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sysfs: use rb-tree for name lookups 

sysfs: use rb-tree for name lookups

Use red-black tree for name lookups.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Mikulas Patocka 2011-07-25 17:55:57 -04:00 committed by Greg Kroah-Hartman
parent 7f9838fd01
commit 4f72c0cab4
2 changed files with 55 additions and 7 deletions
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55
fs/sysfs/dir.c
View File

@ -45,6 +45,9 @@ 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)
@ -60,6 +63,23 @@ static void sysfs_link_sibling(struct sysfs_dirent *sd)
}
sd->s_sibling = *pos;
*pos = sd;
p = &parent_sd->s_dir.name_tree.rb_node;
parent = NULL;
while (*p) {
int c;
parent = *p;
#define node rb_entry(parent, struct sysfs_dirent, name_node)
c = strcmp(sd->s_name, node->s_name);
if (c < 0) {
p = &node->name_node.rb_left;
} else {
p = &node->name_node.rb_right;
}
#undef node
}
rb_link_node(&sd->name_node, parent, p);
rb_insert_color(&sd->name_node, &parent_sd->s_dir.name_tree);
}
/**
@ -87,6 +107,8 @@ static void sysfs_unlink_sibling(struct sysfs_dirent *sd)
break;
}
}
rb_erase(&sd->name_node, &sd->s_parent->s_dir.name_tree);
}
/**
@ -546,15 +568,36 @@ struct sysfs_dirent *sysfs_find_dirent(struct sysfs_dirent *parent_sd,
const void *ns,
const unsigned char *name)
{
struct sysfs_dirent *sd;
struct rb_node *p = parent_sd->s_dir.name_tree.rb_node;
struct sysfs_dirent *found = NULL;
for (sd = parent_sd->s_dir.children; sd; sd = sd->s_sibling) {
if (ns && sd->s_ns && (sd->s_ns != ns))
continue;
if (!strcmp(sd->s_name, name))
return sd;
while (p) {
int c;
#define node rb_entry(p, struct sysfs_dirent, name_node)
c = strcmp(name, node->s_name);
if (c < 0) {
p = node->name_node.rb_left;
} else if (c > 0) {
p = node->name_node.rb_right;
} else {
found = node;
p = node->name_node.rb_left;
}
#undef node
}
if (found && ns) {
while (found->s_ns && found->s_ns != ns) {
p = rb_next(&found->name_node);
if (!p)
return NULL;
found = rb_entry(p, struct sysfs_dirent, name_node);
if (strcmp(name, found->s_name))
return NULL;
}
}
return found;
}
/**

5
fs/sysfs/sysfs.h
View File

@ -11,6 +11,7 @@
#include <linux/lockdep.h>
#include <linux/kobject_ns.h>
#include <linux/fs.h>
#include <linux/rbtree.h>
struct sysfs_open_dirent;
@ -21,6 +22,8 @@ struct sysfs_elem_dir {
struct sysfs_dirent *children;
unsigned long subdirs;
struct rb_root name_tree;
};
struct sysfs_elem_symlink {
@ -61,6 +64,8 @@ struct sysfs_dirent {
struct sysfs_dirent *s_sibling;
const char *s_name;
struct rb_node name_node;
const void *s_ns; /* namespace tag */
union {
struct sysfs_elem_dir s_dir;