netlink: Rename pid to portid to avoid confusion

It is a frequent mistake to confuse the netlink port identifier with a
process identifier.  Try to reduce this confusion by renaming fields
that hold port identifiers portid instead of pid.

I have carefully avoided changing the structures exported to
userspace to avoid changing the userspace API.

I have successfully built an allyesconfig kernel with this change.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/udp_diag.c b/net/ipv4/udp_diag.c
index d2f336e..505b30a 100644
--- a/net/ipv4/udp_diag.c
+++ b/net/ipv4/udp_diag.c
@@ -26,7 +26,7 @@
 
 	return inet_sk_diag_fill(sk, NULL, skb, req,
 			sk_user_ns(NETLINK_CB(cb->skb).ssk),
-			NETLINK_CB(cb->skb).pid,
+			NETLINK_CB(cb->skb).portid,
 			cb->nlh->nlmsg_seq, NLM_F_MULTI, cb->nlh);
 }
 
@@ -72,14 +72,14 @@
 
 	err = inet_sk_diag_fill(sk, NULL, rep, req,
 			   sk_user_ns(NETLINK_CB(in_skb).ssk),
-			   NETLINK_CB(in_skb).pid,
+			   NETLINK_CB(in_skb).portid,
 			   nlh->nlmsg_seq, 0, nlh);
 	if (err < 0) {
 		WARN_ON(err == -EMSGSIZE);
 		kfree_skb(rep);
 		goto out;
 	}
-	err = netlink_unicast(net->diag_nlsk, rep, NETLINK_CB(in_skb).pid,
+	err = netlink_unicast(net->diag_nlsk, rep, NETLINK_CB(in_skb).portid,
 			      MSG_DONTWAIT);
 	if (err > 0)
 		err = 0;