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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> |
94bebf4d | 14 | #include <asm/semaphore.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 | */ |
fb6896da | 33 | 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 | */ |
fb6896da | 52 | 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 | ||
b6b4a439 TH |
65 | /** |
66 | * sysfs_get_active - get an active reference to sysfs_dirent | |
67 | * @sd: sysfs_dirent to get an active reference to | |
68 | * | |
69 | * Get an active reference of @sd. This function is noop if @sd | |
70 | * is NULL. | |
71 | * | |
72 | * RETURNS: | |
73 | * Pointer to @sd on success, NULL on failure. | |
74 | */ | |
75 | struct sysfs_dirent *sysfs_get_active(struct sysfs_dirent *sd) | |
76 | { | |
8619f979 TH |
77 | if (unlikely(!sd)) |
78 | return NULL; | |
79 | ||
80 | while (1) { | |
81 | int v, t; | |
82 | ||
83 | v = atomic_read(&sd->s_active); | |
84 | if (unlikely(v < 0)) | |
85 | return NULL; | |
86 | ||
87 | t = atomic_cmpxchg(&sd->s_active, v, v + 1); | |
88 | if (likely(t == v)) | |
89 | return sd; | |
90 | if (t < 0) | |
91 | return NULL; | |
92 | ||
93 | cpu_relax(); | |
b6b4a439 | 94 | } |
b6b4a439 TH |
95 | } |
96 | ||
97 | /** | |
98 | * sysfs_put_active - put an active reference to sysfs_dirent | |
99 | * @sd: sysfs_dirent to put an active reference to | |
100 | * | |
101 | * Put an active reference to @sd. This function is noop if @sd | |
102 | * is NULL. | |
103 | */ | |
104 | void sysfs_put_active(struct sysfs_dirent *sd) | |
105 | { | |
8619f979 TH |
106 | struct completion *cmpl; |
107 | int v; | |
108 | ||
109 | if (unlikely(!sd)) | |
110 | return; | |
111 | ||
112 | v = atomic_dec_return(&sd->s_active); | |
113 | if (likely(v != SD_DEACTIVATED_BIAS)) | |
114 | return; | |
115 | ||
116 | /* atomic_dec_return() is a mb(), we'll always see the updated | |
0c73f18b | 117 | * sd->s_sibling. |
8619f979 | 118 | */ |
0c73f18b | 119 | cmpl = (void *)sd->s_sibling; |
8619f979 | 120 | complete(cmpl); |
b6b4a439 TH |
121 | } |
122 | ||
123 | /** | |
124 | * sysfs_get_active_two - get active references to sysfs_dirent and parent | |
125 | * @sd: sysfs_dirent of interest | |
126 | * | |
127 | * Get active reference to @sd and its parent. Parent's active | |
128 | * reference is grabbed first. This function is noop if @sd is | |
129 | * NULL. | |
130 | * | |
131 | * RETURNS: | |
132 | * Pointer to @sd on success, NULL on failure. | |
133 | */ | |
134 | struct sysfs_dirent *sysfs_get_active_two(struct sysfs_dirent *sd) | |
135 | { | |
136 | if (sd) { | |
137 | if (sd->s_parent && unlikely(!sysfs_get_active(sd->s_parent))) | |
138 | return NULL; | |
139 | if (unlikely(!sysfs_get_active(sd))) { | |
140 | sysfs_put_active(sd->s_parent); | |
141 | return NULL; | |
142 | } | |
143 | } | |
144 | return sd; | |
145 | } | |
146 | ||
147 | /** | |
148 | * sysfs_put_active_two - put active references to sysfs_dirent and parent | |
149 | * @sd: sysfs_dirent of interest | |
150 | * | |
151 | * Put active references to @sd and its parent. This function is | |
152 | * noop if @sd is NULL. | |
153 | */ | |
154 | void sysfs_put_active_two(struct sysfs_dirent *sd) | |
155 | { | |
156 | if (sd) { | |
157 | sysfs_put_active(sd); | |
158 | sysfs_put_active(sd->s_parent); | |
159 | } | |
160 | } | |
161 | ||
162 | /** | |
163 | * sysfs_deactivate - deactivate sysfs_dirent | |
164 | * @sd: sysfs_dirent to deactivate | |
165 | * | |
8619f979 | 166 | * Deny new active references and drain existing ones. |
b6b4a439 | 167 | */ |
fb6896da | 168 | static void sysfs_deactivate(struct sysfs_dirent *sd) |
b6b4a439 | 169 | { |
8619f979 TH |
170 | DECLARE_COMPLETION_ONSTACK(wait); |
171 | int v; | |
b6b4a439 | 172 | |
380e6fbb | 173 | BUG_ON(sd->s_sibling || !(sd->s_flags & SYSFS_FLAG_REMOVED)); |
0c73f18b | 174 | sd->s_sibling = (void *)&wait; |
8619f979 TH |
175 | |
176 | /* atomic_add_return() is a mb(), put_active() will always see | |
0c73f18b | 177 | * the updated sd->s_sibling. |
b6b4a439 | 178 | */ |
8619f979 TH |
179 | v = atomic_add_return(SD_DEACTIVATED_BIAS, &sd->s_active); |
180 | ||
181 | if (v != SD_DEACTIVATED_BIAS) | |
182 | wait_for_completion(&wait); | |
183 | ||
0c73f18b | 184 | sd->s_sibling = NULL; |
b6b4a439 TH |
185 | } |
186 | ||
42b37df6 | 187 | static int sysfs_alloc_ino(ino_t *pino) |
2b611bb7 TH |
188 | { |
189 | int ino, rc; | |
190 | ||
191 | retry: | |
192 | spin_lock(&sysfs_ino_lock); | |
193 | rc = ida_get_new_above(&sysfs_ino_ida, 2, &ino); | |
194 | spin_unlock(&sysfs_ino_lock); | |
195 | ||
196 | if (rc == -EAGAIN) { | |
197 | if (ida_pre_get(&sysfs_ino_ida, GFP_KERNEL)) | |
198 | goto retry; | |
199 | rc = -ENOMEM; | |
200 | } | |
201 | ||
202 | *pino = ino; | |
203 | return rc; | |
204 | } | |
205 | ||
206 | static void sysfs_free_ino(ino_t ino) | |
207 | { | |
208 | spin_lock(&sysfs_ino_lock); | |
209 | ida_remove(&sysfs_ino_ida, ino); | |
210 | spin_unlock(&sysfs_ino_lock); | |
211 | } | |
212 | ||
fa7f912a TH |
213 | void release_sysfs_dirent(struct sysfs_dirent * sd) |
214 | { | |
13b3086d TH |
215 | struct sysfs_dirent *parent_sd; |
216 | ||
217 | repeat: | |
3007e997 TH |
218 | /* Moving/renaming is always done while holding reference. |
219 | * sd->s_parent won't change beneath us. | |
220 | */ | |
13b3086d TH |
221 | parent_sd = sd->s_parent; |
222 | ||
b402d72c | 223 | if (sysfs_type(sd) == SYSFS_KOBJ_LINK) |
2b29ac25 | 224 | sysfs_put(sd->s_elem.symlink.target_sd); |
b402d72c | 225 | if (sysfs_type(sd) & SYSFS_COPY_NAME) |
0c096b50 | 226 | kfree(sd->s_name); |
fa7f912a | 227 | kfree(sd->s_iattr); |
2b611bb7 | 228 | sysfs_free_ino(sd->s_ino); |
fa7f912a | 229 | kmem_cache_free(sysfs_dir_cachep, sd); |
13b3086d TH |
230 | |
231 | sd = parent_sd; | |
232 | if (sd && atomic_dec_and_test(&sd->s_count)) | |
233 | goto repeat; | |
fa7f912a TH |
234 | } |
235 | ||
1da177e4 LT |
236 | static void sysfs_d_iput(struct dentry * dentry, struct inode * inode) |
237 | { | |
238 | struct sysfs_dirent * sd = dentry->d_fsdata; | |
239 | ||
240 | if (sd) { | |
5f995323 TH |
241 | /* sd->s_dentry is protected with sysfs_assoc_lock. |
242 | * This allows sysfs_drop_dentry() to dereference it. | |
dd14cbc9 | 243 | */ |
5f995323 | 244 | spin_lock(&sysfs_assoc_lock); |
dd14cbc9 TH |
245 | |
246 | /* The dentry might have been deleted or another | |
247 | * lookup could have happened updating sd->s_dentry to | |
248 | * point the new dentry. Ignore if it isn't pointing | |
249 | * to this dentry. | |
250 | */ | |
251 | if (sd->s_dentry == dentry) | |
252 | sd->s_dentry = NULL; | |
5f995323 | 253 | spin_unlock(&sysfs_assoc_lock); |
1da177e4 LT |
254 | sysfs_put(sd); |
255 | } | |
256 | iput(inode); | |
257 | } | |
258 | ||
259 | static struct dentry_operations sysfs_dentry_ops = { | |
260 | .d_iput = sysfs_d_iput, | |
261 | }; | |
262 | ||
3e519038 | 263 | struct sysfs_dirent *sysfs_new_dirent(const char *name, umode_t mode, int type) |
1da177e4 | 264 | { |
0c096b50 TH |
265 | char *dup_name = NULL; |
266 | struct sysfs_dirent *sd = NULL; | |
267 | ||
268 | if (type & SYSFS_COPY_NAME) { | |
269 | name = dup_name = kstrdup(name, GFP_KERNEL); | |
270 | if (!name) | |
271 | goto err_out; | |
272 | } | |
1da177e4 | 273 | |
c3762229 | 274 | sd = kmem_cache_zalloc(sysfs_dir_cachep, GFP_KERNEL); |
1da177e4 | 275 | if (!sd) |
0c096b50 | 276 | goto err_out; |
1da177e4 | 277 | |
0c096b50 TH |
278 | if (sysfs_alloc_ino(&sd->s_ino)) |
279 | goto err_out; | |
2b611bb7 | 280 | |
1da177e4 | 281 | atomic_set(&sd->s_count, 1); |
8619f979 | 282 | atomic_set(&sd->s_active, 0); |
eea3f891 | 283 | atomic_set(&sd->s_event, 1); |
a26cd722 | 284 | |
0c096b50 | 285 | sd->s_name = name; |
a26cd722 | 286 | sd->s_mode = mode; |
b402d72c | 287 | sd->s_flags = type; |
1da177e4 LT |
288 | |
289 | return sd; | |
0c096b50 TH |
290 | |
291 | err_out: | |
292 | kfree(dup_name); | |
293 | kmem_cache_free(sysfs_dir_cachep, sd); | |
294 | return NULL; | |
1da177e4 LT |
295 | } |
296 | ||
3007e997 TH |
297 | /** |
298 | * sysfs_attach_dentry - associate sysfs_dirent with dentry | |
299 | * @sd: target sysfs_dirent | |
300 | * @dentry: dentry to associate | |
301 | * | |
302 | * Associate @sd with @dentry. This is protected by | |
303 | * sysfs_assoc_lock to avoid race with sysfs_d_iput(). | |
304 | * | |
305 | * LOCKING: | |
306 | * mutex_lock(sysfs_mutex) | |
307 | */ | |
198a2a84 TH |
308 | static void sysfs_attach_dentry(struct sysfs_dirent *sd, struct dentry *dentry) |
309 | { | |
310 | dentry->d_op = &sysfs_dentry_ops; | |
311 | dentry->d_fsdata = sysfs_get(sd); | |
312 | ||
313 | /* protect sd->s_dentry against sysfs_d_iput */ | |
5f995323 | 314 | spin_lock(&sysfs_assoc_lock); |
198a2a84 | 315 | sd->s_dentry = dentry; |
5f995323 | 316 | spin_unlock(&sysfs_assoc_lock); |
198a2a84 TH |
317 | |
318 | d_rehash(dentry); | |
319 | } | |
320 | ||
fb6896da TH |
321 | static int sysfs_ilookup_test(struct inode *inode, void *arg) |
322 | { | |
323 | struct sysfs_dirent *sd = arg; | |
324 | return inode->i_ino == sd->s_ino; | |
325 | } | |
326 | ||
3007e997 | 327 | /** |
fb6896da TH |
328 | * sysfs_addrm_start - prepare for sysfs_dirent add/remove |
329 | * @acxt: pointer to sysfs_addrm_cxt to be used | |
330 | * @parent_sd: parent sysfs_dirent | |
3007e997 | 331 | * |
fb6896da TH |
332 | * This function is called when the caller is about to add or |
333 | * remove sysfs_dirent under @parent_sd. This function acquires | |
334 | * sysfs_mutex, grabs inode for @parent_sd if available and lock | |
335 | * i_mutex of it. @acxt is used to keep and pass context to | |
336 | * other addrm functions. | |
3007e997 TH |
337 | * |
338 | * LOCKING: | |
fb6896da TH |
339 | * Kernel thread context (may sleep). sysfs_mutex is locked on |
340 | * return. i_mutex of parent inode is locked on return if | |
341 | * available. | |
3007e997 | 342 | */ |
fb6896da TH |
343 | void sysfs_addrm_start(struct sysfs_addrm_cxt *acxt, |
344 | struct sysfs_dirent *parent_sd) | |
b592fcfe | 345 | { |
fb6896da | 346 | struct inode *inode; |
b592fcfe | 347 | |
fb6896da TH |
348 | memset(acxt, 0, sizeof(*acxt)); |
349 | acxt->parent_sd = parent_sd; | |
350 | ||
351 | /* Lookup parent inode. inode initialization and I_NEW | |
352 | * clearing are protected by sysfs_mutex. By grabbing it and | |
353 | * looking up with _nowait variant, inode state can be | |
354 | * determined reliably. | |
355 | */ | |
356 | mutex_lock(&sysfs_mutex); | |
357 | ||
358 | inode = ilookup5_nowait(sysfs_sb, parent_sd->s_ino, sysfs_ilookup_test, | |
359 | parent_sd); | |
360 | ||
361 | if (inode && !(inode->i_state & I_NEW)) { | |
362 | /* parent inode available */ | |
363 | acxt->parent_inode = inode; | |
364 | ||
365 | /* sysfs_mutex is below i_mutex in lock hierarchy. | |
366 | * First, trylock i_mutex. If fails, unlock | |
367 | * sysfs_mutex and lock them in order. | |
368 | */ | |
369 | if (!mutex_trylock(&inode->i_mutex)) { | |
370 | mutex_unlock(&sysfs_mutex); | |
371 | mutex_lock(&inode->i_mutex); | |
372 | mutex_lock(&sysfs_mutex); | |
373 | } | |
374 | } else | |
375 | iput(inode); | |
376 | } | |
377 | ||
378 | /** | |
379 | * sysfs_add_one - add sysfs_dirent to parent | |
380 | * @acxt: addrm context to use | |
381 | * @sd: sysfs_dirent to be added | |
382 | * | |
383 | * Get @acxt->parent_sd and set sd->s_parent to it and increment | |
384 | * nlink of parent inode if @sd is a directory. @sd is NOT | |
385 | * linked into the children list of the parent. The caller | |
386 | * should invoke sysfs_link_sibling() after this function | |
387 | * completes if @sd needs to be on the children list. | |
388 | * | |
389 | * This function should be called between calls to | |
390 | * sysfs_addrm_start() and sysfs_addrm_finish() and should be | |
391 | * passed the same @acxt as passed to sysfs_addrm_start(). | |
392 | * | |
393 | * LOCKING: | |
394 | * Determined by sysfs_addrm_start(). | |
395 | */ | |
396 | void sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd) | |
397 | { | |
398 | sd->s_parent = sysfs_get(acxt->parent_sd); | |
399 | ||
400 | if (sysfs_type(sd) == SYSFS_DIR && acxt->parent_inode) | |
401 | inc_nlink(acxt->parent_inode); | |
402 | ||
403 | acxt->cnt++; | |
404 | } | |
405 | ||
406 | /** | |
407 | * sysfs_remove_one - remove sysfs_dirent from parent | |
408 | * @acxt: addrm context to use | |
409 | * @sd: sysfs_dirent to be added | |
410 | * | |
411 | * Mark @sd removed and drop nlink of parent inode if @sd is a | |
412 | * directory. @sd is NOT unlinked from the children list of the | |
413 | * parent. The caller is repsonsible for removing @sd from the | |
414 | * children list before calling this function. | |
415 | * | |
416 | * This function should be called between calls to | |
417 | * sysfs_addrm_start() and sysfs_addrm_finish() and should be | |
418 | * passed the same @acxt as passed to sysfs_addrm_start(). | |
419 | * | |
420 | * LOCKING: | |
421 | * Determined by sysfs_addrm_start(). | |
422 | */ | |
423 | void sysfs_remove_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd) | |
424 | { | |
425 | BUG_ON(sd->s_sibling || (sd->s_flags & SYSFS_FLAG_REMOVED)); | |
426 | ||
427 | sd->s_flags |= SYSFS_FLAG_REMOVED; | |
428 | sd->s_sibling = acxt->removed; | |
429 | acxt->removed = sd; | |
430 | ||
431 | if (sysfs_type(sd) == SYSFS_DIR && acxt->parent_inode) | |
432 | drop_nlink(acxt->parent_inode); | |
433 | ||
434 | acxt->cnt++; | |
435 | } | |
436 | ||
a0edd7c8 TH |
437 | /** |
438 | * sysfs_drop_dentry - drop dentry for the specified sysfs_dirent | |
439 | * @sd: target sysfs_dirent | |
440 | * | |
441 | * Drop dentry for @sd. @sd must have been unlinked from its | |
442 | * parent on entry to this function such that it can't be looked | |
443 | * up anymore. | |
444 | * | |
445 | * @sd->s_dentry which is protected with sysfs_assoc_lock points | |
446 | * to the currently associated dentry but we're not holding a | |
447 | * reference to it and racing with dput(). Grab dcache_lock and | |
448 | * verify dentry before dropping it. If @sd->s_dentry is NULL or | |
449 | * dput() beats us, no need to bother. | |
450 | */ | |
451 | static void sysfs_drop_dentry(struct sysfs_dirent *sd) | |
452 | { | |
453 | struct dentry *dentry = NULL; | |
454 | struct inode *inode; | |
455 | ||
456 | /* We're not holding a reference to ->s_dentry dentry but the | |
457 | * field will stay valid as long as sysfs_assoc_lock is held. | |
458 | */ | |
459 | spin_lock(&sysfs_assoc_lock); | |
460 | spin_lock(&dcache_lock); | |
461 | ||
462 | /* drop dentry if it's there and dput() didn't kill it yet */ | |
463 | if (sd->s_dentry && sd->s_dentry->d_inode) { | |
464 | dentry = dget_locked(sd->s_dentry); | |
465 | spin_lock(&dentry->d_lock); | |
466 | __d_drop(dentry); | |
467 | spin_unlock(&dentry->d_lock); | |
468 | } | |
469 | ||
470 | spin_unlock(&dcache_lock); | |
471 | spin_unlock(&sysfs_assoc_lock); | |
472 | ||
473 | dput(dentry); | |
474 | /* XXX: unpin if directory, this will go away soon */ | |
475 | if (sysfs_type(sd) == SYSFS_DIR) | |
476 | dput(dentry); | |
477 | ||
478 | /* adjust nlink and update timestamp */ | |
479 | inode = ilookup(sysfs_sb, sd->s_ino); | |
480 | if (inode) { | |
481 | mutex_lock(&inode->i_mutex); | |
482 | ||
483 | inode->i_ctime = CURRENT_TIME; | |
484 | drop_nlink(inode); | |
485 | if (sysfs_type(sd) == SYSFS_DIR) | |
486 | drop_nlink(inode); | |
487 | ||
488 | mutex_unlock(&inode->i_mutex); | |
489 | iput(inode); | |
490 | } | |
491 | } | |
492 | ||
fb6896da TH |
493 | /** |
494 | * sysfs_addrm_finish - finish up sysfs_dirent add/remove | |
495 | * @acxt: addrm context to finish up | |
496 | * | |
497 | * Finish up sysfs_dirent add/remove. Resources acquired by | |
498 | * sysfs_addrm_start() are released and removed sysfs_dirents are | |
499 | * cleaned up. Timestamps on the parent inode are updated. | |
500 | * | |
501 | * LOCKING: | |
502 | * All mutexes acquired by sysfs_addrm_start() are released. | |
503 | * | |
504 | * RETURNS: | |
505 | * Number of added/removed sysfs_dirents since sysfs_addrm_start(). | |
506 | */ | |
507 | int sysfs_addrm_finish(struct sysfs_addrm_cxt *acxt) | |
508 | { | |
509 | /* release resources acquired by sysfs_addrm_start() */ | |
510 | mutex_unlock(&sysfs_mutex); | |
511 | if (acxt->parent_inode) { | |
512 | struct inode *inode = acxt->parent_inode; | |
513 | ||
514 | /* if added/removed, update timestamps on the parent */ | |
515 | if (acxt->cnt) | |
516 | inode->i_ctime = inode->i_mtime = CURRENT_TIME; | |
517 | ||
518 | mutex_unlock(&inode->i_mutex); | |
519 | iput(inode); | |
520 | } | |
521 | ||
522 | /* kill removed sysfs_dirents */ | |
523 | while (acxt->removed) { | |
524 | struct sysfs_dirent *sd = acxt->removed; | |
525 | ||
526 | acxt->removed = sd->s_sibling; | |
527 | sd->s_sibling = NULL; | |
528 | ||
529 | sysfs_drop_dentry(sd); | |
530 | sysfs_deactivate(sd); | |
531 | sysfs_put(sd); | |
13b3086d | 532 | } |
fb6896da TH |
533 | |
534 | return acxt->cnt; | |
b592fcfe EB |
535 | } |
536 | ||
f0b0af47 TH |
537 | /** |
538 | * sysfs_find_dirent - find sysfs_dirent with the given name | |
539 | * @parent_sd: sysfs_dirent to search under | |
540 | * @name: name to look for | |
541 | * | |
542 | * Look for sysfs_dirent with name @name under @parent_sd. | |
c516865c | 543 | * |
f0b0af47 | 544 | * LOCKING: |
3007e997 | 545 | * mutex_lock(sysfs_mutex) |
c516865c | 546 | * |
f0b0af47 TH |
547 | * RETURNS: |
548 | * Pointer to sysfs_dirent if found, NULL if not. | |
c516865c | 549 | */ |
f0b0af47 TH |
550 | struct sysfs_dirent *sysfs_find_dirent(struct sysfs_dirent *parent_sd, |
551 | const unsigned char *name) | |
c516865c | 552 | { |
f0b0af47 TH |
553 | struct sysfs_dirent *sd; |
554 | ||
555 | for (sd = parent_sd->s_children; sd; sd = sd->s_sibling) | |
556 | if (sysfs_type(sd) && !strcmp(sd->s_name, name)) | |
557 | return sd; | |
558 | return NULL; | |
559 | } | |
c516865c | 560 | |
f0b0af47 TH |
561 | /** |
562 | * sysfs_get_dirent - find and get sysfs_dirent with the given name | |
563 | * @parent_sd: sysfs_dirent to search under | |
564 | * @name: name to look for | |
565 | * | |
566 | * Look for sysfs_dirent with name @name under @parent_sd and get | |
567 | * it if found. | |
568 | * | |
569 | * LOCKING: | |
3007e997 | 570 | * Kernel thread context (may sleep). Grabs sysfs_mutex. |
f0b0af47 TH |
571 | * |
572 | * RETURNS: | |
573 | * Pointer to sysfs_dirent if found, NULL if not. | |
574 | */ | |
575 | struct sysfs_dirent *sysfs_get_dirent(struct sysfs_dirent *parent_sd, | |
576 | const unsigned char *name) | |
577 | { | |
578 | struct sysfs_dirent *sd; | |
579 | ||
3007e997 | 580 | mutex_lock(&sysfs_mutex); |
f0b0af47 TH |
581 | sd = sysfs_find_dirent(parent_sd, name); |
582 | sysfs_get(sd); | |
3007e997 | 583 | mutex_unlock(&sysfs_mutex); |
f0b0af47 TH |
584 | |
585 | return sd; | |
c516865c MS |
586 | } |
587 | ||
608e266a TH |
588 | static int create_dir(struct kobject *kobj, struct sysfs_dirent *parent_sd, |
589 | const char *name, struct sysfs_dirent **p_sd) | |
1da177e4 | 590 | { |
608e266a | 591 | struct dentry *parent = parent_sd->s_dentry; |
fb6896da | 592 | struct sysfs_addrm_cxt acxt; |
1da177e4 LT |
593 | int error; |
594 | umode_t mode = S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO; | |
dfeb9fb0 | 595 | struct dentry *dentry; |
fc9f54b9 | 596 | struct inode *inode; |
dfeb9fb0 | 597 | struct sysfs_dirent *sd; |
1da177e4 | 598 | |
fb6896da | 599 | sysfs_addrm_start(&acxt, parent_sd); |
dfeb9fb0 | 600 | |
fc9f54b9 | 601 | /* allocate */ |
dfeb9fb0 TH |
602 | dentry = lookup_one_len(name, parent, strlen(name)); |
603 | if (IS_ERR(dentry)) { | |
604 | error = PTR_ERR(dentry); | |
fb6896da | 605 | goto out_finish; |
dfeb9fb0 TH |
606 | } |
607 | ||
608 | error = -EEXIST; | |
fc9f54b9 | 609 | if (dentry->d_inode) |
dfeb9fb0 TH |
610 | goto out_dput; |
611 | ||
a26cd722 | 612 | error = -ENOMEM; |
3e519038 | 613 | sd = sysfs_new_dirent(name, mode, SYSFS_DIR); |
a26cd722 | 614 | if (!sd) |
dfeb9fb0 | 615 | goto out_drop; |
3e519038 | 616 | sd->s_elem.dir.kobj = kobj; |
dfeb9fb0 | 617 | |
8312a8d7 | 618 | inode = sysfs_get_inode(sd); |
fc9f54b9 | 619 | if (!inode) |
dfeb9fb0 TH |
620 | goto out_sput; |
621 | ||
8312a8d7 TH |
622 | if (inode->i_state & I_NEW) { |
623 | inode->i_op = &sysfs_dir_inode_operations; | |
624 | inode->i_fop = &sysfs_dir_operations; | |
625 | /* directory inodes start off with i_nlink == 2 (for ".") */ | |
626 | inc_nlink(inode); | |
627 | } | |
fc9f54b9 TH |
628 | |
629 | /* link in */ | |
630 | error = -EEXIST; | |
fb6896da | 631 | if (sysfs_find_dirent(parent_sd, name)) |
fc9f54b9 TH |
632 | goto out_iput; |
633 | ||
fb6896da TH |
634 | sysfs_add_one(&acxt, sd); |
635 | sysfs_link_sibling(sd); | |
fc9f54b9 | 636 | sysfs_instantiate(dentry, inode); |
fb6896da | 637 | sysfs_attach_dentry(sd, dentry); |
3007e997 | 638 | |
608e266a | 639 | *p_sd = sd; |
dfeb9fb0 | 640 | error = 0; |
fb6896da | 641 | goto out_finish; /* pin directory dentry in core */ |
dfeb9fb0 | 642 | |
fc9f54b9 TH |
643 | out_iput: |
644 | iput(inode); | |
dfeb9fb0 | 645 | out_sput: |
dfeb9fb0 TH |
646 | sysfs_put(sd); |
647 | out_drop: | |
648 | d_drop(dentry); | |
649 | out_dput: | |
650 | dput(dentry); | |
fb6896da TH |
651 | out_finish: |
652 | sysfs_addrm_finish(&acxt); | |
1da177e4 LT |
653 | return error; |
654 | } | |
655 | ||
608e266a TH |
656 | int sysfs_create_subdir(struct kobject *kobj, const char *name, |
657 | struct sysfs_dirent **p_sd) | |
1da177e4 | 658 | { |
608e266a | 659 | return create_dir(kobj, kobj->sd, name, p_sd); |
1da177e4 LT |
660 | } |
661 | ||
662 | /** | |
663 | * sysfs_create_dir - create a directory for an object. | |
1da177e4 | 664 | * @kobj: object we're creating directory for. |
608e266a | 665 | * @shadow_parent: parent object. |
1da177e4 | 666 | */ |
608e266a TH |
667 | int sysfs_create_dir(struct kobject *kobj, |
668 | struct sysfs_dirent *shadow_parent_sd) | |
1da177e4 | 669 | { |
608e266a | 670 | struct sysfs_dirent *parent_sd, *sd; |
1da177e4 LT |
671 | int error = 0; |
672 | ||
673 | BUG_ON(!kobj); | |
674 | ||
608e266a TH |
675 | if (shadow_parent_sd) |
676 | parent_sd = shadow_parent_sd; | |
b592fcfe | 677 | else if (kobj->parent) |
608e266a | 678 | parent_sd = kobj->parent->sd; |
1da177e4 | 679 | else if (sysfs_mount && sysfs_mount->mnt_sb) |
608e266a | 680 | parent_sd = sysfs_mount->mnt_sb->s_root->d_fsdata; |
1da177e4 LT |
681 | else |
682 | return -EFAULT; | |
683 | ||
608e266a | 684 | error = create_dir(kobj, parent_sd, kobject_name(kobj), &sd); |
1da177e4 | 685 | if (!error) |
608e266a | 686 | kobj->sd = sd; |
1da177e4 LT |
687 | return error; |
688 | } | |
689 | ||
1da177e4 LT |
690 | static struct dentry * sysfs_lookup(struct inode *dir, struct dentry *dentry, |
691 | struct nameidata *nd) | |
692 | { | |
693 | struct sysfs_dirent * parent_sd = dentry->d_parent->d_fsdata; | |
694 | struct sysfs_dirent * sd; | |
b402d72c | 695 | struct bin_attribute *bin_attr; |
fc9f54b9 TH |
696 | struct inode *inode; |
697 | int found = 0; | |
1da177e4 | 698 | |
0c73f18b | 699 | for (sd = parent_sd->s_children; sd; sd = sd->s_sibling) { |
b402d72c | 700 | if ((sysfs_type(sd) & SYSFS_NOT_PINNED) && |
fc9f54b9 TH |
701 | !strcmp(sd->s_name, dentry->d_name.name)) { |
702 | found = 1; | |
1da177e4 LT |
703 | break; |
704 | } | |
705 | } | |
706 | ||
fc9f54b9 TH |
707 | /* no such entry */ |
708 | if (!found) | |
709 | return NULL; | |
710 | ||
711 | /* attach dentry and inode */ | |
8312a8d7 | 712 | inode = sysfs_get_inode(sd); |
fc9f54b9 TH |
713 | if (!inode) |
714 | return ERR_PTR(-ENOMEM); | |
715 | ||
3007e997 TH |
716 | mutex_lock(&sysfs_mutex); |
717 | ||
8312a8d7 TH |
718 | if (inode->i_state & I_NEW) { |
719 | /* initialize inode according to type */ | |
b402d72c TH |
720 | switch (sysfs_type(sd)) { |
721 | case SYSFS_KOBJ_ATTR: | |
8312a8d7 TH |
722 | inode->i_size = PAGE_SIZE; |
723 | inode->i_fop = &sysfs_file_operations; | |
b402d72c TH |
724 | break; |
725 | case SYSFS_KOBJ_BIN_ATTR: | |
726 | bin_attr = sd->s_elem.bin_attr.bin_attr; | |
8312a8d7 TH |
727 | inode->i_size = bin_attr->size; |
728 | inode->i_fop = &bin_fops; | |
b402d72c TH |
729 | break; |
730 | case SYSFS_KOBJ_LINK: | |
8312a8d7 | 731 | inode->i_op = &sysfs_symlink_inode_operations; |
b402d72c TH |
732 | break; |
733 | default: | |
734 | BUG(); | |
735 | } | |
8312a8d7 | 736 | } |
fc9f54b9 TH |
737 | |
738 | sysfs_instantiate(dentry, inode); | |
739 | sysfs_attach_dentry(sd, dentry); | |
740 | ||
3007e997 TH |
741 | mutex_unlock(&sysfs_mutex); |
742 | ||
fc9f54b9 | 743 | return NULL; |
1da177e4 LT |
744 | } |
745 | ||
c5ef1c42 | 746 | const struct inode_operations sysfs_dir_inode_operations = { |
1da177e4 | 747 | .lookup = sysfs_lookup, |
988d186d | 748 | .setattr = sysfs_setattr, |
1da177e4 LT |
749 | }; |
750 | ||
608e266a | 751 | static void remove_dir(struct sysfs_dirent *sd) |
1da177e4 | 752 | { |
fb6896da | 753 | struct sysfs_addrm_cxt acxt; |
1da177e4 | 754 | |
fb6896da TH |
755 | sysfs_addrm_start(&acxt, sd->s_parent); |
756 | sysfs_unlink_sibling(sd); | |
757 | sysfs_remove_one(&acxt, sd); | |
758 | sysfs_addrm_finish(&acxt); | |
1da177e4 LT |
759 | } |
760 | ||
608e266a | 761 | void sysfs_remove_subdir(struct sysfs_dirent *sd) |
1da177e4 | 762 | { |
608e266a | 763 | remove_dir(sd); |
1da177e4 LT |
764 | } |
765 | ||
766 | ||
608e266a | 767 | static void __sysfs_remove_dir(struct sysfs_dirent *dir_sd) |
1da177e4 | 768 | { |
fb6896da | 769 | struct sysfs_addrm_cxt acxt; |
0c73f18b | 770 | struct sysfs_dirent **pos; |
1da177e4 | 771 | |
608e266a | 772 | if (!dir_sd) |
1da177e4 LT |
773 | return; |
774 | ||
608e266a | 775 | pr_debug("sysfs %s: removing dir\n", dir_sd->s_name); |
fb6896da | 776 | sysfs_addrm_start(&acxt, dir_sd); |
608e266a | 777 | pos = &dir_sd->s_children; |
0c73f18b TH |
778 | while (*pos) { |
779 | struct sysfs_dirent *sd = *pos; | |
780 | ||
b402d72c | 781 | if (sysfs_type(sd) && (sysfs_type(sd) & SYSFS_NOT_PINNED)) { |
0c73f18b | 782 | *pos = sd->s_sibling; |
fb6896da TH |
783 | sd->s_sibling = NULL; |
784 | sysfs_remove_one(&acxt, sd); | |
0c73f18b TH |
785 | } else |
786 | pos = &(*pos)->s_sibling; | |
1da177e4 | 787 | } |
fb6896da | 788 | sysfs_addrm_finish(&acxt); |
0ab66088 | 789 | |
608e266a | 790 | remove_dir(dir_sd); |
b592fcfe EB |
791 | } |
792 | ||
793 | /** | |
794 | * sysfs_remove_dir - remove an object's directory. | |
795 | * @kobj: object. | |
796 | * | |
797 | * The only thing special about this is that we remove any files in | |
798 | * the directory before we remove the directory, and we've inlined | |
799 | * what used to be sysfs_rmdir() below, instead of calling separately. | |
800 | */ | |
801 | ||
802 | void sysfs_remove_dir(struct kobject * kobj) | |
803 | { | |
608e266a | 804 | struct sysfs_dirent *sd = kobj->sd; |
aecdceda | 805 | |
5f995323 | 806 | spin_lock(&sysfs_assoc_lock); |
608e266a | 807 | kobj->sd = NULL; |
5f995323 | 808 | spin_unlock(&sysfs_assoc_lock); |
aecdceda | 809 | |
608e266a | 810 | __sysfs_remove_dir(sd); |
1da177e4 LT |
811 | } |
812 | ||
608e266a | 813 | int sysfs_rename_dir(struct kobject *kobj, struct sysfs_dirent *new_parent_sd, |
b592fcfe | 814 | const char *new_name) |
1da177e4 | 815 | { |
608e266a TH |
816 | struct sysfs_dirent *sd = kobj->sd; |
817 | struct dentry *new_parent = new_parent_sd->s_dentry; | |
0c096b50 TH |
818 | struct dentry *new_dentry; |
819 | char *dup_name; | |
996b7376 | 820 | int error; |
1da177e4 | 821 | |
608e266a | 822 | if (!new_parent_sd) |
b592fcfe | 823 | return -EFAULT; |
1da177e4 | 824 | |
b592fcfe | 825 | mutex_lock(&new_parent->d_inode->i_mutex); |
1da177e4 | 826 | |
b592fcfe | 827 | new_dentry = lookup_one_len(new_name, new_parent, strlen(new_name)); |
996b7376 TH |
828 | if (IS_ERR(new_dentry)) { |
829 | error = PTR_ERR(new_dentry); | |
830 | goto out_unlock; | |
1da177e4 | 831 | } |
996b7376 TH |
832 | |
833 | /* By allowing two different directories with the same | |
834 | * d_parent we allow this routine to move between different | |
835 | * shadows of the same directory | |
836 | */ | |
837 | error = -EINVAL; | |
608e266a | 838 | if (sd->s_parent->s_dentry->d_inode != new_parent->d_inode || |
996b7376 | 839 | new_dentry->d_parent->d_inode != new_parent->d_inode || |
608e266a | 840 | new_dentry == sd->s_dentry) |
996b7376 TH |
841 | goto out_dput; |
842 | ||
843 | error = -EEXIST; | |
844 | if (new_dentry->d_inode) | |
845 | goto out_dput; | |
846 | ||
0c096b50 TH |
847 | /* rename kobject and sysfs_dirent */ |
848 | error = -ENOMEM; | |
849 | new_name = dup_name = kstrdup(new_name, GFP_KERNEL); | |
850 | if (!new_name) | |
851 | goto out_drop; | |
852 | ||
996b7376 TH |
853 | error = kobject_set_name(kobj, "%s", new_name); |
854 | if (error) | |
0c096b50 | 855 | goto out_free; |
996b7376 | 856 | |
0c096b50 TH |
857 | kfree(sd->s_name); |
858 | sd->s_name = new_name; | |
859 | ||
860 | /* move under the new parent */ | |
996b7376 | 861 | d_add(new_dentry, NULL); |
608e266a | 862 | d_move(sd->s_dentry, new_dentry); |
996b7376 | 863 | |
3007e997 TH |
864 | mutex_lock(&sysfs_mutex); |
865 | ||
0c73f18b | 866 | sysfs_unlink_sibling(sd); |
608e266a | 867 | sysfs_get(new_parent_sd); |
7f7cfffe | 868 | sysfs_put(sd->s_parent); |
608e266a | 869 | sd->s_parent = new_parent_sd; |
0c73f18b | 870 | sysfs_link_sibling(sd); |
996b7376 | 871 | |
3007e997 TH |
872 | mutex_unlock(&sysfs_mutex); |
873 | ||
996b7376 TH |
874 | error = 0; |
875 | goto out_unlock; | |
876 | ||
0c096b50 TH |
877 | out_free: |
878 | kfree(dup_name); | |
996b7376 TH |
879 | out_drop: |
880 | d_drop(new_dentry); | |
881 | out_dput: | |
882 | dput(new_dentry); | |
883 | out_unlock: | |
b592fcfe | 884 | mutex_unlock(&new_parent->d_inode->i_mutex); |
1da177e4 LT |
885 | return error; |
886 | } | |
887 | ||
8a82472f CH |
888 | int sysfs_move_dir(struct kobject *kobj, struct kobject *new_parent) |
889 | { | |
890 | struct dentry *old_parent_dentry, *new_parent_dentry, *new_dentry; | |
891 | struct sysfs_dirent *new_parent_sd, *sd; | |
892 | int error; | |
893 | ||
8a82472f | 894 | old_parent_dentry = kobj->parent ? |
608e266a | 895 | kobj->parent->sd->s_dentry : sysfs_mount->mnt_sb->s_root; |
c744aeae | 896 | new_parent_dentry = new_parent ? |
608e266a | 897 | new_parent->sd->s_dentry : sysfs_mount->mnt_sb->s_root; |
8a82472f | 898 | |
0de1517e ML |
899 | if (old_parent_dentry->d_inode == new_parent_dentry->d_inode) |
900 | return 0; /* nothing to move */ | |
8a82472f CH |
901 | again: |
902 | mutex_lock(&old_parent_dentry->d_inode->i_mutex); | |
903 | if (!mutex_trylock(&new_parent_dentry->d_inode->i_mutex)) { | |
904 | mutex_unlock(&old_parent_dentry->d_inode->i_mutex); | |
905 | goto again; | |
906 | } | |
907 | ||
908 | new_parent_sd = new_parent_dentry->d_fsdata; | |
608e266a | 909 | sd = kobj->sd; |
8a82472f CH |
910 | |
911 | new_dentry = lookup_one_len(kobj->name, new_parent_dentry, | |
912 | strlen(kobj->name)); | |
913 | if (IS_ERR(new_dentry)) { | |
914 | error = PTR_ERR(new_dentry); | |
915 | goto out; | |
916 | } else | |
917 | error = 0; | |
918 | d_add(new_dentry, NULL); | |
608e266a | 919 | d_move(sd->s_dentry, new_dentry); |
8a82472f CH |
920 | dput(new_dentry); |
921 | ||
922 | /* Remove from old parent's list and insert into new parent's list. */ | |
3007e997 TH |
923 | mutex_lock(&sysfs_mutex); |
924 | ||
0c73f18b | 925 | sysfs_unlink_sibling(sd); |
7f7cfffe TH |
926 | sysfs_get(new_parent_sd); |
927 | sysfs_put(sd->s_parent); | |
928 | sd->s_parent = new_parent_sd; | |
0c73f18b | 929 | sysfs_link_sibling(sd); |
8a82472f | 930 | |
3007e997 | 931 | mutex_unlock(&sysfs_mutex); |
8a82472f CH |
932 | out: |
933 | mutex_unlock(&new_parent_dentry->d_inode->i_mutex); | |
934 | mutex_unlock(&old_parent_dentry->d_inode->i_mutex); | |
935 | ||
936 | return error; | |
937 | } | |
938 | ||
1da177e4 LT |
939 | static int sysfs_dir_open(struct inode *inode, struct file *file) |
940 | { | |
f427f5d5 | 941 | struct dentry * dentry = file->f_path.dentry; |
1da177e4 | 942 | struct sysfs_dirent * parent_sd = dentry->d_fsdata; |
a26cd722 | 943 | struct sysfs_dirent * sd; |
1da177e4 | 944 | |
3e519038 | 945 | sd = sysfs_new_dirent("_DIR_", 0, 0); |
3007e997 TH |
946 | if (sd) { |
947 | mutex_lock(&sysfs_mutex); | |
fb6896da TH |
948 | sd->s_parent = sysfs_get(parent_sd); |
949 | sysfs_link_sibling(sd); | |
3007e997 TH |
950 | mutex_unlock(&sysfs_mutex); |
951 | } | |
1da177e4 | 952 | |
a26cd722 TH |
953 | file->private_data = sd; |
954 | return sd ? 0 : -ENOMEM; | |
1da177e4 LT |
955 | } |
956 | ||
957 | static int sysfs_dir_close(struct inode *inode, struct file *file) | |
958 | { | |
1da177e4 LT |
959 | struct sysfs_dirent * cursor = file->private_data; |
960 | ||
3007e997 | 961 | mutex_lock(&sysfs_mutex); |
0c73f18b | 962 | sysfs_unlink_sibling(cursor); |
3007e997 | 963 | mutex_unlock(&sysfs_mutex); |
1da177e4 LT |
964 | |
965 | release_sysfs_dirent(cursor); | |
966 | ||
967 | return 0; | |
968 | } | |
969 | ||
970 | /* Relationship between s_mode and the DT_xxx types */ | |
971 | static inline unsigned char dt_type(struct sysfs_dirent *sd) | |
972 | { | |
973 | return (sd->s_mode >> 12) & 15; | |
974 | } | |
975 | ||
976 | static int sysfs_readdir(struct file * filp, void * dirent, filldir_t filldir) | |
977 | { | |
f427f5d5 | 978 | struct dentry *dentry = filp->f_path.dentry; |
1da177e4 LT |
979 | struct sysfs_dirent * parent_sd = dentry->d_fsdata; |
980 | struct sysfs_dirent *cursor = filp->private_data; | |
0c73f18b | 981 | struct sysfs_dirent **pos; |
1da177e4 LT |
982 | ino_t ino; |
983 | int i = filp->f_pos; | |
984 | ||
985 | switch (i) { | |
986 | case 0: | |
dc351252 | 987 | ino = parent_sd->s_ino; |
1da177e4 LT |
988 | if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0) |
989 | break; | |
990 | filp->f_pos++; | |
991 | i++; | |
992 | /* fallthrough */ | |
993 | case 1: | |
13b3086d TH |
994 | if (parent_sd->s_parent) |
995 | ino = parent_sd->s_parent->s_ino; | |
996 | else | |
997 | ino = parent_sd->s_ino; | |
1da177e4 LT |
998 | if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0) |
999 | break; | |
1000 | filp->f_pos++; | |
1001 | i++; | |
1002 | /* fallthrough */ | |
1003 | default: | |
3007e997 TH |
1004 | mutex_lock(&sysfs_mutex); |
1005 | ||
0c73f18b TH |
1006 | pos = &parent_sd->s_children; |
1007 | while (*pos != cursor) | |
1008 | pos = &(*pos)->s_sibling; | |
1009 | ||
1010 | /* unlink cursor */ | |
1011 | *pos = cursor->s_sibling; | |
1012 | ||
1bfba4e8 | 1013 | if (filp->f_pos == 2) |
0c73f18b | 1014 | pos = &parent_sd->s_children; |
1bfba4e8 | 1015 | |
0c73f18b TH |
1016 | for ( ; *pos; pos = &(*pos)->s_sibling) { |
1017 | struct sysfs_dirent *next = *pos; | |
1da177e4 LT |
1018 | const char * name; |
1019 | int len; | |
1020 | ||
b402d72c | 1021 | if (!sysfs_type(next)) |
1da177e4 LT |
1022 | continue; |
1023 | ||
0c096b50 | 1024 | name = next->s_name; |
1da177e4 | 1025 | len = strlen(name); |
dc351252 | 1026 | ino = next->s_ino; |
1da177e4 LT |
1027 | |
1028 | if (filldir(dirent, name, len, filp->f_pos, ino, | |
1029 | dt_type(next)) < 0) | |
0c73f18b | 1030 | break; |
1da177e4 | 1031 | |
1da177e4 LT |
1032 | filp->f_pos++; |
1033 | } | |
0c73f18b TH |
1034 | |
1035 | /* put cursor back in */ | |
1036 | cursor->s_sibling = *pos; | |
1037 | *pos = cursor; | |
3007e997 TH |
1038 | |
1039 | mutex_unlock(&sysfs_mutex); | |
1da177e4 LT |
1040 | } |
1041 | return 0; | |
1042 | } | |
1043 | ||
1044 | static loff_t sysfs_dir_lseek(struct file * file, loff_t offset, int origin) | |
1045 | { | |
f427f5d5 | 1046 | struct dentry * dentry = file->f_path.dentry; |
1da177e4 | 1047 | |
1da177e4 LT |
1048 | switch (origin) { |
1049 | case 1: | |
1050 | offset += file->f_pos; | |
1051 | case 0: | |
1052 | if (offset >= 0) | |
1053 | break; | |
1054 | default: | |
1da177e4 LT |
1055 | return -EINVAL; |
1056 | } | |
1057 | if (offset != file->f_pos) { | |
3007e997 TH |
1058 | mutex_lock(&sysfs_mutex); |
1059 | ||
1da177e4 LT |
1060 | file->f_pos = offset; |
1061 | if (file->f_pos >= 2) { | |
1062 | struct sysfs_dirent *sd = dentry->d_fsdata; | |
1063 | struct sysfs_dirent *cursor = file->private_data; | |
0c73f18b | 1064 | struct sysfs_dirent **pos; |
1da177e4 LT |
1065 | loff_t n = file->f_pos - 2; |
1066 | ||
0c73f18b TH |
1067 | sysfs_unlink_sibling(cursor); |
1068 | ||
1069 | pos = &sd->s_children; | |
1070 | while (n && *pos) { | |
1071 | struct sysfs_dirent *next = *pos; | |
b402d72c | 1072 | if (sysfs_type(next)) |
1da177e4 | 1073 | n--; |
0c73f18b | 1074 | pos = &(*pos)->s_sibling; |
1da177e4 | 1075 | } |
0c73f18b TH |
1076 | |
1077 | cursor->s_sibling = *pos; | |
1078 | *pos = cursor; | |
1da177e4 | 1079 | } |
3007e997 TH |
1080 | |
1081 | mutex_unlock(&sysfs_mutex); | |
1da177e4 | 1082 | } |
3007e997 | 1083 | |
1da177e4 LT |
1084 | return offset; |
1085 | } | |
1086 | ||
b592fcfe EB |
1087 | |
1088 | /** | |
1089 | * sysfs_make_shadowed_dir - Setup so a directory can be shadowed | |
1090 | * @kobj: object we're creating shadow of. | |
1091 | */ | |
1092 | ||
1093 | int sysfs_make_shadowed_dir(struct kobject *kobj, | |
1094 | void * (*follow_link)(struct dentry *, struct nameidata *)) | |
1095 | { | |
1096 | struct inode *inode; | |
1097 | struct inode_operations *i_op; | |
1098 | ||
608e266a | 1099 | inode = kobj->sd->s_dentry->d_inode; |
b592fcfe EB |
1100 | if (inode->i_op != &sysfs_dir_inode_operations) |
1101 | return -EINVAL; | |
1102 | ||
1103 | i_op = kmalloc(sizeof(*i_op), GFP_KERNEL); | |
1104 | if (!i_op) | |
1105 | return -ENOMEM; | |
1106 | ||
1107 | memcpy(i_op, &sysfs_dir_inode_operations, sizeof(*i_op)); | |
1108 | i_op->follow_link = follow_link; | |
1109 | ||
1110 | /* Locking of inode->i_op? | |
1111 | * Since setting i_op is a single word write and they | |
1112 | * are atomic we should be ok here. | |
1113 | */ | |
1114 | inode->i_op = i_op; | |
1115 | return 0; | |
1116 | } | |
1117 | ||
1118 | /** | |
1119 | * sysfs_create_shadow_dir - create a shadow directory for an object. | |
1120 | * @kobj: object we're creating directory for. | |
1121 | * | |
1122 | * sysfs_make_shadowed_dir must already have been called on this | |
1123 | * directory. | |
1124 | */ | |
1125 | ||
608e266a | 1126 | struct sysfs_dirent *sysfs_create_shadow_dir(struct kobject *kobj) |
b592fcfe | 1127 | { |
608e266a | 1128 | struct dentry *dir = kobj->sd->s_dentry; |
13b3086d TH |
1129 | struct inode *inode = dir->d_inode; |
1130 | struct dentry *parent = dir->d_parent; | |
1131 | struct sysfs_dirent *parent_sd = parent->d_fsdata; | |
1132 | struct dentry *shadow; | |
b592fcfe | 1133 | struct sysfs_dirent *sd; |
fb6896da | 1134 | struct sysfs_addrm_cxt acxt; |
b592fcfe | 1135 | |
608e266a | 1136 | sd = ERR_PTR(-EINVAL); |
b592fcfe EB |
1137 | if (!sysfs_is_shadowed_inode(inode)) |
1138 | goto out; | |
1139 | ||
1140 | shadow = d_alloc(parent, &dir->d_name); | |
1141 | if (!shadow) | |
1142 | goto nomem; | |
1143 | ||
3e519038 | 1144 | sd = sysfs_new_dirent("_SHADOW_", inode->i_mode, SYSFS_DIR); |
b592fcfe EB |
1145 | if (!sd) |
1146 | goto nomem; | |
3e519038 | 1147 | sd->s_elem.dir.kobj = kobj; |
b592fcfe | 1148 | |
fb6896da TH |
1149 | sysfs_addrm_start(&acxt, parent_sd); |
1150 | ||
1151 | /* add but don't link into children list */ | |
1152 | sysfs_add_one(&acxt, sd); | |
1153 | ||
1154 | /* attach and instantiate dentry */ | |
1155 | sysfs_attach_dentry(sd, shadow); | |
b592fcfe | 1156 | d_instantiate(shadow, igrab(inode)); |
fb6896da TH |
1157 | inc_nlink(inode); /* tj: synchronization? */ |
1158 | ||
1159 | sysfs_addrm_finish(&acxt); | |
b592fcfe EB |
1160 | |
1161 | dget(shadow); /* Extra count - pin the dentry in core */ | |
1162 | ||
1163 | out: | |
608e266a | 1164 | return sd; |
b592fcfe EB |
1165 | nomem: |
1166 | dput(shadow); | |
608e266a | 1167 | sd = ERR_PTR(-ENOMEM); |
b592fcfe EB |
1168 | goto out; |
1169 | } | |
1170 | ||
1171 | /** | |
1172 | * sysfs_remove_shadow_dir - remove an object's directory. | |
608e266a | 1173 | * @shadow_sd: sysfs_dirent of shadow directory |
b592fcfe EB |
1174 | * |
1175 | * The only thing special about this is that we remove any files in | |
1176 | * the directory before we remove the directory, and we've inlined | |
1177 | * what used to be sysfs_rmdir() below, instead of calling separately. | |
1178 | */ | |
1179 | ||
608e266a | 1180 | void sysfs_remove_shadow_dir(struct sysfs_dirent *shadow_sd) |
b592fcfe | 1181 | { |
608e266a | 1182 | __sysfs_remove_dir(shadow_sd); |
b592fcfe EB |
1183 | } |
1184 | ||
4b6f5d20 | 1185 | const struct file_operations sysfs_dir_operations = { |
1da177e4 LT |
1186 | .open = sysfs_dir_open, |
1187 | .release = sysfs_dir_close, | |
1188 | .llseek = sysfs_dir_lseek, | |
1189 | .read = generic_read_dir, | |
1190 | .readdir = sysfs_readdir, | |
1191 | }; |