inet: includes a sock_common in request_sock

TCP listener refactoring, part 5 :

We want to be able to insert request sockets (SYN_RECV) into main
ehash table instead of the per listener hash table to allow RCU
lookups and remove listener lock contention.

This patch includes the needed struct sock_common in front
of struct request_sock

This means there is no more inet6_request_sock IPv6 specific
structure.

Following inet_request_sock fields were renamed as they became
macros to reference fields from struct sock_common.
Prefix ir_ was chosen to avoid name collisions.

loc_port   -> ir_loc_port
loc_addr   -> ir_loc_addr
rmt_addr   -> ir_rmt_addr
rmt_port   -> ir_rmt_port
iif        -> ir_iif

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index e4695dd..114d1b74 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -835,11 +835,11 @@
 	skb = tcp_make_synack(sk, dst, req, NULL);
 
 	if (skb) {
-		__tcp_v4_send_check(skb, ireq->loc_addr, ireq->rmt_addr);
+		__tcp_v4_send_check(skb, ireq->ir_loc_addr, ireq->ir_rmt_addr);
 
 		skb_set_queue_mapping(skb, queue_mapping);
-		err = ip_build_and_send_pkt(skb, sk, ireq->loc_addr,
-					    ireq->rmt_addr,
+		err = ip_build_and_send_pkt(skb, sk, ireq->ir_loc_addr,
+					    ireq->ir_rmt_addr,
 					    ireq->opt);
 		err = net_xmit_eval(err);
 		if (!tcp_rsk(req)->snt_synack && !err)
@@ -972,7 +972,7 @@
 {
 	union tcp_md5_addr *addr;
 
-	addr = (union tcp_md5_addr *)&inet_rsk(req)->rmt_addr;
+	addr = (union tcp_md5_addr *)&inet_rsk(req)->ir_rmt_addr;
 	return tcp_md5_do_lookup(sk, addr, AF_INET);
 }
 
@@ -1149,8 +1149,8 @@
 		saddr = inet_sk(sk)->inet_saddr;
 		daddr = inet_sk(sk)->inet_daddr;
 	} else if (req) {
-		saddr = inet_rsk(req)->loc_addr;
-		daddr = inet_rsk(req)->rmt_addr;
+		saddr = inet_rsk(req)->ir_loc_addr;
+		daddr = inet_rsk(req)->ir_rmt_addr;
 	} else {
 		const struct iphdr *iph = ip_hdr(skb);
 		saddr = iph->saddr;
@@ -1366,8 +1366,8 @@
 		kfree_skb(skb_synack);
 		return -1;
 	}
-	err = ip_build_and_send_pkt(skb_synack, sk, ireq->loc_addr,
-				    ireq->rmt_addr, ireq->opt);
+	err = ip_build_and_send_pkt(skb_synack, sk, ireq->ir_loc_addr,
+				    ireq->ir_rmt_addr, ireq->opt);
 	err = net_xmit_eval(err);
 	if (!err)
 		tcp_rsk(req)->snt_synack = tcp_time_stamp;
@@ -1502,8 +1502,8 @@
 	tcp_openreq_init(req, &tmp_opt, skb);
 
 	ireq = inet_rsk(req);
-	ireq->loc_addr = daddr;
-	ireq->rmt_addr = saddr;
+	ireq->ir_loc_addr = daddr;
+	ireq->ir_rmt_addr = saddr;
 	ireq->no_srccheck = inet_sk(sk)->transparent;
 	ireq->opt = tcp_v4_save_options(skb);
 
@@ -1578,15 +1578,15 @@
 	    fastopen_cookie_present(&valid_foc) ? &valid_foc : NULL);
 
 	if (skb_synack) {
-		__tcp_v4_send_check(skb_synack, ireq->loc_addr, ireq->rmt_addr);
+		__tcp_v4_send_check(skb_synack, ireq->ir_loc_addr, ireq->ir_rmt_addr);
 		skb_set_queue_mapping(skb_synack, skb_get_queue_mapping(skb));
 	} else
 		goto drop_and_free;
 
 	if (likely(!do_fastopen)) {
 		int err;
-		err = ip_build_and_send_pkt(skb_synack, sk, ireq->loc_addr,
-		     ireq->rmt_addr, ireq->opt);
+		err = ip_build_and_send_pkt(skb_synack, sk, ireq->ir_loc_addr,
+		     ireq->ir_rmt_addr, ireq->opt);
 		err = net_xmit_eval(err);
 		if (err || want_cookie)
 			goto drop_and_free;
@@ -1644,9 +1644,9 @@
 	newtp		      = tcp_sk(newsk);
 	newinet		      = inet_sk(newsk);
 	ireq		      = inet_rsk(req);
-	newinet->inet_daddr   = ireq->rmt_addr;
-	newinet->inet_rcv_saddr = ireq->loc_addr;
-	newinet->inet_saddr	      = ireq->loc_addr;
+	newinet->inet_daddr   = ireq->ir_rmt_addr;
+	newinet->inet_rcv_saddr = ireq->ir_loc_addr;
+	newinet->inet_saddr	      = ireq->ir_loc_addr;
 	inet_opt	      = ireq->opt;
 	rcu_assign_pointer(newinet->inet_opt, inet_opt);
 	ireq->opt	      = NULL;
@@ -2548,10 +2548,10 @@
 	seq_printf(f, "%4d: %08X:%04X %08X:%04X"
 		" %02X %08X:%08X %02X:%08lX %08X %5u %8d %u %d %pK%n",
 		i,
-		ireq->loc_addr,
+		ireq->ir_loc_addr,
 		ntohs(inet_sk(sk)->inet_sport),
-		ireq->rmt_addr,
-		ntohs(ireq->rmt_port),
+		ireq->ir_rmt_addr,
+		ntohs(ireq->ir_rmt_port),
 		TCP_SYN_RECV,
 		0, 0, /* could print option size, but that is af dependent. */
 		1,    /* timers active (only the expire timer) */