From df2f1063dd7c506c9790a60fd65cf1c22c1693b1 Mon Sep 17 00:00:00 2001
From: Bernard Pidoux <f6bvp@amsat.org>
Date: Sat, 21 Mar 2009 13:33:55 -0700
Subject: [PATCH] --- yaml --- r: 135349 b: refs/heads/master c:
 f99bcff7a290768e035f3d4726e103c6ebe858bf h: refs/heads/master i:   135347:
 ae1f37b3a2476fd96ba0ee980f1012e2f3165ce7 v: v3

---
 [refs]                   |  2 +-
 trunk/net/ax25/af_ax25.c | 12 ++++++++++++
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/[refs] b/[refs]
index 45b6974b0d62..6bbce12229af 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 60784427ab331dc13c070ac4b0cc9a735bdfa9c0
+refs/heads/master: f99bcff7a290768e035f3d4726e103c6ebe858bf
diff --git a/trunk/net/ax25/af_ax25.c b/trunk/net/ax25/af_ax25.c
index fd9d06f291dc..7da5ebb84e97 100644
--- a/trunk/net/ax25/af_ax25.c
+++ b/trunk/net/ax25/af_ax25.c
@@ -1435,6 +1435,11 @@ static int ax25_sendmsg(struct kiocb *iocb, struct socket *sock,
 	size_t size;
 	int lv, err, addr_len = msg->msg_namelen;
 
+	/* AX.25 empty data frame has no meaning : don't send */
+	if (len == 0) {
+		return (0);
+	}
+
 	if (msg->msg_flags & ~(MSG_DONTWAIT|MSG_EOR|MSG_CMSG_COMPAT))
 		return -EINVAL;
 
@@ -1634,6 +1639,13 @@ static int ax25_recvmsg(struct kiocb *iocb, struct socket *sock,
 	skb_reset_transport_header(skb);
 	copied = skb->len;
 
+	/* AX.25 empty data frame has no meaning : ignore it */
+	if (copied == 0) {
+		err = copied;
+		skb_free_datagram(sk, skb);
+		goto out;
+	}
+
 	if (copied > size) {
 		copied = size;
 		msg->msg_flags |= MSG_TRUNC;