From 4e4d6d860b9393c5395ba5920edb5b4c5d43a3a3 Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Sun, 18 Dec 2011 20:05:43 -0800 Subject: sysfs: Add s_hash to sysfs_dirent and order directory entries by hash Compute a 31 bit hash of directory entries (that can fit in a signed 32bit off_t) and index the sysfs directory entries by that hash, replacing the per directory indexes by name and by inode. Because we now only use a single rbtree this reduces the size of sysfs_dirent by 2 pointers. Because we have fewer cases to deal with the code is now simpler. For now I use the simple hash that the dcache uses as that is easy to use and seems simple enough. In addition to makeing the code simpler using a hash for the file position in readdir brings sysfs in line with other filesystems that have non-trivial directory structures. Signed-off-by: Eric W. Biederman Signed-off-by: Greg Kroah-Hartman --- fs/sysfs/sysfs.h | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) (limited to 'fs/sysfs/sysfs.h') diff --git a/fs/sysfs/sysfs.h b/fs/sysfs/sysfs.h index 7484a36ee678..2b5c923b4b90 100644 --- a/fs/sysfs/sysfs.h +++ b/fs/sysfs/sysfs.h @@ -20,9 +20,8 @@ struct sysfs_elem_dir { struct kobject *kobj; unsigned long subdirs; - - struct rb_root inode_tree; - struct rb_root name_tree; + /* children rbtree starts here and goes through sd->s_rb */ + struct rb_root children; }; struct sysfs_elem_symlink { @@ -62,8 +61,7 @@ struct sysfs_dirent { struct sysfs_dirent *s_parent; const char *s_name; - struct rb_node inode_node; - struct rb_node name_node; + struct rb_node s_rb; union { struct completion *completion; @@ -71,6 +69,7 @@ struct sysfs_dirent { } u; const void *s_ns; /* namespace tag */ + unsigned int s_hash; /* ns + name hash */ union { struct sysfs_elem_dir s_dir; struct sysfs_elem_symlink s_symlink; -- cgit v1.2.3