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Commit | Line | Data |
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b8441ed2 TH |
1 | /* |
2 | * kernfs.h - pseudo filesystem decoupled from vfs locking | |
3 | * | |
4 | * This file is released under the GPLv2. | |
5 | */ | |
6 | ||
7 | #ifndef __LINUX_KERNFS_H | |
8 | #define __LINUX_KERNFS_H | |
9 | ||
879f40d1 | 10 | #include <linux/kernel.h> |
5d0e26bb | 11 | #include <linux/err.h> |
dd8a5b03 TH |
12 | #include <linux/list.h> |
13 | #include <linux/mutex.h> | |
bc755553 | 14 | #include <linux/idr.h> |
517e64f5 | 15 | #include <linux/lockdep.h> |
cf9e5a73 TH |
16 | #include <linux/rbtree.h> |
17 | #include <linux/atomic.h> | |
87da1493 | 18 | #include <linux/completion.h> |
879f40d1 | 19 | |
5d60418e | 20 | struct file; |
917f56ca | 21 | struct dentry; |
5d60418e | 22 | struct iattr; |
dd8a5b03 TH |
23 | struct seq_file; |
24 | struct vm_area_struct; | |
4b93dc9b TH |
25 | struct super_block; |
26 | struct file_system_type; | |
5d60418e | 27 | |
c525aadd TH |
28 | struct kernfs_open_node; |
29 | struct kernfs_iattrs; | |
cf9e5a73 TH |
30 | |
31 | enum kernfs_node_type { | |
df23fc39 TH |
32 | KERNFS_DIR = 0x0001, |
33 | KERNFS_FILE = 0x0002, | |
34 | KERNFS_LINK = 0x0004, | |
cf9e5a73 TH |
35 | }; |
36 | ||
df23fc39 | 37 | #define KERNFS_TYPE_MASK 0x000f |
0890147f | 38 | #define KERNFS_ACTIVE_REF KERNFS_FILE |
df23fc39 | 39 | #define KERNFS_FLAG_MASK ~KERNFS_TYPE_MASK |
cf9e5a73 TH |
40 | |
41 | enum kernfs_node_flag { | |
798c75a0 | 42 | KERNFS_REMOVED = 0x0010, |
df23fc39 TH |
43 | KERNFS_NS = 0x0020, |
44 | KERNFS_HAS_SEQ_SHOW = 0x0040, | |
45 | KERNFS_HAS_MMAP = 0x0080, | |
46 | KERNFS_LOCKDEP = 0x0100, | |
2063d608 | 47 | KERNFS_STATIC_NAME = 0x0200, |
cf9e5a73 TH |
48 | }; |
49 | ||
324a56e1 TH |
50 | /* type-specific structures for kernfs_node union members */ |
51 | struct kernfs_elem_dir { | |
cf9e5a73 | 52 | unsigned long subdirs; |
adc5e8b5 | 53 | /* children rbtree starts here and goes through kn->rb */ |
cf9e5a73 TH |
54 | struct rb_root children; |
55 | ||
56 | /* | |
57 | * The kernfs hierarchy this directory belongs to. This fits | |
324a56e1 | 58 | * better directly in kernfs_node but is here to save space. |
cf9e5a73 TH |
59 | */ |
60 | struct kernfs_root *root; | |
61 | }; | |
62 | ||
324a56e1 TH |
63 | struct kernfs_elem_symlink { |
64 | struct kernfs_node *target_kn; | |
cf9e5a73 TH |
65 | }; |
66 | ||
324a56e1 | 67 | struct kernfs_elem_attr { |
cf9e5a73 | 68 | const struct kernfs_ops *ops; |
c525aadd | 69 | struct kernfs_open_node *open; |
cf9e5a73 TH |
70 | loff_t size; |
71 | }; | |
72 | ||
73 | /* | |
324a56e1 TH |
74 | * kernfs_node - the building block of kernfs hierarchy. Each and every |
75 | * kernfs node is represented by single kernfs_node. Most fields are | |
cf9e5a73 TH |
76 | * private to kernfs and shouldn't be accessed directly by kernfs users. |
77 | * | |
324a56e1 TH |
78 | * As long as s_count reference is held, the kernfs_node itself is |
79 | * accessible. Dereferencing elem or any other outer entity requires | |
80 | * active reference. | |
cf9e5a73 | 81 | */ |
324a56e1 | 82 | struct kernfs_node { |
adc5e8b5 TH |
83 | atomic_t count; |
84 | atomic_t active; | |
cf9e5a73 TH |
85 | #ifdef CONFIG_DEBUG_LOCK_ALLOC |
86 | struct lockdep_map dep_map; | |
87 | #endif | |
88 | /* the following two fields are published */ | |
adc5e8b5 TH |
89 | struct kernfs_node *parent; |
90 | const char *name; | |
cf9e5a73 | 91 | |
adc5e8b5 | 92 | struct rb_node rb; |
cf9e5a73 | 93 | |
7653fe9d | 94 | union { |
87da1493 | 95 | struct completion *completion; |
7653fe9d GKH |
96 | struct kernfs_node *removed_list; |
97 | } u; | |
98 | ||
adc5e8b5 | 99 | const void *ns; /* namespace tag */ |
9b0925a6 | 100 | unsigned int hash; /* ns + name hash */ |
cf9e5a73 | 101 | union { |
adc5e8b5 TH |
102 | struct kernfs_elem_dir dir; |
103 | struct kernfs_elem_symlink symlink; | |
104 | struct kernfs_elem_attr attr; | |
cf9e5a73 TH |
105 | }; |
106 | ||
107 | void *priv; | |
108 | ||
adc5e8b5 TH |
109 | unsigned short flags; |
110 | umode_t mode; | |
111 | unsigned int ino; | |
c525aadd | 112 | struct kernfs_iattrs *iattr; |
cf9e5a73 | 113 | }; |
b8441ed2 | 114 | |
80b9bbef TH |
115 | /* |
116 | * kernfs_dir_ops may be specified on kernfs_create_root() to support | |
117 | * directory manipulation syscalls. These optional callbacks are invoked | |
118 | * on the matching syscalls and can perform any kernfs operations which | |
119 | * don't necessarily have to be the exact operation requested. | |
120 | */ | |
121 | struct kernfs_dir_ops { | |
122 | int (*mkdir)(struct kernfs_node *parent, const char *name, | |
123 | umode_t mode); | |
124 | int (*rmdir)(struct kernfs_node *kn); | |
125 | int (*rename)(struct kernfs_node *kn, struct kernfs_node *new_parent, | |
126 | const char *new_name); | |
127 | }; | |
128 | ||
ba7443bc TH |
129 | struct kernfs_root { |
130 | /* published fields */ | |
324a56e1 | 131 | struct kernfs_node *kn; |
bc755553 TH |
132 | |
133 | /* private fields, do not use outside kernfs proper */ | |
134 | struct ida ino_ida; | |
80b9bbef | 135 | struct kernfs_dir_ops *dir_ops; |
ba7443bc TH |
136 | }; |
137 | ||
c525aadd | 138 | struct kernfs_open_file { |
dd8a5b03 | 139 | /* published fields */ |
324a56e1 | 140 | struct kernfs_node *kn; |
dd8a5b03 TH |
141 | struct file *file; |
142 | ||
143 | /* private fields, do not use outside kernfs proper */ | |
144 | struct mutex mutex; | |
145 | int event; | |
146 | struct list_head list; | |
147 | ||
148 | bool mmapped; | |
149 | const struct vm_operations_struct *vm_ops; | |
150 | }; | |
151 | ||
f6acf8bb TH |
152 | struct kernfs_ops { |
153 | /* | |
154 | * Read is handled by either seq_file or raw_read(). | |
155 | * | |
d19b9846 TH |
156 | * If seq_show() is present, seq_file path is active. Other seq |
157 | * operations are optional and if not implemented, the behavior is | |
158 | * equivalent to single_open(). @sf->private points to the | |
c525aadd | 159 | * associated kernfs_open_file. |
f6acf8bb TH |
160 | * |
161 | * read() is bounced through kernel buffer and a read larger than | |
162 | * PAGE_SIZE results in partial operation of PAGE_SIZE. | |
163 | */ | |
164 | int (*seq_show)(struct seq_file *sf, void *v); | |
d19b9846 TH |
165 | |
166 | void *(*seq_start)(struct seq_file *sf, loff_t *ppos); | |
167 | void *(*seq_next)(struct seq_file *sf, void *v, loff_t *ppos); | |
168 | void (*seq_stop)(struct seq_file *sf, void *v); | |
f6acf8bb | 169 | |
c525aadd | 170 | ssize_t (*read)(struct kernfs_open_file *of, char *buf, size_t bytes, |
f6acf8bb TH |
171 | loff_t off); |
172 | ||
173 | /* | |
174 | * write() is bounced through kernel buffer and a write larger than | |
175 | * PAGE_SIZE results in partial operation of PAGE_SIZE. | |
176 | */ | |
c525aadd | 177 | ssize_t (*write)(struct kernfs_open_file *of, char *buf, size_t bytes, |
f6acf8bb TH |
178 | loff_t off); |
179 | ||
c525aadd | 180 | int (*mmap)(struct kernfs_open_file *of, struct vm_area_struct *vma); |
517e64f5 TH |
181 | |
182 | #ifdef CONFIG_DEBUG_LOCK_ALLOC | |
183 | struct lock_class_key lockdep_key; | |
184 | #endif | |
f6acf8bb TH |
185 | }; |
186 | ||
879f40d1 TH |
187 | #ifdef CONFIG_SYSFS |
188 | ||
df23fc39 | 189 | static inline enum kernfs_node_type kernfs_type(struct kernfs_node *kn) |
cf9e5a73 | 190 | { |
df23fc39 | 191 | return kn->flags & KERNFS_TYPE_MASK; |
cf9e5a73 TH |
192 | } |
193 | ||
194 | /** | |
195 | * kernfs_enable_ns - enable namespace under a directory | |
324a56e1 | 196 | * @kn: directory of interest, should be empty |
cf9e5a73 | 197 | * |
324a56e1 TH |
198 | * This is to be called right after @kn is created to enable namespace |
199 | * under it. All children of @kn must have non-NULL namespace tags and | |
cf9e5a73 TH |
200 | * only the ones which match the super_block's tag will be visible. |
201 | */ | |
324a56e1 | 202 | static inline void kernfs_enable_ns(struct kernfs_node *kn) |
cf9e5a73 | 203 | { |
df23fc39 | 204 | WARN_ON_ONCE(kernfs_type(kn) != KERNFS_DIR); |
adc5e8b5 | 205 | WARN_ON_ONCE(!RB_EMPTY_ROOT(&kn->dir.children)); |
df23fc39 | 206 | kn->flags |= KERNFS_NS; |
cf9e5a73 TH |
207 | } |
208 | ||
ac9bba03 TH |
209 | /** |
210 | * kernfs_ns_enabled - test whether namespace is enabled | |
324a56e1 | 211 | * @kn: the node to test |
ac9bba03 TH |
212 | * |
213 | * Test whether namespace filtering is enabled for the children of @ns. | |
214 | */ | |
324a56e1 | 215 | static inline bool kernfs_ns_enabled(struct kernfs_node *kn) |
ac9bba03 | 216 | { |
df23fc39 | 217 | return kn->flags & KERNFS_NS; |
ac9bba03 TH |
218 | } |
219 | ||
324a56e1 TH |
220 | struct kernfs_node *kernfs_find_and_get_ns(struct kernfs_node *parent, |
221 | const char *name, const void *ns); | |
222 | void kernfs_get(struct kernfs_node *kn); | |
223 | void kernfs_put(struct kernfs_node *kn); | |
ccf73cf3 | 224 | |
80b9bbef TH |
225 | struct kernfs_root *kernfs_create_root(struct kernfs_dir_ops *kdops, |
226 | void *priv); | |
ba7443bc TH |
227 | void kernfs_destroy_root(struct kernfs_root *root); |
228 | ||
324a56e1 | 229 | struct kernfs_node *kernfs_create_dir_ns(struct kernfs_node *parent, |
bb8b9d09 TH |
230 | const char *name, umode_t mode, |
231 | void *priv, const void *ns); | |
2063d608 TH |
232 | struct kernfs_node *__kernfs_create_file(struct kernfs_node *parent, |
233 | const char *name, | |
234 | umode_t mode, loff_t size, | |
235 | const struct kernfs_ops *ops, | |
236 | void *priv, const void *ns, | |
237 | bool name_is_static, | |
238 | struct lock_class_key *key); | |
324a56e1 TH |
239 | struct kernfs_node *kernfs_create_link(struct kernfs_node *parent, |
240 | const char *name, | |
241 | struct kernfs_node *target); | |
242 | void kernfs_remove(struct kernfs_node *kn); | |
243 | int kernfs_remove_by_name_ns(struct kernfs_node *parent, const char *name, | |
879f40d1 | 244 | const void *ns); |
324a56e1 | 245 | int kernfs_rename_ns(struct kernfs_node *kn, struct kernfs_node *new_parent, |
890ece16 | 246 | const char *new_name, const void *new_ns); |
324a56e1 TH |
247 | int kernfs_setattr(struct kernfs_node *kn, const struct iattr *iattr); |
248 | void kernfs_notify(struct kernfs_node *kn); | |
879f40d1 | 249 | |
4b93dc9b TH |
250 | const void *kernfs_super_ns(struct super_block *sb); |
251 | struct dentry *kernfs_mount_ns(struct file_system_type *fs_type, int flags, | |
252 | struct kernfs_root *root, const void *ns); | |
253 | void kernfs_kill_sb(struct super_block *sb); | |
254 | ||
255 | void kernfs_init(void); | |
256 | ||
879f40d1 TH |
257 | #else /* CONFIG_SYSFS */ |
258 | ||
df23fc39 | 259 | static inline enum kernfs_node_type kernfs_type(struct kernfs_node *kn) |
cf9e5a73 TH |
260 | { return 0; } /* whatever */ |
261 | ||
324a56e1 | 262 | static inline void kernfs_enable_ns(struct kernfs_node *kn) { } |
cf9e5a73 | 263 | |
324a56e1 | 264 | static inline bool kernfs_ns_enabled(struct kernfs_node *kn) |
ac9bba03 TH |
265 | { return false; } |
266 | ||
324a56e1 TH |
267 | static inline struct kernfs_node * |
268 | kernfs_find_and_get_ns(struct kernfs_node *parent, const char *name, | |
ccf73cf3 TH |
269 | const void *ns) |
270 | { return NULL; } | |
271 | ||
324a56e1 TH |
272 | static inline void kernfs_get(struct kernfs_node *kn) { } |
273 | static inline void kernfs_put(struct kernfs_node *kn) { } | |
ccf73cf3 | 274 | |
80b9bbef TH |
275 | static inline struct kernfs_root * |
276 | kernfs_create_root(struct kernfs_dir_ops *kdops, void *priv) | |
ba7443bc TH |
277 | { return ERR_PTR(-ENOSYS); } |
278 | ||
279 | static inline void kernfs_destroy_root(struct kernfs_root *root) { } | |
280 | ||
324a56e1 | 281 | static inline struct kernfs_node * |
bb8b9d09 TH |
282 | kernfs_create_dir_ns(struct kernfs_node *parent, const char *name, |
283 | umode_t mode, void *priv, const void *ns) | |
93b2b8e4 TH |
284 | { return ERR_PTR(-ENOSYS); } |
285 | ||
324a56e1 | 286 | static inline struct kernfs_node * |
2063d608 TH |
287 | __kernfs_create_file(struct kernfs_node *parent, const char *name, |
288 | umode_t mode, loff_t size, const struct kernfs_ops *ops, | |
289 | void *priv, const void *ns, bool name_is_static, | |
290 | struct lock_class_key *key) | |
496f7394 TH |
291 | { return ERR_PTR(-ENOSYS); } |
292 | ||
324a56e1 TH |
293 | static inline struct kernfs_node * |
294 | kernfs_create_link(struct kernfs_node *parent, const char *name, | |
295 | struct kernfs_node *target) | |
5d0e26bb TH |
296 | { return ERR_PTR(-ENOSYS); } |
297 | ||
324a56e1 | 298 | static inline void kernfs_remove(struct kernfs_node *kn) { } |
879f40d1 | 299 | |
324a56e1 | 300 | static inline int kernfs_remove_by_name_ns(struct kernfs_node *kn, |
879f40d1 TH |
301 | const char *name, const void *ns) |
302 | { return -ENOSYS; } | |
303 | ||
324a56e1 TH |
304 | static inline int kernfs_rename_ns(struct kernfs_node *kn, |
305 | struct kernfs_node *new_parent, | |
890ece16 TH |
306 | const char *new_name, const void *new_ns) |
307 | { return -ENOSYS; } | |
308 | ||
324a56e1 | 309 | static inline int kernfs_setattr(struct kernfs_node *kn, |
5d60418e TH |
310 | const struct iattr *iattr) |
311 | { return -ENOSYS; } | |
312 | ||
324a56e1 | 313 | static inline void kernfs_notify(struct kernfs_node *kn) { } |
024f6471 | 314 | |
4b93dc9b TH |
315 | static inline const void *kernfs_super_ns(struct super_block *sb) |
316 | { return NULL; } | |
317 | ||
318 | static inline struct dentry * | |
319 | kernfs_mount_ns(struct file_system_type *fs_type, int flags, | |
320 | struct kernfs_root *root, const void *ns) | |
321 | { return ERR_PTR(-ENOSYS); } | |
322 | ||
323 | static inline void kernfs_kill_sb(struct super_block *sb) { } | |
324 | ||
325 | static inline void kernfs_init(void) { } | |
326 | ||
879f40d1 TH |
327 | #endif /* CONFIG_SYSFS */ |
328 | ||
324a56e1 TH |
329 | static inline struct kernfs_node * |
330 | kernfs_find_and_get(struct kernfs_node *kn, const char *name) | |
ccf73cf3 | 331 | { |
324a56e1 | 332 | return kernfs_find_and_get_ns(kn, name, NULL); |
ccf73cf3 TH |
333 | } |
334 | ||
324a56e1 | 335 | static inline struct kernfs_node * |
bb8b9d09 TH |
336 | kernfs_create_dir(struct kernfs_node *parent, const char *name, umode_t mode, |
337 | void *priv) | |
93b2b8e4 | 338 | { |
bb8b9d09 | 339 | return kernfs_create_dir_ns(parent, name, mode, priv, NULL); |
93b2b8e4 TH |
340 | } |
341 | ||
324a56e1 TH |
342 | static inline struct kernfs_node * |
343 | kernfs_create_file_ns(struct kernfs_node *parent, const char *name, | |
517e64f5 TH |
344 | umode_t mode, loff_t size, const struct kernfs_ops *ops, |
345 | void *priv, const void *ns) | |
346 | { | |
347 | struct lock_class_key *key = NULL; | |
348 | ||
349 | #ifdef CONFIG_DEBUG_LOCK_ALLOC | |
350 | key = (struct lock_class_key *)&ops->lockdep_key; | |
351 | #endif | |
2063d608 TH |
352 | return __kernfs_create_file(parent, name, mode, size, ops, priv, ns, |
353 | false, key); | |
517e64f5 TH |
354 | } |
355 | ||
324a56e1 TH |
356 | static inline struct kernfs_node * |
357 | kernfs_create_file(struct kernfs_node *parent, const char *name, umode_t mode, | |
496f7394 TH |
358 | loff_t size, const struct kernfs_ops *ops, void *priv) |
359 | { | |
360 | return kernfs_create_file_ns(parent, name, mode, size, ops, priv, NULL); | |
361 | } | |
362 | ||
324a56e1 | 363 | static inline int kernfs_remove_by_name(struct kernfs_node *parent, |
879f40d1 TH |
364 | const char *name) |
365 | { | |
366 | return kernfs_remove_by_name_ns(parent, name, NULL); | |
367 | } | |
368 | ||
4b93dc9b TH |
369 | static inline struct dentry * |
370 | kernfs_mount(struct file_system_type *fs_type, int flags, | |
371 | struct kernfs_root *root) | |
372 | { | |
373 | return kernfs_mount_ns(fs_type, flags, root, NULL); | |
374 | } | |
375 | ||
b8441ed2 | 376 | #endif /* __LINUX_KERNFS_H */ |