mirror of
https://github.com/torvalds/linux.git
synced 2024-11-15 08:31:55 +00:00
932ea2e374
Looking carefully at the rename code we have a subtle dependency that the structure of sysfs not change while we are performing a rename. If the parent directory of the object we are renaming changes while the rename is being performed nasty things could happen when we go to release our locks. So introduce a sysfs_rename_mutex to prevent this highly unlikely theoretical issue. In addition hold sysfs_rename_mutex over all calls to sysfs_get_dentry. Allowing sysfs_get_dentry to be simplified in the future. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Tejun Heo <htejun@gmail.com> Cc: Cornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
120 lines
3.6 KiB
C
120 lines
3.6 KiB
C
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;
|
|
atomic_t s_active;
|
|
struct sysfs_dirent * s_parent;
|
|
struct sysfs_dirent * s_sibling;
|
|
struct sysfs_dirent * 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;
|
|
|
|
unsigned int s_flags;
|
|
umode_t s_mode;
|
|
ino_t s_ino;
|
|
struct dentry * s_dentry;
|
|
struct iattr * s_iattr;
|
|
atomic_t s_event;
|
|
};
|
|
|
|
#define SD_DEACTIVATED_BIAS INT_MIN
|
|
|
|
struct sysfs_addrm_cxt {
|
|
struct sysfs_dirent *parent_sd;
|
|
struct inode *parent_inode;
|
|
struct sysfs_dirent *removed;
|
|
int cnt;
|
|
};
|
|
|
|
extern struct sysfs_dirent sysfs_root;
|
|
extern struct kmem_cache *sysfs_dir_cachep;
|
|
|
|
extern struct dentry *sysfs_get_dentry(struct sysfs_dirent *sd);
|
|
extern struct sysfs_dirent *sysfs_get_active(struct sysfs_dirent *sd);
|
|
extern void sysfs_put_active(struct sysfs_dirent *sd);
|
|
extern struct sysfs_dirent *sysfs_get_active_two(struct sysfs_dirent *sd);
|
|
extern void sysfs_put_active_two(struct sysfs_dirent *sd);
|
|
extern void sysfs_addrm_start(struct sysfs_addrm_cxt *acxt,
|
|
struct sysfs_dirent *parent_sd);
|
|
extern int sysfs_add_one(struct sysfs_addrm_cxt *acxt,
|
|
struct sysfs_dirent *sd);
|
|
extern void sysfs_remove_one(struct sysfs_addrm_cxt *acxt,
|
|
struct sysfs_dirent *sd);
|
|
extern void sysfs_addrm_finish(struct sysfs_addrm_cxt *acxt);
|
|
|
|
extern struct inode * sysfs_get_inode(struct sysfs_dirent *sd);
|
|
|
|
extern void release_sysfs_dirent(struct sysfs_dirent * sd);
|
|
extern struct sysfs_dirent *sysfs_find_dirent(struct sysfs_dirent *parent_sd,
|
|
const unsigned char *name);
|
|
extern struct sysfs_dirent *sysfs_get_dirent(struct sysfs_dirent *parent_sd,
|
|
const unsigned char *name);
|
|
extern struct sysfs_dirent *sysfs_new_dirent(const char *name, umode_t mode,
|
|
int type);
|
|
|
|
extern int sysfs_add_file(struct sysfs_dirent *dir_sd,
|
|
const struct attribute *attr, int type);
|
|
extern int sysfs_hash_and_remove(struct sysfs_dirent *dir_sd, const char *name);
|
|
extern struct sysfs_dirent *sysfs_find(struct sysfs_dirent *dir, const char * name);
|
|
|
|
extern int sysfs_create_subdir(struct kobject *kobj, const char *name,
|
|
struct sysfs_dirent **p_sd);
|
|
extern void sysfs_remove_subdir(struct sysfs_dirent *sd);
|
|
|
|
extern int sysfs_setattr(struct dentry *dentry, struct iattr *iattr);
|
|
|
|
extern spinlock_t sysfs_assoc_lock;
|
|
extern struct mutex sysfs_mutex;
|
|
extern struct mutex sysfs_rename_mutex;
|
|
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 unsigned int sysfs_type(struct sysfs_dirent *sd)
|
|
{
|
|
return sd->s_flags & SYSFS_TYPE_MASK;
|
|
}
|
|
|
|
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);
|
|
}
|