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Commit | Line | Data |
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1da177e4 | 1 | /* |
6d66f5cd TH |
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. | |
1da177e4 LT |
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> | |
5f45f1a7 | 19 | #include <linux/namei.h> |
2b611bb7 | 20 | #include <linux/idr.h> |
8619f979 | 21 | #include <linux/completion.h> |
869512ab | 22 | #include <linux/mutex.h> |
c6f87733 | 23 | #include <linux/slab.h> |
4c3da220 | 24 | #include <linux/security.h> |
1da177e4 LT |
25 | #include "sysfs.h" |
26 | ||
3007e997 | 27 | DEFINE_MUTEX(sysfs_mutex); |
f7a75f0a | 28 | DEFINE_SPINLOCK(sysfs_assoc_lock); |
1da177e4 | 29 | |
f7a75f0a | 30 | static DEFINE_SPINLOCK(sysfs_ino_lock); |
2b611bb7 TH |
31 | static DEFINE_IDA(sysfs_ino_ida); |
32 | ||
0c73f18b TH |
33 | /** |
34 | * sysfs_link_sibling - link sysfs_dirent into sibling list | |
35 | * @sd: sysfs_dirent of interest | |
36 | * | |
37 | * Link @sd into its sibling list which starts from | |
bc747f37 | 38 | * sd->s_parent->s_dir.children. |
0c73f18b TH |
39 | * |
40 | * Locking: | |
3007e997 | 41 | * mutex_lock(sysfs_mutex) |
0c73f18b | 42 | */ |
41fc1c27 | 43 | static void sysfs_link_sibling(struct sysfs_dirent *sd) |
0c73f18b TH |
44 | { |
45 | struct sysfs_dirent *parent_sd = sd->s_parent; | |
3efa65b9 | 46 | struct sysfs_dirent **pos; |
0c73f18b TH |
47 | |
48 | BUG_ON(sd->s_sibling); | |
3efa65b9 EB |
49 | |
50 | /* Store directory entries in order by ino. This allows | |
51 | * readdir to properly restart without having to add a | |
bc747f37 | 52 | * cursor into the s_dir.children list. |
3efa65b9 | 53 | */ |
bc747f37 | 54 | for (pos = &parent_sd->s_dir.children; *pos; pos = &(*pos)->s_sibling) { |
3efa65b9 EB |
55 | if (sd->s_ino < (*pos)->s_ino) |
56 | break; | |
57 | } | |
58 | sd->s_sibling = *pos; | |
59 | *pos = sd; | |
0c73f18b TH |
60 | } |
61 | ||
62 | /** | |
63 | * sysfs_unlink_sibling - unlink sysfs_dirent from sibling list | |
64 | * @sd: sysfs_dirent of interest | |
65 | * | |
66 | * Unlink @sd from its sibling list which starts from | |
bc747f37 | 67 | * sd->s_parent->s_dir.children. |
0c73f18b TH |
68 | * |
69 | * Locking: | |
3007e997 | 70 | * mutex_lock(sysfs_mutex) |
0c73f18b | 71 | */ |
41fc1c27 | 72 | static void sysfs_unlink_sibling(struct sysfs_dirent *sd) |
0c73f18b TH |
73 | { |
74 | struct sysfs_dirent **pos; | |
75 | ||
bc747f37 TH |
76 | for (pos = &sd->s_parent->s_dir.children; *pos; |
77 | pos = &(*pos)->s_sibling) { | |
0c73f18b TH |
78 | if (*pos == sd) { |
79 | *pos = sd->s_sibling; | |
80 | sd->s_sibling = NULL; | |
81 | break; | |
82 | } | |
83 | } | |
84 | } | |
85 | ||
b6b4a439 TH |
86 | /** |
87 | * sysfs_get_active - get an active reference to sysfs_dirent | |
88 | * @sd: sysfs_dirent to get an active reference to | |
89 | * | |
90 | * Get an active reference of @sd. This function is noop if @sd | |
91 | * is NULL. | |
92 | * | |
93 | * RETURNS: | |
94 | * Pointer to @sd on success, NULL on failure. | |
95 | */ | |
78e9d367 | 96 | static struct sysfs_dirent *sysfs_get_active(struct sysfs_dirent *sd) |
b6b4a439 | 97 | { |
8619f979 TH |
98 | if (unlikely(!sd)) |
99 | return NULL; | |
100 | ||
101 | while (1) { | |
102 | int v, t; | |
103 | ||
104 | v = atomic_read(&sd->s_active); | |
105 | if (unlikely(v < 0)) | |
106 | return NULL; | |
107 | ||
108 | t = atomic_cmpxchg(&sd->s_active, v, v + 1); | |
109 | if (likely(t == v)) | |
110 | return sd; | |
111 | if (t < 0) | |
112 | return NULL; | |
113 | ||
114 | cpu_relax(); | |
b6b4a439 | 115 | } |
b6b4a439 TH |
116 | } |
117 | ||
118 | /** | |
119 | * sysfs_put_active - put an active reference to sysfs_dirent | |
120 | * @sd: sysfs_dirent to put an active reference to | |
121 | * | |
122 | * Put an active reference to @sd. This function is noop if @sd | |
123 | * is NULL. | |
124 | */ | |
78e9d367 | 125 | static void sysfs_put_active(struct sysfs_dirent *sd) |
b6b4a439 | 126 | { |
8619f979 TH |
127 | struct completion *cmpl; |
128 | int v; | |
129 | ||
130 | if (unlikely(!sd)) | |
131 | return; | |
132 | ||
133 | v = atomic_dec_return(&sd->s_active); | |
134 | if (likely(v != SD_DEACTIVATED_BIAS)) | |
135 | return; | |
136 | ||
137 | /* atomic_dec_return() is a mb(), we'll always see the updated | |
0c73f18b | 138 | * sd->s_sibling. |
8619f979 | 139 | */ |
0c73f18b | 140 | cmpl = (void *)sd->s_sibling; |
8619f979 | 141 | complete(cmpl); |
b6b4a439 TH |
142 | } |
143 | ||
144 | /** | |
145 | * sysfs_get_active_two - get active references to sysfs_dirent and parent | |
146 | * @sd: sysfs_dirent of interest | |
147 | * | |
148 | * Get active reference to @sd and its parent. Parent's active | |
149 | * reference is grabbed first. This function is noop if @sd is | |
150 | * NULL. | |
151 | * | |
152 | * RETURNS: | |
153 | * Pointer to @sd on success, NULL on failure. | |
154 | */ | |
155 | struct sysfs_dirent *sysfs_get_active_two(struct sysfs_dirent *sd) | |
156 | { | |
157 | if (sd) { | |
158 | if (sd->s_parent && unlikely(!sysfs_get_active(sd->s_parent))) | |
159 | return NULL; | |
160 | if (unlikely(!sysfs_get_active(sd))) { | |
161 | sysfs_put_active(sd->s_parent); | |
162 | return NULL; | |
163 | } | |
164 | } | |
165 | return sd; | |
166 | } | |
167 | ||
168 | /** | |
169 | * sysfs_put_active_two - put active references to sysfs_dirent and parent | |
170 | * @sd: sysfs_dirent of interest | |
171 | * | |
172 | * Put active references to @sd and its parent. This function is | |
173 | * noop if @sd is NULL. | |
174 | */ | |
175 | void sysfs_put_active_two(struct sysfs_dirent *sd) | |
176 | { | |
177 | if (sd) { | |
178 | sysfs_put_active(sd); | |
179 | sysfs_put_active(sd->s_parent); | |
180 | } | |
181 | } | |
182 | ||
183 | /** | |
184 | * sysfs_deactivate - deactivate sysfs_dirent | |
185 | * @sd: sysfs_dirent to deactivate | |
186 | * | |
8619f979 | 187 | * Deny new active references and drain existing ones. |
b6b4a439 | 188 | */ |
fb6896da | 189 | static void sysfs_deactivate(struct sysfs_dirent *sd) |
b6b4a439 | 190 | { |
8619f979 TH |
191 | DECLARE_COMPLETION_ONSTACK(wait); |
192 | int v; | |
b6b4a439 | 193 | |
380e6fbb | 194 | BUG_ON(sd->s_sibling || !(sd->s_flags & SYSFS_FLAG_REMOVED)); |
0c73f18b | 195 | sd->s_sibling = (void *)&wait; |
8619f979 TH |
196 | |
197 | /* atomic_add_return() is a mb(), put_active() will always see | |
0c73f18b | 198 | * the updated sd->s_sibling. |
b6b4a439 | 199 | */ |
8619f979 TH |
200 | v = atomic_add_return(SD_DEACTIVATED_BIAS, &sd->s_active); |
201 | ||
202 | if (v != SD_DEACTIVATED_BIAS) | |
203 | wait_for_completion(&wait); | |
204 | ||
0c73f18b | 205 | sd->s_sibling = NULL; |
b6b4a439 TH |
206 | } |
207 | ||
42b37df6 | 208 | static int sysfs_alloc_ino(ino_t *pino) |
2b611bb7 TH |
209 | { |
210 | int ino, rc; | |
211 | ||
212 | retry: | |
213 | spin_lock(&sysfs_ino_lock); | |
214 | rc = ida_get_new_above(&sysfs_ino_ida, 2, &ino); | |
215 | spin_unlock(&sysfs_ino_lock); | |
216 | ||
217 | if (rc == -EAGAIN) { | |
218 | if (ida_pre_get(&sysfs_ino_ida, GFP_KERNEL)) | |
219 | goto retry; | |
220 | rc = -ENOMEM; | |
221 | } | |
222 | ||
223 | *pino = ino; | |
224 | return rc; | |
225 | } | |
226 | ||
227 | static void sysfs_free_ino(ino_t ino) | |
228 | { | |
229 | spin_lock(&sysfs_ino_lock); | |
230 | ida_remove(&sysfs_ino_ida, ino); | |
231 | spin_unlock(&sysfs_ino_lock); | |
232 | } | |
233 | ||
fa7f912a TH |
234 | void release_sysfs_dirent(struct sysfs_dirent * sd) |
235 | { | |
13b3086d TH |
236 | struct sysfs_dirent *parent_sd; |
237 | ||
238 | repeat: | |
3007e997 TH |
239 | /* Moving/renaming is always done while holding reference. |
240 | * sd->s_parent won't change beneath us. | |
241 | */ | |
13b3086d TH |
242 | parent_sd = sd->s_parent; |
243 | ||
b402d72c | 244 | if (sysfs_type(sd) == SYSFS_KOBJ_LINK) |
b1fc3d61 | 245 | sysfs_put(sd->s_symlink.target_sd); |
b402d72c | 246 | if (sysfs_type(sd) & SYSFS_COPY_NAME) |
0c096b50 | 247 | kfree(sd->s_name); |
4c3da220 EB |
248 | if (sd->s_iattr && sd->s_iattr->ia_secdata) |
249 | security_release_secctx(sd->s_iattr->ia_secdata, | |
250 | sd->s_iattr->ia_secdata_len); | |
fa7f912a | 251 | kfree(sd->s_iattr); |
2b611bb7 | 252 | sysfs_free_ino(sd->s_ino); |
fa7f912a | 253 | kmem_cache_free(sysfs_dir_cachep, sd); |
13b3086d TH |
254 | |
255 | sd = parent_sd; | |
256 | if (sd && atomic_dec_and_test(&sd->s_count)) | |
257 | goto repeat; | |
fa7f912a TH |
258 | } |
259 | ||
e8f077c8 EB |
260 | static int sysfs_dentry_delete(struct dentry *dentry) |
261 | { | |
262 | struct sysfs_dirent *sd = dentry->d_fsdata; | |
263 | return !!(sd->s_flags & SYSFS_FLAG_REMOVED); | |
264 | } | |
265 | ||
266 | static int sysfs_dentry_revalidate(struct dentry *dentry, struct nameidata *nd) | |
267 | { | |
268 | struct sysfs_dirent *sd = dentry->d_fsdata; | |
269 | int is_dir; | |
270 | ||
271 | mutex_lock(&sysfs_mutex); | |
272 | ||
273 | /* The sysfs dirent has been deleted */ | |
274 | if (sd->s_flags & SYSFS_FLAG_REMOVED) | |
275 | goto out_bad; | |
276 | ||
832b6af1 EB |
277 | /* The sysfs dirent has been moved? */ |
278 | if (dentry->d_parent->d_fsdata != sd->s_parent) | |
279 | goto out_bad; | |
280 | ||
281 | /* The sysfs dirent has been renamed */ | |
282 | if (strcmp(dentry->d_name.name, sd->s_name) != 0) | |
283 | goto out_bad; | |
284 | ||
e8f077c8 EB |
285 | mutex_unlock(&sysfs_mutex); |
286 | out_valid: | |
287 | return 1; | |
288 | out_bad: | |
289 | /* Remove the dentry from the dcache hashes. | |
290 | * If this is a deleted dentry we use d_drop instead of d_delete | |
291 | * so sysfs doesn't need to cope with negative dentries. | |
832b6af1 EB |
292 | * |
293 | * If this is a dentry that has simply been renamed we | |
294 | * use d_drop to remove it from the dcache lookup on its | |
295 | * old parent. If this dentry persists later when a lookup | |
296 | * is performed at its new name the dentry will be readded | |
297 | * to the dcache hashes. | |
e8f077c8 EB |
298 | */ |
299 | is_dir = (sysfs_type(sd) == SYSFS_DIR); | |
300 | mutex_unlock(&sysfs_mutex); | |
301 | if (is_dir) { | |
302 | /* If we have submounts we must allow the vfs caches | |
303 | * to lie about the state of the filesystem to prevent | |
304 | * leaks and other nasty things. | |
305 | */ | |
306 | if (have_submounts(dentry)) | |
307 | goto out_valid; | |
308 | shrink_dcache_parent(dentry); | |
309 | } | |
310 | d_drop(dentry); | |
311 | return 0; | |
312 | } | |
313 | ||
28a027cf | 314 | static void sysfs_dentry_iput(struct dentry *dentry, struct inode *inode) |
1da177e4 LT |
315 | { |
316 | struct sysfs_dirent * sd = dentry->d_fsdata; | |
317 | ||
5a26b79c | 318 | sysfs_put(sd); |
1da177e4 LT |
319 | iput(inode); |
320 | } | |
321 | ||
ee1ec329 | 322 | static const struct dentry_operations sysfs_dentry_ops = { |
e8f077c8 EB |
323 | .d_revalidate = sysfs_dentry_revalidate, |
324 | .d_delete = sysfs_dentry_delete, | |
28a027cf | 325 | .d_iput = sysfs_dentry_iput, |
1da177e4 LT |
326 | }; |
327 | ||
3e519038 | 328 | struct sysfs_dirent *sysfs_new_dirent(const char *name, umode_t mode, int type) |
1da177e4 | 329 | { |
0c096b50 | 330 | char *dup_name = NULL; |
01da2425 | 331 | struct sysfs_dirent *sd; |
0c096b50 TH |
332 | |
333 | if (type & SYSFS_COPY_NAME) { | |
334 | name = dup_name = kstrdup(name, GFP_KERNEL); | |
335 | if (!name) | |
01da2425 | 336 | return NULL; |
0c096b50 | 337 | } |
1da177e4 | 338 | |
c3762229 | 339 | sd = kmem_cache_zalloc(sysfs_dir_cachep, GFP_KERNEL); |
1da177e4 | 340 | if (!sd) |
01da2425 | 341 | goto err_out1; |
1da177e4 | 342 | |
0c096b50 | 343 | if (sysfs_alloc_ino(&sd->s_ino)) |
01da2425 | 344 | goto err_out2; |
2b611bb7 | 345 | |
1da177e4 | 346 | atomic_set(&sd->s_count, 1); |
8619f979 | 347 | atomic_set(&sd->s_active, 0); |
a26cd722 | 348 | |
0c096b50 | 349 | sd->s_name = name; |
a26cd722 | 350 | sd->s_mode = mode; |
b402d72c | 351 | sd->s_flags = type; |
1da177e4 LT |
352 | |
353 | return sd; | |
0c096b50 | 354 | |
01da2425 | 355 | err_out2: |
0c096b50 | 356 | kmem_cache_free(sysfs_dir_cachep, sd); |
01da2425 AM |
357 | err_out1: |
358 | kfree(dup_name); | |
0c096b50 | 359 | return NULL; |
1da177e4 LT |
360 | } |
361 | ||
3007e997 | 362 | /** |
fb6896da TH |
363 | * sysfs_addrm_start - prepare for sysfs_dirent add/remove |
364 | * @acxt: pointer to sysfs_addrm_cxt to be used | |
365 | * @parent_sd: parent sysfs_dirent | |
3007e997 | 366 | * |
fb6896da TH |
367 | * This function is called when the caller is about to add or |
368 | * remove sysfs_dirent under @parent_sd. This function acquires | |
a16bbc34 | 369 | * sysfs_mutex. @acxt is used to keep and pass context to |
fb6896da | 370 | * other addrm functions. |
3007e997 TH |
371 | * |
372 | * LOCKING: | |
fb6896da | 373 | * Kernel thread context (may sleep). sysfs_mutex is locked on |
a16bbc34 | 374 | * return. |
3007e997 | 375 | */ |
fb6896da TH |
376 | void sysfs_addrm_start(struct sysfs_addrm_cxt *acxt, |
377 | struct sysfs_dirent *parent_sd) | |
b592fcfe | 378 | { |
fb6896da TH |
379 | memset(acxt, 0, sizeof(*acxt)); |
380 | acxt->parent_sd = parent_sd; | |
381 | ||
fb6896da | 382 | mutex_lock(&sysfs_mutex); |
fb6896da TH |
383 | } |
384 | ||
385 | /** | |
36ce6dad | 386 | * __sysfs_add_one - add sysfs_dirent to parent without warning |
fb6896da TH |
387 | * @acxt: addrm context to use |
388 | * @sd: sysfs_dirent to be added | |
389 | * | |
390 | * Get @acxt->parent_sd and set sd->s_parent to it and increment | |
181b2e4b TH |
391 | * nlink of parent inode if @sd is a directory and link into the |
392 | * children list of the parent. | |
fb6896da TH |
393 | * |
394 | * This function should be called between calls to | |
395 | * sysfs_addrm_start() and sysfs_addrm_finish() and should be | |
396 | * passed the same @acxt as passed to sysfs_addrm_start(). | |
397 | * | |
398 | * LOCKING: | |
399 | * Determined by sysfs_addrm_start(). | |
23dc2799 TH |
400 | * |
401 | * RETURNS: | |
402 | * 0 on success, -EEXIST if entry with the given name already | |
403 | * exists. | |
fb6896da | 404 | */ |
36ce6dad | 405 | int __sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd) |
fb6896da | 406 | { |
6b0bfe93 EB |
407 | struct sysfs_inode_attrs *ps_iattr; |
408 | ||
0599ad53 | 409 | if (sysfs_find_dirent(acxt->parent_sd, sd->s_name)) |
23dc2799 TH |
410 | return -EEXIST; |
411 | ||
fb6896da TH |
412 | sd->s_parent = sysfs_get(acxt->parent_sd); |
413 | ||
41fc1c27 | 414 | sysfs_link_sibling(sd); |
23dc2799 | 415 | |
6b0bfe93 EB |
416 | /* Update timestamps on the parent */ |
417 | ps_iattr = acxt->parent_sd->s_iattr; | |
418 | if (ps_iattr) { | |
419 | struct iattr *ps_iattrs = &ps_iattr->ia_iattr; | |
420 | ps_iattrs->ia_ctime = ps_iattrs->ia_mtime = CURRENT_TIME; | |
421 | } | |
422 | ||
23dc2799 | 423 | return 0; |
fb6896da TH |
424 | } |
425 | ||
425cb029 AC |
426 | /** |
427 | * sysfs_pathname - return full path to sysfs dirent | |
428 | * @sd: sysfs_dirent whose path we want | |
429 | * @path: caller allocated buffer | |
430 | * | |
431 | * Gives the name "/" to the sysfs_root entry; any path returned | |
432 | * is relative to wherever sysfs is mounted. | |
433 | * | |
434 | * XXX: does no error checking on @path size | |
435 | */ | |
436 | static char *sysfs_pathname(struct sysfs_dirent *sd, char *path) | |
437 | { | |
438 | if (sd->s_parent) { | |
439 | sysfs_pathname(sd->s_parent, path); | |
440 | strcat(path, "/"); | |
441 | } | |
442 | strcat(path, sd->s_name); | |
443 | return path; | |
444 | } | |
445 | ||
36ce6dad CH |
446 | /** |
447 | * sysfs_add_one - add sysfs_dirent to parent | |
448 | * @acxt: addrm context to use | |
449 | * @sd: sysfs_dirent to be added | |
450 | * | |
451 | * Get @acxt->parent_sd and set sd->s_parent to it and increment | |
452 | * nlink of parent inode if @sd is a directory and link into the | |
453 | * children list of the parent. | |
454 | * | |
455 | * This function should be called between calls to | |
456 | * sysfs_addrm_start() and sysfs_addrm_finish() and should be | |
457 | * passed the same @acxt as passed to sysfs_addrm_start(). | |
458 | * | |
459 | * LOCKING: | |
460 | * Determined by sysfs_addrm_start(). | |
461 | * | |
462 | * RETURNS: | |
463 | * 0 on success, -EEXIST if entry with the given name already | |
464 | * exists. | |
465 | */ | |
466 | int sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd) | |
467 | { | |
468 | int ret; | |
469 | ||
470 | ret = __sysfs_add_one(acxt, sd); | |
425cb029 AC |
471 | if (ret == -EEXIST) { |
472 | char *path = kzalloc(PATH_MAX, GFP_KERNEL); | |
473 | WARN(1, KERN_WARNING | |
474 | "sysfs: cannot create duplicate filename '%s'\n", | |
475 | (path == NULL) ? sd->s_name : | |
476 | strcat(strcat(sysfs_pathname(acxt->parent_sd, path), "/"), | |
477 | sd->s_name)); | |
478 | kfree(path); | |
479 | } | |
480 | ||
36ce6dad CH |
481 | return ret; |
482 | } | |
483 | ||
fb6896da TH |
484 | /** |
485 | * sysfs_remove_one - remove sysfs_dirent from parent | |
486 | * @acxt: addrm context to use | |
9fd5b1c9 | 487 | * @sd: sysfs_dirent to be removed |
fb6896da TH |
488 | * |
489 | * Mark @sd removed and drop nlink of parent inode if @sd is a | |
181b2e4b | 490 | * directory. @sd is unlinked from the children list. |
fb6896da TH |
491 | * |
492 | * This function should be called between calls to | |
493 | * sysfs_addrm_start() and sysfs_addrm_finish() and should be | |
494 | * passed the same @acxt as passed to sysfs_addrm_start(). | |
495 | * | |
496 | * LOCKING: | |
497 | * Determined by sysfs_addrm_start(). | |
498 | */ | |
499 | void sysfs_remove_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd) | |
500 | { | |
6b0bfe93 EB |
501 | struct sysfs_inode_attrs *ps_iattr; |
502 | ||
41fc1c27 TH |
503 | BUG_ON(sd->s_flags & SYSFS_FLAG_REMOVED); |
504 | ||
505 | sysfs_unlink_sibling(sd); | |
fb6896da | 506 | |
6b0bfe93 EB |
507 | /* Update timestamps on the parent */ |
508 | ps_iattr = acxt->parent_sd->s_iattr; | |
509 | if (ps_iattr) { | |
510 | struct iattr *ps_iattrs = &ps_iattr->ia_iattr; | |
511 | ps_iattrs->ia_ctime = ps_iattrs->ia_mtime = CURRENT_TIME; | |
512 | } | |
513 | ||
fb6896da TH |
514 | sd->s_flags |= SYSFS_FLAG_REMOVED; |
515 | sd->s_sibling = acxt->removed; | |
516 | acxt->removed = sd; | |
a0edd7c8 TH |
517 | } |
518 | ||
fb6896da TH |
519 | /** |
520 | * sysfs_addrm_finish - finish up sysfs_dirent add/remove | |
521 | * @acxt: addrm context to finish up | |
522 | * | |
523 | * Finish up sysfs_dirent add/remove. Resources acquired by | |
524 | * sysfs_addrm_start() are released and removed sysfs_dirents are | |
a16bbc34 | 525 | * cleaned up. |
fb6896da TH |
526 | * |
527 | * LOCKING: | |
a16bbc34 | 528 | * sysfs_mutex is released. |
fb6896da | 529 | */ |
990e53f8 | 530 | void sysfs_addrm_finish(struct sysfs_addrm_cxt *acxt) |
fb6896da TH |
531 | { |
532 | /* release resources acquired by sysfs_addrm_start() */ | |
533 | mutex_unlock(&sysfs_mutex); | |
fb6896da TH |
534 | |
535 | /* kill removed sysfs_dirents */ | |
536 | while (acxt->removed) { | |
537 | struct sysfs_dirent *sd = acxt->removed; | |
538 | ||
539 | acxt->removed = sd->s_sibling; | |
540 | sd->s_sibling = NULL; | |
541 | ||
fb6896da | 542 | sysfs_deactivate(sd); |
e0edd3c6 | 543 | unmap_bin_file(sd); |
fb6896da | 544 | sysfs_put(sd); |
13b3086d | 545 | } |
b592fcfe EB |
546 | } |
547 | ||
f0b0af47 TH |
548 | /** |
549 | * sysfs_find_dirent - find sysfs_dirent with the given name | |
550 | * @parent_sd: sysfs_dirent to search under | |
551 | * @name: name to look for | |
552 | * | |
553 | * Look for sysfs_dirent with name @name under @parent_sd. | |
c516865c | 554 | * |
f0b0af47 | 555 | * LOCKING: |
3007e997 | 556 | * mutex_lock(sysfs_mutex) |
c516865c | 557 | * |
f0b0af47 TH |
558 | * RETURNS: |
559 | * Pointer to sysfs_dirent if found, NULL if not. | |
c516865c | 560 | */ |
f0b0af47 TH |
561 | struct sysfs_dirent *sysfs_find_dirent(struct sysfs_dirent *parent_sd, |
562 | const unsigned char *name) | |
c516865c | 563 | { |
f0b0af47 TH |
564 | struct sysfs_dirent *sd; |
565 | ||
bc747f37 | 566 | for (sd = parent_sd->s_dir.children; sd; sd = sd->s_sibling) |
3efa65b9 | 567 | if (!strcmp(sd->s_name, name)) |
f0b0af47 TH |
568 | return sd; |
569 | return NULL; | |
570 | } | |
c516865c | 571 | |
f0b0af47 TH |
572 | /** |
573 | * sysfs_get_dirent - find and get sysfs_dirent with the given name | |
574 | * @parent_sd: sysfs_dirent to search under | |
575 | * @name: name to look for | |
576 | * | |
577 | * Look for sysfs_dirent with name @name under @parent_sd and get | |
578 | * it if found. | |
579 | * | |
580 | * LOCKING: | |
3007e997 | 581 | * Kernel thread context (may sleep). Grabs sysfs_mutex. |
f0b0af47 TH |
582 | * |
583 | * RETURNS: | |
584 | * Pointer to sysfs_dirent if found, NULL if not. | |
585 | */ | |
586 | struct sysfs_dirent *sysfs_get_dirent(struct sysfs_dirent *parent_sd, | |
587 | const unsigned char *name) | |
588 | { | |
589 | struct sysfs_dirent *sd; | |
590 | ||
3007e997 | 591 | mutex_lock(&sysfs_mutex); |
f0b0af47 TH |
592 | sd = sysfs_find_dirent(parent_sd, name); |
593 | sysfs_get(sd); | |
3007e997 | 594 | mutex_unlock(&sysfs_mutex); |
f0b0af47 TH |
595 | |
596 | return sd; | |
c516865c | 597 | } |
f1282c84 | 598 | EXPORT_SYMBOL_GPL(sysfs_get_dirent); |
c516865c | 599 | |
608e266a TH |
600 | static int create_dir(struct kobject *kobj, struct sysfs_dirent *parent_sd, |
601 | const char *name, struct sysfs_dirent **p_sd) | |
1da177e4 | 602 | { |
1da177e4 | 603 | umode_t mode = S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO; |
51225039 | 604 | struct sysfs_addrm_cxt acxt; |
dfeb9fb0 | 605 | struct sysfs_dirent *sd; |
23dc2799 | 606 | int rc; |
1da177e4 | 607 | |
fc9f54b9 | 608 | /* allocate */ |
3e519038 | 609 | sd = sysfs_new_dirent(name, mode, SYSFS_DIR); |
a26cd722 | 610 | if (!sd) |
51225039 | 611 | return -ENOMEM; |
b1fc3d61 | 612 | sd->s_dir.kobj = kobj; |
dfeb9fb0 | 613 | |
fc9f54b9 | 614 | /* link in */ |
51225039 | 615 | sysfs_addrm_start(&acxt, parent_sd); |
23dc2799 TH |
616 | rc = sysfs_add_one(&acxt, sd); |
617 | sysfs_addrm_finish(&acxt); | |
967e35dc | 618 | |
23dc2799 TH |
619 | if (rc == 0) |
620 | *p_sd = sd; | |
621 | else | |
967e35dc | 622 | sysfs_put(sd); |
dfeb9fb0 | 623 | |
23dc2799 | 624 | return rc; |
1da177e4 LT |
625 | } |
626 | ||
608e266a TH |
627 | int sysfs_create_subdir(struct kobject *kobj, const char *name, |
628 | struct sysfs_dirent **p_sd) | |
1da177e4 | 629 | { |
608e266a | 630 | return create_dir(kobj, kobj->sd, name, p_sd); |
1da177e4 LT |
631 | } |
632 | ||
633 | /** | |
634 | * sysfs_create_dir - create a directory for an object. | |
1da177e4 LT |
635 | * @kobj: object we're creating directory for. |
636 | */ | |
90bc6135 | 637 | int sysfs_create_dir(struct kobject * kobj) |
1da177e4 | 638 | { |
608e266a | 639 | struct sysfs_dirent *parent_sd, *sd; |
1da177e4 LT |
640 | int error = 0; |
641 | ||
642 | BUG_ON(!kobj); | |
643 | ||
90bc6135 | 644 | if (kobj->parent) |
608e266a | 645 | parent_sd = kobj->parent->sd; |
1da177e4 | 646 | else |
7d0c7d67 | 647 | parent_sd = &sysfs_root; |
1da177e4 | 648 | |
608e266a | 649 | error = create_dir(kobj, parent_sd, kobject_name(kobj), &sd); |
1da177e4 | 650 | if (!error) |
608e266a | 651 | kobj->sd = sd; |
1da177e4 LT |
652 | return error; |
653 | } | |
654 | ||
1da177e4 LT |
655 | static struct dentry * sysfs_lookup(struct inode *dir, struct dentry *dentry, |
656 | struct nameidata *nd) | |
657 | { | |
6cb52147 | 658 | struct dentry *ret = NULL; |
a7a04754 TH |
659 | struct sysfs_dirent *parent_sd = dentry->d_parent->d_fsdata; |
660 | struct sysfs_dirent *sd; | |
fc9f54b9 | 661 | struct inode *inode; |
1da177e4 | 662 | |
6cb52147 TH |
663 | mutex_lock(&sysfs_mutex); |
664 | ||
94777e09 | 665 | sd = sysfs_find_dirent(parent_sd, dentry->d_name.name); |
1da177e4 | 666 | |
fc9f54b9 | 667 | /* no such entry */ |
e49452c6 TH |
668 | if (!sd) { |
669 | ret = ERR_PTR(-ENOENT); | |
6cb52147 | 670 | goto out_unlock; |
e49452c6 | 671 | } |
fc9f54b9 TH |
672 | |
673 | /* attach dentry and inode */ | |
8312a8d7 | 674 | inode = sysfs_get_inode(sd); |
6cb52147 TH |
675 | if (!inode) { |
676 | ret = ERR_PTR(-ENOMEM); | |
677 | goto out_unlock; | |
678 | } | |
3007e997 | 679 | |
d6b4fd2f | 680 | /* instantiate and hash dentry */ |
832b6af1 EB |
681 | ret = d_find_alias(inode); |
682 | if (!ret) { | |
683 | dentry->d_op = &sysfs_dentry_ops; | |
684 | dentry->d_fsdata = sysfs_get(sd); | |
685 | d_add(dentry, inode); | |
686 | } else { | |
687 | d_move(ret, dentry); | |
688 | iput(inode); | |
689 | } | |
fc9f54b9 | 690 | |
6cb52147 | 691 | out_unlock: |
3007e997 | 692 | mutex_unlock(&sysfs_mutex); |
6cb52147 | 693 | return ret; |
1da177e4 LT |
694 | } |
695 | ||
c5ef1c42 | 696 | const struct inode_operations sysfs_dir_inode_operations = { |
1da177e4 | 697 | .lookup = sysfs_lookup, |
e61ab4ae | 698 | .permission = sysfs_permission, |
988d186d | 699 | .setattr = sysfs_setattr, |
e61ab4ae | 700 | .getattr = sysfs_getattr, |
ddd29ec6 | 701 | .setxattr = sysfs_setxattr, |
1da177e4 LT |
702 | }; |
703 | ||
608e266a | 704 | static void remove_dir(struct sysfs_dirent *sd) |
1da177e4 | 705 | { |
fb6896da | 706 | struct sysfs_addrm_cxt acxt; |
1da177e4 | 707 | |
fb6896da | 708 | sysfs_addrm_start(&acxt, sd->s_parent); |
fb6896da TH |
709 | sysfs_remove_one(&acxt, sd); |
710 | sysfs_addrm_finish(&acxt); | |
1da177e4 LT |
711 | } |
712 | ||
608e266a | 713 | void sysfs_remove_subdir(struct sysfs_dirent *sd) |
1da177e4 | 714 | { |
608e266a | 715 | remove_dir(sd); |
1da177e4 LT |
716 | } |
717 | ||
718 | ||
608e266a | 719 | static void __sysfs_remove_dir(struct sysfs_dirent *dir_sd) |
1da177e4 | 720 | { |
fb6896da | 721 | struct sysfs_addrm_cxt acxt; |
0c73f18b | 722 | struct sysfs_dirent **pos; |
1da177e4 | 723 | |
608e266a | 724 | if (!dir_sd) |
1da177e4 LT |
725 | return; |
726 | ||
608e266a | 727 | pr_debug("sysfs %s: removing dir\n", dir_sd->s_name); |
fb6896da | 728 | sysfs_addrm_start(&acxt, dir_sd); |
bc747f37 | 729 | pos = &dir_sd->s_dir.children; |
0c73f18b TH |
730 | while (*pos) { |
731 | struct sysfs_dirent *sd = *pos; | |
732 | ||
3efa65b9 | 733 | if (sysfs_type(sd) != SYSFS_DIR) |
fb6896da | 734 | sysfs_remove_one(&acxt, sd); |
41fc1c27 | 735 | else |
0c73f18b | 736 | pos = &(*pos)->s_sibling; |
1da177e4 | 737 | } |
fb6896da | 738 | sysfs_addrm_finish(&acxt); |
0ab66088 | 739 | |
608e266a | 740 | remove_dir(dir_sd); |
b592fcfe EB |
741 | } |
742 | ||
743 | /** | |
744 | * sysfs_remove_dir - remove an object's directory. | |
745 | * @kobj: object. | |
746 | * | |
747 | * The only thing special about this is that we remove any files in | |
748 | * the directory before we remove the directory, and we've inlined | |
749 | * what used to be sysfs_rmdir() below, instead of calling separately. | |
750 | */ | |
751 | ||
752 | void sysfs_remove_dir(struct kobject * kobj) | |
753 | { | |
608e266a | 754 | struct sysfs_dirent *sd = kobj->sd; |
aecdceda | 755 | |
5f995323 | 756 | spin_lock(&sysfs_assoc_lock); |
608e266a | 757 | kobj->sd = NULL; |
5f995323 | 758 | spin_unlock(&sysfs_assoc_lock); |
aecdceda | 759 | |
608e266a | 760 | __sysfs_remove_dir(sd); |
1da177e4 LT |
761 | } |
762 | ||
ca1bab38 EB |
763 | int sysfs_rename(struct sysfs_dirent *sd, |
764 | struct sysfs_dirent *new_parent_sd, const char *new_name) | |
1da177e4 | 765 | { |
51225039 | 766 | const char *dup_name = NULL; |
996b7376 | 767 | int error; |
1da177e4 | 768 | |
832b6af1 | 769 | mutex_lock(&sysfs_mutex); |
932ea2e3 | 770 | |
9918f9a4 | 771 | error = 0; |
ca1bab38 EB |
772 | if ((sd->s_parent == new_parent_sd) && |
773 | (strcmp(sd->s_name, new_name) == 0)) | |
9918f9a4 EB |
774 | goto out; /* nothing to rename */ |
775 | ||
9918f9a4 | 776 | error = -EEXIST; |
ca1bab38 | 777 | if (sysfs_find_dirent(new_parent_sd, new_name)) |
832b6af1 | 778 | goto out; |
996b7376 | 779 | |
0b4a4fea | 780 | /* rename sysfs_dirent */ |
ca1bab38 EB |
781 | if (strcmp(sd->s_name, new_name) != 0) { |
782 | error = -ENOMEM; | |
783 | new_name = dup_name = kstrdup(new_name, GFP_KERNEL); | |
784 | if (!new_name) | |
785 | goto out; | |
786 | ||
787 | dup_name = sd->s_name; | |
788 | sd->s_name = new_name; | |
789 | } | |
0c096b50 | 790 | |
ca1bab38 EB |
791 | /* Remove from old parent's list and insert into new parent's list. */ |
792 | if (sd->s_parent != new_parent_sd) { | |
793 | sysfs_unlink_sibling(sd); | |
794 | sysfs_get(new_parent_sd); | |
795 | sysfs_put(sd->s_parent); | |
796 | sd->s_parent = new_parent_sd; | |
797 | sysfs_link_sibling(sd); | |
798 | } | |
0c096b50 | 799 | |
996b7376 | 800 | error = 0; |
832b6af1 | 801 | out: |
9918f9a4 | 802 | mutex_unlock(&sysfs_mutex); |
51225039 | 803 | kfree(dup_name); |
1da177e4 LT |
804 | return error; |
805 | } | |
806 | ||
ca1bab38 EB |
807 | int sysfs_rename_dir(struct kobject *kobj, const char *new_name) |
808 | { | |
809 | return sysfs_rename(kobj->sd, kobj->sd->s_parent, new_name); | |
810 | } | |
811 | ||
51225039 | 812 | int sysfs_move_dir(struct kobject *kobj, struct kobject *new_parent_kobj) |
8a82472f | 813 | { |
51225039 TH |
814 | struct sysfs_dirent *sd = kobj->sd; |
815 | struct sysfs_dirent *new_parent_sd; | |
8a82472f | 816 | |
51225039 | 817 | BUG_ON(!sd->s_parent); |
ca1bab38 | 818 | new_parent_sd = new_parent_kobj && new_parent_kobj->sd ? |
a6a83577 | 819 | new_parent_kobj->sd : &sysfs_root; |
51225039 | 820 | |
ca1bab38 | 821 | return sysfs_rename(sd, new_parent_sd, sd->s_name); |
8a82472f CH |
822 | } |
823 | ||
1da177e4 LT |
824 | /* Relationship between s_mode and the DT_xxx types */ |
825 | static inline unsigned char dt_type(struct sysfs_dirent *sd) | |
826 | { | |
827 | return (sd->s_mode >> 12) & 15; | |
828 | } | |
829 | ||
830 | static int sysfs_readdir(struct file * filp, void * dirent, filldir_t filldir) | |
831 | { | |
f427f5d5 | 832 | struct dentry *dentry = filp->f_path.dentry; |
1da177e4 | 833 | struct sysfs_dirent * parent_sd = dentry->d_fsdata; |
3efa65b9 | 834 | struct sysfs_dirent *pos; |
1da177e4 | 835 | ino_t ino; |
1da177e4 | 836 | |
3efa65b9 EB |
837 | if (filp->f_pos == 0) { |
838 | ino = parent_sd->s_ino; | |
839 | if (filldir(dirent, ".", 1, filp->f_pos, ino, DT_DIR) == 0) | |
1da177e4 | 840 | filp->f_pos++; |
3efa65b9 EB |
841 | } |
842 | if (filp->f_pos == 1) { | |
843 | if (parent_sd->s_parent) | |
844 | ino = parent_sd->s_parent->s_ino; | |
845 | else | |
846 | ino = parent_sd->s_ino; | |
847 | if (filldir(dirent, "..", 2, filp->f_pos, ino, DT_DIR) == 0) | |
1da177e4 | 848 | filp->f_pos++; |
3efa65b9 EB |
849 | } |
850 | if ((filp->f_pos > 1) && (filp->f_pos < INT_MAX)) { | |
851 | mutex_lock(&sysfs_mutex); | |
0c73f18b | 852 | |
3efa65b9 | 853 | /* Skip the dentries we have already reported */ |
bc747f37 | 854 | pos = parent_sd->s_dir.children; |
3efa65b9 EB |
855 | while (pos && (filp->f_pos > pos->s_ino)) |
856 | pos = pos->s_sibling; | |
3007e997 | 857 | |
3efa65b9 EB |
858 | for ( ; pos; pos = pos->s_sibling) { |
859 | const char * name; | |
860 | int len; | |
1da177e4 | 861 | |
3efa65b9 EB |
862 | name = pos->s_name; |
863 | len = strlen(name); | |
864 | filp->f_pos = ino = pos->s_ino; | |
1da177e4 | 865 | |
3efa65b9 EB |
866 | if (filldir(dirent, name, len, filp->f_pos, ino, |
867 | dt_type(pos)) < 0) | |
1da177e4 | 868 | break; |
1da177e4 | 869 | } |
3efa65b9 EB |
870 | if (!pos) |
871 | filp->f_pos = INT_MAX; | |
3007e997 | 872 | mutex_unlock(&sysfs_mutex); |
1da177e4 | 873 | } |
3efa65b9 | 874 | return 0; |
1da177e4 LT |
875 | } |
876 | ||
3efa65b9 | 877 | |
4b6f5d20 | 878 | const struct file_operations sysfs_dir_operations = { |
1da177e4 LT |
879 | .read = generic_read_dir, |
880 | .readdir = sysfs_readdir, | |
3222a3e5 | 881 | .llseek = generic_file_llseek, |
1da177e4 | 882 | }; |