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/can/gw.c b/net/can/gw.c
index b54d5e6..127879c 100644
--- a/net/can/gw.c
+++ b/net/can/gw.c
@@ -549,7 +549,7 @@
 		if (idx < s_idx)
 			goto cont;
 
-		if (cgw_put_job(skb, gwj, RTM_NEWROUTE, NETLINK_CB(cb->skb).pid,
+		if (cgw_put_job(skb, gwj, RTM_NEWROUTE, NETLINK_CB(cb->skb).portid,
 		    cb->nlh->nlmsg_seq, NLM_F_MULTI) < 0)
 			break;
 cont: