KEYS: Move the unreferenced key reaper to the keys garbage collector file

Move the unreferenced key reaper function to the keys garbage collector file
as that's a more appropriate place with the dead key link reaper.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>

security/keys/gc.c

@@ -10,6 +10,8 @@
  */
 
 #include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/security.h>
 #include <keys/keyring-type.h>
 #include "internal.h"
 
@@ -19,12 +21,18 @@
 unsigned key_gc_delay = 5 * 60;
 
 /*
- * Reaper
+ * Reaper for unused keys.
+ */
+static void key_gc_unused_keys(struct work_struct *work);
+DECLARE_WORK(key_gc_unused_work, key_gc_unused_keys);
+
+/*
+ * Reaper for links from keyrings to dead keys.
  */
 static void key_gc_timer_func(unsigned long);
-static void key_garbage_collector(struct work_struct *);
+static void key_gc_dead_links(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 DECLARE_WORK(key_gc_work, key_gc_dead_links);
 static key_serial_t key_gc_cursor; /* the last key the gc considered */
 static bool key_gc_again;
 static unsigned long key_gc_executing;
@@ -108,10 +116,12 @@ static bool key_gc_keyring(struct key *keyring, time_t limit)
 }
 
 /*
- * Garbage collector for keys.  This involves scanning the keyrings for dead,
- * expired and revoked keys that have overstayed their welcome
+ * Garbage collector for links to dead 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)
+static void key_gc_dead_links(struct work_struct *work)
 {
 	struct rb_node *rb;
 	key_serial_t cursor;
@@ -220,3 +230,68 @@ static void key_garbage_collector(struct work_struct *work)
 	}
 	kleave(" [end]");
 }
+
+/*
+ * Garbage collector for unused keys.
+ *
+ * This is done in process context so that we don't have to disable interrupts
+ * all over the place.  key_put() schedules this rather than trying to do the
+ * cleanup itself, which means key_put() doesn't have to sleep.
+ */
+static void key_gc_unused_keys(struct work_struct *work)
+{
+	struct rb_node *_n;
+	struct key *key;
+
+go_again:
+	/* look for a dead key in the tree */
+	spin_lock(&key_serial_lock);
+
+	for (_n = rb_first(&key_serial_tree); _n; _n = rb_next(_n)) {
+		key = rb_entry(_n, struct key, serial_node);
+
+		if (atomic_read(&key->usage) == 0)
+			goto found_dead_key;
+	}
+
+	spin_unlock(&key_serial_lock);
+	return;
+
+found_dead_key:
+	/* we found a dead key - once we've removed it from the tree, we can
+	 * drop the lock */
+	rb_erase(&key->serial_node, &key_serial_tree);
+	spin_unlock(&key_serial_lock);
+
+	key_check(key);
+
+	security_key_free(key);
+
+	/* deal with the user's key tracking and quota */
+	if (test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) {
+		spin_lock(&key->user->lock);
+		key->user->qnkeys--;
+		key->user->qnbytes -= key->quotalen;
+		spin_unlock(&key->user->lock);
+	}
+
+	atomic_dec(&key->user->nkeys);
+	if (test_bit(KEY_FLAG_INSTANTIATED, &key->flags))
+		atomic_dec(&key->user->nikeys);
+
+	key_user_put(key->user);
+
+	/* now throw away the key memory */
+	if (key->type->destroy)
+		key->type->destroy(key);
+
+	kfree(key->description);
+
+#ifdef KEY_DEBUGGING
+	key->magic = KEY_DEBUG_MAGIC_X;
+#endif
+	kmem_cache_free(key_jar, key);
+
+	/* there may, of course, be more than one key to destroy */
+	goto go_again;
+}

security/keys/internal.h

@@ -75,6 +75,7 @@ extern unsigned key_quota_maxbytes;
 #define KEYQUOTA_LINK_BYTES	4		/* a link in a keyring is worth 4 bytes */
 
 
+extern struct kmem_cache *key_jar;
 extern struct rb_root key_serial_tree;
 extern spinlock_t key_serial_lock;
 extern struct mutex key_construction_mutex;
@@ -146,6 +147,7 @@ extern key_ref_t lookup_user_key(key_serial_t id, unsigned long flags,
 
 extern long join_session_keyring(const char *name);
 
+extern struct work_struct key_gc_unused_work;
 extern unsigned key_gc_delay;
 extern void keyring_gc(struct key *keyring, time_t limit);
 extern void key_schedule_gc(time_t expiry_at);

security/keys/key.c

@@ -21,7 +21,7 @@
 #include <linux/user_namespace.h>
 #include "internal.h"
 
-static struct kmem_cache	*key_jar;
+struct kmem_cache *key_jar;
 struct rb_root		key_serial_tree; /* tree of keys indexed by serial */
 DEFINE_SPINLOCK(key_serial_lock);
 
@@ -36,9 +36,6 @@ unsigned int key_quota_maxbytes = 20000;	/* general key space quota */
 static LIST_HEAD(key_types_list);
 static DECLARE_RWSEM(key_types_sem);
 
-static void key_cleanup(struct work_struct *work);
-static DECLARE_WORK(key_cleanup_task, key_cleanup);
-
 /* We serialise key instantiation and link */
 DEFINE_MUTEX(key_construction_mutex);
 
@@ -591,71 +588,6 @@ int key_reject_and_link(struct key *key,
 }
 EXPORT_SYMBOL(key_reject_and_link);
 
-/*
- * Garbage collect keys in process context so that we don't have to disable
- * interrupts all over the place.
- *
- * key_put() schedules this rather than trying to do the cleanup itself, which
- * means key_put() doesn't have to sleep.
- */
-static void key_cleanup(struct work_struct *work)
-{
-	struct rb_node *_n;
-	struct key *key;
-
-go_again:
-	/* look for a dead key in the tree */
-	spin_lock(&key_serial_lock);
-
-	for (_n = rb_first(&key_serial_tree); _n; _n = rb_next(_n)) {
-		key = rb_entry(_n, struct key, serial_node);
-
-		if (atomic_read(&key->usage) == 0)
-			goto found_dead_key;
-	}
-
-	spin_unlock(&key_serial_lock);
-	return;
-
-found_dead_key:
-	/* we found a dead key - once we've removed it from the tree, we can
-	 * drop the lock */
-	rb_erase(&key->serial_node, &key_serial_tree);
-	spin_unlock(&key_serial_lock);
-
-	key_check(key);
-
-	security_key_free(key);
-
-	/* deal with the user's key tracking and quota */
-	if (test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) {
-		spin_lock(&key->user->lock);
-		key->user->qnkeys--;
-		key->user->qnbytes -= key->quotalen;
-		spin_unlock(&key->user->lock);
-	}
-
-	atomic_dec(&key->user->nkeys);
-	if (test_bit(KEY_FLAG_INSTANTIATED, &key->flags))
-		atomic_dec(&key->user->nikeys);
-
-	key_user_put(key->user);
-
-	/* now throw away the key memory */
-	if (key->type->destroy)
-		key->type->destroy(key);
-
-	kfree(key->description);
-
-#ifdef KEY_DEBUGGING
-	key->magic = KEY_DEBUG_MAGIC_X;
-#endif
-	kmem_cache_free(key_jar, key);
-
-	/* there may, of course, be more than one key to destroy */
-	goto go_again;
-}
-
 /**
  * key_put - Discard a reference to a key.
  * @key: The key to discard a reference from.
@@ -670,7 +602,7 @@ void key_put(struct key *key)
 		key_check(key);
 
 		if (atomic_dec_and_test(&key->usage))
-			schedule_work(&key_cleanup_task);
+			schedule_work(&key_gc_unused_work);
 	}
 }
 EXPORT_SYMBOL(key_put);