tcp: replace tcp_sock argument with sock in some places

These places have a tcp_sock, but we'd prefer the sock itself to
get net from it. Fortunately, tcp_sk macro is just a type cast, so
this replace is really cheap.
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv4/tcp_input.c

@@ -1169,10 +1169,11 @@ static void tcp_mark_lost_retrans(struct sock *sk)
 		tp->lost_retrans_low = new_low_seq;
 }
 
-static int tcp_check_dsack(struct tcp_sock *tp, struct sk_buff *ack_skb,
+static int tcp_check_dsack(struct sock *sk, struct sk_buff *ack_skb,
 			   struct tcp_sack_block_wire *sp, int num_sacks,
 			   u32 prior_snd_una)
 {
+	struct tcp_sock *tp = tcp_sk(sk);
 	u32 start_seq_0 = get_unaligned_be32(&sp[0].start_seq);
 	u32 end_seq_0 = get_unaligned_be32(&sp[0].end_seq);
 	int dup_sack = 0;
@@ -1434,7 +1435,7 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb,
 		tcp_highest_sack_reset(sk);
 	}
 
-	found_dup_sack = tcp_check_dsack(tp, ack_skb, sp_wire,
+	found_dup_sack = tcp_check_dsack(sk, ack_skb, sp_wire,
 					 num_sacks, prior_snd_una);
 	if (found_dup_sack)
 		flag |= FLAG_DSACKING_ACK;
@@ -3711,8 +3712,10 @@ static inline int tcp_sack_extend(struct tcp_sack_block *sp, u32 seq,
 	return 0;
 }
 
-static void tcp_dsack_set(struct tcp_sock *tp, u32 seq, u32 end_seq)
+static void tcp_dsack_set(struct sock *sk, u32 seq, u32 end_seq)
 {
+	struct tcp_sock *tp = tcp_sk(sk);
+
 	if (tcp_is_sack(tp) && sysctl_tcp_dsack) {
 		int mib_idx;
 
@@ -3731,10 +3734,12 @@ static void tcp_dsack_set(struct tcp_sock *tp, u32 seq, u32 end_seq)
 	}
 }
 
-static void tcp_dsack_extend(struct tcp_sock *tp, u32 seq, u32 end_seq)
+static void tcp_dsack_extend(struct sock *sk, u32 seq, u32 end_seq)
 {
+	struct tcp_sock *tp = tcp_sk(sk);
+
 	if (!tp->rx_opt.dsack)
-		tcp_dsack_set(tp, seq, end_seq);
+		tcp_dsack_set(sk, seq, end_seq);
 	else
 		tcp_sack_extend(tp->duplicate_sack, seq, end_seq);
 }
@@ -3753,7 +3758,7 @@ static void tcp_send_dupack(struct sock *sk, struct sk_buff *skb)
 
 			if (after(TCP_SKB_CB(skb)->end_seq, tp->rcv_nxt))
 				end_seq = tp->rcv_nxt;
-			tcp_dsack_set(tp, TCP_SKB_CB(skb)->seq, end_seq);
+			tcp_dsack_set(sk, TCP_SKB_CB(skb)->seq, end_seq);
 		}
 	}
 
@@ -3906,7 +3911,7 @@ static void tcp_ofo_queue(struct sock *sk)
 			__u32 dsack = dsack_high;
 			if (before(TCP_SKB_CB(skb)->end_seq, dsack_high))
 				dsack_high = TCP_SKB_CB(skb)->end_seq;
-			tcp_dsack_extend(tp, TCP_SKB_CB(skb)->seq, dsack);
+			tcp_dsack_extend(sk, TCP_SKB_CB(skb)->seq, dsack);
 		}
 
 		if (!after(TCP_SKB_CB(skb)->end_seq, tp->rcv_nxt)) {
@@ -4035,7 +4040,7 @@ queue_and_out:
 	if (!after(TCP_SKB_CB(skb)->end_seq, tp->rcv_nxt)) {
 		/* A retransmit, 2nd most common case.  Force an immediate ack. */
 		NET_INC_STATS_BH(LINUX_MIB_DELAYEDACKLOST);
-		tcp_dsack_set(tp, TCP_SKB_CB(skb)->seq, TCP_SKB_CB(skb)->end_seq);
+		tcp_dsack_set(sk, TCP_SKB_CB(skb)->seq, TCP_SKB_CB(skb)->end_seq);
 
 out_of_window:
 		tcp_enter_quickack_mode(sk);
@@ -4057,7 +4062,7 @@ drop:
 			   tp->rcv_nxt, TCP_SKB_CB(skb)->seq,
 			   TCP_SKB_CB(skb)->end_seq);
 
-		tcp_dsack_set(tp, TCP_SKB_CB(skb)->seq, tp->rcv_nxt);
+		tcp_dsack_set(sk, TCP_SKB_CB(skb)->seq, tp->rcv_nxt);
 
 		/* If window is closed, drop tail of packet. But after
 		 * remembering D-SACK for its head made in previous line.
@@ -4122,12 +4127,12 @@ drop:
 			if (!after(end_seq, TCP_SKB_CB(skb1)->end_seq)) {
 				/* All the bits are present. Drop. */
 				__kfree_skb(skb);
-				tcp_dsack_set(tp, seq, end_seq);
+				tcp_dsack_set(sk, seq, end_seq);
 				goto add_sack;
 			}
 			if (after(seq, TCP_SKB_CB(skb1)->seq)) {
 				/* Partial overlap. */
-				tcp_dsack_set(tp, seq,
+				tcp_dsack_set(sk, seq,
 					      TCP_SKB_CB(skb1)->end_seq);
 			} else {
 				skb1 = skb1->prev;
@@ -4140,12 +4145,12 @@ drop:
 		       (struct sk_buff *)&tp->out_of_order_queue &&
 		       after(end_seq, TCP_SKB_CB(skb1)->seq)) {
 			if (before(end_seq, TCP_SKB_CB(skb1)->end_seq)) {
-				tcp_dsack_extend(tp, TCP_SKB_CB(skb1)->seq,
+				tcp_dsack_extend(sk, TCP_SKB_CB(skb1)->seq,
 						 end_seq);
 				break;
 			}
 			__skb_unlink(skb1, &tp->out_of_order_queue);
-			tcp_dsack_extend(tp, TCP_SKB_CB(skb1)->seq,
+			tcp_dsack_extend(sk, TCP_SKB_CB(skb1)->seq,
 					 TCP_SKB_CB(skb1)->end_seq);
 			__kfree_skb(skb1);
 		}