diff --git a/security/keys/gc.c b/security/keys/gc.c
new file mode 100644
index 0000000..44adc32
--- /dev/null
+++ b/security/keys/gc.c
@@ -0,0 +1,193 @@
+/* Key garbage collector
+ *
+ * Copyright (C) 2009 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+
+#include <linux/module.h>
+#include <keys/keyring-type.h>
+#include "internal.h"
+
+/*
+ * Delay between key revocation/expiry in seconds
+ */
+unsigned key_gc_delay = 5 * 60;
+
+/*
+ * Reaper
+ */
+static void key_gc_timer_func(unsigned long);
+static void key_garbage_collector(struct work_struct *);
+static DEFINE_TIMER(key_gc_timer, key_gc_timer_func, 0, 0);
+static DECLARE_WORK(key_gc_work, key_garbage_collector);
+static key_serial_t key_gc_cursor; /* the last key the gc considered */
+static unsigned long key_gc_executing;
+static time_t key_gc_next_run = LONG_MAX;
+
+/*
+ * Schedule a garbage collection run
+ * - precision isn't particularly important
+ */
+void key_schedule_gc(time_t gc_at)
+{
+	unsigned long expires;
+	time_t now = current_kernel_time().tv_sec;
+
+	kenter("%ld", gc_at - now);
+
+	gc_at += key_gc_delay;
+
+	if (now >= gc_at) {
+		schedule_work(&key_gc_work);
+	} else if (gc_at < key_gc_next_run) {
+		expires = jiffies + (gc_at - now) * HZ;
+		mod_timer(&key_gc_timer, expires);
+	}
+}
+
+/*
+ * The garbage collector timer kicked off
+ */
+static void key_gc_timer_func(unsigned long data)
+{
+	kenter("");
+	key_gc_next_run = LONG_MAX;
+	schedule_work(&key_gc_work);
+}
+
+/*
+ * Garbage collect pointers from a keyring
+ * - return true if we altered the keyring
+ */
+static bool key_gc_keyring(struct key *keyring, time_t limit)
+{
+	struct keyring_list *klist;
+	struct key *key;
+	int loop;
+
+	kenter("%x", key_serial(keyring));
+
+	if (test_bit(KEY_FLAG_REVOKED, &keyring->flags))
+		goto dont_gc;
+
+	/* scan the keyring looking for dead keys */
+	klist = rcu_dereference(keyring->payload.subscriptions);
+	if (!klist)
+		goto dont_gc;
+
+	for (loop = klist->nkeys - 1; loop >= 0; loop--) {
+		key = klist->keys[loop];
+		if (test_bit(KEY_FLAG_DEAD, &key->flags) ||
+		    (key->expiry > 0 && key->expiry <= limit))
+			goto do_gc;
+	}
+
+dont_gc:
+	kleave(" = false");
+	return false;
+
+do_gc:
+	key_gc_cursor = keyring->serial;
+	key_get(keyring);
+	spin_unlock(&key_serial_lock);
+	keyring_gc(keyring, limit);
+	key_put(keyring);
+	kleave(" = true");
+	return true;
+}
+
+/*
+ * Garbage collector for keys
+ * - this involves scanning the keyrings for dead, expired and revoked keys
+ *   that have overstayed their welcome
+ */
+static void key_garbage_collector(struct work_struct *work)
+{
+	struct rb_node *rb;
+	key_serial_t cursor;
+	struct key *key, *xkey;
+	time_t new_timer = LONG_MAX, limit;
+
+	kenter("");
+
+	if (test_and_set_bit(0, &key_gc_executing)) {
+		key_schedule_gc(current_kernel_time().tv_sec);
+		return;
+	}
+
+	limit = current_kernel_time().tv_sec;
+	if (limit > key_gc_delay)
+		limit -= key_gc_delay;
+	else
+		limit = key_gc_delay;
+
+	spin_lock(&key_serial_lock);
+
+	if (RB_EMPTY_ROOT(&key_serial_tree))
+		goto reached_the_end;
+
+	cursor = key_gc_cursor;
+	if (cursor < 0)
+		cursor = 0;
+
+	/* find the first key above the cursor */
+	key = NULL;
+	rb = key_serial_tree.rb_node;
+	while (rb) {
+		xkey = rb_entry(rb, struct key, serial_node);
+		if (cursor < xkey->serial) {
+			key = xkey;
+			rb = rb->rb_left;
+		} else if (cursor > xkey->serial) {
+			rb = rb->rb_right;
+		} else {
+			rb = rb_next(rb);
+			if (!rb)
+				goto reached_the_end;
+			key = rb_entry(rb, struct key, serial_node);
+			break;
+		}
+	}
+
+	if (!key)
+		goto reached_the_end;
+
+	/* trawl through the keys looking for keyrings */
+	for (;;) {
+		if (key->expiry > 0 && key->expiry < new_timer)
+			new_timer = key->expiry;
+
+		if (key->type == &key_type_keyring &&
+		    key_gc_keyring(key, limit)) {
+			/* the gc ate our lock */
+			schedule_work(&key_gc_work);
+			goto no_unlock;
+		}
+
+		rb = rb_next(&key->serial_node);
+		if (!rb) {
+			key_gc_cursor = 0;
+			break;
+		}
+		key = rb_entry(rb, struct key, serial_node);
+	}
+
+out:
+	spin_unlock(&key_serial_lock);
+no_unlock:
+	clear_bit(0, &key_gc_executing);
+	if (new_timer < LONG_MAX)
+		key_schedule_gc(new_timer);
+
+	kleave("");
+	return;
+
+reached_the_end:
+	key_gc_cursor = 0;
+	goto out;
+}