sysfs: use rb-tree for inode number lookup
sysfs: use rb-tree for inode number lookup
This patch makes sysfs use red-black tree for inode number lookup.
Together with a previous patch to use red-black tree for name lookup,
this patch makes all sysfs lookups to have O(log n) complexity.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c
index a484697..c3646d9 100644
--- a/fs/sysfs/dir.c
+++ b/fs/sysfs/dir.c
@@ -43,26 +43,30 @@
static void sysfs_link_sibling(struct sysfs_dirent *sd)
{
struct sysfs_dirent *parent_sd = sd->s_parent;
- struct sysfs_dirent **pos;
struct rb_node **p;
struct rb_node *parent;
- BUG_ON(sd->s_sibling);
-
if (sysfs_type(sd) == SYSFS_DIR)
parent_sd->s_dir.subdirs++;
- /* Store directory entries in order by ino. This allows
- * readdir to properly restart without having to add a
- * cursor into the s_dir.children list.
- */
- for (pos = &parent_sd->s_dir.children; *pos; pos = &(*pos)->s_sibling) {
- if (sd->s_ino < (*pos)->s_ino)
- break;
+ p = &parent_sd->s_dir.inode_tree.rb_node;
+ parent = NULL;
+ while (*p) {
+ parent = *p;
+#define node rb_entry(parent, struct sysfs_dirent, inode_node)
+ if (sd->s_ino < node->s_ino) {
+ p = &node->inode_node.rb_left;
+ } else if (sd->s_ino > node->s_ino) {
+ p = &node->inode_node.rb_right;
+ } else {
+ printk(KERN_CRIT "sysfs: inserting duplicate inode '%lx'\n", sd->s_ino);
+ BUG();
+ }
+#undef node
}
- sd->s_sibling = *pos;
- *pos = sd;
+ rb_link_node(&sd->inode_node, parent, p);
+ rb_insert_color(&sd->inode_node, &parent_sd->s_dir.inode_tree);
p = &parent_sd->s_dir.name_tree.rb_node;
parent = NULL;
@@ -94,20 +98,10 @@
*/
static void sysfs_unlink_sibling(struct sysfs_dirent *sd)
{
- struct sysfs_dirent **pos;
-
if (sysfs_type(sd) == SYSFS_DIR)
sd->s_parent->s_dir.subdirs--;
- for (pos = &sd->s_parent->s_dir.children; *pos;
- pos = &(*pos)->s_sibling) {
- if (*pos == sd) {
- *pos = sd->s_sibling;
- sd->s_sibling = NULL;
- break;
- }
- }
-
+ rb_erase(&sd->inode_node, &sd->s_parent->s_dir.inode_tree);
rb_erase(&sd->name_node, &sd->s_parent->s_dir.name_tree);
}
@@ -788,21 +782,19 @@
static void __sysfs_remove_dir(struct sysfs_dirent *dir_sd)
{
struct sysfs_addrm_cxt acxt;
- struct sysfs_dirent **pos;
+ struct rb_node *pos;
if (!dir_sd)
return;
pr_debug("sysfs %s: removing dir\n", dir_sd->s_name);
sysfs_addrm_start(&acxt, dir_sd);
- pos = &dir_sd->s_dir.children;
- while (*pos) {
- struct sysfs_dirent *sd = *pos;
-
+ pos = rb_first(&dir_sd->s_dir.inode_tree);
+ while (pos) {
+ struct sysfs_dirent *sd = rb_entry(pos, struct sysfs_dirent, inode_node);
+ pos = rb_next(pos);
if (sysfs_type(sd) != SYSFS_DIR)
sysfs_remove_one(&acxt, sd);
- else
- pos = &(*pos)->s_sibling;
}
sysfs_addrm_finish(&acxt);
@@ -925,12 +917,28 @@
pos = NULL;
}
if (!pos && (ino > 1) && (ino < INT_MAX)) {
- pos = parent_sd->s_dir.children;
- while (pos && (ino > pos->s_ino))
- pos = pos->s_sibling;
+ struct rb_node *p = parent_sd->s_dir.inode_tree.rb_node;
+ while (p) {
+#define node rb_entry(p, struct sysfs_dirent, inode_node)
+ if (ino < node->s_ino) {
+ pos = node;
+ p = node->inode_node.rb_left;
+ } else if (ino > node->s_ino) {
+ p = node->inode_node.rb_right;
+ } else {
+ pos = node;
+ break;
+ }
+#undef node
+ }
}
- while (pos && pos->s_ns && pos->s_ns != ns)
- pos = pos->s_sibling;
+ while (pos && pos->s_ns && pos->s_ns != ns) {
+ struct rb_node *p = rb_next(&pos->inode_node);
+ if (!p)
+ pos = NULL;
+ else
+ pos = rb_entry(p, struct sysfs_dirent, inode_node);
+ }
return pos;
}
@@ -938,10 +946,13 @@
struct sysfs_dirent *parent_sd, ino_t ino, struct sysfs_dirent *pos)
{
pos = sysfs_dir_pos(ns, parent_sd, ino, pos);
- if (pos)
- pos = pos->s_sibling;
- while (pos && pos->s_ns && pos->s_ns != ns)
- pos = pos->s_sibling;
+ if (pos) do {
+ struct rb_node *p = rb_next(&pos->inode_node);
+ if (!p)
+ pos = NULL;
+ else
+ pos = rb_entry(p, struct sysfs_dirent, inode_node);
+ } while (pos && pos->s_ns && pos->s_ns != ns);
return pos;
}
diff --git a/fs/sysfs/sysfs.h b/fs/sysfs/sysfs.h
index 3c26168..ce29e28 100644
--- a/fs/sysfs/sysfs.h
+++ b/fs/sysfs/sysfs.h
@@ -18,11 +18,10 @@
/* type-specific structures for sysfs_dirent->s_* union members */
struct sysfs_elem_dir {
struct kobject *kobj;
- /* children list starts here and goes through sd->s_sibling */
- struct sysfs_dirent *children;
unsigned long subdirs;
+ struct rb_root inode_tree;
struct rb_root name_tree;
};
@@ -61,9 +60,9 @@
struct lockdep_map dep_map;
#endif
struct sysfs_dirent *s_parent;
- struct sysfs_dirent *s_sibling;
const char *s_name;
+ struct rb_node inode_node;
struct rb_node name_node;
union {