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>
This commit is contained in:
Mikulas Patocka
Greg Kroah-Hartman
parent
58f2a4c793
commit
a406f75840
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@ -43,26 +43,30 @@ static DEFINE_IDA(sysfs_ino_ida);
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static void sysfs_link_sibling(struct sysfs_dirent *sd)
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{
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struct sysfs_dirent *parent_sd = sd->s_parent;
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struct sysfs_dirent **pos;
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struct rb_node **p;
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struct rb_node *parent;
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BUG_ON(sd->s_sibling);
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if (sysfs_type(sd) == SYSFS_DIR)
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parent_sd->s_dir.subdirs++;
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/* Store directory entries in order by ino. This allows
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* readdir to properly restart without having to add a
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* cursor into the s_dir.children list.
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*/
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for (pos = &parent_sd->s_dir.children; *pos; pos = &(*pos)->s_sibling) {
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if (sd->s_ino < (*pos)->s_ino)
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break;
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p = &parent_sd->s_dir.inode_tree.rb_node;
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parent = NULL;
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while (*p) {
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parent = *p;
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#define node rb_entry(parent, struct sysfs_dirent, inode_node)
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if (sd->s_ino < node->s_ino) {
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p = &node->inode_node.rb_left;
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} else if (sd->s_ino > node->s_ino) {
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p = &node->inode_node.rb_right;
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} else {
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printk(KERN_CRIT "sysfs: inserting duplicate inode '%lx'\n", sd->s_ino);
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BUG();
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}
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#undef node
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}
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sd->s_sibling = *pos;
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*pos = sd;
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rb_link_node(&sd->inode_node, parent, p);
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rb_insert_color(&sd->inode_node, &parent_sd->s_dir.inode_tree);
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p = &parent_sd->s_dir.name_tree.rb_node;
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parent = NULL;
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@ -94,20 +98,10 @@ static void sysfs_link_sibling(struct sysfs_dirent *sd)
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*/
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static void sysfs_unlink_sibling(struct sysfs_dirent *sd)
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{
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struct sysfs_dirent **pos;
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if (sysfs_type(sd) == SYSFS_DIR)
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sd->s_parent->s_dir.subdirs--;
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for (pos = &sd->s_parent->s_dir.children; *pos;
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pos = &(*pos)->s_sibling) {
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if (*pos == sd) {
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*pos = sd->s_sibling;
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sd->s_sibling = NULL;
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break;
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}
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}
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rb_erase(&sd->inode_node, &sd->s_parent->s_dir.inode_tree);
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rb_erase(&sd->name_node, &sd->s_parent->s_dir.name_tree);
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}
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@ -788,21 +782,19 @@ void sysfs_remove_subdir(struct sysfs_dirent *sd)
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static void __sysfs_remove_dir(struct sysfs_dirent *dir_sd)
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{
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struct sysfs_addrm_cxt acxt;
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struct sysfs_dirent **pos;
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struct rb_node *pos;
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if (!dir_sd)
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return;
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pr_debug("sysfs %s: removing dir\n", dir_sd->s_name);
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sysfs_addrm_start(&acxt, dir_sd);
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pos = &dir_sd->s_dir.children;
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while (*pos) {
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struct sysfs_dirent *sd = *pos;
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pos = rb_first(&dir_sd->s_dir.inode_tree);
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while (pos) {
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struct sysfs_dirent *sd = rb_entry(pos, struct sysfs_dirent, inode_node);
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pos = rb_next(pos);
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if (sysfs_type(sd) != SYSFS_DIR)
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sysfs_remove_one(&acxt, sd);
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else
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pos = &(*pos)->s_sibling;
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}
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sysfs_addrm_finish(&acxt);
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@ -925,12 +917,28 @@ static struct sysfs_dirent *sysfs_dir_pos(const void *ns,
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pos = NULL;
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}
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if (!pos && (ino > 1) && (ino < INT_MAX)) {
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pos = parent_sd->s_dir.children;
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while (pos && (ino > pos->s_ino))
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pos = pos->s_sibling;
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struct rb_node *p = parent_sd->s_dir.inode_tree.rb_node;
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while (p) {
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#define node rb_entry(p, struct sysfs_dirent, inode_node)
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if (ino < node->s_ino) {
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pos = node;
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p = node->inode_node.rb_left;
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} else if (ino > node->s_ino) {
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p = node->inode_node.rb_right;
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} else {
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pos = node;
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break;
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}
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#undef node
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}
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}
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while (pos && pos->s_ns && pos->s_ns != ns) {
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struct rb_node *p = rb_next(&pos->inode_node);
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if (!p)
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pos = NULL;
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else
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pos = rb_entry(p, struct sysfs_dirent, inode_node);
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}
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while (pos && pos->s_ns && pos->s_ns != ns)
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pos = pos->s_sibling;
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return pos;
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}
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@ -938,10 +946,13 @@ static struct sysfs_dirent *sysfs_dir_next_pos(const void *ns,
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struct sysfs_dirent *parent_sd, ino_t ino, struct sysfs_dirent *pos)
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{
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pos = sysfs_dir_pos(ns, parent_sd, ino, pos);
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if (pos)
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pos = pos->s_sibling;
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while (pos && pos->s_ns && pos->s_ns != ns)
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pos = pos->s_sibling;
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if (pos) do {
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struct rb_node *p = rb_next(&pos->inode_node);
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if (!p)
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pos = NULL;
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else
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pos = rb_entry(p, struct sysfs_dirent, inode_node);
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} while (pos && pos->s_ns && pos->s_ns != ns);
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return pos;
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}
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@ -18,11 +18,10 @@ struct sysfs_open_dirent;
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/* type-specific structures for sysfs_dirent->s_* union members */
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struct sysfs_elem_dir {
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struct kobject *kobj;
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/* children list starts here and goes through sd->s_sibling */
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struct sysfs_dirent *children;
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unsigned long subdirs;
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struct rb_root inode_tree;
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struct rb_root name_tree;
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};
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@ -61,9 +60,9 @@ struct sysfs_dirent {
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struct lockdep_map dep_map;
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#endif
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struct sysfs_dirent *s_parent;
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struct sysfs_dirent *s_sibling;
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const char *s_name;
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struct rb_node inode_node;
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struct rb_node name_node;
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union {
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