xref: /openbmc/linux/fs/sysfs/sysfs.h (revision e23feb16)
1 /*
2  * fs/sysfs/sysfs.h - sysfs internal header file
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 
11 #include <linux/lockdep.h>
12 #include <linux/kobject_ns.h>
13 #include <linux/fs.h>
14 #include <linux/rbtree.h>
15 
16 struct sysfs_open_dirent;
17 
18 /* type-specific structures for sysfs_dirent->s_* union members */
19 struct sysfs_elem_dir {
20 	struct kobject		*kobj;
21 
22 	unsigned long		subdirs;
23 	/* children rbtree starts here and goes through sd->s_rb */
24 	struct rb_root		children;
25 };
26 
27 struct sysfs_elem_symlink {
28 	struct sysfs_dirent	*target_sd;
29 };
30 
31 struct sysfs_elem_attr {
32 	struct attribute	*attr;
33 	struct sysfs_open_dirent *open;
34 };
35 
36 struct sysfs_elem_bin_attr {
37 	struct bin_attribute	*bin_attr;
38 	struct hlist_head	buffers;
39 };
40 
41 struct sysfs_inode_attrs {
42 	struct iattr	ia_iattr;
43 	void		*ia_secdata;
44 	u32		ia_secdata_len;
45 };
46 
47 /*
48  * sysfs_dirent - the building block of sysfs hierarchy.  Each and
49  * every sysfs node is represented by single sysfs_dirent.
50  *
51  * As long as s_count reference is held, the sysfs_dirent itself is
52  * accessible.  Dereferencing s_elem or any other outer entity
53  * requires s_active reference.
54  */
55 struct sysfs_dirent {
56 	atomic_t		s_count;
57 	atomic_t		s_active;
58 #ifdef CONFIG_DEBUG_LOCK_ALLOC
59 	struct lockdep_map	dep_map;
60 #endif
61 	struct sysfs_dirent	*s_parent;
62 	const char		*s_name;
63 
64 	struct rb_node		s_rb;
65 
66 	union {
67 		struct completion	*completion;
68 		struct sysfs_dirent	*removed_list;
69 	} u;
70 
71 	const void		*s_ns; /* namespace tag */
72 	unsigned int		s_hash; /* ns + name hash */
73 	union {
74 		struct sysfs_elem_dir		s_dir;
75 		struct sysfs_elem_symlink	s_symlink;
76 		struct sysfs_elem_attr		s_attr;
77 		struct sysfs_elem_bin_attr	s_bin_attr;
78 	};
79 
80 	unsigned short		s_flags;
81 	umode_t			s_mode;
82 	unsigned int		s_ino;
83 	struct sysfs_inode_attrs *s_iattr;
84 };
85 
86 #define SD_DEACTIVATED_BIAS		INT_MIN
87 
88 #define SYSFS_TYPE_MASK			0x00ff
89 #define SYSFS_DIR			0x0001
90 #define SYSFS_KOBJ_ATTR			0x0002
91 #define SYSFS_KOBJ_BIN_ATTR		0x0004
92 #define SYSFS_KOBJ_LINK			0x0008
93 #define SYSFS_COPY_NAME			(SYSFS_DIR | SYSFS_KOBJ_LINK)
94 #define SYSFS_ACTIVE_REF		(SYSFS_KOBJ_ATTR | SYSFS_KOBJ_BIN_ATTR)
95 
96 /* identify any namespace tag on sysfs_dirents */
97 #define SYSFS_NS_TYPE_MASK		0xf00
98 #define SYSFS_NS_TYPE_SHIFT		8
99 
100 #define SYSFS_FLAG_MASK			~(SYSFS_NS_TYPE_MASK|SYSFS_TYPE_MASK)
101 #define SYSFS_FLAG_REMOVED		0x02000
102 
103 static inline unsigned int sysfs_type(struct sysfs_dirent *sd)
104 {
105 	return sd->s_flags & SYSFS_TYPE_MASK;
106 }
107 
108 /*
109  * Return any namespace tags on this dirent.
110  * enum kobj_ns_type is defined in linux/kobject.h
111  */
112 static inline enum kobj_ns_type sysfs_ns_type(struct sysfs_dirent *sd)
113 {
114 	return (sd->s_flags & SYSFS_NS_TYPE_MASK) >> SYSFS_NS_TYPE_SHIFT;
115 }
116 
117 #ifdef CONFIG_DEBUG_LOCK_ALLOC
118 #define sysfs_dirent_init_lockdep(sd)				\
119 do {								\
120 	struct attribute *attr = sd->s_attr.attr;		\
121 	struct lock_class_key *key = attr->key;			\
122 	if (!key)						\
123 		key = &attr->skey;				\
124 								\
125 	lockdep_init_map(&sd->dep_map, "s_active", key, 0);	\
126 } while (0)
127 #else
128 #define sysfs_dirent_init_lockdep(sd) do {} while (0)
129 #endif
130 
131 /*
132  * Context structure to be used while adding/removing nodes.
133  */
134 struct sysfs_addrm_cxt {
135 	struct sysfs_dirent	*parent_sd;
136 	struct sysfs_dirent	*removed;
137 };
138 
139 /*
140  * mount.c
141  */
142 
143 /*
144  * Each sb is associated with a set of namespace tags (i.e.
145  * the network namespace of the task which mounted this sysfs
146  * instance).
147  */
148 struct sysfs_super_info {
149 	void *ns[KOBJ_NS_TYPES];
150 };
151 #define sysfs_info(SB) ((struct sysfs_super_info *)(SB->s_fs_info))
152 extern struct sysfs_dirent sysfs_root;
153 extern struct kmem_cache *sysfs_dir_cachep;
154 
155 /*
156  * dir.c
157  */
158 extern struct mutex sysfs_mutex;
159 extern spinlock_t sysfs_assoc_lock;
160 extern const struct dentry_operations sysfs_dentry_ops;
161 
162 extern const struct file_operations sysfs_dir_operations;
163 extern const struct inode_operations sysfs_dir_inode_operations;
164 
165 struct dentry *sysfs_get_dentry(struct sysfs_dirent *sd);
166 struct sysfs_dirent *sysfs_get_active(struct sysfs_dirent *sd);
167 void sysfs_put_active(struct sysfs_dirent *sd);
168 void sysfs_addrm_start(struct sysfs_addrm_cxt *acxt,
169 		       struct sysfs_dirent *parent_sd);
170 int __sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd);
171 int sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd);
172 void sysfs_remove_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd);
173 void sysfs_addrm_finish(struct sysfs_addrm_cxt *acxt);
174 
175 struct sysfs_dirent *sysfs_find_dirent(struct sysfs_dirent *parent_sd,
176 				       const void *ns,
177 				       const unsigned char *name);
178 struct sysfs_dirent *sysfs_get_dirent(struct sysfs_dirent *parent_sd,
179 				      const void *ns,
180 				      const unsigned char *name);
181 struct sysfs_dirent *sysfs_new_dirent(const char *name, umode_t mode, int type);
182 
183 void release_sysfs_dirent(struct sysfs_dirent *sd);
184 
185 int sysfs_create_subdir(struct kobject *kobj, const char *name,
186 			struct sysfs_dirent **p_sd);
187 void sysfs_remove_subdir(struct sysfs_dirent *sd);
188 
189 int sysfs_rename(struct sysfs_dirent *sd, struct sysfs_dirent *new_parent_sd,
190 		 const void *ns, const char *new_name);
191 
192 static inline struct sysfs_dirent *__sysfs_get(struct sysfs_dirent *sd)
193 {
194 	if (sd) {
195 		WARN_ON(!atomic_read(&sd->s_count));
196 		atomic_inc(&sd->s_count);
197 	}
198 	return sd;
199 }
200 #define sysfs_get(sd) __sysfs_get(sd)
201 
202 static inline void __sysfs_put(struct sysfs_dirent *sd)
203 {
204 	if (sd && atomic_dec_and_test(&sd->s_count))
205 		release_sysfs_dirent(sd);
206 }
207 #define sysfs_put(sd) __sysfs_put(sd)
208 
209 /*
210  * inode.c
211  */
212 struct inode *sysfs_get_inode(struct super_block *sb, struct sysfs_dirent *sd);
213 void sysfs_evict_inode(struct inode *inode);
214 int sysfs_sd_setattr(struct sysfs_dirent *sd, struct iattr *iattr);
215 int sysfs_permission(struct inode *inode, int mask);
216 int sysfs_setattr(struct dentry *dentry, struct iattr *iattr);
217 int sysfs_getattr(struct vfsmount *mnt, struct dentry *dentry,
218 		  struct kstat *stat);
219 int sysfs_setxattr(struct dentry *dentry, const char *name, const void *value,
220 		   size_t size, int flags);
221 int sysfs_hash_and_remove(struct sysfs_dirent *dir_sd, const void *ns,
222 			  const char *name);
223 int sysfs_inode_init(void);
224 
225 /*
226  * file.c
227  */
228 extern const struct file_operations sysfs_file_operations;
229 
230 int sysfs_add_file(struct sysfs_dirent *dir_sd,
231 		   const struct attribute *attr, int type);
232 
233 int sysfs_add_file_mode(struct sysfs_dirent *dir_sd,
234 			const struct attribute *attr, int type, umode_t amode);
235 /*
236  * bin.c
237  */
238 extern const struct file_operations bin_fops;
239 void unmap_bin_file(struct sysfs_dirent *attr_sd);
240 
241 /*
242  * symlink.c
243  */
244 extern const struct inode_operations sysfs_symlink_inode_operations;
245 int sysfs_create_link_sd(struct sysfs_dirent *sd, struct kobject *target,
246 			 const char *name);
247