struct sysfs_elem_dir {
struct kobject * kobj;
};
struct sysfs_elem_symlink {
struct sysfs_dirent * target_sd;
};
struct sysfs_elem_attr {
struct attribute * attr;
};
struct sysfs_elem_bin_attr {
struct bin_attribute * bin_attr;
};
/*
* As long as s_count reference is held, the sysfs_dirent itself is
* accessible. Dereferencing s_elem or any other outer entity
* requires s_active reference.
*/
struct sysfs_dirent {
atomic_t s_count;
struct rw_semaphore s_active;
struct sysfs_dirent * s_parent;
struct list_head s_sibling;
struct list_head s_children;
const char * s_name;
union {
struct sysfs_elem_dir dir;
struct sysfs_elem_symlink symlink;
struct sysfs_elem_attr attr;
struct sysfs_elem_bin_attr bin_attr;
} s_elem;
int s_type;
umode_t s_mode;
ino_t s_ino;
struct dentry * s_dentry;
struct iattr * s_iattr;
atomic_t s_event;
};
/*
* A sysfs file which deletes another file when written to need to
* write lock the s_active of the victim while its s_active is read
* locked for the write operation. Tell lockdep that this is okay.
*/
enum sysfs_s_active_class
{
SYSFS_S_ACTIVE_NORMAL, /* file r/w access, etc - default */
SYSFS_S_ACTIVE_DEACTIVATE, /* file deactivation */
};
extern struct vfsmount * sysfs_mount;
extern struct kmem_cache *sysfs_dir_cachep;
extern void sysfs_delete_inode(struct inode *inode);
extern struct inode * sysfs_new_inode(mode_t mode, struct sysfs_dirent *);
extern int sysfs_create(struct sysfs_dirent *sd, struct dentry *dentry,
int mode, int (*init)(struct inode *));
extern void release_sysfs_dirent(struct sysfs_dirent * sd);
extern int sysfs_dirent_exist(struct sysfs_dirent *, const unsigned char *);
extern struct sysfs_dirent *sysfs_new_dirent(const char *name, umode_t mode,
int type);
extern void sysfs_attach_dirent(struct sysfs_dirent *sd,
struct sysfs_dirent *parent_sd,
struct dentry *dentry);
extern int sysfs_add_file(struct dentry *, const struct attribute *, int);
extern int sysfs_hash_and_remove(struct dentry * dir, const char * name);
extern struct sysfs_dirent *sysfs_find(struct sysfs_dirent *dir, const char * name);
extern int sysfs_create_subdir(struct kobject *, const char *, struct dentry **);
extern void sysfs_remove_subdir(struct dentry *);
extern void sysfs_drop_dentry(struct sysfs_dirent *sd);
extern int sysfs_setattr(struct dentry *dentry, struct iattr *iattr);
extern spinlock_t sysfs_lock;
extern spinlock_t kobj_sysfs_assoc_lock;
extern struct rw_semaphore sysfs_rename_sem;
extern struct super_block * sysfs_sb;
extern const struct file_operations sysfs_dir_operations;
extern const struct file_operations sysfs_file_operations;
extern const struct file_operations bin_fops;
extern const struct inode_operations sysfs_dir_inode_operations;
extern const struct inode_operations sysfs_symlink_inode_operations;
static inline struct sysfs_dirent * sysfs_get(struct sysfs_dirent * sd)
{
if (sd) {
WARN_ON(!atomic_read(&sd->s_count));
atomic_inc(&sd->s_count);
}
return sd;
}
static inline void sysfs_put(struct sysfs_dirent * sd)
{
if (sd && atomic_dec_and_test(&sd->s_count))
release_sysfs_dirent(sd);
}
/**
* sysfs_get_active - get an active reference to sysfs_dirent
* @sd: sysfs_dirent to get an active reference to
*
* Get an active reference of @sd. This function is noop if @sd
* is NULL.
*
* RETURNS:
* Pointer to @sd on success, NULL on failure.
*/
static inline struct sysfs_dirent *sysfs_get_active(struct sysfs_dirent *sd)
{
if (sd) {
if (unlikely(!down_read_trylock(&sd->s_active)))
sd = NULL;
}
return sd;
}
/**
* sysfs_put_active - put an active reference to sysfs_dirent
* @sd: sysfs_dirent to put an active reference to
*
* Put an active reference to @sd. This function is noop if @sd
* is NULL.
*/
static inline void sysfs_put_active(struct sysfs_dirent *sd)
{
if (sd)
up_read(&sd->s_active);
}
/**
* sysfs_get_active_two - get active references to sysfs_dirent and parent
* @sd: sysfs_dirent of interest
*
* Get active reference to @sd and its parent. Parent's active
* reference is grabbed first. This function is noop if @sd is
* NULL.
*
* RETURNS:
* Pointer to @sd on success, NULL on failure.
*/
static inline struct sysfs_dirent *sysfs_get_active_two(struct sysfs_dirent *sd)
{
if (sd) {
if (sd->s_parent && unlikely(!sysfs_get_active(sd->s_parent)))
return NULL;
if (unlikely(!sysfs_get_active(sd))) {
sysfs_put_active(sd->s_parent);
return NULL;
}
}
return sd;
}
/**
* sysfs_put_active_two - put active references to sysfs_dirent and parent
* @sd: sysfs_dirent of interest
*
* Put active references to @sd and its parent. This function is
* noop if @sd is NULL.
*/
static inline void sysfs_put_active_two(struct sysfs_dirent *sd)
{
if (sd) {
sysfs_put_active(sd);
sysfs_put_active(sd->s_parent);
}
}
/**
* sysfs_deactivate - deactivate sysfs_dirent
* @sd: sysfs_dirent to deactivate
*
* Deny new active references and drain existing ones. s_active
* will be unlocked when the sysfs_dirent is released.
*/
static inline void sysfs_deactivate(struct sysfs_dirent *sd)
{
down_write_nested(&sd->s_active, SYSFS_S_ACTIVE_DEACTIVATE);
/* s_active will be unlocked by the thread doing the final put
* on @sd. Lie to lockdep.
*/
rwsem_release(&sd->s_active.dep_map, 1, _RET_IP_);
}
static inline int sysfs_is_shadowed_inode(struct inode *inode)
{
return S_ISDIR(inode->i_mode) && inode->i_op->follow_link;
}
