Merge tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linuxgrafted

Pull I3C updates from Alexandre Belloni:
 "A new driver this cycle, for the AMD AXI I3C controller.

  There are also new features such as IBI wakeup support, SETAASA device
  discovery and ACPI support for the the DAA methods, meaning we can now
  communicate with the SPD devices on DDR5 modules.

  New driver:
   - AMD AXI I3C master controller

  Subsystem:
   - I3C Common Command Code (CCC) handling improvements, especially
     around GET CCCs
   - SETAASA device discovery support
   - ACPI support for all existing DAA methods like SETDASA, SETNEWDA as
     well as I2C devices on I3C bus
   - IBI-based wakeup support

  Drivers:
   - dw: SETAASA support
   - mipi-i3c-hci: advertise IBI wakeup capability, AMD_PT I3C
     controller support, PIO queue management support for HCI v1.2
   - renesas: improve suspend to RAM support, add runtime PM support"

* tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linux: (70 commits)
  i3c: dw: reduce do_daa time if there's no client
  i3c: mipi-i3c-hci: Add support for AMD_PT I3C controller
  i3c: mipi-i3c-hci: Add PIO queue management support for HCI v1.2
  i3c: mipi-i3c-hci: Fix missing STAT_IBI_STATUS_THLD in PIO mode
  i3c: dw: rename "pclk" to "apb" to match dt-binding
  i3c: dw: make struct dw_i3c_cmd smaller
  i3c: dw: use COMMAND_PORT_TRANSFER_ARG instead of hardcoding
  i3c: renesas: Don't register devices when ENTDAA times out
  i3c: master: dw-i3c-master: fix OD timing for first broadcast
  i3c: mipi-i3c-hci: Advertise IBI wakeup capability
  i3c: mipi-i3c-hci: Factor out i3c_hci_sysdev()
  i3c: mipi-i3c-hci-pci: Propagate I3C wakeup requirements to PCI
  i3c: master: Reject IBI requests from non-IBI-capable devices
  i3c: master: Add helper to query bus wakeup requirements
  i3c: master: Report wakeup events for IBIs
  i3c: master: Support IBI-based wakeup capability
  i3c: master: Fix potential UAF in i3c_device_match()
  i3c: master: Fix potential UAF in i3c_device_uevent()
  i3c: Make dev->desc locking assumptions explicit
  i3c: master: Fix use-after-free of master->this
  ...

1 files changed, 317 insertions, 0 deletions

diff --git a/net/ipv4/tcp_htcp.c b/net/ipv4/tcp_htcp.c
new file mode 100644
index 000000000..81b96331b
--- /dev/null
+++ b/net/ipv4/tcp_htcp.c
@@ -0,0 +1,317 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * H-TCP congestion control. The algorithm is detailed in:
+ * R.N.Shorten, D.J.Leith:
+ *   "H-TCP: TCP for high-speed and long-distance networks"
+ *   Proc. PFLDnet, Argonne, 2004.
+ * https://www.hamilton.ie/net/htcp3.pdf
+ */
+
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <net/tcp.h>
+
+#define ALPHA_BASE	(1<<7)	/* 1.0 with shift << 7 */
+#define BETA_MIN	(1<<6)	/* 0.5 with shift << 7 */
+#define BETA_MAX	102	/* 0.8 with shift << 7 */
+
+static int use_rtt_scaling __read_mostly = 1;
+module_param(use_rtt_scaling, int, 0644);
+MODULE_PARM_DESC(use_rtt_scaling, "turn on/off RTT scaling");
+
+static int use_bandwidth_switch __read_mostly = 1;
+module_param(use_bandwidth_switch, int, 0644);
+MODULE_PARM_DESC(use_bandwidth_switch, "turn on/off bandwidth switcher");
+
+struct htcp {
+	u32	alpha;		/* Fixed point arith, << 7 */
+	u8	beta;           /* Fixed point arith, << 7 */
+	u8	modeswitch;	/* Delay modeswitch
+				   until we had at least one congestion event */
+	u16	pkts_acked;
+	u32	packetcount;
+	u32	minRTT;
+	u32	maxRTT;
+	u32	last_cong;	/* Time since last congestion event end */
+	u32	undo_last_cong;
+
+	u32	undo_maxRTT;
+	u32	undo_old_maxB;
+
+	/* Bandwidth estimation */
+	u32	minB;
+	u32	maxB;
+	u32	old_maxB;
+	u32	Bi;
+	u32	lasttime;
+};
+
+static inline u32 htcp_cong_time(const struct htcp *ca)
+{
+	return jiffies - ca->last_cong;
+}
+
+static inline u32 htcp_ccount(const struct htcp *ca)
+{
+	return htcp_cong_time(ca) / ca->minRTT;
+}
+
+static inline void htcp_reset(struct htcp *ca)
+{
+	ca->undo_last_cong = ca->last_cong;
+	ca->undo_maxRTT = ca->maxRTT;
+	ca->undo_old_maxB = ca->old_maxB;
+
+	ca->last_cong = jiffies;
+}
+
+static u32 htcp_cwnd_undo(struct sock *sk)
+{
+	struct htcp *ca = inet_csk_ca(sk);
+
+	if (ca->undo_last_cong) {
+		ca->last_cong = ca->undo_last_cong;
+		ca->maxRTT = ca->undo_maxRTT;
+		ca->old_maxB = ca->undo_old_maxB;
+		ca->undo_last_cong = 0;
+	}
+
+	return tcp_reno_undo_cwnd(sk);
+}
+
+static inline void measure_rtt(struct sock *sk, u32 srtt)
+{
+	const struct inet_connection_sock *icsk = inet_csk(sk);
+	struct htcp *ca = inet_csk_ca(sk);
+
+	/* keep track of minimum RTT seen so far, minRTT is zero at first */
+	if (ca->minRTT > srtt || !ca->minRTT)
+		ca->minRTT = srtt;
+
+	/* max RTT */
+	if (icsk->icsk_ca_state == TCP_CA_Open) {
+		if (ca->maxRTT < ca->minRTT)
+			ca->maxRTT = ca->minRTT;
+		if (ca->maxRTT < srtt &&
+		    srtt <= ca->maxRTT + msecs_to_jiffies(20))
+			ca->maxRTT = srtt;
+	}
+}
+
+static void measure_achieved_throughput(struct sock *sk,
+					const struct ack_sample *sample)
+{
+	const struct inet_connection_sock *icsk = inet_csk(sk);
+	const struct tcp_sock *tp = tcp_sk(sk);
+	struct htcp *ca = inet_csk_ca(sk);
+	u32 now = tcp_jiffies32;
+
+	if (icsk->icsk_ca_state == TCP_CA_Open)
+		ca->pkts_acked = sample->pkts_acked;
+
+	if (sample->rtt_us > 0)
+		measure_rtt(sk, usecs_to_jiffies(sample->rtt_us));
+
+	if (!use_bandwidth_switch)
+		return;
+
+	/* achieved throughput calculations */
+	if (!((1 << icsk->icsk_ca_state) & (TCPF_CA_Open | TCPF_CA_Disorder))) {
+		ca->packetcount = 0;
+		ca->lasttime = now;
+		return;
+	}
+
+	ca->packetcount += sample->pkts_acked;
+
+	if (ca->packetcount >= tcp_snd_cwnd(tp) - (ca->alpha >> 7 ? : 1) &&
+	    now - ca->lasttime >= ca->minRTT &&
+	    ca->minRTT > 0) {
+		__u32 cur_Bi = ca->packetcount * HZ / (now - ca->lasttime);
+
+		if (htcp_ccount(ca) <= 3) {
+			/* just after backoff */
+			ca->minB = ca->maxB = ca->Bi = cur_Bi;
+		} else {
+			ca->Bi = (3 * ca->Bi + cur_Bi) / 4;
+			if (ca->Bi > ca->maxB)
+				ca->maxB = ca->Bi;
+			if (ca->minB > ca->maxB)
+				ca->minB = ca->maxB;
+		}
+		ca->packetcount = 0;
+		ca->lasttime = now;
+	}
+}
+
+static inline void htcp_beta_update(struct htcp *ca, u32 minRTT, u32 maxRTT)
+{
+	if (use_bandwidth_switch) {
+		u32 maxB = ca->maxB;
+		u32 old_maxB = ca->old_maxB;
+
+		ca->old_maxB = ca->maxB;
+		if (!between(5 * maxB, 4 * old_maxB, 6 * old_maxB)) {
+			ca->beta = BETA_MIN;
+			ca->modeswitch = 0;
+			return;
+		}
+	}
+
+	if (ca->modeswitch && minRTT > msecs_to_jiffies(10) && maxRTT) {
+		ca->beta = (minRTT << 7) / maxRTT;
+		if (ca->beta < BETA_MIN)
+			ca->beta = BETA_MIN;
+		else if (ca->beta > BETA_MAX)
+			ca->beta = BETA_MAX;
+	} else {
+		ca->beta = BETA_MIN;
+		ca->modeswitch = 1;
+	}
+}
+
+static inline void htcp_alpha_update(struct htcp *ca)
+{
+	u32 minRTT = ca->minRTT;
+	u32 factor = 1;
+	u32 diff = htcp_cong_time(ca);
+
+	if (diff > HZ) {
+		diff -= HZ;
+		factor = 1 + (10 * diff + ((diff / 2) * (diff / 2) / HZ)) / HZ;
+	}
+
+	if (use_rtt_scaling && minRTT) {
+		u32 scale = (HZ << 3) / (10 * minRTT);
+
+		/* clamping ratio to interval [0.5,10]<<3 */
+		scale = clamp(scale, 1U << 2, 10U << 3);
+		factor = (factor << 3) / scale;
+		if (!factor)
+			factor = 1;
+	}
+
+	ca->alpha = 2 * factor * ((1 << 7) - ca->beta);
+	if (!ca->alpha)
+		ca->alpha = ALPHA_BASE;
+}
+
+/*
+ * After we have the rtt data to calculate beta, we'd still prefer to wait one
+ * rtt before we adjust our beta to ensure we are working from a consistent
+ * data.
+ *
+ * This function should be called when we hit a congestion event since only at
+ * that point do we really have a real sense of maxRTT (the queues en route
+ * were getting just too full now).
+ */
+static void htcp_param_update(struct sock *sk)
+{
+	struct htcp *ca = inet_csk_ca(sk);
+	u32 minRTT = ca->minRTT;
+	u32 maxRTT = ca->maxRTT;
+
+	htcp_beta_update(ca, minRTT, maxRTT);
+	htcp_alpha_update(ca);
+
+	/* add slowly fading memory for maxRTT to accommodate routing changes */
+	if (minRTT > 0 && maxRTT > minRTT)
+		ca->maxRTT = minRTT + ((maxRTT - minRTT) * 95) / 100;
+}
+
+static u32 htcp_recalc_ssthresh(struct sock *sk)
+{
+	const struct tcp_sock *tp = tcp_sk(sk);
+	const struct htcp *ca = inet_csk_ca(sk);
+
+	htcp_param_update(sk);
+	return max((tcp_snd_cwnd(tp) * ca->beta) >> 7, 2U);
+}
+
+static void htcp_cong_avoid(struct sock *sk, u32 ack, u32 acked)
+{
+	struct tcp_sock *tp = tcp_sk(sk);
+	struct htcp *ca = inet_csk_ca(sk);
+
+	if (!tcp_is_cwnd_limited(sk))
+		return;
+
+	if (tcp_in_slow_start(tp))
+		tcp_slow_start(tp, acked);
+	else {
+		/* In dangerous area, increase slowly.
+		 * In theory this is tp->snd_cwnd += alpha / tp->snd_cwnd
+		 */
+		if ((tp->snd_cwnd_cnt * ca->alpha)>>7 >= tcp_snd_cwnd(tp)) {
+			if (tcp_snd_cwnd(tp) < tp->snd_cwnd_clamp)
+				tcp_snd_cwnd_set(tp, tcp_snd_cwnd(tp) + 1);
+			tp->snd_cwnd_cnt = 0;
+			htcp_alpha_update(ca);
+		} else
+			tp->snd_cwnd_cnt += ca->pkts_acked;
+
+		ca->pkts_acked = 1;
+	}
+}
+
+static void htcp_init(struct sock *sk)
+{
+	struct htcp *ca = inet_csk_ca(sk);
+
+	memset(ca, 0, sizeof(struct htcp));
+	ca->alpha = ALPHA_BASE;
+	ca->beta = BETA_MIN;
+	ca->pkts_acked = 1;
+	ca->last_cong = jiffies;
+}
+
+static void htcp_state(struct sock *sk, u8 new_state)
+{
+	switch (new_state) {
+	case TCP_CA_Open:
+		{
+			struct htcp *ca = inet_csk_ca(sk);
+
+			if (ca->undo_last_cong) {
+				ca->last_cong = jiffies;
+				ca->undo_last_cong = 0;
+			}
+		}
+		break;
+	case TCP_CA_CWR:
+	case TCP_CA_Recovery:
+	case TCP_CA_Loss:
+		htcp_reset(inet_csk_ca(sk));
+		break;
+	}
+}
+
+static struct tcp_congestion_ops htcp __read_mostly = {
+	.init		= htcp_init,
+	.ssthresh	= htcp_recalc_ssthresh,
+	.cong_avoid	= htcp_cong_avoid,
+	.set_state	= htcp_state,
+	.undo_cwnd	= htcp_cwnd_undo,
+	.pkts_acked	= measure_achieved_throughput,
+	.owner		= THIS_MODULE,
+	.name		= "htcp",
+};
+
+static int __init htcp_register(void)
+{
+	BUILD_BUG_ON(sizeof(struct htcp) > ICSK_CA_PRIV_SIZE);
+	BUILD_BUG_ON(BETA_MIN >= BETA_MAX);
+	return tcp_register_congestion_control(&htcp);
+}
+
+static void __exit htcp_unregister(void)
+{
+	tcp_unregister_congestion_control(&htcp);
+}
+
+module_init(htcp_register);
+module_exit(htcp_unregister);
+
+MODULE_AUTHOR("Baruch Even");
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("H-TCP");