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

Pull networking updates from David Miller:
 "Most notable changes in here:

   1) By far the biggest accomplishment, thanks to a large range of
      contributors, is the addition of multi-send for transmit.  This is
      the result of discussions back in Chicago, and the hard work of
      several individuals.

      Now, when the ->ndo_start_xmit() method of a driver sees
      skb->xmit_more as true, it can choose to defer the doorbell
      telling the driver to start processing the new TX queue entires.

      skb->xmit_more means that the generic networking is guaranteed to
      call the driver immediately with another SKB to send.

      There is logic added to the qdisc layer to dequeue multiple
      packets at a time, and the handling mis-predicted offloads in
      software is now done with no locks held.

      Finally, pktgen is extended to have a "burst" parameter that can
      be used to test a multi-send implementation.

      Several drivers have xmit_more support: i40e, igb, ixgbe, mlx4,
      virtio_net

      Adding support is almost trivial, so export more drivers to
      support this optimization soon.

      I want to thank, in no particular or implied order, Jesper
      Dangaard Brouer, Eric Dumazet, Alexander Duyck, Tom Herbert, Jamal
      Hadi Salim, John Fastabend, Florian Westphal, Daniel Borkmann,
      David Tat, Hannes Frederic Sowa, and Rusty Russell.

   2) PTP and timestamping support in bnx2x, from Michal Kalderon.

   3) Allow adjusting the rx_copybreak threshold for a driver via
      ethtool, and add rx_copybreak support to enic driver.  From
      Govindarajulu Varadarajan.

   4) Significant enhancements to the generic PHY layer and the bcm7xxx
      driver in particular (EEE support, auto power down, etc.) from
      Florian Fainelli.

   5) Allow raw buffers to be used for flow dissection, allowing drivers
      to determine the optimal "linear pull" size for devices that DMA
      into pools of pages.  The objective is to get exactly the
      necessary amount of headers into the linear SKB area pre-pulled,
      but no more.  The new interface drivers use is eth_get_headlen().
      From WANG Cong, with driver conversions (several had their own
      by-hand duplicated implementations) by Alexander Duyck and Eric
      Dumazet.

   6) Support checksumming more smoothly and efficiently for
      encapsulations, and add "foo over UDP" facility.  From Tom
      Herbert.

   7) Add Broadcom SF2 switch driver to DSA layer, from Florian
      Fainelli.

   8) eBPF now can load programs via a system call and has an extensive
      testsuite.  Alexei Starovoitov and Daniel Borkmann.

   9) Major overhaul of the packet scheduler to use RCU in several major
      areas such as the classifiers and rate estimators.  From John
      Fastabend.

  10) Add driver for Intel FM10000 Ethernet Switch, from Alexander
      Duyck.

  11) Rearrange TCP_SKB_CB() to reduce cache line misses, from Eric
      Dumazet.

  12) Add Datacenter TCP congestion control algorithm support, From
      Florian Westphal.

  13) Reorganize sk_buff so that __copy_skb_header() is significantly
      faster.  From Eric Dumazet"

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (1558 commits)
  netlabel: directly return netlbl_unlabel_genl_init()
  net: add netdev_txq_bql_{enqueue, complete}_prefetchw() helpers
  net: description of dma_cookie cause make xmldocs warning
  cxgb4: clean up a type issue
  cxgb4: potential shift wrapping bug
  i40e: skb->xmit_more support
  net: fs_enet: Add NAPI TX
  net: fs_enet: Remove non NAPI RX
  r8169:add support for RTL8168EP
  net_sched: copy exts->type in tcf_exts_change()
  wimax: convert printk to pr_foo()
  af_unix: remove 0 assignment on static
  ipv6: Do not warn for informational ICMP messages, regardless of type.
  Update Intel Ethernet Driver maintainers list
  bridge: Save frag_max_size between PRE_ROUTING and POST_ROUTING
  tipc: fix bug in multicast congestion handling
  net: better IFF_XMIT_DST_RELEASE support
  net/mlx4_en: remove NETDEV_TX_BUSY
  3c59x: fix bad split of cpu_to_le32(pci_map_single())
  net: bcmgenet: fix Tx ring priority programming
  ...

1 files changed, 344 insertions, 0 deletions

diff --git a/net/ipv4/tcp_dctcp.c b/net/ipv4/tcp_dctcp.c
new file mode 100644
index 000000000000..b504371af742
--- /dev/null
+++ b/net/ipv4/tcp_dctcp.c
@@ -0,0 +1,344 @@
+/* DataCenter TCP (DCTCP) congestion control.
+ *
+ * http://simula.stanford.edu/~alizade/Site/DCTCP.html
+ *
+ * This is an implementation of DCTCP over Reno, an enhancement to the
+ * TCP congestion control algorithm designed for data centers. DCTCP
+ * leverages Explicit Congestion Notification (ECN) in the network to
+ * provide multi-bit feedback to the end hosts. DCTCP's goal is to meet
+ * the following three data center transport requirements:
+ *
+ *  - High burst tolerance (incast due to partition/aggregate)
+ *  - Low latency (short flows, queries)
+ *  - High throughput (continuous data updates, large file transfers)
+ *    with commodity shallow buffered switches
+ *
+ * The algorithm is described in detail in the following two papers:
+ *
+ * 1) Mohammad Alizadeh, Albert Greenberg, David A. Maltz, Jitendra Padhye,
+ *    Parveen Patel, Balaji Prabhakar, Sudipta Sengupta, and Murari Sridharan:
+ *      "Data Center TCP (DCTCP)", Data Center Networks session
+ *      Proc. ACM SIGCOMM, New Delhi, 2010.
+ *   http://simula.stanford.edu/~alizade/Site/DCTCP_files/dctcp-final.pdf
+ *
+ * 2) Mohammad Alizadeh, Adel Javanmard, and Balaji Prabhakar:
+ *      "Analysis of DCTCP: Stability, Convergence, and Fairness"
+ *      Proc. ACM SIGMETRICS, San Jose, 2011.
+ *   http://simula.stanford.edu/~alizade/Site/DCTCP_files/dctcp_analysis-full.pdf
+ *
+ * Initial prototype from Abdul Kabbani, Masato Yasuda and Mohammad Alizadeh.
+ *
+ * Authors:
+ *
+ *	Daniel Borkmann <dborkman@redhat.com>
+ *	Florian Westphal <fw@strlen.de>
+ *	Glenn Judd <glenn.judd@morganstanley.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or (at
+ * your option) any later version.
+ */
+
+#include <linux/module.h>
+#include <linux/mm.h>
+#include <net/tcp.h>
+#include <linux/inet_diag.h>
+
+#define DCTCP_MAX_ALPHA	1024U
+
+struct dctcp {
+	u32 acked_bytes_ecn;
+	u32 acked_bytes_total;
+	u32 prior_snd_una;
+	u32 prior_rcv_nxt;
+	u32 dctcp_alpha;
+	u32 next_seq;
+	u32 ce_state;
+	u32 delayed_ack_reserved;
+};
+
+static unsigned int dctcp_shift_g __read_mostly = 4; /* g = 1/2^4 */
+module_param(dctcp_shift_g, uint, 0644);
+MODULE_PARM_DESC(dctcp_shift_g, "parameter g for updating dctcp_alpha");
+
+static unsigned int dctcp_alpha_on_init __read_mostly = DCTCP_MAX_ALPHA;
+module_param(dctcp_alpha_on_init, uint, 0644);
+MODULE_PARM_DESC(dctcp_alpha_on_init, "parameter for initial alpha value");
+
+static unsigned int dctcp_clamp_alpha_on_loss __read_mostly;
+module_param(dctcp_clamp_alpha_on_loss, uint, 0644);
+MODULE_PARM_DESC(dctcp_clamp_alpha_on_loss,
+		 "parameter for clamping alpha on loss");
+
+static struct tcp_congestion_ops dctcp_reno;
+
+static void dctcp_reset(const struct tcp_sock *tp, struct dctcp *ca)
+{
+	ca->next_seq = tp->snd_nxt;
+
+	ca->acked_bytes_ecn = 0;
+	ca->acked_bytes_total = 0;
+}
+
+static void dctcp_init(struct sock *sk)
+{
+	const struct tcp_sock *tp = tcp_sk(sk);
+
+	if ((tp->ecn_flags & TCP_ECN_OK) ||
+	    (sk->sk_state == TCP_LISTEN ||
+	     sk->sk_state == TCP_CLOSE)) {
+		struct dctcp *ca = inet_csk_ca(sk);
+
+		ca->prior_snd_una = tp->snd_una;
+		ca->prior_rcv_nxt = tp->rcv_nxt;
+
+		ca->dctcp_alpha = min(dctcp_alpha_on_init, DCTCP_MAX_ALPHA);
+
+		ca->delayed_ack_reserved = 0;
+		ca->ce_state = 0;
+
+		dctcp_reset(tp, ca);
+		return;
+	}
+
+	/* No ECN support? Fall back to Reno. Also need to clear
+	 * ECT from sk since it is set during 3WHS for DCTCP.
+	 */
+	inet_csk(sk)->icsk_ca_ops = &dctcp_reno;
+	INET_ECN_dontxmit(sk);
+}
+
+static u32 dctcp_ssthresh(struct sock *sk)
+{
+	const struct dctcp *ca = inet_csk_ca(sk);
+	struct tcp_sock *tp = tcp_sk(sk);
+
+	return max(tp->snd_cwnd - ((tp->snd_cwnd * ca->dctcp_alpha) >> 11U), 2U);
+}
+
+/* Minimal DCTP CE state machine:
+ *
+ * S:	0 <- last pkt was non-CE
+ *	1 <- last pkt was CE
+ */
+
+static void dctcp_ce_state_0_to_1(struct sock *sk)
+{
+	struct dctcp *ca = inet_csk_ca(sk);
+	struct tcp_sock *tp = tcp_sk(sk);
+
+	/* State has changed from CE=0 to CE=1 and delayed
+	 * ACK has not sent yet.
+	 */
+	if (!ca->ce_state && ca->delayed_ack_reserved) {
+		u32 tmp_rcv_nxt;
+
+		/* Save current rcv_nxt. */
+		tmp_rcv_nxt = tp->rcv_nxt;
+
+		/* Generate previous ack with CE=0. */
+		tp->ecn_flags &= ~TCP_ECN_DEMAND_CWR;
+		tp->rcv_nxt = ca->prior_rcv_nxt;
+
+		tcp_send_ack(sk);
+
+		/* Recover current rcv_nxt. */
+		tp->rcv_nxt = tmp_rcv_nxt;
+	}
+
+	ca->prior_rcv_nxt = tp->rcv_nxt;
+	ca->ce_state = 1;
+
+	tp->ecn_flags |= TCP_ECN_DEMAND_CWR;
+}
+
+static void dctcp_ce_state_1_to_0(struct sock *sk)
+{
+	struct dctcp *ca = inet_csk_ca(sk);
+	struct tcp_sock *tp = tcp_sk(sk);
+
+	/* State has changed from CE=1 to CE=0 and delayed
+	 * ACK has not sent yet.
+	 */
+	if (ca->ce_state && ca->delayed_ack_reserved) {
+		u32 tmp_rcv_nxt;
+
+		/* Save current rcv_nxt. */
+		tmp_rcv_nxt = tp->rcv_nxt;
+
+		/* Generate previous ack with CE=1. */
+		tp->ecn_flags |= TCP_ECN_DEMAND_CWR;
+		tp->rcv_nxt = ca->prior_rcv_nxt;
+
+		tcp_send_ack(sk);
+
+		/* Recover current rcv_nxt. */
+		tp->rcv_nxt = tmp_rcv_nxt;
+	}
+
+	ca->prior_rcv_nxt = tp->rcv_nxt;
+	ca->ce_state = 0;
+
+	tp->ecn_flags &= ~TCP_ECN_DEMAND_CWR;
+}
+
+static void dctcp_update_alpha(struct sock *sk, u32 flags)
+{
+	const struct tcp_sock *tp = tcp_sk(sk);
+	struct dctcp *ca = inet_csk_ca(sk);
+	u32 acked_bytes = tp->snd_una - ca->prior_snd_una;
+
+	/* If ack did not advance snd_una, count dupack as MSS size.
+	 * If ack did update window, do not count it at all.
+	 */
+	if (acked_bytes == 0 && !(flags & CA_ACK_WIN_UPDATE))
+		acked_bytes = inet_csk(sk)->icsk_ack.rcv_mss;
+	if (acked_bytes) {
+		ca->acked_bytes_total += acked_bytes;
+		ca->prior_snd_una = tp->snd_una;
+
+		if (flags & CA_ACK_ECE)
+			ca->acked_bytes_ecn += acked_bytes;
+	}
+
+	/* Expired RTT */
+	if (!before(tp->snd_una, ca->next_seq)) {
+		/* For avoiding denominator == 1. */
+		if (ca->acked_bytes_total == 0)
+			ca->acked_bytes_total = 1;
+
+		/* alpha = (1 - g) * alpha + g * F */
+		ca->dctcp_alpha = ca->dctcp_alpha -
+				  (ca->dctcp_alpha >> dctcp_shift_g) +
+				  (ca->acked_bytes_ecn << (10U - dctcp_shift_g)) /
+				  ca->acked_bytes_total;
+
+		if (ca->dctcp_alpha > DCTCP_MAX_ALPHA)
+			/* Clamp dctcp_alpha to max. */
+			ca->dctcp_alpha = DCTCP_MAX_ALPHA;
+
+		dctcp_reset(tp, ca);
+	}
+}
+
+static void dctcp_state(struct sock *sk, u8 new_state)
+{
+	if (dctcp_clamp_alpha_on_loss && new_state == TCP_CA_Loss) {
+		struct dctcp *ca = inet_csk_ca(sk);
+
+		/* If this extension is enabled, we clamp dctcp_alpha to
+		 * max on packet loss; the motivation is that dctcp_alpha
+		 * is an indicator to the extend of congestion and packet
+		 * loss is an indicator of extreme congestion; setting
+		 * this in practice turned out to be beneficial, and
+		 * effectively assumes total congestion which reduces the
+		 * window by half.
+		 */
+		ca->dctcp_alpha = DCTCP_MAX_ALPHA;
+	}
+}
+
+static void dctcp_update_ack_reserved(struct sock *sk, enum tcp_ca_event ev)
+{
+	struct dctcp *ca = inet_csk_ca(sk);
+
+	switch (ev) {
+	case CA_EVENT_DELAYED_ACK:
+		if (!ca->delayed_ack_reserved)
+			ca->delayed_ack_reserved = 1;
+		break;
+	case CA_EVENT_NON_DELAYED_ACK:
+		if (ca->delayed_ack_reserved)
+			ca->delayed_ack_reserved = 0;
+		break;
+	default:
+		/* Don't care for the rest. */
+		break;
+	}
+}
+
+static void dctcp_cwnd_event(struct sock *sk, enum tcp_ca_event ev)
+{
+	switch (ev) {
+	case CA_EVENT_ECN_IS_CE:
+		dctcp_ce_state_0_to_1(sk);
+		break;
+	case CA_EVENT_ECN_NO_CE:
+		dctcp_ce_state_1_to_0(sk);
+		break;
+	case CA_EVENT_DELAYED_ACK:
+	case CA_EVENT_NON_DELAYED_ACK:
+		dctcp_update_ack_reserved(sk, ev);
+		break;
+	default:
+		/* Don't care for the rest. */
+		break;
+	}
+}
+
+static void dctcp_get_info(struct sock *sk, u32 ext, struct sk_buff *skb)
+{
+	const struct dctcp *ca = inet_csk_ca(sk);
+
+	/* Fill it also in case of VEGASINFO due to req struct limits.
+	 * We can still correctly retrieve it later.
+	 */
+	if (ext & (1 << (INET_DIAG_DCTCPINFO - 1)) ||
+	    ext & (1 << (INET_DIAG_VEGASINFO - 1))) {
+		struct tcp_dctcp_info info;
+
+		memset(&info, 0, sizeof(info));
+		if (inet_csk(sk)->icsk_ca_ops != &dctcp_reno) {
+			info.dctcp_enabled = 1;
+			info.dctcp_ce_state = (u16) ca->ce_state;
+			info.dctcp_alpha = ca->dctcp_alpha;
+			info.dctcp_ab_ecn = ca->acked_bytes_ecn;
+			info.dctcp_ab_tot = ca->acked_bytes_total;
+		}
+
+		nla_put(skb, INET_DIAG_DCTCPINFO, sizeof(info), &info);
+	}
+}
+
+static struct tcp_congestion_ops dctcp __read_mostly = {
+	.init		= dctcp_init,
+	.in_ack_event   = dctcp_update_alpha,
+	.cwnd_event	= dctcp_cwnd_event,
+	.ssthresh	= dctcp_ssthresh,
+	.cong_avoid	= tcp_reno_cong_avoid,
+	.set_state	= dctcp_state,
+	.get_info	= dctcp_get_info,
+	.flags		= TCP_CONG_NEEDS_ECN,
+	.owner		= THIS_MODULE,
+	.name		= "dctcp",
+};
+
+static struct tcp_congestion_ops dctcp_reno __read_mostly = {
+	.ssthresh	= tcp_reno_ssthresh,
+	.cong_avoid	= tcp_reno_cong_avoid,
+	.get_info	= dctcp_get_info,
+	.owner		= THIS_MODULE,
+	.name		= "dctcp-reno",
+};
+
+static int __init dctcp_register(void)
+{
+	BUILD_BUG_ON(sizeof(struct dctcp) > ICSK_CA_PRIV_SIZE);
+	return tcp_register_congestion_control(&dctcp);
+}
+
+static void __exit dctcp_unregister(void)
+{
+	tcp_unregister_congestion_control(&dctcp);
+}
+
+module_init(dctcp_register);
+module_exit(dctcp_unregister);
+
+MODULE_AUTHOR("Daniel Borkmann <dborkman@redhat.com>");
+MODULE_AUTHOR("Florian Westphal <fw@strlen.de>");
+MODULE_AUTHOR("Glenn Judd <glenn.judd@morganstanley.com>");
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("DataCenter TCP (DCTCP)");