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authorEric W. Biederman <ebiederm@xmission.com>2011-12-19 08:05:43 +0400
committerGreg Kroah-Hartman <gregkh@suse.de>2012-01-25 00:36:17 +0400
commit4e4d6d860b9393c5395ba5920edb5b4c5d43a3a3 (patch)
tree245addd82a018bd6a9483b01decfada9a13ffc3e /fs/sysfs/sysfs.h
parentdcd6c92267155e70a94b3927bce681ce74b80d1f (diff)
downloadlinux-4e4d6d860b9393c5395ba5920edb5b4c5d43a3a3.tar.xz
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 <ebiederm@xmission.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'fs/sysfs/sysfs.h')
-rw-r--r--fs/sysfs/sysfs.h9
1 files changed, 4 insertions, 5 deletions
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;