sysfs: make sysfs_dirent->s_element a union
Make sd->s_element a union of sysfs_elem_{dir|symlink|attr|bin_attr}
and rename it to s_elem. This is to achieve...
* some level of type checking : changing symlink to point to
sysfs_dirent instead of kobject is much safer and less painful now.
* easier / standardized dereferencing
* allow sysfs_elem_* to contain more than one entry
Where possible, pointer is obtained by directly deferencing from sd
instead of going through other entities. This reduces dependencies to
dentry, inode and kobject. to_attr() and to_bin_attr() are unused now
and removed.
This is in preparation of object reference simplification.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/fs/sysfs/sysfs.h b/fs/sysfs/sysfs.h
index d34b008..39ab04813 100644
--- a/fs/sysfs/sysfs.h
+++ b/fs/sysfs/sysfs.h
@@ -1,10 +1,33 @@
+struct sysfs_elem_dir {
+ struct kobject * kobj;
+};
+
+struct sysfs_elem_symlink {
+ struct kobject * target_kobj;
+};
+
+struct sysfs_elem_attr {
+ struct attribute * attr;
+};
+
+struct sysfs_elem_bin_attr {
+ struct bin_attribute * bin_attr;
+};
+
struct sysfs_dirent {
atomic_t s_count;
struct sysfs_dirent * s_parent;
struct list_head s_sibling;
struct list_head s_children;
const char * s_name;
- void * s_element;
+
+ 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;
@@ -22,8 +45,8 @@
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, void *element,
- umode_t mode, int type);
+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);
@@ -47,10 +70,6 @@
extern const struct inode_operations sysfs_dir_inode_operations;
extern const struct inode_operations sysfs_symlink_inode_operations;
-struct sysfs_symlink {
- struct kobject * target_kobj;
-};
-
struct sysfs_buffer {
struct list_head associates;
size_t count;
@@ -70,19 +89,7 @@
static inline struct kobject * to_kobj(struct dentry * dentry)
{
struct sysfs_dirent * sd = dentry->d_fsdata;
- return ((struct kobject *) sd->s_element);
-}
-
-static inline struct attribute * to_attr(struct dentry * dentry)
-{
- struct sysfs_dirent * sd = dentry->d_fsdata;
- return ((struct attribute *) sd->s_element);
-}
-
-static inline struct bin_attribute * to_bin_attr(struct dentry * dentry)
-{
- struct sysfs_dirent * sd = dentry->d_fsdata;
- return ((struct bin_attribute *) sd->s_element);
+ return sd->s_elem.dir.kobj;
}
static inline struct kobject *sysfs_get_kobject(struct dentry *dentry)
@@ -92,11 +99,10 @@
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);
+ if (sd->s_type & SYSFS_KOBJ_LINK)
+ kobj = kobject_get(sd->s_elem.symlink.target_kobj);
+ else
+ kobj = kobject_get(sd->s_elem.dir.kobj);
}
spin_unlock(&dcache_lock);
