Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * fs/libfs.c | |
3 | * Library for filesystems writers. | |
4 | */ | |
5 | ||
6 | #include <linux/module.h> | |
7 | #include <linux/pagemap.h> | |
8 | #include <linux/mount.h> | |
9 | #include <linux/vfs.h> | |
7cf34c76 IM |
10 | #include <linux/mutex.h> |
11 | ||
1da177e4 LT |
12 | #include <asm/uaccess.h> |
13 | ||
14 | int simple_getattr(struct vfsmount *mnt, struct dentry *dentry, | |
15 | struct kstat *stat) | |
16 | { | |
17 | struct inode *inode = dentry->d_inode; | |
18 | generic_fillattr(inode, stat); | |
19 | stat->blocks = inode->i_mapping->nrpages << (PAGE_CACHE_SHIFT - 9); | |
20 | return 0; | |
21 | } | |
22 | ||
726c3342 | 23 | int simple_statfs(struct dentry *dentry, struct kstatfs *buf) |
1da177e4 | 24 | { |
726c3342 | 25 | buf->f_type = dentry->d_sb->s_magic; |
1da177e4 LT |
26 | buf->f_bsize = PAGE_CACHE_SIZE; |
27 | buf->f_namelen = NAME_MAX; | |
28 | return 0; | |
29 | } | |
30 | ||
31 | /* | |
32 | * Retaining negative dentries for an in-memory filesystem just wastes | |
33 | * memory and lookup time: arrange for them to be deleted immediately. | |
34 | */ | |
35 | static int simple_delete_dentry(struct dentry *dentry) | |
36 | { | |
37 | return 1; | |
38 | } | |
39 | ||
40 | /* | |
41 | * Lookup the data. This is trivial - if the dentry didn't already | |
42 | * exist, we know it is negative. Set d_op to delete negative dentries. | |
43 | */ | |
44 | struct dentry *simple_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd) | |
45 | { | |
46 | static struct dentry_operations simple_dentry_operations = { | |
47 | .d_delete = simple_delete_dentry, | |
48 | }; | |
49 | ||
50 | if (dentry->d_name.len > NAME_MAX) | |
51 | return ERR_PTR(-ENAMETOOLONG); | |
52 | dentry->d_op = &simple_dentry_operations; | |
53 | d_add(dentry, NULL); | |
54 | return NULL; | |
55 | } | |
56 | ||
57 | int simple_sync_file(struct file * file, struct dentry *dentry, int datasync) | |
58 | { | |
59 | return 0; | |
60 | } | |
61 | ||
62 | int dcache_dir_open(struct inode *inode, struct file *file) | |
63 | { | |
64 | static struct qstr cursor_name = {.len = 1, .name = "."}; | |
65 | ||
0f7fc9e4 | 66 | file->private_data = d_alloc(file->f_path.dentry, &cursor_name); |
1da177e4 LT |
67 | |
68 | return file->private_data ? 0 : -ENOMEM; | |
69 | } | |
70 | ||
71 | int dcache_dir_close(struct inode *inode, struct file *file) | |
72 | { | |
73 | dput(file->private_data); | |
74 | return 0; | |
75 | } | |
76 | ||
77 | loff_t dcache_dir_lseek(struct file *file, loff_t offset, int origin) | |
78 | { | |
0f7fc9e4 | 79 | mutex_lock(&file->f_path.dentry->d_inode->i_mutex); |
1da177e4 LT |
80 | switch (origin) { |
81 | case 1: | |
82 | offset += file->f_pos; | |
83 | case 0: | |
84 | if (offset >= 0) | |
85 | break; | |
86 | default: | |
0f7fc9e4 | 87 | mutex_unlock(&file->f_path.dentry->d_inode->i_mutex); |
1da177e4 LT |
88 | return -EINVAL; |
89 | } | |
90 | if (offset != file->f_pos) { | |
91 | file->f_pos = offset; | |
92 | if (file->f_pos >= 2) { | |
93 | struct list_head *p; | |
94 | struct dentry *cursor = file->private_data; | |
95 | loff_t n = file->f_pos - 2; | |
96 | ||
97 | spin_lock(&dcache_lock); | |
5160ee6f | 98 | list_del(&cursor->d_u.d_child); |
0f7fc9e4 JJS |
99 | p = file->f_path.dentry->d_subdirs.next; |
100 | while (n && p != &file->f_path.dentry->d_subdirs) { | |
1da177e4 | 101 | struct dentry *next; |
5160ee6f | 102 | next = list_entry(p, struct dentry, d_u.d_child); |
1da177e4 LT |
103 | if (!d_unhashed(next) && next->d_inode) |
104 | n--; | |
105 | p = p->next; | |
106 | } | |
5160ee6f | 107 | list_add_tail(&cursor->d_u.d_child, p); |
1da177e4 LT |
108 | spin_unlock(&dcache_lock); |
109 | } | |
110 | } | |
0f7fc9e4 | 111 | mutex_unlock(&file->f_path.dentry->d_inode->i_mutex); |
1da177e4 LT |
112 | return offset; |
113 | } | |
114 | ||
115 | /* Relationship between i_mode and the DT_xxx types */ | |
116 | static inline unsigned char dt_type(struct inode *inode) | |
117 | { | |
118 | return (inode->i_mode >> 12) & 15; | |
119 | } | |
120 | ||
121 | /* | |
122 | * Directory is locked and all positive dentries in it are safe, since | |
123 | * for ramfs-type trees they can't go away without unlink() or rmdir(), | |
124 | * both impossible due to the lock on directory. | |
125 | */ | |
126 | ||
127 | int dcache_readdir(struct file * filp, void * dirent, filldir_t filldir) | |
128 | { | |
0f7fc9e4 | 129 | struct dentry *dentry = filp->f_path.dentry; |
1da177e4 | 130 | struct dentry *cursor = filp->private_data; |
5160ee6f | 131 | struct list_head *p, *q = &cursor->d_u.d_child; |
1da177e4 LT |
132 | ino_t ino; |
133 | int i = filp->f_pos; | |
134 | ||
135 | switch (i) { | |
136 | case 0: | |
137 | ino = dentry->d_inode->i_ino; | |
138 | if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0) | |
139 | break; | |
140 | filp->f_pos++; | |
141 | i++; | |
142 | /* fallthrough */ | |
143 | case 1: | |
144 | ino = parent_ino(dentry); | |
145 | if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0) | |
146 | break; | |
147 | filp->f_pos++; | |
148 | i++; | |
149 | /* fallthrough */ | |
150 | default: | |
151 | spin_lock(&dcache_lock); | |
1bfba4e8 AM |
152 | if (filp->f_pos == 2) |
153 | list_move(q, &dentry->d_subdirs); | |
154 | ||
1da177e4 LT |
155 | for (p=q->next; p != &dentry->d_subdirs; p=p->next) { |
156 | struct dentry *next; | |
5160ee6f | 157 | next = list_entry(p, struct dentry, d_u.d_child); |
1da177e4 LT |
158 | if (d_unhashed(next) || !next->d_inode) |
159 | continue; | |
160 | ||
161 | spin_unlock(&dcache_lock); | |
162 | if (filldir(dirent, next->d_name.name, next->d_name.len, filp->f_pos, next->d_inode->i_ino, dt_type(next->d_inode)) < 0) | |
163 | return 0; | |
164 | spin_lock(&dcache_lock); | |
165 | /* next is still alive */ | |
1bfba4e8 | 166 | list_move(q, p); |
1da177e4 LT |
167 | p = q; |
168 | filp->f_pos++; | |
169 | } | |
170 | spin_unlock(&dcache_lock); | |
171 | } | |
172 | return 0; | |
173 | } | |
174 | ||
175 | ssize_t generic_read_dir(struct file *filp, char __user *buf, size_t siz, loff_t *ppos) | |
176 | { | |
177 | return -EISDIR; | |
178 | } | |
179 | ||
4b6f5d20 | 180 | const struct file_operations simple_dir_operations = { |
1da177e4 LT |
181 | .open = dcache_dir_open, |
182 | .release = dcache_dir_close, | |
183 | .llseek = dcache_dir_lseek, | |
184 | .read = generic_read_dir, | |
185 | .readdir = dcache_readdir, | |
8ae0b778 | 186 | .fsync = simple_sync_file, |
1da177e4 LT |
187 | }; |
188 | ||
92e1d5be | 189 | const struct inode_operations simple_dir_inode_operations = { |
1da177e4 LT |
190 | .lookup = simple_lookup, |
191 | }; | |
192 | ||
759b9775 HD |
193 | static const struct super_operations simple_super_operations = { |
194 | .statfs = simple_statfs, | |
195 | }; | |
196 | ||
1da177e4 LT |
197 | /* |
198 | * Common helper for pseudo-filesystems (sockfs, pipefs, bdev - stuff that | |
199 | * will never be mountable) | |
200 | */ | |
454e2398 | 201 | int get_sb_pseudo(struct file_system_type *fs_type, char *name, |
ee9b6d61 | 202 | const struct super_operations *ops, unsigned long magic, |
454e2398 | 203 | struct vfsmount *mnt) |
1da177e4 LT |
204 | { |
205 | struct super_block *s = sget(fs_type, NULL, set_anon_super, NULL); | |
1da177e4 LT |
206 | struct dentry *dentry; |
207 | struct inode *root; | |
208 | struct qstr d_name = {.name = name, .len = strlen(name)}; | |
209 | ||
210 | if (IS_ERR(s)) | |
454e2398 | 211 | return PTR_ERR(s); |
1da177e4 LT |
212 | |
213 | s->s_flags = MS_NOUSER; | |
214 | s->s_maxbytes = ~0ULL; | |
215 | s->s_blocksize = 1024; | |
216 | s->s_blocksize_bits = 10; | |
217 | s->s_magic = magic; | |
759b9775 | 218 | s->s_op = ops ? ops : &simple_super_operations; |
1da177e4 LT |
219 | s->s_time_gran = 1; |
220 | root = new_inode(s); | |
221 | if (!root) | |
222 | goto Enomem; | |
1a1c9bb4 JL |
223 | /* |
224 | * since this is the first inode, make it number 1. New inodes created | |
225 | * after this must take care not to collide with it (by passing | |
226 | * max_reserved of 1 to iunique). | |
227 | */ | |
228 | root->i_ino = 1; | |
1da177e4 LT |
229 | root->i_mode = S_IFDIR | S_IRUSR | S_IWUSR; |
230 | root->i_uid = root->i_gid = 0; | |
231 | root->i_atime = root->i_mtime = root->i_ctime = CURRENT_TIME; | |
232 | dentry = d_alloc(NULL, &d_name); | |
233 | if (!dentry) { | |
234 | iput(root); | |
235 | goto Enomem; | |
236 | } | |
237 | dentry->d_sb = s; | |
238 | dentry->d_parent = dentry; | |
239 | d_instantiate(dentry, root); | |
240 | s->s_root = dentry; | |
241 | s->s_flags |= MS_ACTIVE; | |
454e2398 | 242 | return simple_set_mnt(mnt, s); |
1da177e4 LT |
243 | |
244 | Enomem: | |
245 | up_write(&s->s_umount); | |
246 | deactivate_super(s); | |
454e2398 | 247 | return -ENOMEM; |
1da177e4 LT |
248 | } |
249 | ||
250 | int simple_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry) | |
251 | { | |
252 | struct inode *inode = old_dentry->d_inode; | |
253 | ||
254 | inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
d8c76e6f | 255 | inc_nlink(inode); |
1da177e4 LT |
256 | atomic_inc(&inode->i_count); |
257 | dget(dentry); | |
258 | d_instantiate(dentry, inode); | |
259 | return 0; | |
260 | } | |
261 | ||
262 | static inline int simple_positive(struct dentry *dentry) | |
263 | { | |
264 | return dentry->d_inode && !d_unhashed(dentry); | |
265 | } | |
266 | ||
267 | int simple_empty(struct dentry *dentry) | |
268 | { | |
269 | struct dentry *child; | |
270 | int ret = 0; | |
271 | ||
272 | spin_lock(&dcache_lock); | |
5160ee6f | 273 | list_for_each_entry(child, &dentry->d_subdirs, d_u.d_child) |
1da177e4 LT |
274 | if (simple_positive(child)) |
275 | goto out; | |
276 | ret = 1; | |
277 | out: | |
278 | spin_unlock(&dcache_lock); | |
279 | return ret; | |
280 | } | |
281 | ||
282 | int simple_unlink(struct inode *dir, struct dentry *dentry) | |
283 | { | |
284 | struct inode *inode = dentry->d_inode; | |
285 | ||
286 | inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
9a53c3a7 | 287 | drop_nlink(inode); |
1da177e4 LT |
288 | dput(dentry); |
289 | return 0; | |
290 | } | |
291 | ||
292 | int simple_rmdir(struct inode *dir, struct dentry *dentry) | |
293 | { | |
294 | if (!simple_empty(dentry)) | |
295 | return -ENOTEMPTY; | |
296 | ||
9a53c3a7 | 297 | drop_nlink(dentry->d_inode); |
1da177e4 | 298 | simple_unlink(dir, dentry); |
9a53c3a7 | 299 | drop_nlink(dir); |
1da177e4 LT |
300 | return 0; |
301 | } | |
302 | ||
303 | int simple_rename(struct inode *old_dir, struct dentry *old_dentry, | |
304 | struct inode *new_dir, struct dentry *new_dentry) | |
305 | { | |
306 | struct inode *inode = old_dentry->d_inode; | |
307 | int they_are_dirs = S_ISDIR(old_dentry->d_inode->i_mode); | |
308 | ||
309 | if (!simple_empty(new_dentry)) | |
310 | return -ENOTEMPTY; | |
311 | ||
312 | if (new_dentry->d_inode) { | |
313 | simple_unlink(new_dir, new_dentry); | |
314 | if (they_are_dirs) | |
9a53c3a7 | 315 | drop_nlink(old_dir); |
1da177e4 | 316 | } else if (they_are_dirs) { |
9a53c3a7 | 317 | drop_nlink(old_dir); |
d8c76e6f | 318 | inc_nlink(new_dir); |
1da177e4 LT |
319 | } |
320 | ||
321 | old_dir->i_ctime = old_dir->i_mtime = new_dir->i_ctime = | |
322 | new_dir->i_mtime = inode->i_ctime = CURRENT_TIME; | |
323 | ||
324 | return 0; | |
325 | } | |
326 | ||
327 | int simple_readpage(struct file *file, struct page *page) | |
328 | { | |
c0d92cbc | 329 | clear_highpage(page); |
1da177e4 LT |
330 | flush_dcache_page(page); |
331 | SetPageUptodate(page); | |
1da177e4 LT |
332 | unlock_page(page); |
333 | return 0; | |
334 | } | |
335 | ||
336 | int simple_prepare_write(struct file *file, struct page *page, | |
337 | unsigned from, unsigned to) | |
338 | { | |
339 | if (!PageUptodate(page)) { | |
340 | if (to - from != PAGE_CACHE_SIZE) { | |
341 | void *kaddr = kmap_atomic(page, KM_USER0); | |
342 | memset(kaddr, 0, from); | |
343 | memset(kaddr + to, 0, PAGE_CACHE_SIZE - to); | |
344 | flush_dcache_page(page); | |
345 | kunmap_atomic(kaddr, KM_USER0); | |
346 | } | |
1da177e4 LT |
347 | } |
348 | return 0; | |
349 | } | |
350 | ||
351 | int simple_commit_write(struct file *file, struct page *page, | |
955eff5a | 352 | unsigned from, unsigned to) |
1da177e4 LT |
353 | { |
354 | struct inode *inode = page->mapping->host; | |
355 | loff_t pos = ((loff_t)page->index << PAGE_CACHE_SHIFT) + to; | |
356 | ||
955eff5a NP |
357 | if (!PageUptodate(page)) |
358 | SetPageUptodate(page); | |
1da177e4 LT |
359 | /* |
360 | * No need to use i_size_read() here, the i_size | |
1b1dcc1b | 361 | * cannot change under us because we hold the i_mutex. |
1da177e4 LT |
362 | */ |
363 | if (pos > inode->i_size) | |
364 | i_size_write(inode, pos); | |
365 | set_page_dirty(page); | |
366 | return 0; | |
367 | } | |
368 | ||
1a1c9bb4 JL |
369 | /* |
370 | * the inodes created here are not hashed. If you use iunique to generate | |
371 | * unique inode values later for this filesystem, then you must take care | |
372 | * to pass it an appropriate max_reserved value to avoid collisions. | |
373 | */ | |
1da177e4 LT |
374 | int simple_fill_super(struct super_block *s, int magic, struct tree_descr *files) |
375 | { | |
1da177e4 LT |
376 | struct inode *inode; |
377 | struct dentry *root; | |
378 | struct dentry *dentry; | |
379 | int i; | |
380 | ||
381 | s->s_blocksize = PAGE_CACHE_SIZE; | |
382 | s->s_blocksize_bits = PAGE_CACHE_SHIFT; | |
383 | s->s_magic = magic; | |
759b9775 | 384 | s->s_op = &simple_super_operations; |
1da177e4 LT |
385 | s->s_time_gran = 1; |
386 | ||
387 | inode = new_inode(s); | |
388 | if (!inode) | |
389 | return -ENOMEM; | |
1a1c9bb4 JL |
390 | /* |
391 | * because the root inode is 1, the files array must not contain an | |
392 | * entry at index 1 | |
393 | */ | |
394 | inode->i_ino = 1; | |
1da177e4 LT |
395 | inode->i_mode = S_IFDIR | 0755; |
396 | inode->i_uid = inode->i_gid = 0; | |
1da177e4 LT |
397 | inode->i_blocks = 0; |
398 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; | |
399 | inode->i_op = &simple_dir_inode_operations; | |
400 | inode->i_fop = &simple_dir_operations; | |
7656f328 | 401 | inode->i_nlink = 2; |
1da177e4 LT |
402 | root = d_alloc_root(inode); |
403 | if (!root) { | |
404 | iput(inode); | |
405 | return -ENOMEM; | |
406 | } | |
407 | for (i = 0; !files->name || files->name[0]; i++, files++) { | |
408 | if (!files->name) | |
409 | continue; | |
1a1c9bb4 JL |
410 | |
411 | /* warn if it tries to conflict with the root inode */ | |
412 | if (unlikely(i == 1)) | |
413 | printk(KERN_WARNING "%s: %s passed in a files array" | |
414 | "with an index of 1!\n", __func__, | |
415 | s->s_type->name); | |
416 | ||
1da177e4 LT |
417 | dentry = d_alloc_name(root, files->name); |
418 | if (!dentry) | |
419 | goto out; | |
420 | inode = new_inode(s); | |
421 | if (!inode) | |
422 | goto out; | |
423 | inode->i_mode = S_IFREG | files->mode; | |
424 | inode->i_uid = inode->i_gid = 0; | |
1da177e4 LT |
425 | inode->i_blocks = 0; |
426 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; | |
427 | inode->i_fop = files->ops; | |
428 | inode->i_ino = i; | |
429 | d_add(dentry, inode); | |
430 | } | |
431 | s->s_root = root; | |
432 | return 0; | |
433 | out: | |
434 | d_genocide(root); | |
435 | dput(root); | |
436 | return -ENOMEM; | |
437 | } | |
438 | ||
439 | static DEFINE_SPINLOCK(pin_fs_lock); | |
440 | ||
1f5ce9e9 | 441 | int simple_pin_fs(struct file_system_type *type, struct vfsmount **mount, int *count) |
1da177e4 LT |
442 | { |
443 | struct vfsmount *mnt = NULL; | |
444 | spin_lock(&pin_fs_lock); | |
445 | if (unlikely(!*mount)) { | |
446 | spin_unlock(&pin_fs_lock); | |
1f5ce9e9 | 447 | mnt = vfs_kern_mount(type, 0, type->name, NULL); |
1da177e4 LT |
448 | if (IS_ERR(mnt)) |
449 | return PTR_ERR(mnt); | |
450 | spin_lock(&pin_fs_lock); | |
451 | if (!*mount) | |
452 | *mount = mnt; | |
453 | } | |
454 | mntget(*mount); | |
455 | ++*count; | |
456 | spin_unlock(&pin_fs_lock); | |
457 | mntput(mnt); | |
458 | return 0; | |
459 | } | |
460 | ||
461 | void simple_release_fs(struct vfsmount **mount, int *count) | |
462 | { | |
463 | struct vfsmount *mnt; | |
464 | spin_lock(&pin_fs_lock); | |
465 | mnt = *mount; | |
466 | if (!--*count) | |
467 | *mount = NULL; | |
468 | spin_unlock(&pin_fs_lock); | |
469 | mntput(mnt); | |
470 | } | |
471 | ||
472 | ssize_t simple_read_from_buffer(void __user *to, size_t count, loff_t *ppos, | |
473 | const void *from, size_t available) | |
474 | { | |
475 | loff_t pos = *ppos; | |
476 | if (pos < 0) | |
477 | return -EINVAL; | |
478 | if (pos >= available) | |
479 | return 0; | |
480 | if (count > available - pos) | |
481 | count = available - pos; | |
482 | if (copy_to_user(to, from + pos, count)) | |
483 | return -EFAULT; | |
484 | *ppos = pos + count; | |
485 | return count; | |
486 | } | |
487 | ||
488 | /* | |
489 | * Transaction based IO. | |
490 | * The file expects a single write which triggers the transaction, and then | |
491 | * possibly a read which collects the result - which is stored in a | |
492 | * file-local buffer. | |
493 | */ | |
494 | char *simple_transaction_get(struct file *file, const char __user *buf, size_t size) | |
495 | { | |
496 | struct simple_transaction_argresp *ar; | |
497 | static DEFINE_SPINLOCK(simple_transaction_lock); | |
498 | ||
499 | if (size > SIMPLE_TRANSACTION_LIMIT - 1) | |
500 | return ERR_PTR(-EFBIG); | |
501 | ||
502 | ar = (struct simple_transaction_argresp *)get_zeroed_page(GFP_KERNEL); | |
503 | if (!ar) | |
504 | return ERR_PTR(-ENOMEM); | |
505 | ||
506 | spin_lock(&simple_transaction_lock); | |
507 | ||
508 | /* only one write allowed per open */ | |
509 | if (file->private_data) { | |
510 | spin_unlock(&simple_transaction_lock); | |
511 | free_page((unsigned long)ar); | |
512 | return ERR_PTR(-EBUSY); | |
513 | } | |
514 | ||
515 | file->private_data = ar; | |
516 | ||
517 | spin_unlock(&simple_transaction_lock); | |
518 | ||
519 | if (copy_from_user(ar->data, buf, size)) | |
520 | return ERR_PTR(-EFAULT); | |
521 | ||
522 | return ar->data; | |
523 | } | |
524 | ||
525 | ssize_t simple_transaction_read(struct file *file, char __user *buf, size_t size, loff_t *pos) | |
526 | { | |
527 | struct simple_transaction_argresp *ar = file->private_data; | |
528 | ||
529 | if (!ar) | |
530 | return 0; | |
531 | return simple_read_from_buffer(buf, size, pos, ar->data, ar->size); | |
532 | } | |
533 | ||
534 | int simple_transaction_release(struct inode *inode, struct file *file) | |
535 | { | |
536 | free_page((unsigned long)file->private_data); | |
537 | return 0; | |
538 | } | |
539 | ||
acaefc25 AB |
540 | /* Simple attribute files */ |
541 | ||
542 | struct simple_attr { | |
543 | u64 (*get)(void *); | |
544 | void (*set)(void *, u64); | |
545 | char get_buf[24]; /* enough to store a u64 and "\n\0" */ | |
546 | char set_buf[24]; | |
547 | void *data; | |
548 | const char *fmt; /* format for read operation */ | |
7cf34c76 | 549 | struct mutex mutex; /* protects access to these buffers */ |
acaefc25 AB |
550 | }; |
551 | ||
552 | /* simple_attr_open is called by an actual attribute open file operation | |
553 | * to set the attribute specific access operations. */ | |
554 | int simple_attr_open(struct inode *inode, struct file *file, | |
555 | u64 (*get)(void *), void (*set)(void *, u64), | |
556 | const char *fmt) | |
557 | { | |
558 | struct simple_attr *attr; | |
559 | ||
560 | attr = kmalloc(sizeof(*attr), GFP_KERNEL); | |
561 | if (!attr) | |
562 | return -ENOMEM; | |
563 | ||
564 | attr->get = get; | |
565 | attr->set = set; | |
8e18e294 | 566 | attr->data = inode->i_private; |
acaefc25 | 567 | attr->fmt = fmt; |
7cf34c76 | 568 | mutex_init(&attr->mutex); |
acaefc25 AB |
569 | |
570 | file->private_data = attr; | |
571 | ||
572 | return nonseekable_open(inode, file); | |
573 | } | |
574 | ||
575 | int simple_attr_close(struct inode *inode, struct file *file) | |
576 | { | |
577 | kfree(file->private_data); | |
578 | return 0; | |
579 | } | |
580 | ||
581 | /* read from the buffer that is filled with the get function */ | |
582 | ssize_t simple_attr_read(struct file *file, char __user *buf, | |
583 | size_t len, loff_t *ppos) | |
584 | { | |
585 | struct simple_attr *attr; | |
586 | size_t size; | |
587 | ssize_t ret; | |
588 | ||
589 | attr = file->private_data; | |
590 | ||
591 | if (!attr->get) | |
592 | return -EACCES; | |
593 | ||
7cf34c76 | 594 | mutex_lock(&attr->mutex); |
acaefc25 AB |
595 | if (*ppos) /* continued read */ |
596 | size = strlen(attr->get_buf); | |
597 | else /* first read */ | |
598 | size = scnprintf(attr->get_buf, sizeof(attr->get_buf), | |
599 | attr->fmt, | |
600 | (unsigned long long)attr->get(attr->data)); | |
601 | ||
602 | ret = simple_read_from_buffer(buf, len, ppos, attr->get_buf, size); | |
7cf34c76 | 603 | mutex_unlock(&attr->mutex); |
acaefc25 AB |
604 | return ret; |
605 | } | |
606 | ||
607 | /* interpret the buffer as a number to call the set function with */ | |
608 | ssize_t simple_attr_write(struct file *file, const char __user *buf, | |
609 | size_t len, loff_t *ppos) | |
610 | { | |
611 | struct simple_attr *attr; | |
612 | u64 val; | |
613 | size_t size; | |
614 | ssize_t ret; | |
615 | ||
616 | attr = file->private_data; | |
617 | ||
618 | if (!attr->set) | |
619 | return -EACCES; | |
620 | ||
7cf34c76 | 621 | mutex_lock(&attr->mutex); |
acaefc25 AB |
622 | ret = -EFAULT; |
623 | size = min(sizeof(attr->set_buf) - 1, len); | |
624 | if (copy_from_user(attr->set_buf, buf, size)) | |
625 | goto out; | |
626 | ||
627 | ret = len; /* claim we got the whole input */ | |
628 | attr->set_buf[size] = '\0'; | |
629 | val = simple_strtol(attr->set_buf, NULL, 0); | |
630 | attr->set(attr->data, val); | |
631 | out: | |
7cf34c76 | 632 | mutex_unlock(&attr->mutex); |
acaefc25 AB |
633 | return ret; |
634 | } | |
635 | ||
1da177e4 LT |
636 | EXPORT_SYMBOL(dcache_dir_close); |
637 | EXPORT_SYMBOL(dcache_dir_lseek); | |
638 | EXPORT_SYMBOL(dcache_dir_open); | |
639 | EXPORT_SYMBOL(dcache_readdir); | |
640 | EXPORT_SYMBOL(generic_read_dir); | |
641 | EXPORT_SYMBOL(get_sb_pseudo); | |
642 | EXPORT_SYMBOL(simple_commit_write); | |
643 | EXPORT_SYMBOL(simple_dir_inode_operations); | |
644 | EXPORT_SYMBOL(simple_dir_operations); | |
645 | EXPORT_SYMBOL(simple_empty); | |
646 | EXPORT_SYMBOL(d_alloc_name); | |
647 | EXPORT_SYMBOL(simple_fill_super); | |
648 | EXPORT_SYMBOL(simple_getattr); | |
649 | EXPORT_SYMBOL(simple_link); | |
650 | EXPORT_SYMBOL(simple_lookup); | |
651 | EXPORT_SYMBOL(simple_pin_fs); | |
652 | EXPORT_SYMBOL(simple_prepare_write); | |
653 | EXPORT_SYMBOL(simple_readpage); | |
654 | EXPORT_SYMBOL(simple_release_fs); | |
655 | EXPORT_SYMBOL(simple_rename); | |
656 | EXPORT_SYMBOL(simple_rmdir); | |
657 | EXPORT_SYMBOL(simple_statfs); | |
658 | EXPORT_SYMBOL(simple_sync_file); | |
659 | EXPORT_SYMBOL(simple_unlink); | |
660 | EXPORT_SYMBOL(simple_read_from_buffer); | |
661 | EXPORT_SYMBOL(simple_transaction_get); | |
662 | EXPORT_SYMBOL(simple_transaction_read); | |
663 | EXPORT_SYMBOL(simple_transaction_release); | |
acaefc25 AB |
664 | EXPORT_SYMBOL_GPL(simple_attr_open); |
665 | EXPORT_SYMBOL_GPL(simple_attr_close); | |
666 | EXPORT_SYMBOL_GPL(simple_attr_read); | |
667 | EXPORT_SYMBOL_GPL(simple_attr_write); |