2 * kernfs.h - pseudo filesystem decoupled from vfs locking
4 * This file is released under the GPLv2.
7 #ifndef __LINUX_KERNFS_H
8 #define __LINUX_KERNFS_H
10 #include <linux/kernel.h>
11 #include <linux/err.h>
12 #include <linux/list.h>
13 #include <linux/mutex.h>
14 #include <linux/idr.h>
15 #include <linux/lockdep.h>
16 #include <linux/rbtree.h>
17 #include <linux/atomic.h>
18 #include <linux/completion.h>
23 struct vm_area_struct;
25 struct file_system_type;
27 struct sysfs_open_dirent;
28 struct sysfs_inode_attrs;
30 enum kernfs_node_type {
32 SYSFS_KOBJ_ATTR = 0x0002,
33 SYSFS_KOBJ_LINK = 0x0004,
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
41 enum 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,
49 /* type-specific structures for sysfs_dirent->s_* union members */
50 struct sysfs_elem_dir {
51 unsigned long subdirs;
52 /* children rbtree starts here and goes through sd->s_rb */
53 struct rb_root children;
56 * The kernfs hierarchy this directory belongs to. This fits
57 * better directly in sysfs_dirent but is here to save space.
59 struct kernfs_root *root;
62 struct sysfs_elem_symlink {
63 struct sysfs_dirent *target_sd;
66 struct sysfs_elem_attr {
67 const struct kernfs_ops *ops;
68 struct sysfs_open_dirent *open;
73 * sysfs_dirent - the building block of sysfs hierarchy. Each and every
74 * sysfs node is represented by single sysfs_dirent. Most fields are
75 * private to kernfs and shouldn't be accessed directly by kernfs users.
77 * As long as s_count reference is held, the sysfs_dirent itself is
78 * accessible. Dereferencing s_elem or any other outer entity
79 * requires s_active reference.
84 #ifdef CONFIG_DEBUG_LOCK_ALLOC
85 struct lockdep_map dep_map;
87 /* the following two fields are published */
88 struct sysfs_dirent *s_parent;
94 struct completion *completion;
95 struct sysfs_dirent *removed_list;
98 const void *s_ns; /* namespace tag */
99 unsigned int s_hash; /* ns + name hash */
101 struct sysfs_elem_dir s_dir;
102 struct sysfs_elem_symlink s_symlink;
103 struct sysfs_elem_attr s_attr;
108 unsigned short s_flags;
111 struct sysfs_inode_attrs *s_iattr;
115 /* published fields */
116 struct sysfs_dirent *sd;
118 /* private fields, do not use outside kernfs proper */
122 struct sysfs_open_file {
123 /* published fields */
124 struct sysfs_dirent *sd;
127 /* private fields, do not use outside kernfs proper */
130 struct list_head list;
133 const struct vm_operations_struct *vm_ops;
138 * Read is handled by either seq_file or raw_read().
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
143 * associated sysfs_open_file.
145 * read() is bounced through kernel buffer and a read larger than
146 * PAGE_SIZE results in partial operation of PAGE_SIZE.
148 int (*seq_show)(struct seq_file *sf, void *v);
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);
154 ssize_t (*read)(struct sysfs_open_file *of, char *buf, size_t bytes,
158 * write() is bounced through kernel buffer and a write larger than
159 * PAGE_SIZE results in partial operation of PAGE_SIZE.
161 ssize_t (*write)(struct sysfs_open_file *of, char *buf, size_t bytes,
164 int (*mmap)(struct sysfs_open_file *of, struct vm_area_struct *vma);
166 #ifdef CONFIG_DEBUG_LOCK_ALLOC
167 struct lock_class_key lockdep_key;
173 static inline enum kernfs_node_type sysfs_type(struct sysfs_dirent *sd)
175 return sd->s_flags & SYSFS_TYPE_MASK;
179 * kernfs_enable_ns - enable namespace under a directory
180 * @sd: directory of interest, should be empty
182 * This is to be called right after @sd is created to enable namespace
183 * under it. All children of @sd must have non-NULL namespace tags and
184 * only the ones which match the super_block's tag will be visible.
186 static inline void kernfs_enable_ns(struct sysfs_dirent *sd)
188 WARN_ON_ONCE(sysfs_type(sd) != SYSFS_DIR);
189 WARN_ON_ONCE(!RB_EMPTY_ROOT(&sd->s_dir.children));
190 sd->s_flags |= SYSFS_FLAG_NS;
193 struct sysfs_dirent *kernfs_find_and_get_ns(struct sysfs_dirent *parent,
194 const char *name, const void *ns);
195 void kernfs_get(struct sysfs_dirent *sd);
196 void kernfs_put(struct sysfs_dirent *sd);
198 struct kernfs_root *kernfs_create_root(void *priv);
199 void kernfs_destroy_root(struct kernfs_root *root);
201 struct sysfs_dirent *kernfs_create_dir_ns(struct sysfs_dirent *parent,
202 const char *name, void *priv,
204 struct sysfs_dirent *kernfs_create_file_ns_key(struct sysfs_dirent *parent,
206 umode_t mode, loff_t size,
207 const struct kernfs_ops *ops,
208 void *priv, const void *ns,
209 struct lock_class_key *key);
210 struct sysfs_dirent *kernfs_create_link(struct sysfs_dirent *parent,
212 struct sysfs_dirent *target);
213 void kernfs_remove(struct sysfs_dirent *sd);
214 int kernfs_remove_by_name_ns(struct sysfs_dirent *parent, const char *name,
216 int kernfs_rename_ns(struct sysfs_dirent *sd, struct sysfs_dirent *new_parent,
217 const char *new_name, const void *new_ns);
218 int kernfs_setattr(struct sysfs_dirent *sd, const struct iattr *iattr);
219 void kernfs_notify(struct sysfs_dirent *sd);
221 const void *kernfs_super_ns(struct super_block *sb);
222 struct dentry *kernfs_mount_ns(struct file_system_type *fs_type, int flags,
223 struct kernfs_root *root, const void *ns);
224 void kernfs_kill_sb(struct super_block *sb);
226 void kernfs_init(void);
228 #else /* CONFIG_SYSFS */
230 static inline enum kernfs_node_type sysfs_type(struct sysfs_dirent *sd)
231 { return 0; } /* whatever */
233 static inline void kernfs_enable_ns(struct sysfs_dirent *sd) { }
235 static inline struct sysfs_dirent *
236 kernfs_find_and_get_ns(struct sysfs_dirent *parent, const char *name,
240 static inline void kernfs_get(struct sysfs_dirent *sd) { }
241 static inline void kernfs_put(struct sysfs_dirent *sd) { }
243 static inline struct kernfs_root *kernfs_create_root(void *priv)
244 { return ERR_PTR(-ENOSYS); }
246 static inline void kernfs_destroy_root(struct kernfs_root *root) { }
248 static inline struct sysfs_dirent *
249 kernfs_create_dir_ns(struct sysfs_dirent *parent, const char *name, void *priv,
251 { return ERR_PTR(-ENOSYS); }
253 static inline struct sysfs_dirent *
254 kernfs_create_file_ns_key(struct sysfs_dirent *parent, const char *name,
255 umode_t mode, loff_t size,
256 const struct kernfs_ops *ops, void *priv,
257 const void *ns, struct lock_class_key *key)
258 { return ERR_PTR(-ENOSYS); }
260 static inline struct sysfs_dirent *
261 kernfs_create_link(struct sysfs_dirent *parent, const char *name,
262 struct sysfs_dirent *target)
263 { return ERR_PTR(-ENOSYS); }
265 static inline void kernfs_remove(struct sysfs_dirent *sd) { }
267 static inline int kernfs_remove_by_name_ns(struct sysfs_dirent *parent,
268 const char *name, const void *ns)
271 static inline int kernfs_rename_ns(struct sysfs_dirent *sd,
272 struct sysfs_dirent *new_parent,
273 const char *new_name, const void *new_ns)
276 static inline int kernfs_setattr(struct sysfs_dirent *sd,
277 const struct iattr *iattr)
280 static inline void kernfs_notify(struct sysfs_dirent *sd) { }
282 static inline const void *kernfs_super_ns(struct super_block *sb)
285 static inline struct dentry *
286 kernfs_mount_ns(struct file_system_type *fs_type, int flags,
287 struct kernfs_root *root, const void *ns)
288 { return ERR_PTR(-ENOSYS); }
290 static inline void kernfs_kill_sb(struct super_block *sb) { }
292 static inline void kernfs_init(void) { }
294 #endif /* CONFIG_SYSFS */
296 static inline struct sysfs_dirent *
297 kernfs_find_and_get(struct sysfs_dirent *sd, const char *name)
299 return kernfs_find_and_get_ns(sd, name, NULL);
302 static inline struct sysfs_dirent *
303 kernfs_create_dir(struct sysfs_dirent *parent, const char *name, void *priv)
305 return kernfs_create_dir_ns(parent, name, priv, NULL);
308 static inline struct sysfs_dirent *
309 kernfs_create_file_ns(struct sysfs_dirent *parent, const char *name,
310 umode_t mode, loff_t size, const struct kernfs_ops *ops,
311 void *priv, const void *ns)
313 struct lock_class_key *key = NULL;
315 #ifdef CONFIG_DEBUG_LOCK_ALLOC
316 key = (struct lock_class_key *)&ops->lockdep_key;
318 return kernfs_create_file_ns_key(parent, name, mode, size, ops, priv,
322 static inline struct sysfs_dirent *
323 kernfs_create_file(struct sysfs_dirent *parent, const char *name, umode_t mode,
324 loff_t size, const struct kernfs_ops *ops, void *priv)
326 return kernfs_create_file_ns(parent, name, mode, size, ops, priv, NULL);
329 static inline int kernfs_remove_by_name(struct sysfs_dirent *parent,
332 return kernfs_remove_by_name_ns(parent, name, NULL);
335 static inline struct dentry *
336 kernfs_mount(struct file_system_type *fs_type, int flags,
337 struct kernfs_root *root)
339 return kernfs_mount_ns(fs_type, flags, root, NULL);
342 #endif /* __LINUX_KERNFS_H */