From: bluhm <bluhm@openbsd.org>
Date: Sun, 31 May 2015 20:10:44 +0000 (+0000)
Subject: If the first list was empty, ml_join() did not not clear the second
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=7fb1b5fb8ba9047910f944576bd398e074d250ad;p=openbsd

If the first list was empty, ml_join() did not not clear the second
list after transferring all elements away.  Reorder the conditionals
to make sure that ml_init() is always called for a non empty second
list.  This makes all cases consistent and is less surprising.
OK dlg@
---

diff --git a/sys/kern/uipc_mbuf.c b/sys/kern/uipc_mbuf.c
index 704bc98af1e..a230b8e3bcc 100644
--- a/sys/kern/uipc_mbuf.c
+++ b/sys/kern/uipc_mbuf.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: uipc_mbuf.c,v 1.203 2015/04/13 08:45:48 mpi Exp $	*/
+/*	$OpenBSD: uipc_mbuf.c,v 1.204 2015/05/31 20:10:44 bluhm Exp $	*/
 /*	$NetBSD: uipc_mbuf.c,v 1.15.4.1 1996/06/13 17:11:44 cgd Exp $	*/
 
 /*
@@ -1266,10 +1266,11 @@ ml_enqueue(struct mbuf_list *ml, struct mbuf *m)
 void
 ml_join(struct mbuf_list *mla, struct mbuf_list *mlb)
 {
-	if (mla->ml_tail == NULL)
-		*mla = *mlb;
-	else if (mlb->ml_tail != NULL) {
-		mla->ml_tail->m_nextpkt = mlb->ml_head;
+	if (!ml_empty(mlb)) {
+		if (ml_empty(mla))
+			mla->ml_head = mlb->ml_head;
+		else
+			mla->ml_tail->m_nextpkt = mlb->ml_head;
 		mla->ml_tail = mlb->ml_tail;
 		mla->ml_len += mlb->ml_len;