tipc: move linearization of buffers to generic code

BugLink: http://bugs.launchpad.net/bugs/1567064

In commit 5cbb28a4 ("tipc: linearize arriving NAME_DISTR
and LINK_PROTO buffers") we added linearization of NAME_DISTRIBUTOR,
LINK_PROTOCOL/RESET and LINK_PROTOCOL/ACTIVATE to the function
tipc_udp_recv(). The location of the change was selected in order
to make the commit easily appliable to 'net' and 'stable'.

We now move this linearization to where it should be done, in the
functions tipc_named_rcv() and tipc_link_proto_rcv() respectively.
Reviewed-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
(cherry picked from commit c7cad0d6)
Signed-off-by: Joseph Salisbury <joseph.salisbury@canonical.com>
Acked-by: Brad Figg <brad.figg@canonical.com>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>

net/tipc/link.c

@@ -1262,6 +1262,8 @@ static int tipc_link_proto_rcv(struct tipc_link *l, struct sk_buff *skb,
 		/* fall thru' */
 
 	case ACTIVATE_MSG:
+		skb_linearize(skb);
+		hdr = buf_msg(skb);
 
 		/* Complete own link name with peer's interface name */
 		if_name =  strrchr(l->name, ':') + 1;

net/tipc/name_distr.c

@@ -397,6 +397,7 @@ void tipc_named_rcv(struct net *net, struct sk_buff_head *inputq)
 
 	spin_lock_bh(&tn->nametbl_lock);
 	for (skb = skb_dequeue(inputq); skb; skb = skb_dequeue(inputq)) {
+		skb_linearize(skb);
 		msg = buf_msg(skb);
 		mtype = msg_type(msg);
 		item = (struct distr_item *)msg_data(msg);

net/tipc/udp_media.c

@@ -48,7 +48,6 @@
 #include <linux/tipc_netlink.h>
 #include "core.h"
 #include "bearer.h"
-#include "msg.h"
 
 /* IANA assigned UDP port */
 #define UDP_PORT_DEFAULT	6118
@@ -224,10 +223,6 @@ static int tipc_udp_recv(struct sock *sk, struct sk_buff *skb)
 {
 	struct udp_bearer *ub;
 	struct tipc_bearer *b;
-	int usr = msg_user(buf_msg(skb));
-
-	if ((usr == LINK_PROTOCOL) || (usr == NAME_DISTRIBUTOR))
-		skb_linearize(skb);
 
 	ub = rcu_dereference_sk_user_data(sk);
 	if (!ub) {