Generalise tcp_listen_opt

@@ -379,22 +379,7 @@ struct tcp_sock {
 
 	__u32	total_retrans;	/* Total retransmits for entire connection */
 
-	/* The syn_wait_lock is necessary only to avoid proc interface having
-	 * to grab the main lock sock while browsing the listening hash
-	 * (otherwise it's deadlock prone).
-	 * This lock is acquired in read mode only from listening_get_next()
-	 * and it's acquired in write mode _only_ from code that is actively
-	 * changing the syn_wait_queue. All readers that are holding
-	 * the master sock lock don't need to grab this lock in read mode
-	 * too as the syn_wait_queue writes are always protected from
-	 * the main sock lock.
-	 */
-	rwlock_t		syn_wait_lock;
-	struct tcp_listen_opt	*listen_opt;
-
-	/* FIFO of established children */
-	struct request_sock	*accept_queue;
-	struct request_sock	*accept_queue_tail;
+	struct request_sock_queue accept_queue; /* FIFO of established children */
 
 	unsigned int		keepalive_time;	  /* time before keep alive takes place */
 	unsigned int		keepalive_intvl;  /* time interval between keep alive probes */

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@@ -529,9 +529,9 @@ static int tcpdiag_dump_reqs(struct sk_b
 
 	entry.family = sk->sk_family;
 
-	read_lock_bh(&tp->syn_wait_lock);
+	read_lock_bh(&tp->accept_queue.syn_wait_lock);
 
-	lopt = tp->listen_opt;
+	lopt = tp->accept_queue.listen_opt;
 	if (!lopt || !lopt->qlen)
 		goto out;
 

@@ -588,7 +588,7 @@ static int tcpdiag_dump_reqs(struct sk_b
 	}
 
 out:
-	read_unlock_bh(&tp->syn_wait_lock);
+	read_unlock_bh(&tp->accept_queue.syn_wait_lock);
 
 	return err;
 }

@@ -874,7 +874,7 @@ static struct request_sock *tcp_v4_searc
 					      __u16 rport,
 					      __u32 raddr, __u32 laddr)
 {
-	struct tcp_listen_opt *lopt = tp->listen_opt;
+	struct tcp_listen_opt *lopt = tp->accept_queue.listen_opt;
 	struct request_sock *req, **prev;
 
 	for (prev = &lopt->syn_table[tcp_v4_synq_hash(raddr, rport, lopt->hash_rnd)];

@@ -898,18 +898,10 @@ static struct request_sock *tcp_v4_searc
 static void tcp_v4_synq_add(struct sock *sk, struct request_sock *req)
 {
 	struct tcp_sock *tp = tcp_sk(sk);
-	struct tcp_listen_opt *lopt = tp->listen_opt;
+	struct tcp_listen_opt *lopt = tp->accept_queue.listen_opt;
 	u32 h = tcp_v4_synq_hash(inet_rsk(req)->rmt_addr, inet_rsk(req)->rmt_port, lopt->hash_rnd);
 
-	req->expires = jiffies + TCP_TIMEOUT_INIT;
-	req->retrans = 0;
-	req->sk = NULL;
-	req->dl_next = lopt->syn_table[h];
-
-	write_lock(&tp->syn_wait_lock);
-	lopt->syn_table[h] = req;
-	write_unlock(&tp->syn_wait_lock);
-
+	reqsk_queue_hash_req(&tp->accept_queue, h, req, TCP_TIMEOUT_INIT);
 	tcp_synq_added(sk);
 }
 

@@ -2167,17 +2159,17 @@ static void *listening_get_next(struct s
 			if (++st->sbucket >= TCP_SYNQ_HSIZE)
 				break;
 get_req:
-			req = tp->listen_opt->syn_table[st->sbucket];
+			req = tp->accept_queue.listen_opt->syn_table[st->sbucket];
 		}
 		sk	  = sk_next(st->syn_wait_sk);
 		st->state = TCP_SEQ_STATE_LISTENING;
-		read_unlock_bh(&tp->syn_wait_lock);
+		read_unlock_bh(&tp->accept_queue.syn_wait_lock);
 	} else {
 	       	tp = tcp_sk(sk);
-		read_lock_bh(&tp->syn_wait_lock);
-		if (tp->listen_opt && tp->listen_opt->qlen)
+		read_lock_bh(&tp->accept_queue.syn_wait_lock);
+		if (reqsk_queue_len(&tp->accept_queue))
 			goto start_req;
-		read_unlock_bh(&tp->syn_wait_lock);
+		read_unlock_bh(&tp->accept_queue.syn_wait_lock);
 		sk = sk_next(sk);
 	}
 get_sk:

@@ -2187,8 +2179,8 @@ get_sk:
 			goto out;
 		}
 	       	tp = tcp_sk(sk);
-		read_lock_bh(&tp->syn_wait_lock);
-		if (tp->listen_opt && tp->listen_opt->qlen) {
+		read_lock_bh(&tp->accept_queue.syn_wait_lock);
+		if (reqsk_queue_len(&tp->accept_queue)) {
 start_req:
 			st->uid		= sock_i_uid(sk);
 			st->syn_wait_sk = sk;

@@ -2196,7 +2188,7 @@ start_req:
 			st->sbucket	= 0;
 			goto get_req;
 		}
-		read_unlock_bh(&tp->syn_wait_lock);
+		read_unlock_bh(&tp->accept_queue.syn_wait_lock);
 	}
 	if (++st->bucket < TCP_LHTABLE_SIZE) {
 		sk = sk_head(&tcp_listening_hash[st->bucket]);

@@ -2383,7 +2375,7 @@ static void tcp_seq_stop(struct seq_file
 	case TCP_SEQ_STATE_OPENREQ:
 		if (v) {
 			struct tcp_sock *tp = tcp_sk(st->syn_wait_sk);
-			read_unlock_bh(&tp->syn_wait_lock);
+			read_unlock_bh(&tp->accept_queue.syn_wait_lock);
 		}
 	case TCP_SEQ_STATE_LISTENING:
 		if (v != SEQ_START_TOKEN)

@@ -790,10 +790,8 @@ struct sock *tcp_create_openreq_child(st
 		newtp->probes_out = 0;
 		newtp->rx_opt.num_sacks = 0;
 		newtp->urg_data = 0;
-		newtp->listen_opt = NULL;
-		newtp->accept_queue = newtp->accept_queue_tail = NULL;
-		/* Deinitialize syn_wait_lock to trap illegal accesses. */
-		memset(&newtp->syn_wait_lock, 0, sizeof(newtp->syn_wait_lock));
+		/* Deinitialize accept_queue to trap illegal accesses. */
+		memset(&newtp->accept_queue, 0, sizeof(newtp->accept_queue));
 
 		/* Back to base struct sock members. */
 		newsk->sk_err = 0;

@@ -464,7 +464,7 @@ out_unlock:
 static void tcp_synack_timer(struct sock *sk)
 {
 	struct tcp_sock *tp = tcp_sk(sk);
-	struct tcp_listen_opt *lopt = tp->listen_opt;
+	struct tcp_listen_opt *lopt = tp->accept_queue.listen_opt;
 	int max_retries = tp->syn_retries ? : sysctl_tcp_synack_retries;
 	int thresh = max_retries;
 	unsigned long now = jiffies;

@@ -527,12 +527,8 @@ static void tcp_synack_timer(struct sock
 				}
 
 				/* Drop this request */
-				write_lock(&tp->syn_wait_lock);
-				*reqp = req->dl_next;
-				write_unlock(&tp->syn_wait_lock);
-				lopt->qlen--;
-				if (req->retrans == 0)
-					lopt->qlen_young--;
+				tcp_synq_unlink(tp, req, reqp);
+				reqsk_queue_removed(&tp->accept_queue, req);
 				reqsk_free(req);
 				continue;
 			}

@@ -401,7 +401,7 @@ static struct request_sock *tcp_v6_searc
 					      struct in6_addr *laddr,
 					      int iif)
 {
-	struct tcp_listen_opt *lopt = tp->listen_opt;
+	struct tcp_listen_opt *lopt = tp->accept_queue.listen_opt;
 	struct request_sock *req, **prev;  
 
 	for (prev = &lopt->syn_table[tcp_v6_synq_hash(raddr, rport, lopt->hash_rnd)];

@@ -1267,18 +1267,10 @@ static struct sock *tcp_v6_hnd_req(struc
 static void tcp_v6_synq_add(struct sock *sk, struct request_sock *req)
 {
 	struct tcp_sock *tp = tcp_sk(sk);
-	struct tcp_listen_opt *lopt = tp->listen_opt;
+	struct tcp_listen_opt *lopt = tp->accept_queue.listen_opt;
 	u32 h = tcp_v6_synq_hash(&tcp6_rsk(req)->rmt_addr, inet_rsk(req)->rmt_port, lopt->hash_rnd);
 
-	req->sk = NULL;
-	req->expires = jiffies + TCP_TIMEOUT_INIT;
-	req->retrans = 0;
-	req->dl_next = lopt->syn_table[h];
-
-	write_lock(&tp->syn_wait_lock);
-	lopt->syn_table[h] = req;
-	write_unlock(&tp->syn_wait_lock);
-
+	reqsk_queue_hash_req(&tp->accept_queue, h, req, TCP_TIMEOUT_INIT);
 	tcp_synq_added(sk);
 }