KEYS: Make /proc/keys use keyid not numread as file position [try #6]

Make the file position maintained by /proc/keys represent the ID of the key
just read rather than the number of keys read.  This should make it faster to
perform a lookup as we don't have to scan the key ID tree from the beginning to
find the current position.

Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>

diff --git a/security/keys/proc.c b/security/keys/proc.c
index 39793c7..624c650 100644 (file)
--- a/security/keys/proc.c
+++ b/security/keys/proc.c
@@ -91,57 +91,90 @@ __initcall(key_proc_init);
  */
 #ifdef CONFIG_KEYS_DEBUG_PROC_KEYS
 
-static struct rb_node *__key_serial_next(struct rb_node *n)
+static struct rb_node *key_serial_next(struct rb_node *n)
 {
+       struct user_namespace *user_ns = current_user_ns();
+
+       n = rb_next(n);
        while (n) {
                struct key *key = rb_entry(n, struct key, serial_node);
-               if (key->user->user_ns == current_user_ns())
+               if (key->user->user_ns == user_ns)
                        break;
                n = rb_next(n);
        }
        return n;
 }
 
-static struct rb_node *key_serial_next(struct rb_node *n)
+static int proc_keys_open(struct inode *inode, struct file *file)
 {
-       return __key_serial_next(rb_next(n));
+       return seq_open(file, &proc_keys_ops);
 }
 
-static struct rb_node *key_serial_first(struct rb_root *r)
+static struct key *find_ge_key(key_serial_t id)
 {
-       struct rb_node *n = rb_first(r);
-       return __key_serial_next(n);
-}
+       struct user_namespace *user_ns = current_user_ns();
+       struct rb_node *n = key_serial_tree.rb_node;
+       struct key *minkey = NULL;
 
-static int proc_keys_open(struct inode *inode, struct file *file)
-{
-       return seq_open(file, &proc_keys_ops);
+       while (n) {
+               struct key *key = rb_entry(n, struct key, serial_node);
+               if (id < key->serial) {
+                       if (!minkey || minkey->serial > key->serial)
+                               minkey = key;
+                       n = n->rb_left;
+               } else if (id > key->serial) {
+                       n = n->rb_right;
+               } else {
+                       minkey = key;
+                       break;
+               }
+               key = NULL;
+       }
 
+       if (!minkey)
+               return NULL;
+
+       for (;;) {
+               if (minkey->user->user_ns == user_ns)
+                       return minkey;
+               n = rb_next(&minkey->serial_node);
+               if (!n)
+                       return NULL;
+               minkey = rb_entry(n, struct key, serial_node);
+       }
 }
 
 static void *proc_keys_start(struct seq_file *p, loff_t *_pos)
        __acquires(key_serial_lock)
 {
-       struct rb_node *_p;
-       loff_t pos = *_pos;
+       key_serial_t pos = *_pos;
+       struct key *key;
 
        spin_lock(&key_serial_lock);
 
-       _p = key_serial_first(&key_serial_tree);
-       while (pos > 0 && _p) {
-               pos--;
-               _p = key_serial_next(_p);
-       }
-
-       return _p;
+       if (*_pos > INT_MAX)
+               return NULL;
+       key = find_ge_key(pos);
+       if (!key)
+               return NULL;
+       *_pos = key->serial;
+       return &key->serial_node;
+}
 
+static inline key_serial_t key_node_serial(struct rb_node *n)
+{
+       struct key *key = rb_entry(n, struct key, serial_node);
+       return key->serial;
 }
 
 static void *proc_keys_next(struct seq_file *p, void *v, loff_t *_pos)
 {
-       (*_pos)++;
-       return key_serial_next((struct rb_node *) v);
+       struct rb_node *n;
 
+       n = key_serial_next(v);
+       if (n)
+               *_pos = key_node_serial(n);
+       return n;
 }
 
 static void proc_keys_stop(struct seq_file *p, void *v)