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Commit 4f72c0ca authored by Mikulas Patocka's avatar Mikulas Patocka Committed by Greg Kroah-Hartman
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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: default avatarMikulas Patocka <mpatocka@redhat.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent 7f9838fd

fs/sysfs/dir.c

+50 −7
Original line number Diff line number Diff line
@@ -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;



	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;

	struct rb_node *p = parent_sd->s_dir.name_tree.rb_node;

	struct sysfs_dirent *found = NULL;



	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;

}



/**

fs/sysfs/sysfs.h

+5 −0
Original line number Diff line number Diff line
@@ -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;