1045 | default: | |
3007e997 TH |
1046 | mutex_lock(&sysfs_mutex); |
1047 | ||
0c73f18b TH |
1048 | pos = &parent_sd->s_children; |
1049 | while (*pos != cursor) | |
1050 | pos = &(*pos)->s_sibling; | |
1051 | ||
1052 | /* unlink cursor */ | |
1053 | *pos = cursor->s_sibling; | |
1054 | ||
1bfba4e8 | 1055 | if (filp->f_pos == 2) |
0c73f18b | 1056 | pos = &parent_sd->s_children; |
1bfba4e8 | 1057 | |
0c73f18b TH |
1058 | for ( ; *pos; pos = &(*pos)->s_sibling) { |
1059 | struct sysfs_dirent *next = *pos; | |
1da177e4 LT |
1060 | const char * name; |
1061 | int len; | |
1062 | ||
b402d72c | 1063 | if (!sysfs_type(next)) |
1da177e4 LT |
1064 | continue; |
1065 | ||
0c096b50 | 1066 | name = next->s_name; |
1da177e4 | 1067 | len = strlen(name); |
dc351252 | 1068 | ino = next->s_ino; |
1da177e4 LT |
1069 | |
1070 | if (filldir(dirent, name, len, filp->f_pos, ino, | |
1071 | dt_type(next)) < 0) | |
0c73f18b | 1072 | break; |
1da177e4 | 1073 | |
1da177e4 LT |
1074 | filp->f_pos++; |
1075 | } | |
0c73f18b TH |
1076 | |
1077 | /* put cursor back in */ | |
1078 | cursor->s_sibling = *pos; | |
1079 | *pos = cursor; | |
3007e997 TH |
1080 | |
1081 | mutex_unlock(&sysfs_mutex); | |
1da177e4 LT |
1082 | } |
1083 | return 0; | |
1084 | } | |
1085 | ||
1086 | static loff_t sysfs_dir_lseek(struct file * file, loff_t offset, int origin) | |
1087 | { | |
f427f5d5 | 1088 | struct dentry * dentry = file->f_path.dentry; |
1da177e4 | 1089 | |
1da177e4 LT |
1090 | switch (origin) { |
1091 | case 1: | |
1092 | offset += file->f_pos; | |
1093 | case 0: | |
1094 | if (offset >= 0) | |
1095 | break; | |
1096 | default: | |
1da177e4 LT |
1097 | return -EINVAL; |
1098 | } | |
1099 | if (offset != file->f_pos) { | |
3007e997 TH |
1100 | mutex_lock(&sysfs_mutex); |
1101 | ||
1da177e4 LT |
1102 | file->f_pos = offset; |
1103 | if (file->f_pos >= 2) { | |
1104 | struct sysfs_dirent *sd = dentry->d_fsdata; | |
1105 | struct sysfs_dirent *cursor = file->private_data; | |
0c73f18b | 1106 | struct sysfs_dirent **pos; |
1da177e4 LT |
1107 | loff_t n = file->f_pos - 2; |
1108 | ||
0c73f18b TH |
1109 | sysfs_unlink_sibling(cursor); |
1110 | ||
1111 | pos = &sd->s_children; | |
1112 | while (n && *pos) { | |
1113 | struct sysfs_dirent *next = *pos; | |
b402d72c | 1114 | if (sysfs_type(next)) |
1da177e4 | 1115 | n--; |
0c73f18b | 1116 | pos = &(*pos)->s_sibling; |
1da177e4 | 1117 | } |
0c73f18b TH |
1118 | |
1119 | cursor->s_sibling = *pos; | |
1120 | *pos = cursor; | |
1da177e4 | 1121 | } |
3007e997 TH |
1122 | |
1123 | mutex_unlock(&sysfs_mutex); | |
1da177e4 | 1124 | } |
3007e997 | 1125 | |
1da177e4 LT |
1126 | return offset; |
1127 | } | |
1128 | ||
4b6f5d20 | 1129 | const struct file_operations sysfs_dir_operations = { |
1da177e4 LT |
1130 | .open = sysfs_dir_open, |
1131 | .release = sysfs_dir_close, | |
1132 | .llseek = sysfs_dir_lseek, | |
1133 | .read = generic_read_dir, | |
1134 | .readdir = sysfs_readdir, | |
1135 | }; |