Merge tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-nextgrafted

Pull networking updates from Jakub Kicinski:
 "Core:

   - Add dedicated kmem_cache for typical/small skb->head, avoid having
     to access struct page at kfree time, and improve memory use.

   - Introduce sysctl to set default RPS configuration for new netdevs.

   - Define Netlink protocol specification format which can be used to
     describe messages used by each family and auto-generate parsers.
     Add tools for generating kernel data structures and uAPI headers.

   - Expose all net/core sysctls inside netns.

   - Remove 4s sleep in netpoll if carrier is instantly detected on
     boot.

   - Add configurable limit of MDB entries per port, and port-vlan.

   - Continue populating drop reasons throughout the stack.

   - Retire a handful of legacy Qdiscs and classifiers.

  Protocols:

   - Support IPv4 big TCP (TSO frames larger than 64kB).

   - Add IP_LOCAL_PORT_RANGE socket option, to control local port range
     on socket by socket basis.

   - Track and report in procfs number of MPTCP sockets used.

   - Support mixing IPv4 and IPv6 flows in the in-kernel MPTCP path
     manager.

   - IPv6: don't check net.ipv6.route.max_size and rely on garbage
     collection to free memory (similarly to IPv4).

   - Support Penultimate Segment Pop (PSP) flavor in SRv6 (RFC8986).

   - ICMP: add per-rate limit counters.

   - Add support for user scanning requests in ieee802154.

   - Remove static WEP support.

   - Support minimal Wi-Fi 7 Extremely High Throughput (EHT) rate
     reporting.

   - WiFi 7 EHT channel puncturing support (client & AP).

  BPF:

   - Add a rbtree data structure following the "next-gen data structure"
     precedent set by recently added linked list, that is, by using
     kfunc + kptr instead of adding a new BPF map type.

   - Expose XDP hints via kfuncs with initial support for RX hash and
     timestamp metadata.

   - Add BPF_F_NO_TUNNEL_KEY extension to bpf_skb_set_tunnel_key to
     better support decap on GRE tunnel devices not operating in collect
     metadata.

   - Improve x86 JIT's codegen for PROBE_MEM runtime error checks.

   - Remove the need for trace_printk_lock for bpf_trace_printk and
     bpf_trace_vprintk helpers.

   - Extend libbpf's bpf_tracing.h support for tracing arguments of
     kprobes/uprobes and syscall as a special case.

   - Significantly reduce the search time for module symbols by
     livepatch and BPF.

   - Enable cpumasks to be used as kptrs, which is useful for tracing
     programs tracking which tasks end up running on which CPUs in
     different time intervals.

   - Add support for BPF trampoline on s390x and riscv64.

   - Add capability to export the XDP features supported by the NIC.

   - Add __bpf_kfunc tag for marking kernel functions as kfuncs.

   - Add cgroup.memory=nobpf kernel parameter option to disable BPF
     memory accounting for container environments.

  Netfilter:

   - Remove the CLUSTERIP target. It has been marked as obsolete for
     years, and we still have WARN splats wrt races of the out-of-band
     /proc interface installed by this target.

   - Add 'destroy' commands to nf_tables. They are identical to the
     existing 'delete' commands, but do not return an error if the
     referenced object (set, chain, rule...) did not exist.

  Driver API:

   - Improve cpumask_local_spread() locality to help NICs set the right
     IRQ affinity on AMD platforms.

   - Separate C22 and C45 MDIO bus transactions more clearly.

   - Introduce new DCB table to control DSCP rewrite on egress.

   - Support configuration of Physical Layer Collision Avoidance (PLCA)
     Reconciliation Sublayer (RS) (802.3cg-2019). Modern version of
     shared medium Ethernet.

   - Support for MAC Merge layer (IEEE 802.3-2018 clause 99). Allowing
     preemption of low priority frames by high priority frames.

   - Add support for controlling MACSec offload using netlink SET.

   - Rework devlink instance refcounts to allow registration and
     de-registration under the instance lock. Split the code into
     multiple files, drop some of the unnecessarily granular locks and
     factor out common parts of netlink operation handling.

   - Add TX frame aggregation parameters (for USB drivers).

   - Add a new attr TCA_EXT_WARN_MSG to report TC (offload) warning
     messages with notifications for debug.

   - Allow offloading of UDP NEW connections via act_ct.

   - Add support for per action HW stats in TC.

   - Support hardware miss to TC action (continue processing in SW from
     a specific point in the action chain).

   - Warn if old Wireless Extension user space interface is used with
     modern cfg80211/mac80211 drivers. Do not support Wireless
     Extensions for Wi-Fi 7 devices at all. Everyone should switch to
     using nl80211 interface instead.

   - Improve the CAN bit timing configuration. Use extack to return
     error messages directly to user space, update the SJW handling,
     including the definition of a new default value that will benefit
     CAN-FD controllers, by increasing their oscillator tolerance.

  New hardware / drivers:

   - Ethernet:
      - nVidia BlueField-3 support (control traffic driver)
      - Ethernet support for imx93 SoCs
      - Motorcomm yt8531 gigabit Ethernet PHY
      - onsemi NCN26000 10BASE-T1S PHY (with support for PLCA)
      - Microchip LAN8841 PHY (incl. cable diagnostics and PTP)
      - Amlogic gxl MDIO mux

   - WiFi:
      - RealTek RTL8188EU (rtl8xxxu)
      - Qualcomm Wi-Fi 7 devices (ath12k)

   - CAN:
      - Renesas R-Car V4H

  Drivers:

   - Bluetooth:
      - Set Per Platform Antenna Gain (PPAG) for Intel controllers.

   - Ethernet NICs:
      - Intel (1G, igc):
         - support TSN / Qbv / packet scheduling features of i226 model
      - Intel (100G, ice):
         - use GNSS subsystem instead of TTY
         - multi-buffer XDP support
         - extend support for GPIO pins to E823 devices
      - nVidia/Mellanox:
         - update the shared buffer configuration on PFC commands
         - implement PTP adjphase function for HW offset control
         - TC support for Geneve and GRE with VF tunnel offload
         - more efficient crypto key management method
         - multi-port eswitch support
      - Netronome/Corigine:
         - add DCB IEEE support
         - support IPsec offloading for NFP3800
      - Freescale/NXP (enetc):
         - support XDP_REDIRECT for XDP non-linear buffers
         - improve reconfig, avoid link flap and waiting for idle
         - support MAC Merge layer
      - Other NICs:
         - sfc/ef100: add basic devlink support for ef100
         - ionic: rx_push mode operation (writing descriptors via MMIO)
         - bnxt: use the auxiliary bus abstraction for RDMA
         - r8169: disable ASPM and reset bus in case of tx timeout
         - cpsw: support QSGMII mode for J721e CPSW9G
         - cpts: support pulse-per-second output
         - ngbe: add an mdio bus driver
         - usbnet: optimize usbnet_bh() by avoiding unnecessary queuing
         - r8152: handle devices with FW with NCM support
         - amd-xgbe: support 10Mbps, 2.5GbE speeds and rx-adaptation
         - virtio-net: support multi buffer XDP
         - virtio/vsock: replace virtio_vsock_pkt with sk_buff
         - tsnep: XDP support

   - Ethernet high-speed switches:
      - nVidia/Mellanox (mlxsw):
         - add support for latency TLV (in FW control messages)
      - Microchip (sparx5):
         - separate explicit and implicit traffic forwarding rules, make
           the implicit rules always active
         - add support for egress DSCP rewrite
         - IS0 VCAP support (Ingress Classification)
         - IS2 VCAP filters (protos, L3 addrs, L4 ports, flags, ToS
           etc.)
         - ES2 VCAP support (Egress Access Control)
         - support for Per-Stream Filtering and Policing (802.1Q,
           8.6.5.1)

   - Ethernet embedded switches:
      - Marvell (mv88e6xxx):
         - add MAB (port auth) offload support
         - enable PTP receive for mv88e6390
      - NXP (ocelot):
         - support MAC Merge layer
         - support for the the vsc7512 internal copper phys
      - Microchip:
         - lan9303: convert to PHYLINK
         - lan966x: support TC flower filter statistics
         - lan937x: PTP support for KSZ9563/KSZ8563 and LAN937x
         - lan937x: support Credit Based Shaper configuration
         - ksz9477: support Energy Efficient Ethernet
      - other:
         - qca8k: convert to regmap read/write API, use bulk operations
         - rswitch: Improve TX timestamp accuracy

   - Intel WiFi (iwlwifi):
      - EHT (Wi-Fi 7) rate reporting
      - STEP equalizer support: transfer some STEP (connection to radio
        on platforms with integrated wifi) related parameters from the
        BIOS to the firmware.

   - Qualcomm 802.11ax WiFi (ath11k):
      - IPQ5018 support
      - Fine Timing Measurement (FTM) responder role support
      - channel 177 support

   - MediaTek WiFi (mt76):
      - per-PHY LED support
      - mt7996: EHT (Wi-Fi 7) support
      - Wireless Ethernet Dispatch (WED) reset support
      - switch to using page pool allocator

   - RealTek WiFi (rtw89):
      - support new version of Bluetooth co-existance

   - Mobile:
      - rmnet: support TX aggregation"

* tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1872 commits)
  page_pool: add a comment explaining the fragment counter usage
  net: ethtool: fix __ethtool_dev_mm_supported() implementation
  ethtool: pse-pd: Fix double word in comments
  xsk: add linux/vmalloc.h to xsk.c
  sefltests: netdevsim: wait for devlink instance after netns removal
  selftest: fib_tests: Always cleanup before exit
  net/mlx5e: Align IPsec ASO result memory to be as required by hardware
  net/mlx5e: TC, Set CT miss to the specific ct action instance
  net/mlx5e: Rename CHAIN_TO_REG to MAPPED_OBJ_TO_REG
  net/mlx5: Refactor tc miss handling to a single function
  net/mlx5: Kconfig: Make tc offload depend on tc skb extension
  net/sched: flower: Support hardware miss to tc action
  net/sched: flower: Move filter handle initialization earlier
  net/sched: cls_api: Support hardware miss to tc action
  net/sched: Rename user cookie and act cookie
  sfc: fix builds without CONFIG_RTC_LIB
  sfc: clean up some inconsistent indentings
  net/mlx4_en: Introduce flexible array to silence overflow warning
  net: lan966x: Fix possible deadlock inside PTP
  net/ulp: Remove redundant ->clone() test in inet_clone_ulp().
  ...

1 files changed, 466 insertions, 0 deletions

diff --git a/sound/xen/xen_snd_front_evtchnl.c b/sound/xen/xen_snd_front_evtchnl.c
new file mode 100644
index 000000000..26d1b3987
--- /dev/null
+++ b/sound/xen/xen_snd_front_evtchnl.c
@@ -0,0 +1,466 @@
+// SPDX-License-Identifier: GPL-2.0 OR MIT
+
+/*
+ * Xen para-virtual sound device
+ *
+ * Copyright (C) 2016-2018 EPAM Systems Inc.
+ *
+ * Author: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
+ */
+
+#include <xen/events.h>
+#include <xen/grant_table.h>
+#include <xen/xen.h>
+#include <xen/xenbus.h>
+
+#include "xen_snd_front.h"
+#include "xen_snd_front_alsa.h"
+#include "xen_snd_front_cfg.h"
+#include "xen_snd_front_evtchnl.h"
+
+static irqreturn_t evtchnl_interrupt_req(int irq, void *dev_id)
+{
+	struct xen_snd_front_evtchnl *channel = dev_id;
+	struct xen_snd_front_info *front_info = channel->front_info;
+	struct xensnd_resp *resp;
+	RING_IDX i, rp;
+
+	if (unlikely(channel->state != EVTCHNL_STATE_CONNECTED))
+		return IRQ_HANDLED;
+
+	mutex_lock(&channel->ring_io_lock);
+
+again:
+	rp = channel->u.req.ring.sring->rsp_prod;
+	/* Ensure we see queued responses up to rp. */
+	rmb();
+
+	/*
+	 * Assume that the backend is trusted to always write sane values
+	 * to the ring counters, so no overflow checks on frontend side
+	 * are required.
+	 */
+	for (i = channel->u.req.ring.rsp_cons; i != rp; i++) {
+		resp = RING_GET_RESPONSE(&channel->u.req.ring, i);
+		if (resp->id != channel->evt_id)
+			continue;
+		switch (resp->operation) {
+		case XENSND_OP_OPEN:
+		case XENSND_OP_CLOSE:
+		case XENSND_OP_READ:
+		case XENSND_OP_WRITE:
+		case XENSND_OP_TRIGGER:
+			channel->u.req.resp_status = resp->status;
+			complete(&channel->u.req.completion);
+			break;
+		case XENSND_OP_HW_PARAM_QUERY:
+			channel->u.req.resp_status = resp->status;
+			channel->u.req.resp.hw_param =
+					resp->resp.hw_param;
+			complete(&channel->u.req.completion);
+			break;
+
+		default:
+			dev_err(&front_info->xb_dev->dev,
+				"Operation %d is not supported\n",
+				resp->operation);
+			break;
+		}
+	}
+
+	channel->u.req.ring.rsp_cons = i;
+	if (i != channel->u.req.ring.req_prod_pvt) {
+		int more_to_do;
+
+		RING_FINAL_CHECK_FOR_RESPONSES(&channel->u.req.ring,
+					       more_to_do);
+		if (more_to_do)
+			goto again;
+	} else {
+		channel->u.req.ring.sring->rsp_event = i + 1;
+	}
+
+	mutex_unlock(&channel->ring_io_lock);
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t evtchnl_interrupt_evt(int irq, void *dev_id)
+{
+	struct xen_snd_front_evtchnl *channel = dev_id;
+	struct xensnd_event_page *page = channel->u.evt.page;
+	u32 cons, prod;
+
+	if (unlikely(channel->state != EVTCHNL_STATE_CONNECTED))
+		return IRQ_HANDLED;
+
+	mutex_lock(&channel->ring_io_lock);
+
+	prod = page->in_prod;
+	/* Ensure we see ring contents up to prod. */
+	virt_rmb();
+	if (prod == page->in_cons)
+		goto out;
+
+	/*
+	 * Assume that the backend is trusted to always write sane values
+	 * to the ring counters, so no overflow checks on frontend side
+	 * are required.
+	 */
+	for (cons = page->in_cons; cons != prod; cons++) {
+		struct xensnd_evt *event;
+
+		event = &XENSND_IN_RING_REF(page, cons);
+		if (unlikely(event->id != channel->evt_id++))
+			continue;
+
+		switch (event->type) {
+		case XENSND_EVT_CUR_POS:
+			xen_snd_front_alsa_handle_cur_pos(channel,
+							  event->op.cur_pos.position);
+			break;
+		}
+	}
+
+	page->in_cons = cons;
+	/* Ensure ring contents. */
+	virt_wmb();
+
+out:
+	mutex_unlock(&channel->ring_io_lock);
+	return IRQ_HANDLED;
+}
+
+void xen_snd_front_evtchnl_flush(struct xen_snd_front_evtchnl *channel)
+{
+	int notify;
+
+	channel->u.req.ring.req_prod_pvt++;
+	RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&channel->u.req.ring, notify);
+	if (notify)
+		notify_remote_via_irq(channel->irq);
+}
+
+static void evtchnl_free(struct xen_snd_front_info *front_info,
+			 struct xen_snd_front_evtchnl *channel)
+{
+	void *page = NULL;
+
+	if (channel->type == EVTCHNL_TYPE_REQ)
+		page = channel->u.req.ring.sring;
+	else if (channel->type == EVTCHNL_TYPE_EVT)
+		page = channel->u.evt.page;
+
+	if (!page)
+		return;
+
+	channel->state = EVTCHNL_STATE_DISCONNECTED;
+	if (channel->type == EVTCHNL_TYPE_REQ) {
+		/* Release all who still waits for response if any. */
+		channel->u.req.resp_status = -EIO;
+		complete_all(&channel->u.req.completion);
+	}
+
+	if (channel->irq)
+		unbind_from_irqhandler(channel->irq, channel);
+
+	if (channel->port)
+		xenbus_free_evtchn(front_info->xb_dev, channel->port);
+
+	/* End access and free the page. */
+	xenbus_teardown_ring(&page, 1, &channel->gref);
+
+	memset(channel, 0, sizeof(*channel));
+}
+
+void xen_snd_front_evtchnl_free_all(struct xen_snd_front_info *front_info)
+{
+	int i;
+
+	if (!front_info->evt_pairs)
+		return;
+
+	for (i = 0; i < front_info->num_evt_pairs; i++) {
+		evtchnl_free(front_info, &front_info->evt_pairs[i].req);
+		evtchnl_free(front_info, &front_info->evt_pairs[i].evt);
+	}
+
+	kfree(front_info->evt_pairs);
+	front_info->evt_pairs = NULL;
+}
+
+static int evtchnl_alloc(struct xen_snd_front_info *front_info, int index,
+			 struct xen_snd_front_evtchnl *channel,
+			 enum xen_snd_front_evtchnl_type type)
+{
+	struct xenbus_device *xb_dev = front_info->xb_dev;
+	void *page;
+	irq_handler_t handler;
+	char *handler_name = NULL;
+	int ret;
+
+	memset(channel, 0, sizeof(*channel));
+	channel->type = type;
+	channel->index = index;
+	channel->front_info = front_info;
+	channel->state = EVTCHNL_STATE_DISCONNECTED;
+	ret = xenbus_setup_ring(xb_dev, GFP_KERNEL, &page, 1, &channel->gref);
+	if (ret)
+		goto fail;
+
+	handler_name = kasprintf(GFP_KERNEL, "%s-%s", XENSND_DRIVER_NAME,
+				 type == EVTCHNL_TYPE_REQ ?
+				 XENSND_FIELD_RING_REF :
+				 XENSND_FIELD_EVT_RING_REF);
+	if (!handler_name) {
+		ret = -ENOMEM;
+		goto fail;
+	}
+
+	mutex_init(&channel->ring_io_lock);
+
+	if (type == EVTCHNL_TYPE_REQ) {
+		struct xen_sndif_sring *sring = page;
+
+		init_completion(&channel->u.req.completion);
+		mutex_init(&channel->u.req.req_io_lock);
+		XEN_FRONT_RING_INIT(&channel->u.req.ring, sring, XEN_PAGE_SIZE);
+
+		handler = evtchnl_interrupt_req;
+	} else {
+		channel->u.evt.page = page;
+		handler = evtchnl_interrupt_evt;
+	}
+
+	ret = xenbus_alloc_evtchn(xb_dev, &channel->port);
+	if (ret < 0)
+		goto fail;
+
+	ret = bind_evtchn_to_irq(channel->port);
+	if (ret < 0) {
+		dev_err(&xb_dev->dev,
+			"Failed to bind IRQ for domid %d port %d: %d\n",
+			front_info->xb_dev->otherend_id, channel->port, ret);
+		goto fail;
+	}
+
+	channel->irq = ret;
+
+	ret = request_threaded_irq(channel->irq, NULL, handler,
+				   IRQF_ONESHOT, handler_name, channel);
+	if (ret < 0) {
+		dev_err(&xb_dev->dev, "Failed to request IRQ %d: %d\n",
+			channel->irq, ret);
+		goto fail;
+	}
+
+	kfree(handler_name);
+	return 0;
+
+fail:
+	kfree(handler_name);
+	dev_err(&xb_dev->dev, "Failed to allocate ring: %d\n", ret);
+	return ret;
+}
+
+int xen_snd_front_evtchnl_create_all(struct xen_snd_front_info *front_info,
+				     int num_streams)
+{
+	struct xen_front_cfg_card *cfg = &front_info->cfg;
+	struct device *dev = &front_info->xb_dev->dev;
+	int d, ret = 0;
+
+	front_info->evt_pairs =
+			kcalloc(num_streams,
+				sizeof(struct xen_snd_front_evtchnl_pair),
+				GFP_KERNEL);
+	if (!front_info->evt_pairs)
+		return -ENOMEM;
+
+	/* Iterate over devices and their streams and create event channels. */
+	for (d = 0; d < cfg->num_pcm_instances; d++) {
+		struct xen_front_cfg_pcm_instance *pcm_instance;
+		int s, index;
+
+		pcm_instance = &cfg->pcm_instances[d];
+
+		for (s = 0; s < pcm_instance->num_streams_pb; s++) {
+			index = pcm_instance->streams_pb[s].index;
+
+			ret = evtchnl_alloc(front_info, index,
+					    &front_info->evt_pairs[index].req,
+					    EVTCHNL_TYPE_REQ);
+			if (ret < 0) {
+				dev_err(dev, "Error allocating control channel\n");
+				goto fail;
+			}
+
+			ret = evtchnl_alloc(front_info, index,
+					    &front_info->evt_pairs[index].evt,
+					    EVTCHNL_TYPE_EVT);
+			if (ret < 0) {
+				dev_err(dev, "Error allocating in-event channel\n");
+				goto fail;
+			}
+		}
+
+		for (s = 0; s < pcm_instance->num_streams_cap; s++) {
+			index = pcm_instance->streams_cap[s].index;
+
+			ret = evtchnl_alloc(front_info, index,
+					    &front_info->evt_pairs[index].req,
+					    EVTCHNL_TYPE_REQ);
+			if (ret < 0) {
+				dev_err(dev, "Error allocating control channel\n");
+				goto fail;
+			}
+
+			ret = evtchnl_alloc(front_info, index,
+					    &front_info->evt_pairs[index].evt,
+					    EVTCHNL_TYPE_EVT);
+			if (ret < 0) {
+				dev_err(dev, "Error allocating in-event channel\n");
+				goto fail;
+			}
+		}
+	}
+
+	front_info->num_evt_pairs = num_streams;
+	return 0;
+
+fail:
+	xen_snd_front_evtchnl_free_all(front_info);
+	return ret;
+}
+
+static int evtchnl_publish(struct xenbus_transaction xbt,
+			   struct xen_snd_front_evtchnl *channel,
+			   const char *path, const char *node_ring,
+			   const char *node_chnl)
+{
+	struct xenbus_device *xb_dev = channel->front_info->xb_dev;
+	int ret;
+
+	/* Write control channel ring reference. */
+	ret = xenbus_printf(xbt, path, node_ring, "%u", channel->gref);
+	if (ret < 0) {
+		dev_err(&xb_dev->dev, "Error writing ring-ref: %d\n", ret);
+		return ret;
+	}
+
+	/* Write event channel ring reference. */
+	ret = xenbus_printf(xbt, path, node_chnl, "%u", channel->port);
+	if (ret < 0) {
+		dev_err(&xb_dev->dev, "Error writing event channel: %d\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+int xen_snd_front_evtchnl_publish_all(struct xen_snd_front_info *front_info)
+{
+	struct xen_front_cfg_card *cfg = &front_info->cfg;
+	struct xenbus_transaction xbt;
+	int ret, d;
+
+again:
+	ret = xenbus_transaction_start(&xbt);
+	if (ret < 0) {
+		xenbus_dev_fatal(front_info->xb_dev, ret,
+				 "starting transaction");
+		return ret;
+	}
+
+	for (d = 0; d < cfg->num_pcm_instances; d++) {
+		struct xen_front_cfg_pcm_instance *pcm_instance;
+		int s, index;
+
+		pcm_instance = &cfg->pcm_instances[d];
+
+		for (s = 0; s < pcm_instance->num_streams_pb; s++) {
+			index = pcm_instance->streams_pb[s].index;
+
+			ret = evtchnl_publish(xbt,
+					      &front_info->evt_pairs[index].req,
+					      pcm_instance->streams_pb[s].xenstore_path,
+					      XENSND_FIELD_RING_REF,
+					      XENSND_FIELD_EVT_CHNL);
+			if (ret < 0)
+				goto fail;
+
+			ret = evtchnl_publish(xbt,
+					      &front_info->evt_pairs[index].evt,
+					      pcm_instance->streams_pb[s].xenstore_path,
+					      XENSND_FIELD_EVT_RING_REF,
+					      XENSND_FIELD_EVT_EVT_CHNL);
+			if (ret < 0)
+				goto fail;
+		}
+
+		for (s = 0; s < pcm_instance->num_streams_cap; s++) {
+			index = pcm_instance->streams_cap[s].index;
+
+			ret = evtchnl_publish(xbt,
+					      &front_info->evt_pairs[index].req,
+					      pcm_instance->streams_cap[s].xenstore_path,
+					      XENSND_FIELD_RING_REF,
+					      XENSND_FIELD_EVT_CHNL);
+			if (ret < 0)
+				goto fail;
+
+			ret = evtchnl_publish(xbt,
+					      &front_info->evt_pairs[index].evt,
+					      pcm_instance->streams_cap[s].xenstore_path,
+					      XENSND_FIELD_EVT_RING_REF,
+					      XENSND_FIELD_EVT_EVT_CHNL);
+			if (ret < 0)
+				goto fail;
+		}
+	}
+	ret = xenbus_transaction_end(xbt, 0);
+	if (ret < 0) {
+		if (ret == -EAGAIN)
+			goto again;
+
+		xenbus_dev_fatal(front_info->xb_dev, ret,
+				 "completing transaction");
+		goto fail_to_end;
+	}
+	return 0;
+fail:
+	xenbus_transaction_end(xbt, 1);
+fail_to_end:
+	xenbus_dev_fatal(front_info->xb_dev, ret, "writing XenStore");
+	return ret;
+}
+
+void xen_snd_front_evtchnl_pair_set_connected(struct xen_snd_front_evtchnl_pair *evt_pair,
+					      bool is_connected)
+{
+	enum xen_snd_front_evtchnl_state state;
+
+	if (is_connected)
+		state = EVTCHNL_STATE_CONNECTED;
+	else
+		state = EVTCHNL_STATE_DISCONNECTED;
+
+	mutex_lock(&evt_pair->req.ring_io_lock);
+	evt_pair->req.state = state;
+	mutex_unlock(&evt_pair->req.ring_io_lock);
+
+	mutex_lock(&evt_pair->evt.ring_io_lock);
+	evt_pair->evt.state = state;
+	mutex_unlock(&evt_pair->evt.ring_io_lock);
+}
+
+void xen_snd_front_evtchnl_pair_clear(struct xen_snd_front_evtchnl_pair *evt_pair)
+{
+	mutex_lock(&evt_pair->req.ring_io_lock);
+	evt_pair->req.evt_next_id = 0;
+	mutex_unlock(&evt_pair->req.ring_io_lock);
+
+	mutex_lock(&evt_pair->evt.ring_io_lock);
+	evt_pair->evt.evt_next_id = 0;
+	mutex_unlock(&evt_pair->evt.ring_io_lock);
+}
+