From a406f75840e15afbabd98cb64ae36b51424a8033 Mon Sep 17 00:00:00 2001 From: Mikulas Patocka Date: Mon, 25 Jul 2011 17:57:03 -0400 Subject: [PATCH] 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 Signed-off-by: Greg Kroah-Hartman --- fs/sysfs/dir.c | 89 +++++++++++++++++++++++++++--------------------- fs/sysfs/sysfs.h | 5 ++- 2 files changed, 52 insertions(+), 42 deletions(-) diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c index a4846979d4e8..c3646d93a032 100644 --- a/fs/sysfs/dir.c +++ b/fs/sysfs/dir.c @@ -43,26 +43,30 @@ static DEFINE_IDA(sysfs_ino_ida); 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_link_sibling(struct sysfs_dirent *sd) */ 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 @@ void sysfs_remove_subdir(struct sysfs_dirent *sd) 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 @@ static struct sysfs_dirent *sysfs_dir_pos(const void *ns, 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) { + 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) - pos = pos->s_sibling; return pos; } @@ -938,10 +946,13 @@ static struct sysfs_dirent *sysfs_dir_next_pos(const void *ns, 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 3c261681713b..ce29e28b766d 100644 --- a/fs/sysfs/sysfs.h +++ b/fs/sysfs/sysfs.h @@ -18,11 +18,10 @@ struct sysfs_open_dirent; /* 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 sysfs_dirent { 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 { -- 2.30.2