TOMOYO: Simplify garbage collector.

When TOMOYO started using garbage collector at commit 847b173e "TOMOYO: Add
garbage collector.", we waited for close() before kfree(). Thus, elements to be
kfree()d were queued up using tomoyo_gc_list list.

But it turned out that tomoyo_element_linked_by_gc() tends to choke garbage
collector when certain pattern of entries are queued.

Since garbage collector is no longer waiting for close() since commit 2e503bbb
"TOMOYO: Fix lockdep warning.", we can remove tomoyo_gc_list list and
tomoyo_element_linked_by_gc() by doing sequential processing.

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: James Morris <jmorris@namei.org>
diff --git a/security/tomoyo/condition.c b/security/tomoyo/condition.c
index b854959..986330b 100644
--- a/security/tomoyo/condition.c
+++ b/security/tomoyo/condition.c
@@ -400,8 +400,9 @@
 		found = true;
 		goto out;
 	}
-	list_for_each_entry_rcu(ptr, &tomoyo_condition_list, head.list) {
-		if (!tomoyo_same_condition(ptr, entry))
+	list_for_each_entry(ptr, &tomoyo_condition_list, head.list) {
+		if (!tomoyo_same_condition(ptr, entry) ||
+		    atomic_read(&ptr->head.users) == TOMOYO_GC_IN_PROGRESS)
 			continue;
 		/* Same entry found. Share this entry. */
 		atomic_inc(&ptr->head.users);
@@ -411,8 +412,7 @@
 	if (!found) {
 		if (tomoyo_memory_ok(entry)) {
 			atomic_set(&entry->head.users, 1);
-			list_add_rcu(&entry->head.list,
-				     &tomoyo_condition_list);
+			list_add(&entry->head.list, &tomoyo_condition_list);
 		} else {
 			found = true;
 			ptr = NULL;