audit: refactor hold queue flush

The hold queue flush code is an autonomous chunk of code that can be
refactored, removed from kauditd_thread() into flush_hold_queue() and
flattenned for better legibility.
Signed-off-by: Richard Guy Briggs <rbriggs@redhat.com>
Signed-off-by: Eric Paris <eparis@redhat.com>

kernel/audit.c

@@ -417,34 +417,52 @@ static void kauditd_send_skb(struct sk_buff *skb)
 		consume_skb(skb);
 }
 
-static int kauditd_thread(void *dummy)
-{
-	struct sk_buff *skb;
-
-	set_freezable();
-	while (!kthread_should_stop()) {
-		/*
-		 * if auditd just started drain the queue of messages already
-		 * sent to syslog/printk.  remember loss here is ok.  we already
+/*
+ * flush_hold_queue - empty the hold queue if auditd appears
+ *
+ * If auditd just started, drain the queue of messages already
+ * sent to syslog/printk.  Remember loss here is ok.  We already
  * called audit_log_lost() if it didn't go out normally.  so the
  * race between the skb_dequeue and the next check for audit_pid
  * doesn't matter.
  *
-		 * if you ever find kauditd to be too slow we can get a perf win
+ * If you ever find kauditd to be too slow we can get a perf win
  * by doing our own locking and keeping better track if there
  * are messages in this queue.  I don't see the need now, but
  * in 5 years when I want to play with this again I'll see this
  * note and still have no friggin idea what i'm thinking today.
  */
-		if (audit_default && audit_pid) {
+static void flush_hold_queue(void)
+{
+	struct sk_buff *skb;
+
+	if (!audit_default || !audit_pid)
+		return;
+
 	skb = skb_dequeue(&audit_skb_hold_queue);
-			if (unlikely(skb)) {
+	if (likely(!skb))
+		return;
+
 	while (skb && audit_pid) {
 		kauditd_send_skb(skb);
 		skb = skb_dequeue(&audit_skb_hold_queue);
 	}
-			}
-		}
+
+	/*
+	 * if auditd just disappeared but we
+	 * dequeued an skb we need to drop ref
+	 */
+	if (skb)
+		consume_skb(skb);
+}
+
+static int kauditd_thread(void *dummy)
+{
+	struct sk_buff *skb;
+
+	set_freezable();
+	while (!kthread_should_stop()) {
+		flush_hold_queue();
 
 		skb = skb_dequeue(&audit_skb_queue);
 		wake_up(&audit_backlog_wait);