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