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Tejun Heo3e519032007-06-14 03:45:15 +09001struct sysfs_elem_dir {
2 struct kobject * kobj;
3};
4
5struct sysfs_elem_symlink {
Tejun Heo2b29ac22007-06-14 03:45:15 +09006 struct sysfs_dirent * target_sd;
Tejun Heo3e519032007-06-14 03:45:15 +09007};
8
9struct sysfs_elem_attr {
10 struct attribute * attr;
11};
12
13struct sysfs_elem_bin_attr {
14 struct bin_attribute * bin_attr;
15};
16
Tejun Heo0ab66082007-06-14 03:45:16 +090017/*
18 * As long as s_count reference is held, the sysfs_dirent itself is
19 * accessible. Dereferencing s_elem or any other outer entity
20 * requires s_active reference.
21 */
Adam J. Richterd56c3ea2007-02-16 21:35:25 +080022struct sysfs_dirent {
23 atomic_t s_count;
Tejun Heo0ab66082007-06-14 03:45:16 +090024 struct rw_semaphore s_active;
Tejun Heo13b30862007-06-14 03:45:14 +090025 struct sysfs_dirent * s_parent;
Adam J. Richterd56c3ea2007-02-16 21:35:25 +080026 struct list_head s_sibling;
27 struct list_head s_children;
Tejun Heo0c096b52007-06-14 03:45:15 +090028 const char * s_name;
Tejun Heo3e519032007-06-14 03:45:15 +090029
30 union {
31 struct sysfs_elem_dir dir;
32 struct sysfs_elem_symlink symlink;
33 struct sysfs_elem_attr attr;
34 struct sysfs_elem_bin_attr bin_attr;
35 } s_elem;
36
Adam J. Richterd56c3ea2007-02-16 21:35:25 +080037 int s_type;
38 umode_t s_mode;
Eric Sandeendc351252007-06-11 14:02:45 +090039 ino_t s_ino;
Adam J. Richterd56c3ea2007-02-16 21:35:25 +080040 struct dentry * s_dentry;
41 struct iattr * s_iattr;
42 atomic_t s_event;
43};
Linus Torvalds1da177e2005-04-16 15:20:36 -070044
Tejun Heo0ab66082007-06-14 03:45:16 +090045/*
46 * A sysfs file which deletes another file when written to need to
47 * write lock the s_active of the victim while its s_active is read
48 * locked for the write operation. Tell lockdep that this is okay.
49 */
50enum sysfs_s_active_class
51{
52 SYSFS_S_ACTIVE_NORMAL, /* file r/w access, etc - default */
53 SYSFS_S_ACTIVE_DEACTIVATE, /* file deactivation */
54};
55
Linus Torvalds1da177e2005-04-16 15:20:36 -070056extern struct vfsmount * sysfs_mount;
Christoph Lametere18b8902006-12-06 20:33:20 -080057extern struct kmem_cache *sysfs_dir_cachep;
Linus Torvalds1da177e2005-04-16 15:20:36 -070058
Eric W. Biedermanb592fcf2007-01-24 12:35:52 -070059extern void sysfs_delete_inode(struct inode *inode);
Maneesh Soni82155342005-05-31 10:39:52 +053060extern struct inode * sysfs_new_inode(mode_t mode, struct sysfs_dirent *);
Tejun Heo198a2a82007-06-14 03:45:16 +090061extern int sysfs_create(struct sysfs_dirent *sd, struct dentry *dentry,
62 int mode, int (*init)(struct inode *));
Linus Torvalds1da177e2005-04-16 15:20:36 -070063
Tejun Heofa7f9122007-06-14 03:45:13 +090064extern void release_sysfs_dirent(struct sysfs_dirent * sd);
Maneesh Sonic5168652006-03-09 19:40:14 +053065extern int sysfs_dirent_exist(struct sysfs_dirent *, const unsigned char *);
Tejun Heo3e519032007-06-14 03:45:15 +090066extern struct sysfs_dirent *sysfs_new_dirent(const char *name, umode_t mode,
67 int type);
Tejun Heoa26cd722007-06-14 03:45:14 +090068extern void sysfs_attach_dirent(struct sysfs_dirent *sd,
69 struct sysfs_dirent *parent_sd,
70 struct dentry *dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -070071
72extern int sysfs_add_file(struct dentry *, const struct attribute *, int);
Randy.Dunlap995982c2006-07-10 23:05:25 -070073extern int sysfs_hash_and_remove(struct dentry * dir, const char * name);
NeilBrown4508a7a2006-03-20 17:53:53 +110074extern struct sysfs_dirent *sysfs_find(struct sysfs_dirent *dir, const char * name);
Linus Torvalds1da177e2005-04-16 15:20:36 -070075
76extern int sysfs_create_subdir(struct kobject *, const char *, struct dentry **);
77extern void sysfs_remove_subdir(struct dentry *);
78
Tejun Heodbde0fc2007-06-14 03:45:16 +090079extern void sysfs_drop_dentry(struct sysfs_dirent *sd);
Maneesh Soni988d1862005-05-31 10:39:14 +053080extern int sysfs_setattr(struct dentry *dentry, struct iattr *iattr);
Linus Torvalds1da177e2005-04-16 15:20:36 -070081
Tejun Heodd14cbc2007-06-11 14:04:01 +090082extern spinlock_t sysfs_lock;
Tejun Heoaecdced2007-06-14 03:45:15 +090083extern spinlock_t kobj_sysfs_assoc_lock;
Linus Torvalds1da177e2005-04-16 15:20:36 -070084extern struct rw_semaphore sysfs_rename_sem;
85extern struct super_block * sysfs_sb;
Arjan van de Ven4b6f5d22006-03-28 01:56:42 -080086extern const struct file_operations sysfs_dir_operations;
87extern const struct file_operations sysfs_file_operations;
88extern const struct file_operations bin_fops;
Arjan van de Venc5ef1c42007-02-12 00:55:40 -080089extern const struct inode_operations sysfs_dir_inode_operations;
90extern const struct inode_operations sysfs_symlink_inode_operations;
Linus Torvalds1da177e2005-04-16 15:20:36 -070091
Linus Torvalds1da177e2005-04-16 15:20:36 -070092static inline struct sysfs_dirent * sysfs_get(struct sysfs_dirent * sd)
93{
94 if (sd) {
95 WARN_ON(!atomic_read(&sd->s_count));
96 atomic_inc(&sd->s_count);
97 }
98 return sd;
99}
100
101static inline void sysfs_put(struct sysfs_dirent * sd)
102{
Tejun Heo7a23ad42007-06-14 03:45:13 +0900103 if (sd && atomic_dec_and_test(&sd->s_count))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700104 release_sysfs_dirent(sd);
105}
106
Tejun Heo0ab66082007-06-14 03:45:16 +0900107/**
108 * sysfs_get_active - get an active reference to sysfs_dirent
109 * @sd: sysfs_dirent to get an active reference to
110 *
111 * Get an active reference of @sd. This function is noop if @sd
112 * is NULL.
113 *
114 * RETURNS:
115 * Pointer to @sd on success, NULL on failure.
116 */
117static inline struct sysfs_dirent *sysfs_get_active(struct sysfs_dirent *sd)
118{
119 if (sd) {
120 if (unlikely(!down_read_trylock(&sd->s_active)))
121 sd = NULL;
122 }
123 return sd;
124}
125
126/**
127 * sysfs_put_active - put an active reference to sysfs_dirent
128 * @sd: sysfs_dirent to put an active reference to
129 *
130 * Put an active reference to @sd. This function is noop if @sd
131 * is NULL.
132 */
133static inline void sysfs_put_active(struct sysfs_dirent *sd)
134{
135 if (sd)
136 up_read(&sd->s_active);
137}
138
139/**
140 * sysfs_get_active_two - get active references to sysfs_dirent and parent
141 * @sd: sysfs_dirent of interest
142 *
143 * Get active reference to @sd and its parent. Parent's active
144 * reference is grabbed first. This function is noop if @sd is
145 * NULL.
146 *
147 * RETURNS:
148 * Pointer to @sd on success, NULL on failure.
149 */
150static inline struct sysfs_dirent *sysfs_get_active_two(struct sysfs_dirent *sd)
151{
152 if (sd) {
153 if (sd->s_parent && unlikely(!sysfs_get_active(sd->s_parent)))
154 return NULL;
155 if (unlikely(!sysfs_get_active(sd))) {
156 sysfs_put_active(sd->s_parent);
157 return NULL;
158 }
159 }
160 return sd;
161}
162
163/**
164 * sysfs_put_active_two - put active references to sysfs_dirent and parent
165 * @sd: sysfs_dirent of interest
166 *
167 * Put active references to @sd and its parent. This function is
168 * noop if @sd is NULL.
169 */
170static inline void sysfs_put_active_two(struct sysfs_dirent *sd)
171{
172 if (sd) {
173 sysfs_put_active(sd);
174 sysfs_put_active(sd->s_parent);
175 }
176}
177
178/**
179 * sysfs_deactivate - deactivate sysfs_dirent
180 * @sd: sysfs_dirent to deactivate
181 *
182 * Deny new active references and drain existing ones. s_active
183 * will be unlocked when the sysfs_dirent is released.
184 */
185static inline void sysfs_deactivate(struct sysfs_dirent *sd)
186{
187 down_write_nested(&sd->s_active, SYSFS_S_ACTIVE_DEACTIVATE);
188
189 /* s_active will be unlocked by the thread doing the final put
190 * on @sd. Lie to lockdep.
191 */
192 rwsem_release(&sd->s_active.dep_map, 1, _RET_IP_);
193}
194
Eric W. Biedermanb592fcf2007-01-24 12:35:52 -0700195static inline int sysfs_is_shadowed_inode(struct inode *inode)
196{
197 return S_ISDIR(inode->i_mode) && inode->i_op->follow_link;
198}