fs/sysfs/sysfs.h

   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         union {
  33                 struct attribute        *attr;
  34                 struct bin_attribute    *bin_attr;
  35         };
  36         struct sysfs_open_dirent *open;
  37 };
  38
  39 struct sysfs_inode_attrs {
  40         struct iattr    ia_iattr;
  41         void            *ia_secdata;
  42         u32             ia_secdata_len;
  43 };
  44
  45 /*
  46  * sysfs_dirent - the building block of sysfs hierarchy.  Each and
  47  * every sysfs node is represented by single sysfs_dirent.
  48  *
  49  * As long as s_count reference is held, the sysfs_dirent itself is
  50  * accessible.  Dereferencing s_elem or any other outer entity
  51  * requires s_active reference.
  52  */
  53 struct sysfs_dirent {
  54         atomic_t                s_count;
  55         atomic_t                s_active;
  56 #ifdef CONFIG_DEBUG_LOCK_ALLOC
  57         struct lockdep_map      dep_map;
  58 #endif
  59         struct sysfs_dirent     *s_parent;
  60         const char              *s_name;
  61
  62         struct rb_node          s_rb;
  63
  64         union {
  65                 struct completion       *completion;
  66                 struct sysfs_dirent     *removed_list;
  67         } u;
  68
  69         const void              *s_ns; /* namespace tag */
  70         unsigned int            s_hash; /* ns + name hash */
  71         union {
  72                 struct sysfs_elem_dir           s_dir;
  73                 struct sysfs_elem_symlink       s_symlink;
  74                 struct sysfs_elem_attr          s_attr;
  75         };
  76
  77         unsigned short          s_flags;
  78         umode_t                 s_mode;
  79         unsigned int            s_ino;
  80         struct sysfs_inode_attrs *s_iattr;
  81 };
  82
  83 #define SD_DEACTIVATED_BIAS             INT_MIN
  84
  85 #define SYSFS_TYPE_MASK                 0x00ff
  86 #define SYSFS_DIR                       0x0001
  87 #define SYSFS_KOBJ_ATTR                 0x0002
  88 #define SYSFS_KOBJ_BIN_ATTR             0x0004
  89 #define SYSFS_KOBJ_LINK                 0x0008
  90 #define SYSFS_COPY_NAME                 (SYSFS_DIR | SYSFS_KOBJ_LINK)
  91 #define SYSFS_ACTIVE_REF                (SYSFS_KOBJ_ATTR | SYSFS_KOBJ_BIN_ATTR)
  92
  93 /* identify any namespace tag on sysfs_dirents */
  94 #define SYSFS_NS_TYPE_MASK              0xf00
  95 #define SYSFS_NS_TYPE_SHIFT             8
  96
  97 #define SYSFS_FLAG_MASK                 ~(SYSFS_NS_TYPE_MASK|SYSFS_TYPE_MASK)
  98 #define SYSFS_FLAG_REMOVED              0x02000
  99
 100 static inline unsigned int sysfs_type(struct sysfs_dirent *sd)
 101 {
 102         return sd->s_flags & SYSFS_TYPE_MASK;
 103 }
 104
 105 /*
 106  * Return any namespace tags on this dirent.
 107  * enum kobj_ns_type is defined in linux/kobject.h
 108  */
 109 static inline enum kobj_ns_type sysfs_ns_type(struct sysfs_dirent *sd)
 110 {
 111         return (sd->s_flags & SYSFS_NS_TYPE_MASK) >> SYSFS_NS_TYPE_SHIFT;
 112 }
 113
 114 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 115
 116 #define sysfs_dirent_init_lockdep(sd)                           \
 117 do {                                                            \
 118         struct attribute *attr = sd->s_attr.attr;               \
 119         struct lock_class_key *key = attr->key;                 \
 120         if (!key)                                               \
 121                 key = &attr->skey;                              \
 122                                                                 \
 123         lockdep_init_map(&sd->dep_map, "s_active", key, 0);     \
 124 } while (0)
 125
 126 /* Test for attributes that want to ignore lockdep for read-locking */
 127 static inline bool sysfs_ignore_lockdep(struct sysfs_dirent *sd)
 128 {
 129         int type = sysfs_type(sd);
 130
 131         return (type == SYSFS_KOBJ_ATTR || type == SYSFS_KOBJ_BIN_ATTR) &&
 132                 sd->s_attr.attr->ignore_lockdep;
 133 }
 134
 135 #else
 136
 137 #define sysfs_dirent_init_lockdep(sd) do {} while (0)
 138
 139 static inline bool sysfs_ignore_lockdep(struct sysfs_dirent *sd)
 140 {
 141         return true;
 142 }
 143
 144 #endif
 145
 146 /*
 147  * Context structure to be used while adding/removing nodes.
 148  */
 149 struct sysfs_addrm_cxt {
 150         struct sysfs_dirent     *removed;
 151 };
 152
 153 /*
 154  * mount.c
 155  */
 156
 157 /*
 158  * Each sb is associated with a set of namespace tags (i.e.
 159  * the network namespace of the task which mounted this sysfs
 160  * instance).
 161  */
 162 struct sysfs_super_info {
 163         void *ns[KOBJ_NS_TYPES];
 164 };
 165 #define sysfs_info(SB) ((struct sysfs_super_info *)(SB->s_fs_info))
 166 extern struct sysfs_dirent sysfs_root;
 167 extern struct kmem_cache *sysfs_dir_cachep;
 168
 169 /*
 170  * dir.c
 171  */
 172 extern struct mutex sysfs_mutex;
 173 extern spinlock_t sysfs_symlink_target_lock;
 174 extern const struct dentry_operations sysfs_dentry_ops;
 175
 176 extern const struct file_operations sysfs_dir_operations;
 177 extern const struct inode_operations sysfs_dir_inode_operations;
 178
 179 struct sysfs_dirent *sysfs_get_active(struct sysfs_dirent *sd);
 180 void sysfs_put_active(struct sysfs_dirent *sd);
 181 void sysfs_addrm_start(struct sysfs_addrm_cxt *acxt);
 182 void sysfs_warn_dup(struct sysfs_dirent *parent, const char *name);
 183 int __sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd,
 184                     struct sysfs_dirent *parent_sd);
 185 int sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd,
 186                   struct sysfs_dirent *parent_sd);
 187 void sysfs_remove(struct sysfs_dirent *sd);
 188 int sysfs_hash_and_remove(struct sysfs_dirent *dir_sd, const char *name,
 189                           const void *ns);
 190 void sysfs_addrm_finish(struct sysfs_addrm_cxt *acxt);
 191
 192 struct sysfs_dirent *sysfs_find_dirent(struct sysfs_dirent *parent_sd,
 193                                        const unsigned char *name,
 194                                        const void *ns);
 195 struct sysfs_dirent *sysfs_new_dirent(const char *name, umode_t mode, int type);
 196
 197 void release_sysfs_dirent(struct sysfs_dirent *sd);
 198
 199 int sysfs_create_subdir(struct kobject *kobj, const char *name,
 200                         struct sysfs_dirent **p_sd);
 201
 202 int sysfs_rename(struct sysfs_dirent *sd, struct sysfs_dirent *new_parent_sd,
 203                  const char *new_name, const void *new_ns);
 204
 205 static inline struct sysfs_dirent *__sysfs_get(struct sysfs_dirent *sd)
 206 {
 207         if (sd) {
 208                 WARN_ON(!atomic_read(&sd->s_count));
 209                 atomic_inc(&sd->s_count);
 210         }
 211         return sd;
 212 }
 213 #define sysfs_get(sd) __sysfs_get(sd)
 214
 215 static inline void __sysfs_put(struct sysfs_dirent *sd)
 216 {
 217         if (sd && atomic_dec_and_test(&sd->s_count))
 218                 release_sysfs_dirent(sd);
 219 }
 220 #define sysfs_put(sd) __sysfs_put(sd)
 221
 222 /*
 223  * inode.c
 224  */
 225 struct inode *sysfs_get_inode(struct super_block *sb, struct sysfs_dirent *sd);
 226 void sysfs_evict_inode(struct inode *inode);
 227 int sysfs_sd_setattr(struct sysfs_dirent *sd, struct iattr *iattr);
 228 int sysfs_permission(struct inode *inode, int mask);
 229 int sysfs_setattr(struct dentry *dentry, struct iattr *iattr);
 230 int sysfs_getattr(struct vfsmount *mnt, struct dentry *dentry,
 231                   struct kstat *stat);
 232 int sysfs_setxattr(struct dentry *dentry, const char *name, const void *value,
 233                    size_t size, int flags);
 234 int sysfs_inode_init(void);
 235
 236 /*
 237  * file.c
 238  */
 239 extern const struct file_operations sysfs_file_operations;
 240 extern const struct file_operations sysfs_bin_operations;
 241
 242 int sysfs_add_file(struct sysfs_dirent *dir_sd,
 243                    const struct attribute *attr, int type);
 244
 245 int sysfs_add_file_mode_ns(struct sysfs_dirent *dir_sd,
 246                            const struct attribute *attr, int type,
 247                            umode_t amode, const void *ns);
 248 void sysfs_unmap_bin_file(struct sysfs_dirent *sd);
 249
 250 /*
 251  * symlink.c
 252  */
 253 extern const struct inode_operations sysfs_symlink_inode_operations;
 254 int sysfs_create_link_sd(struct sysfs_dirent *sd, struct kobject *target,
 255                          const char *name);