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/fib_frontend.c b/net/ipv4/fib_frontend.c
index dc1f10e..68c93d1 100644
--- a/net/ipv4/fib_frontend.c
+++ b/net/ipv4/fib_frontend.c
@@ -557,7 +557,7 @@
 	cfg->fc_flags = rtm->rtm_flags;
 	cfg->fc_nlflags = nlh->nlmsg_flags;
 
-	cfg->fc_nlinfo.pid = NETLINK_CB(skb).pid;
+	cfg->fc_nlinfo.portid = NETLINK_CB(skb).portid;
 	cfg->fc_nlinfo.nlh = nlh;
 	cfg->fc_nlinfo.nl_net = net;
 
@@ -955,7 +955,7 @@
 	struct fib_result_nl *frn;
 	struct nlmsghdr *nlh;
 	struct fib_table *tb;
-	u32 pid;
+	u32 portid;
 
 	net = sock_net(skb->sk);
 	nlh = nlmsg_hdr(skb);
@@ -973,10 +973,10 @@
 
 	nl_fib_lookup(frn, tb);
 
-	pid = NETLINK_CB(skb).pid;      /* pid of sending process */
-	NETLINK_CB(skb).pid = 0;        /* from kernel */
+	portid = NETLINK_CB(skb).portid;      /* pid of sending process */
+	NETLINK_CB(skb).portid = 0;        /* from kernel */
 	NETLINK_CB(skb).dst_group = 0;  /* unicast */
-	netlink_unicast(net->ipv4.fibnl, skb, pid, MSG_DONTWAIT);
+	netlink_unicast(net->ipv4.fibnl, skb, portid, MSG_DONTWAIT);
 }
 
 static int __net_init nl_fib_lookup_init(struct net *net)