Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next

Pull networking updates from David Miller:
 "This is a re-do of the net-next pull request for the current merge
  window.  The only difference from the one I made the other day is that
  this has Eliezer's interface renames and the timeout handling changes
  made based upon your feedback, as well as a few bug fixes that have
  trickeled in.

  Highlights:

   1) Low latency device polling, eliminating the cost of interrupt
      handling and context switches.  Allows direct polling of a network
      device from socket operations, such as recvmsg() and poll().

      Currently ixgbe, mlx4, and bnx2x support this feature.

      Full high level description, performance numbers, and design in
      commit 0a4db187a999 ("Merge branch 'll_poll'")

      From Eliezer Tamir.

   2) With the routing cache removed, ip_check_mc_rcu() gets exercised
      more than ever before in the case where we have lots of multicast
      addresses.  Use a hash table instead of a simple linked list, from
      Eric Dumazet.

   3) Add driver for Atheros CQA98xx 802.11ac wireless devices, from
      Bartosz Markowski, Janusz Dziedzic, Kalle Valo, Marek Kwaczynski,
      Marek Puzyniak, Michal Kazior, and Sujith Manoharan.

   4) Support reporting the TUN device persist flag to userspace, from
      Pavel Emelyanov.

   5) Allow controlling network device VF link state using netlink, from
      Rony Efraim.

   6) Support GRE tunneling in openvswitch, from Pravin B Shelar.

   7) Adjust SOCK_MIN_RCVBUF and SOCK_MIN_SNDBUF for modern times, from
      Daniel Borkmann and Eric Dumazet.

   8) Allow controlling of TCP quickack behavior on a per-route basis,
      from Cong Wang.

   9) Several bug fixes and improvements to vxlan from Stephen
      Hemminger, Pravin B Shelar, and Mike Rapoport.  In particular,
      support receiving on multiple UDP ports.

  10) Major cleanups, particular in the area of debugging and cookie
      lifetime handline, to the SCTP protocol code.  From Daniel
      Borkmann.

  11) Allow packets to cross network namespaces when traversing tunnel
      devices.  From Nicolas Dichtel.

  12) Allow monitoring netlink traffic via AF_PACKET sockets, in a
      manner akin to how we monitor real network traffic via ptype_all.
      From Daniel Borkmann.

  13) Several bug fixes and improvements for the new alx device driver,
      from Johannes Berg.

  14) Fix scalability issues in the netem packet scheduler's time queue,
      by using an rbtree.  From Eric Dumazet.

  15) Several bug fixes in TCP loss recovery handling, from Yuchung
      Cheng.

  16) Add support for GSO segmentation of MPLS packets, from Simon
      Horman.

  17) Make network notifiers have a real data type for the opaque
      pointer that's passed into them.  Use this to properly handle
      network device flag changes in arp_netdev_event().  From Jiri
      Pirko and Timo Teräs.

  18) Convert several drivers over to module_pci_driver(), from Peter
      Huewe.

  19) tcp_fixup_rcvbuf() can loop 500 times over loopback, just use a
      O(1) calculation instead.  From Eric Dumazet.

  20) Support setting of explicit tunnel peer addresses in ipv6, just
      like ipv4.  From Nicolas Dichtel.

  21) Protect x86 BPF JIT against spraying attacks, from Eric Dumazet.

  22) Prevent a single high rate flow from overruning an individual cpu
      during RX packet processing via selective flow shedding.  From
      Willem de Bruijn.

  23) Don't use spinlocks in TCP md5 signing fast paths, from Eric
      Dumazet.

  24) Don't just drop GSO packets which are above the TBF scheduler's
      burst limit, chop them up so they are in-bounds instead.  Also
      from Eric Dumazet.

  25) VLAN offloads are missed when configured on top of a bridge, fix
      from Vlad Yasevich.

  26) Support IPV6 in ping sockets.  From Lorenzo Colitti.

  27) Receive flow steering targets should be updated at poll() time
      too, from David Majnemer.

  28) Fix several corner case regressions in PMTU/redirect handling due
      to the routing cache removal, from Timo Teräs.

  29) We have to be mindful of ipv4 mapped ipv6 sockets in
      upd_v6_push_pending_frames().  From Hannes Frederic Sowa.

  30) Fix L2TP sequence number handling bugs, from James Chapman."

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (1214 commits)
  drivers/net: caif: fix wrong rtnl_is_locked() usage
  drivers/net: enic: release rtnl_lock on error-path
  vhost-net: fix use-after-free in vhost_net_flush
  net: mv643xx_eth: do not use port number as platform device id
  net: sctp: confirm route during forward progress
  virtio_net: fix race in RX VQ processing
  virtio: support unlocked queue poll
  net/cadence/macb: fix bug/typo in extracting gem_irq_read_clear bit
  Documentation: Fix references to defunct linux-net@vger.kernel.org
  net/fs: change busy poll time accounting
  net: rename low latency sockets functions to busy poll
  bridge: fix some kernel warning in multicast timer
  sfc: Fix memory leak when discarding scattered packets
  sit: fix tunnel update via netlink
  dt:net:stmmac: Add dt specific phy reset callback support.
  dt:net:stmmac: Add support to dwmac version 3.610 and 3.710
  dt:net:stmmac: Allocate platform data only if its NULL.
  net:stmmac: fix memleak in the open method
  ipv6: rt6_check_neigh should successfully verify neigh if no NUD information are available
  net: ipv6: fix wrong ping_v6_sendmsg return value
  ...

1 files changed, 224 insertions, 293 deletions

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 9c6225780bd5..28af45abe062 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -347,24 +347,13 @@ static void tcp_grow_window(struct sock *sk, const struct sk_buff *skb)
 }
 
 /* 3. Tuning rcvbuf, when connection enters established state. */
-
 static void tcp_fixup_rcvbuf(struct sock *sk)
 {
 	u32 mss = tcp_sk(sk)->advmss;
-	u32 icwnd = TCP_DEFAULT_INIT_RCVWND;
 	int rcvmem;
 
-	/* Limit to 10 segments if mss <= 1460,
-	 * or 14600/mss segments, with a minimum of two segments.
-	 */
-	if (mss > 1460)
-		icwnd = max_t(u32, (1460 * TCP_DEFAULT_INIT_RCVWND) / mss, 2);
-
-	rcvmem = SKB_TRUESIZE(mss + MAX_TCP_HEADER);
-	while (tcp_win_from_space(rcvmem) < mss)
-		rcvmem += 128;
-
-	rcvmem *= icwnd;
+	rcvmem = 2 * SKB_TRUESIZE(mss + MAX_TCP_HEADER) *
+		 tcp_default_init_rwnd(mss);
 
 	if (sk->sk_rcvbuf < rcvmem)
 		sk->sk_rcvbuf = min(rcvmem, sysctl_tcp_rmem[2]);
@@ -1257,8 +1246,6 @@ static bool tcp_shifted_skb(struct sock *sk, struct sk_buff *skb,
 
 	if (skb == tp->retransmit_skb_hint)
 		tp->retransmit_skb_hint = prev;
-	if (skb == tp->scoreboard_skb_hint)
-		tp->scoreboard_skb_hint = prev;
 	if (skb == tp->lost_skb_hint) {
 		tp->lost_skb_hint = prev;
 		tp->lost_cnt_hint -= tcp_skb_pcount(prev);
@@ -1966,20 +1953,6 @@ static bool tcp_pause_early_retransmit(struct sock *sk, int flag)
 	return true;
 }
 
-static inline int tcp_skb_timedout(const struct sock *sk,
-				   const struct sk_buff *skb)
-{
-	return tcp_time_stamp - TCP_SKB_CB(skb)->when > inet_csk(sk)->icsk_rto;
-}
-
-static inline int tcp_head_timedout(const struct sock *sk)
-{
-	const struct tcp_sock *tp = tcp_sk(sk);
-
-	return tp->packets_out &&
-	       tcp_skb_timedout(sk, tcp_write_queue_head(sk));
-}
-
 /* Linux NewReno/SACK/FACK/ECN state machine.
  * --------------------------------------
  *
@@ -2086,12 +2059,6 @@ static bool tcp_time_to_recover(struct sock *sk, int flag)
 	if (tcp_dupack_heuristics(tp) > tp->reordering)
 		return true;
 
-	/* Trick#3 : when we use RFC2988 timer restart, fast
-	 * retransmit can be triggered by timeout of queue head.
-	 */
-	if (tcp_is_fack(tp) && tcp_head_timedout(sk))
-		return true;
-
 	/* Trick#4: It is still not OK... But will it be useful to delay
 	 * recovery more?
 	 */
@@ -2128,44 +2095,6 @@ static bool tcp_time_to_recover(struct sock *sk, int flag)
 	return false;
 }
 
-/* New heuristics: it is possible only after we switched to restart timer
- * each time when something is ACKed. Hence, we can detect timed out packets
- * during fast retransmit without falling to slow start.
- *
- * Usefulness of this as is very questionable, since we should know which of
- * the segments is the next to timeout which is relatively expensive to find
- * in general case unless we add some data structure just for that. The
- * current approach certainly won't find the right one too often and when it
- * finally does find _something_ it usually marks large part of the window
- * right away (because a retransmission with a larger timestamp blocks the
- * loop from advancing). -ij
- */
-static void tcp_timeout_skbs(struct sock *sk)
-{
-	struct tcp_sock *tp = tcp_sk(sk);
-	struct sk_buff *skb;
-
-	if (!tcp_is_fack(tp) || !tcp_head_timedout(sk))
-		return;
-
-	skb = tp->scoreboard_skb_hint;
-	if (tp->scoreboard_skb_hint == NULL)
-		skb = tcp_write_queue_head(sk);
-
-	tcp_for_write_queue_from(skb, sk) {
-		if (skb == tcp_send_head(sk))
-			break;
-		if (!tcp_skb_timedout(sk, skb))
-			break;
-
-		tcp_skb_mark_lost(tp, skb);
-	}
-
-	tp->scoreboard_skb_hint = skb;
-
-	tcp_verify_left_out(tp);
-}
-
 /* Detect loss in event "A" above by marking head of queue up as lost.
  * For FACK or non-SACK(Reno) senders, the first "packets" number of segments
  * are considered lost. For RFC3517 SACK, a segment is considered lost if it
@@ -2251,8 +2180,6 @@ static void tcp_update_scoreboard(struct sock *sk, int fast_rexmit)
 		else if (fast_rexmit)
 			tcp_mark_head_lost(sk, 1, 1);
 	}
-
-	tcp_timeout_skbs(sk);
 }
 
 /* CWND moderation, preventing bursts due to too big ACKs
@@ -2307,10 +2234,22 @@ static void DBGUNDO(struct sock *sk, const char *msg)
 #define DBGUNDO(x...) do { } while (0)
 #endif
 
-static void tcp_undo_cwr(struct sock *sk, const bool undo_ssthresh)
+static void tcp_undo_cwnd_reduction(struct sock *sk, bool unmark_loss)
 {
 	struct tcp_sock *tp = tcp_sk(sk);
 
+	if (unmark_loss) {
+		struct sk_buff *skb;
+
+		tcp_for_write_queue(skb, sk) {
+			if (skb == tcp_send_head(sk))
+				break;
+			TCP_SKB_CB(skb)->sacked &= ~TCPCB_LOST;
+		}
+		tp->lost_out = 0;
+		tcp_clear_all_retrans_hints(tp);
+	}
+
 	if (tp->prior_ssthresh) {
 		const struct inet_connection_sock *icsk = inet_csk(sk);
 
@@ -2319,7 +2258,7 @@ static void tcp_undo_cwr(struct sock *sk, const bool undo_ssthresh)
 		else
 			tp->snd_cwnd = max(tp->snd_cwnd, tp->snd_ssthresh << 1);
 
-		if (undo_ssthresh && tp->prior_ssthresh > tp->snd_ssthresh) {
+		if (tp->prior_ssthresh > tp->snd_ssthresh) {
 			tp->snd_ssthresh = tp->prior_ssthresh;
 			TCP_ECN_withdraw_cwr(tp);
 		}
@@ -2327,6 +2266,7 @@ static void tcp_undo_cwr(struct sock *sk, const bool undo_ssthresh)
 		tp->snd_cwnd = max(tp->snd_cwnd, tp->snd_ssthresh);
 	}
 	tp->snd_cwnd_stamp = tcp_time_stamp;
+	tp->undo_marker = 0;
 }
 
 static inline bool tcp_may_undo(const struct tcp_sock *tp)
@@ -2346,14 +2286,13 @@ static bool tcp_try_undo_recovery(struct sock *sk)
 		 * or our original transmission succeeded.
 		 */
 		DBGUNDO(sk, inet_csk(sk)->icsk_ca_state == TCP_CA_Loss ? "loss" : "retrans");
-		tcp_undo_cwr(sk, true);
+		tcp_undo_cwnd_reduction(sk, false);
 		if (inet_csk(sk)->icsk_ca_state == TCP_CA_Loss)
 			mib_idx = LINUX_MIB_TCPLOSSUNDO;
 		else
 			mib_idx = LINUX_MIB_TCPFULLUNDO;
 
 		NET_INC_STATS_BH(sock_net(sk), mib_idx);
-		tp->undo_marker = 0;
 	}
 	if (tp->snd_una == tp->high_seq && tcp_is_reno(tp)) {
 		/* Hold old state until something *above* high_seq
@@ -2367,16 +2306,17 @@ static bool tcp_try_undo_recovery(struct sock *sk)
 }
 
 /* Try to undo cwnd reduction, because D-SACKs acked all retransmitted data */
-static void tcp_try_undo_dsack(struct sock *sk)
+static bool tcp_try_undo_dsack(struct sock *sk)
 {
 	struct tcp_sock *tp = tcp_sk(sk);
 
 	if (tp->undo_marker && !tp->undo_retrans) {
 		DBGUNDO(sk, "D-SACK");
-		tcp_undo_cwr(sk, true);
-		tp->undo_marker = 0;
+		tcp_undo_cwnd_reduction(sk, false);
 		NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPDSACKUNDO);
+		return true;
 	}
+	return false;
 }
 
 /* We can clear retrans_stamp when there are no retransmissions in the
@@ -2408,60 +2348,20 @@ static bool tcp_any_retrans_done(const struct sock *sk)
 	return false;
 }
 
-/* Undo during fast recovery after partial ACK. */
-
-static int tcp_try_undo_partial(struct sock *sk, int acked)
-{
-	struct tcp_sock *tp = tcp_sk(sk);
-	/* Partial ACK arrived. Force Hoe's retransmit. */
-	int failed = tcp_is_reno(tp) || (tcp_fackets_out(tp) > tp->reordering);
-
-	if (tcp_may_undo(tp)) {
-		/* Plain luck! Hole if filled with delayed
-		 * packet, rather than with a retransmit.
-		 */
-		if (!tcp_any_retrans_done(sk))
-			tp->retrans_stamp = 0;
-
-		tcp_update_reordering(sk, tcp_fackets_out(tp) + acked, 1);
-
-		DBGUNDO(sk, "Hoe");
-		tcp_undo_cwr(sk, false);
-		NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPPARTIALUNDO);
-
-		/* So... Do not make Hoe's retransmit yet.
-		 * If the first packet was delayed, the rest
-		 * ones are most probably delayed as well.
-		 */
-		failed = 0;
-	}
-	return failed;
-}
-
 /* Undo during loss recovery after partial ACK or using F-RTO. */
 static bool tcp_try_undo_loss(struct sock *sk, bool frto_undo)
 {
 	struct tcp_sock *tp = tcp_sk(sk);
 
 	if (frto_undo || tcp_may_undo(tp)) {
-		struct sk_buff *skb;
-		tcp_for_write_queue(skb, sk) {
-			if (skb == tcp_send_head(sk))
-				break;
-			TCP_SKB_CB(skb)->sacked &= ~TCPCB_LOST;
-		}
-
-		tcp_clear_all_retrans_hints(tp);
+		tcp_undo_cwnd_reduction(sk, true);
 
 		DBGUNDO(sk, "partial loss");
-		tp->lost_out = 0;
-		tcp_undo_cwr(sk, true);
 		NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPLOSSUNDO);
 		if (frto_undo)
 			NET_INC_STATS_BH(sock_net(sk),
 					 LINUX_MIB_TCPSPURIOUSRTOS);
 		inet_csk(sk)->icsk_retransmits = 0;
-		tp->undo_marker = 0;
 		if (frto_undo || tcp_is_sack(tp))
 			tcp_set_ca_state(sk, TCP_CA_Open);
 		return true;
@@ -2494,12 +2394,14 @@ static void tcp_init_cwnd_reduction(struct sock *sk, const bool set_ssthresh)
 	TCP_ECN_queue_cwr(tp);
 }
 
-static void tcp_cwnd_reduction(struct sock *sk, int newly_acked_sacked,
+static void tcp_cwnd_reduction(struct sock *sk, const int prior_unsacked,
 			       int fast_rexmit)
 {
 	struct tcp_sock *tp = tcp_sk(sk);
 	int sndcnt = 0;
 	int delta = tp->snd_ssthresh - tcp_packets_in_flight(tp);
+	int newly_acked_sacked = prior_unsacked -
+				 (tp->packets_out - tp->sacked_out);
 
 	tp->prr_delivered += newly_acked_sacked;
 	if (tcp_packets_in_flight(tp) > tp->snd_ssthresh) {
@@ -2556,7 +2458,7 @@ static void tcp_try_keep_open(struct sock *sk)
 	}
 }
 
-static void tcp_try_to_open(struct sock *sk, int flag, int newly_acked_sacked)
+static void tcp_try_to_open(struct sock *sk, int flag, const int prior_unsacked)
 {
 	struct tcp_sock *tp = tcp_sk(sk);
 
@@ -2573,7 +2475,7 @@ static void tcp_try_to_open(struct sock *sk, int flag, int newly_acked_sacked)
 		if (inet_csk(sk)->icsk_ca_state != TCP_CA_Open)
 			tcp_moderate_cwnd(tp);
 	} else {
-		tcp_cwnd_reduction(sk, newly_acked_sacked, 0);
+		tcp_cwnd_reduction(sk, prior_unsacked, 0);
 	}
 }
 
@@ -2731,6 +2633,40 @@ static void tcp_process_loss(struct sock *sk, int flag, bool is_dupack)
 	tcp_xmit_retransmit_queue(sk);
 }
 
+/* Undo during fast recovery after partial ACK. */
+static bool tcp_try_undo_partial(struct sock *sk, const int acked,
+				 const int prior_unsacked)
+{
+	struct tcp_sock *tp = tcp_sk(sk);
+
+	if (tp->undo_marker && tcp_packet_delayed(tp)) {
+		/* Plain luck! Hole if filled with delayed
+		 * packet, rather than with a retransmit.
+		 */
+		tcp_update_reordering(sk, tcp_fackets_out(tp) + acked, 1);
+
+		/* We are getting evidence that the reordering degree is higher
+		 * than we realized. If there are no retransmits out then we
+		 * can undo. Otherwise we clock out new packets but do not
+		 * mark more packets lost or retransmit more.
+		 */
+		if (tp->retrans_out) {
+			tcp_cwnd_reduction(sk, prior_unsacked, 0);
+			return true;
+		}
+
+		if (!tcp_any_retrans_done(sk))
+			tp->retrans_stamp = 0;
+
+		DBGUNDO(sk, "partial recovery");
+		tcp_undo_cwnd_reduction(sk, true);
+		NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPPARTIALUNDO);
+		tcp_try_keep_open(sk);
+		return true;
+	}
+	return false;
+}
+
 /* Process an event, which can update packets-in-flight not trivially.
  * Main goal of this function is to calculate new estimate for left_out,
  * taking into account both packets sitting in receiver's buffer and
@@ -2742,15 +2678,14 @@ static void tcp_process_loss(struct sock *sk, int flag, bool is_dupack)
  * It does _not_ decide what to send, it is made in function
  * tcp_xmit_retransmit_queue().
  */
-static void tcp_fastretrans_alert(struct sock *sk, int pkts_acked,
-				  int prior_sacked, int prior_packets,
+static void tcp_fastretrans_alert(struct sock *sk, const int acked,
+				  const int prior_unsacked,
 				  bool is_dupack, int flag)
 {
 	struct inet_connection_sock *icsk = inet_csk(sk);
 	struct tcp_sock *tp = tcp_sk(sk);
-	int do_lost = is_dupack || ((flag & FLAG_DATA_SACKED) &&
+	bool do_lost = is_dupack || ((flag & FLAG_DATA_SACKED) &&
 				    (tcp_fackets_out(tp) > tp->reordering));
-	int newly_acked_sacked = 0;
 	int fast_rexmit = 0;
 
 	if (WARN_ON(!tp->packets_out && tp->sacked_out))
@@ -2802,10 +2737,17 @@ static void tcp_fastretrans_alert(struct sock *sk, int pkts_acked,
 		if (!(flag & FLAG_SND_UNA_ADVANCED)) {
 			if (tcp_is_reno(tp) && is_dupack)
 				tcp_add_reno_sack(sk);
-		} else
-			do_lost = tcp_try_undo_partial(sk, pkts_acked);
-		newly_acked_sacked = prior_packets - tp->packets_out +
-				     tp->sacked_out - prior_sacked;
+		} else {
+			if (tcp_try_undo_partial(sk, acked, prior_unsacked))
+				return;
+			/* Partial ACK arrived. Force fast retransmit. */
+			do_lost = tcp_is_reno(tp) ||
+				  tcp_fackets_out(tp) > tp->reordering;
+		}
+		if (tcp_try_undo_dsack(sk)) {
+			tcp_try_keep_open(sk);
+			return;
+		}
 		break;
 	case TCP_CA_Loss:
 		tcp_process_loss(sk, flag, is_dupack);
@@ -2819,14 +2761,12 @@ static void tcp_fastretrans_alert(struct sock *sk, int pkts_acked,
 			if (is_dupack)
 				tcp_add_reno_sack(sk);
 		}
-		newly_acked_sacked = prior_packets - tp->packets_out +
-				     tp->sacked_out - prior_sacked;
 
 		if (icsk->icsk_ca_state <= TCP_CA_Disorder)
 			tcp_try_undo_dsack(sk);
 
 		if (!tcp_time_to_recover(sk, flag)) {
-			tcp_try_to_open(sk, flag, newly_acked_sacked);
+			tcp_try_to_open(sk, flag, prior_unsacked);
 			return;
 		}
 
@@ -2846,9 +2786,9 @@ static void tcp_fastretrans_alert(struct sock *sk, int pkts_acked,
 		fast_rexmit = 1;
 	}
 
-	if (do_lost || (tcp_is_fack(tp) && tcp_head_timedout(sk)))
+	if (do_lost)
 		tcp_update_scoreboard(sk, fast_rexmit);
-	tcp_cwnd_reduction(sk, newly_acked_sacked, fast_rexmit);
+	tcp_cwnd_reduction(sk, prior_unsacked, fast_rexmit);
 	tcp_xmit_retransmit_queue(sk);
 }
 
@@ -3079,7 +3019,6 @@ static int tcp_clean_rtx_queue(struct sock *sk, int prior_fackets,
 
 		tcp_unlink_write_queue(skb, sk);
 		sk_wmem_free_skb(sk, skb);
-		tp->scoreboard_skb_hint = NULL;
 		if (skb == tp->retransmit_skb_hint)
 			tp->retransmit_skb_hint = NULL;
 		if (skb == tp->lost_skb_hint)
@@ -3333,9 +3272,8 @@ static int tcp_ack(struct sock *sk, const struct sk_buff *skb, int flag)
 	u32 prior_in_flight;
 	u32 prior_fackets;
 	int prior_packets = tp->packets_out;
-	int prior_sacked = tp->sacked_out;
-	int pkts_acked = 0;
-	int previous_packets_out = 0;
+	const int prior_unsacked = tp->packets_out - tp->sacked_out;
+	int acked = 0; /* Number of packets newly acked */
 
 	/* If the ack is older than previous acks
 	 * then we can probably ignore it.
@@ -3410,18 +3348,17 @@ static int tcp_ack(struct sock *sk, const struct sk_buff *skb, int flag)
 		goto no_queue;
 
 	/* See if we can take anything off of the retransmit queue. */
-	previous_packets_out = tp->packets_out;
+	acked = tp->packets_out;
 	flag |= tcp_clean_rtx_queue(sk, prior_fackets, prior_snd_una);
-
-	pkts_acked = previous_packets_out - tp->packets_out;
+	acked -= tp->packets_out;
 
 	if (tcp_ack_is_dubious(sk, flag)) {
 		/* Advance CWND, if state allows this. */
 		if ((flag & FLAG_DATA_ACKED) && tcp_may_raise_cwnd(sk, flag))
 			tcp_cong_avoid(sk, ack, prior_in_flight);
 		is_dupack = !(flag & (FLAG_SND_UNA_ADVANCED | FLAG_NOT_DUP));
-		tcp_fastretrans_alert(sk, pkts_acked, prior_sacked,
-				      prior_packets, is_dupack, flag);
+		tcp_fastretrans_alert(sk, acked, prior_unsacked,
+				      is_dupack, flag);
 	} else {
 		if (flag & FLAG_DATA_ACKED)
 			tcp_cong_avoid(sk, ack, prior_in_flight);
@@ -3443,8 +3380,8 @@ static int tcp_ack(struct sock *sk, const struct sk_buff *skb, int flag)
 no_queue:
 	/* If data was DSACKed, see if we can undo a cwnd reduction. */
 	if (flag & FLAG_DSACKING_ACK)
-		tcp_fastretrans_alert(sk, pkts_acked, prior_sacked,
-				      prior_packets, is_dupack, flag);
+		tcp_fastretrans_alert(sk, acked, prior_unsacked,
+				      is_dupack, flag);
 	/* If this ack opens up a zero window, clear backoff.  It was
 	 * being used to time the probes, and is probably far higher than
 	 * it needs to be for normal retransmission.
@@ -3466,8 +3403,8 @@ old_ack:
 	 */
 	if (TCP_SKB_CB(skb)->sacked) {
 		flag |= tcp_sacktag_write_queue(sk, skb, prior_snd_una);
-		tcp_fastretrans_alert(sk, pkts_acked, prior_sacked,
-				      prior_packets, is_dupack, flag);
+		tcp_fastretrans_alert(sk, acked, prior_unsacked,
+				      is_dupack, flag);
 	}
 
 	SOCK_DEBUG(sk, "Ack %u before %u:%u\n", ack, tp->snd_una, tp->snd_nxt);
@@ -3780,6 +3717,7 @@ void tcp_reset(struct sock *sk)
 static void tcp_fin(struct sock *sk)
 {
 	struct tcp_sock *tp = tcp_sk(sk);
+	const struct dst_entry *dst;
 
 	inet_csk_schedule_ack(sk);
 
@@ -3791,7 +3729,9 @@ static void tcp_fin(struct sock *sk)
 	case TCP_ESTABLISHED:
 		/* Move to CLOSE_WAIT */
 		tcp_set_state(sk, TCP_CLOSE_WAIT);
-		inet_csk(sk)->icsk_ack.pingpong = 1;
+		dst = __sk_dst_get(sk);
+		if (!dst || !dst_metric(dst, RTAX_QUICKACK))
+			inet_csk(sk)->icsk_ack.pingpong = 1;
 		break;
 
 	case TCP_CLOSE_WAIT:
@@ -5601,6 +5541,7 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
 	struct inet_connection_sock *icsk = inet_csk(sk);
 	struct request_sock *req;
 	int queued = 0;
+	bool acceptable;
 
 	tp->rx_opt.saw_tstamp = 0;
 
@@ -5671,157 +5612,147 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
 		return 0;
 
 	/* step 5: check the ACK field */
-	if (true) {
-		int acceptable = tcp_ack(sk, skb, FLAG_SLOWPATH |
-						  FLAG_UPDATE_TS_RECENT) > 0;
-
-		switch (sk->sk_state) {
-		case TCP_SYN_RECV:
-			if (acceptable) {
-				/* Once we leave TCP_SYN_RECV, we no longer
-				 * need req so release it.
-				 */
-				if (req) {
-					tcp_synack_rtt_meas(sk, req);
-					tp->total_retrans = req->num_retrans;
-
-					reqsk_fastopen_remove(sk, req, false);
-				} else {
-					/* Make sure socket is routed, for
-					 * correct metrics.
-					 */
-					icsk->icsk_af_ops->rebuild_header(sk);
-					tcp_init_congestion_control(sk);
+	acceptable = tcp_ack(sk, skb, FLAG_SLOWPATH |
+				      FLAG_UPDATE_TS_RECENT) > 0;
 
-					tcp_mtup_init(sk);
-					tcp_init_buffer_space(sk);
-					tp->copied_seq = tp->rcv_nxt;
-				}
-				smp_mb();
-				tcp_set_state(sk, TCP_ESTABLISHED);
-				sk->sk_state_change(sk);
-
-				/* Note, that this wakeup is only for marginal
-				 * crossed SYN case. Passively open sockets
-				 * are not waked up, because sk->sk_sleep ==
-				 * NULL and sk->sk_socket == NULL.
-				 */
-				if (sk->sk_socket)
-					sk_wake_async(sk,
-						      SOCK_WAKE_IO, POLL_OUT);
-
-				tp->snd_una = TCP_SKB_CB(skb)->ack_seq;
-				tp->snd_wnd = ntohs(th->window) <<
-					      tp->rx_opt.snd_wscale;
-				tcp_init_wl(tp, TCP_SKB_CB(skb)->seq);
-
-				if (tp->rx_opt.tstamp_ok)
-					tp->advmss -= TCPOLEN_TSTAMP_ALIGNED;
-
-				if (req) {
-					/* Re-arm the timer because data may
-					 * have been sent out. This is similar
-					 * to the regular data transmission case
-					 * when new data has just been ack'ed.
-					 *
-					 * (TFO) - we could try to be more
-					 * aggressive and retranmitting any data
-					 * sooner based on when they were sent
-					 * out.
-					 */
-					tcp_rearm_rto(sk);
-				} else
-					tcp_init_metrics(sk);
+	switch (sk->sk_state) {
+	case TCP_SYN_RECV:
+		if (!acceptable)
+			return 1;
 
-				/* Prevent spurious tcp_cwnd_restart() on
-				 * first data packet.
-				 */
-				tp->lsndtime = tcp_time_stamp;
+		/* Once we leave TCP_SYN_RECV, we no longer need req
+		 * so release it.
+		 */
+		if (req) {
+			tcp_synack_rtt_meas(sk, req);
+			tp->total_retrans = req->num_retrans;
 
-				tcp_initialize_rcv_mss(sk);
-				tcp_fast_path_on(tp);
-			} else {
-				return 1;
-			}
-			break;
+			reqsk_fastopen_remove(sk, req, false);
+		} else {
+			/* Make sure socket is routed, for correct metrics. */
+			icsk->icsk_af_ops->rebuild_header(sk);
+			tcp_init_congestion_control(sk);
+
+			tcp_mtup_init(sk);
+			tcp_init_buffer_space(sk);
+			tp->copied_seq = tp->rcv_nxt;
+		}
+		smp_mb();
+		tcp_set_state(sk, TCP_ESTABLISHED);
+		sk->sk_state_change(sk);
+
+		/* Note, that this wakeup is only for marginal crossed SYN case.
+		 * Passively open sockets are not waked up, because
+		 * sk->sk_sleep == NULL and sk->sk_socket == NULL.
+		 */
+		if (sk->sk_socket)
+			sk_wake_async(sk, SOCK_WAKE_IO, POLL_OUT);
+
+		tp->snd_una = TCP_SKB_CB(skb)->ack_seq;
+		tp->snd_wnd = ntohs(th->window) << tp->rx_opt.snd_wscale;
+		tcp_init_wl(tp, TCP_SKB_CB(skb)->seq);
 
-		case TCP_FIN_WAIT1:
-			/* If we enter the TCP_FIN_WAIT1 state and we are a
-			 * Fast Open socket and this is the first acceptable
-			 * ACK we have received, this would have acknowledged
-			 * our SYNACK so stop the SYNACK timer.
+		if (tp->rx_opt.tstamp_ok)
+			tp->advmss -= TCPOLEN_TSTAMP_ALIGNED;
+
+		if (req) {
+			/* Re-arm the timer because data may have been sent out.
+			 * This is similar to the regular data transmission case
+			 * when new data has just been ack'ed.
+			 *
+			 * (TFO) - we could try to be more aggressive and
+			 * retransmitting any data sooner based on when they
+			 * are sent out.
 			 */
-			if (req != NULL) {
-				/* Return RST if ack_seq is invalid.
-				 * Note that RFC793 only says to generate a
-				 * DUPACK for it but for TCP Fast Open it seems
-				 * better to treat this case like TCP_SYN_RECV
-				 * above.
-				 */
-				if (!acceptable)
-					return 1;
-				/* We no longer need the request sock. */
-				reqsk_fastopen_remove(sk, req, false);
-				tcp_rearm_rto(sk);
-			}
-			if (tp->snd_una == tp->write_seq) {
-				struct dst_entry *dst;
-
-				tcp_set_state(sk, TCP_FIN_WAIT2);
-				sk->sk_shutdown |= SEND_SHUTDOWN;
-
-				dst = __sk_dst_get(sk);
-				if (dst)
-					dst_confirm(dst);
-
-				if (!sock_flag(sk, SOCK_DEAD))
-					/* Wake up lingering close() */
-					sk->sk_state_change(sk);
-				else {
-					int tmo;
-
-					if (tp->linger2 < 0 ||
-					    (TCP_SKB_CB(skb)->end_seq != TCP_SKB_CB(skb)->seq &&
-					     after(TCP_SKB_CB(skb)->end_seq - th->fin, tp->rcv_nxt))) {
-						tcp_done(sk);
-						NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPABORTONDATA);
-						return 1;
-					}
+			tcp_rearm_rto(sk);
+		} else
+			tcp_init_metrics(sk);
 
-					tmo = tcp_fin_time(sk);
-					if (tmo > TCP_TIMEWAIT_LEN) {
-						inet_csk_reset_keepalive_timer(sk, tmo - TCP_TIMEWAIT_LEN);
-					} else if (th->fin || sock_owned_by_user(sk)) {
-						/* Bad case. We could lose such FIN otherwise.
-						 * It is not a big problem, but it looks confusing
-						 * and not so rare event. We still can lose it now,
-						 * if it spins in bh_lock_sock(), but it is really
-						 * marginal case.
-						 */
-						inet_csk_reset_keepalive_timer(sk, tmo);
-					} else {
-						tcp_time_wait(sk, TCP_FIN_WAIT2, tmo);
-						goto discard;
-					}
-				}
-			}
-			break;
+		/* Prevent spurious tcp_cwnd_restart() on first data packet */
+		tp->lsndtime = tcp_time_stamp;
 
-		case TCP_CLOSING:
-			if (tp->snd_una == tp->write_seq) {
-				tcp_time_wait(sk, TCP_TIME_WAIT, 0);
-				goto discard;
-			}
+		tcp_initialize_rcv_mss(sk);
+		tcp_fast_path_on(tp);
+		break;
+
+	case TCP_FIN_WAIT1: {
+		struct dst_entry *dst;
+		int tmo;
+
+		/* If we enter the TCP_FIN_WAIT1 state and we are a
+		 * Fast Open socket and this is the first acceptable
+		 * ACK we have received, this would have acknowledged
+		 * our SYNACK so stop the SYNACK timer.
+		 */
+		if (req != NULL) {
+			/* Return RST if ack_seq is invalid.
+			 * Note that RFC793 only says to generate a
+			 * DUPACK for it but for TCP Fast Open it seems
+			 * better to treat this case like TCP_SYN_RECV
+			 * above.
+			 */
+			if (!acceptable)
+				return 1;
+			/* We no longer need the request sock. */
+			reqsk_fastopen_remove(sk, req, false);
+			tcp_rearm_rto(sk);
+		}
+		if (tp->snd_una != tp->write_seq)
 			break;
 
-		case TCP_LAST_ACK:
-			if (tp->snd_una == tp->write_seq) {
-				tcp_update_metrics(sk);
-				tcp_done(sk);
-				goto discard;
-			}
+		tcp_set_state(sk, TCP_FIN_WAIT2);
+		sk->sk_shutdown |= SEND_SHUTDOWN;
+
+		dst = __sk_dst_get(sk);
+		if (dst)
+			dst_confirm(dst);
+
+		if (!sock_flag(sk, SOCK_DEAD)) {
+			/* Wake up lingering close() */
+			sk->sk_state_change(sk);
 			break;
 		}
+
+		if (tp->linger2 < 0 ||
+		    (TCP_SKB_CB(skb)->end_seq != TCP_SKB_CB(skb)->seq &&
+		     after(TCP_SKB_CB(skb)->end_seq - th->fin, tp->rcv_nxt))) {
+			tcp_done(sk);
+			NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPABORTONDATA);
+			return 1;
+		}
+
+		tmo = tcp_fin_time(sk);
+		if (tmo > TCP_TIMEWAIT_LEN) {
+			inet_csk_reset_keepalive_timer(sk, tmo - TCP_TIMEWAIT_LEN);
+		} else if (th->fin || sock_owned_by_user(sk)) {
+			/* Bad case. We could lose such FIN otherwise.
+			 * It is not a big problem, but it looks confusing
+			 * and not so rare event. We still can lose it now,
+			 * if it spins in bh_lock_sock(), but it is really
+			 * marginal case.
+			 */
+			inet_csk_reset_keepalive_timer(sk, tmo);
+		} else {
+			tcp_time_wait(sk, TCP_FIN_WAIT2, tmo);
+			goto discard;
+		}
+		break;
+	}
+
+	case TCP_CLOSING:
+		if (tp->snd_una == tp->write_seq) {
+			tcp_time_wait(sk, TCP_TIME_WAIT, 0);
+			goto discard;
+		}
+		break;
+
+	case TCP_LAST_ACK:
+		if (tp->snd_una == tp->write_seq) {
+			tcp_update_metrics(sk);
+			tcp_done(sk);
+			goto discard;
+		}
+		break;
 	}
 
 	/* step 6: check the URG bit */