+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 struct inode * sysfs_new_inode(mode_t mode, struct sysfs_dirent *);
extern int sysfs_create(struct 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 int sysfs_make_dirent(struct sysfs_dirent *, struct dentry *, void *,
- umode_t, int);
+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 int sysfs_create_subdir(struct kobject *, const char *, struct dentry **);
extern void sysfs_remove_subdir(struct dentry *);
-extern const unsigned char * sysfs_get_name(struct sysfs_dirent *sd);
extern void sysfs_drop_dentry(struct sysfs_dirent *sd, struct dentry *parent);
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 inode_operations sysfs_dir_inode_operations;
extern const struct inode_operations sysfs_symlink_inode_operations;
-struct sysfs_symlink {
- char * link_name;
- struct kobject * target_kobj;
-};
-
-struct sysfs_buffer {
- struct list_head associates;
- size_t count;
- loff_t pos;
- char * page;
- struct sysfs_ops * ops;
- struct semaphore sem;
- int orphaned;
- int needs_read_fill;
- int event;
-};
-
-struct sysfs_buffer_collection {
- struct list_head associates;
-};
-
-static inline struct kobject * to_kobj(struct dentry * dentry)
+static inline struct sysfs_dirent * sysfs_get(struct sysfs_dirent * sd)
{
- struct sysfs_dirent * sd = dentry->d_fsdata;
- return ((struct kobject *) sd->s_element);
+ if (sd) {
+ WARN_ON(!atomic_read(&sd->s_count));
+ atomic_inc(&sd->s_count);
+ }
+ return sd;
}
-static inline struct attribute * to_attr(struct dentry * dentry)
+static inline void sysfs_put(struct sysfs_dirent * sd)
{
- struct sysfs_dirent * sd = dentry->d_fsdata;
- return ((struct attribute *) sd->s_element);
+ if (sd && atomic_dec_and_test(&sd->s_count))
+ release_sysfs_dirent(sd);
}
-static inline struct bin_attribute * to_bin_attr(struct dentry * dentry)
+/**
+ * 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)
{
- struct sysfs_dirent * sd = dentry->d_fsdata;
- return ((struct bin_attribute *) sd->s_element);
+ if (sd) {
+ if (unlikely(!down_read_trylock(&sd->s_active)))
+ sd = NULL;
+ }
+ return sd;
}
-static inline struct kobject *sysfs_get_kobject(struct dentry *dentry)
+/**
+ * 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)
{
- struct kobject * kobj = NULL;
-
- spin_lock(&dcache_lock);
- if (!d_unhashed(dentry)) {
- struct sysfs_dirent * sd = dentry->d_fsdata;
- if (sd->s_type & SYSFS_KOBJ_LINK) {
- struct sysfs_symlink * sl = sd->s_element;
- kobj = kobject_get(sl->target_kobj);
- } else
- kobj = kobject_get(sd->s_element);
- }
- spin_unlock(&dcache_lock);
-
- return kobj;
+ if (sd)
+ up_read(&sd->s_active);
}
-static inline void release_sysfs_dirent(struct sysfs_dirent * sd)
+/**
+ * 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->s_type & SYSFS_KOBJ_LINK) {
- struct sysfs_symlink * sl = sd->s_element;
- kfree(sl->link_name);
- kobject_put(sl->target_kobj);
- kfree(sl);
+ 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;
+ }
}
- kfree(sd->s_iattr);
- kmem_cache_free(sysfs_dir_cachep, sd);
+ return sd;
}
-static inline struct sysfs_dirent * sysfs_get(struct sysfs_dirent * 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) {
- WARN_ON(!atomic_read(&sd->s_count));
- atomic_inc(&sd->s_count);
+ sysfs_put_active(sd);
+ sysfs_put_active(sd->s_parent);
}
- return sd;
}
-static inline void sysfs_put(struct sysfs_dirent * sd)
+/**
+ * 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)
{
- if (atomic_dec_and_test(&sd->s_count))
- release_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)
projects / mirror_ubuntu-focal-kernel.git / blobdiff