selinux: avc: drop unused function avc_disable()

Since commit f22f9aaf ("selinux: remove the runtime disable
functionality") the function avc_disable() is no longer used.
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>

security/selinux/avc.c

@@ -1203,22 +1203,3 @@ u32 avc_policy_seqno(void)
 {
 	return selinux_avc.avc_cache.latest_notif;
 }
-
-void avc_disable(void)
-{
-	/*
-	 * If you are looking at this because you have realized that we are
-	 * not destroying the avc_node_cachep it might be easy to fix, but
-	 * I don't know the memory barrier semantics well enough to know.  It's
-	 * possible that some other task dereferenced security_ops when
-	 * it still pointed to selinux operations.  If that is the case it's
-	 * possible that it is about to use the avc and is about to need the
-	 * avc_node_cachep.  I know I could wrap the security.c security_ops call
-	 * in an rcu_lock, but seriously, it's not worth it.  Instead I just flush
-	 * the cache and get that memory back.
-	 */
-	if (avc_node_cachep) {
-		avc_flush();
-		/* kmem_cache_destroy(avc_node_cachep); */
-	}
-}

security/selinux/include/avc.h

@@ -168,9 +168,6 @@ int avc_get_hash_stats(char *page);
 unsigned int avc_get_cache_threshold(void);
 void avc_set_cache_threshold(unsigned int cache_threshold);
 
-/* Attempt to free avc node cache */
-void avc_disable(void);
-
 #ifdef CONFIG_SECURITY_SELINUX_AVC_STATS
 DECLARE_PER_CPU(struct avc_cache_stats, avc_cache_stats);
 #endif