linux/drivers/greybus/connection.c

940 lines
23 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* Greybus connections
*
* Copyright 2014 Google Inc.
* Copyright 2014 Linaro Ltd.
*/
#include <linux/workqueue.h>
#include <linux/greybus.h>
#include "greybus_trace.h"
#define GB_CONNECTION_CPORT_QUIESCE_TIMEOUT 1000
static void gb_connection_kref_release(struct kref *kref);
static DEFINE_SPINLOCK(gb_connections_lock);
static DEFINE_MUTEX(gb_connection_mutex);
/* Caller holds gb_connection_mutex. */
static bool gb_connection_cport_in_use(struct gb_interface *intf, u16 cport_id)
{
struct gb_host_device *hd = intf->hd;
struct gb_connection *connection;
list_for_each_entry(connection, &hd->connections, hd_links) {
if (connection->intf == intf &&
connection->intf_cport_id == cport_id)
return true;
}
return false;
}
static void gb_connection_get(struct gb_connection *connection)
{
kref_get(&connection->kref);
trace_gb_connection_get(connection);
}
static void gb_connection_put(struct gb_connection *connection)
{
trace_gb_connection_put(connection);
kref_put(&connection->kref, gb_connection_kref_release);
}
/*
* Returns a reference-counted pointer to the connection if found.
*/
static struct gb_connection *
gb_connection_hd_find(struct gb_host_device *hd, u16 cport_id)
{
struct gb_connection *connection;
unsigned long flags;
spin_lock_irqsave(&gb_connections_lock, flags);
list_for_each_entry(connection, &hd->connections, hd_links)
if (connection->hd_cport_id == cport_id) {
gb_connection_get(connection);
goto found;
}
connection = NULL;
found:
spin_unlock_irqrestore(&gb_connections_lock, flags);
return connection;
}
/*
* Callback from the host driver to let us know that data has been
* received on the bundle.
*/
void greybus_data_rcvd(struct gb_host_device *hd, u16 cport_id,
u8 *data, size_t length)
{
struct gb_connection *connection;
trace_gb_hd_in(hd);
connection = gb_connection_hd_find(hd, cport_id);
if (!connection) {
dev_err(&hd->dev,
"nonexistent connection (%zu bytes dropped)\n", length);
return;
}
gb_connection_recv(connection, data, length);
gb_connection_put(connection);
}
EXPORT_SYMBOL_GPL(greybus_data_rcvd);
static void gb_connection_kref_release(struct kref *kref)
{
struct gb_connection *connection;
connection = container_of(kref, struct gb_connection, kref);
trace_gb_connection_release(connection);
kfree(connection);
}
static void gb_connection_init_name(struct gb_connection *connection)
{
u16 hd_cport_id = connection->hd_cport_id;
u16 cport_id = 0;
u8 intf_id = 0;
if (connection->intf) {
intf_id = connection->intf->interface_id;
cport_id = connection->intf_cport_id;
}
snprintf(connection->name, sizeof(connection->name),
"%u/%u:%u", hd_cport_id, intf_id, cport_id);
}
/*
* _gb_connection_create() - create a Greybus connection
* @hd: host device of the connection
* @hd_cport_id: host-device cport id, or -1 for dynamic allocation
* @intf: remote interface, or NULL for static connections
* @bundle: remote-interface bundle (may be NULL)
* @cport_id: remote-interface cport id, or 0 for static connections
* @handler: request handler (may be NULL)
* @flags: connection flags
*
* Create a Greybus connection, representing the bidirectional link
* between a CPort on a (local) Greybus host device and a CPort on
* another Greybus interface.
*
* A connection also maintains the state of operations sent over the
* connection.
*
* Serialised against concurrent create and destroy using the
* gb_connection_mutex.
*
* Return: A pointer to the new connection if successful, or an ERR_PTR
* otherwise.
*/
static struct gb_connection *
_gb_connection_create(struct gb_host_device *hd, int hd_cport_id,
struct gb_interface *intf,
struct gb_bundle *bundle, int cport_id,
gb_request_handler_t handler,
unsigned long flags)
{
struct gb_connection *connection;
int ret;
mutex_lock(&gb_connection_mutex);
if (intf && gb_connection_cport_in_use(intf, cport_id)) {
dev_err(&intf->dev, "cport %u already in use\n", cport_id);
ret = -EBUSY;
goto err_unlock;
}
ret = gb_hd_cport_allocate(hd, hd_cport_id, flags);
if (ret < 0) {
dev_err(&hd->dev, "failed to allocate cport: %d\n", ret);
goto err_unlock;
}
hd_cport_id = ret;
connection = kzalloc(sizeof(*connection), GFP_KERNEL);
if (!connection) {
ret = -ENOMEM;
goto err_hd_cport_release;
}
connection->hd_cport_id = hd_cport_id;
connection->intf_cport_id = cport_id;
connection->hd = hd;
connection->intf = intf;
connection->bundle = bundle;
connection->handler = handler;
connection->flags = flags;
if (intf && (intf->quirks & GB_INTERFACE_QUIRK_NO_CPORT_FEATURES))
connection->flags |= GB_CONNECTION_FLAG_NO_FLOWCTRL;
connection->state = GB_CONNECTION_STATE_DISABLED;
atomic_set(&connection->op_cycle, 0);
mutex_init(&connection->mutex);
spin_lock_init(&connection->lock);
INIT_LIST_HEAD(&connection->operations);
connection->wq = alloc_workqueue("%s:%d", WQ_UNBOUND, 1,
dev_name(&hd->dev), hd_cport_id);
if (!connection->wq) {
ret = -ENOMEM;
goto err_free_connection;
}
kref_init(&connection->kref);
gb_connection_init_name(connection);
spin_lock_irq(&gb_connections_lock);
list_add(&connection->hd_links, &hd->connections);
if (bundle)
list_add(&connection->bundle_links, &bundle->connections);
else
INIT_LIST_HEAD(&connection->bundle_links);
spin_unlock_irq(&gb_connections_lock);
mutex_unlock(&gb_connection_mutex);
trace_gb_connection_create(connection);
return connection;
err_free_connection:
kfree(connection);
err_hd_cport_release:
gb_hd_cport_release(hd, hd_cport_id);
err_unlock:
mutex_unlock(&gb_connection_mutex);
return ERR_PTR(ret);
}
struct gb_connection *
gb_connection_create_static(struct gb_host_device *hd, u16 hd_cport_id,
gb_request_handler_t handler)
{
return _gb_connection_create(hd, hd_cport_id, NULL, NULL, 0, handler,
GB_CONNECTION_FLAG_HIGH_PRIO);
}
struct gb_connection *
gb_connection_create_control(struct gb_interface *intf)
{
return _gb_connection_create(intf->hd, -1, intf, NULL, 0, NULL,
GB_CONNECTION_FLAG_CONTROL |
GB_CONNECTION_FLAG_HIGH_PRIO);
}
struct gb_connection *
gb_connection_create(struct gb_bundle *bundle, u16 cport_id,
gb_request_handler_t handler)
{
struct gb_interface *intf = bundle->intf;
return _gb_connection_create(intf->hd, -1, intf, bundle, cport_id,
handler, 0);
}
EXPORT_SYMBOL_GPL(gb_connection_create);
struct gb_connection *
gb_connection_create_flags(struct gb_bundle *bundle, u16 cport_id,
gb_request_handler_t handler,
unsigned long flags)
{
struct gb_interface *intf = bundle->intf;
if (WARN_ON_ONCE(flags & GB_CONNECTION_FLAG_CORE_MASK))
flags &= ~GB_CONNECTION_FLAG_CORE_MASK;
return _gb_connection_create(intf->hd, -1, intf, bundle, cport_id,
handler, flags);
}
EXPORT_SYMBOL_GPL(gb_connection_create_flags);
struct gb_connection *
gb_connection_create_offloaded(struct gb_bundle *bundle, u16 cport_id,
unsigned long flags)
{
flags |= GB_CONNECTION_FLAG_OFFLOADED;
return gb_connection_create_flags(bundle, cport_id, NULL, flags);
}
EXPORT_SYMBOL_GPL(gb_connection_create_offloaded);
static int gb_connection_hd_cport_enable(struct gb_connection *connection)
{
struct gb_host_device *hd = connection->hd;
int ret;
if (!hd->driver->cport_enable)
return 0;
ret = hd->driver->cport_enable(hd, connection->hd_cport_id,
connection->flags);
if (ret) {
dev_err(&hd->dev, "%s: failed to enable host cport: %d\n",
connection->name, ret);
return ret;
}
return 0;
}
static void gb_connection_hd_cport_disable(struct gb_connection *connection)
{
struct gb_host_device *hd = connection->hd;
int ret;
if (!hd->driver->cport_disable)
return;
ret = hd->driver->cport_disable(hd, connection->hd_cport_id);
if (ret) {
dev_err(&hd->dev, "%s: failed to disable host cport: %d\n",
connection->name, ret);
}
}
static int gb_connection_hd_cport_connected(struct gb_connection *connection)
{
struct gb_host_device *hd = connection->hd;
int ret;
if (!hd->driver->cport_connected)
return 0;
ret = hd->driver->cport_connected(hd, connection->hd_cport_id);
if (ret) {
dev_err(&hd->dev, "%s: failed to set connected state: %d\n",
connection->name, ret);
return ret;
}
return 0;
}
static int gb_connection_hd_cport_flush(struct gb_connection *connection)
{
struct gb_host_device *hd = connection->hd;
int ret;
if (!hd->driver->cport_flush)
return 0;
ret = hd->driver->cport_flush(hd, connection->hd_cport_id);
if (ret) {
dev_err(&hd->dev, "%s: failed to flush host cport: %d\n",
connection->name, ret);
return ret;
}
return 0;
}
static int gb_connection_hd_cport_quiesce(struct gb_connection *connection)
{
struct gb_host_device *hd = connection->hd;
size_t peer_space;
int ret;
if (!hd->driver->cport_quiesce)
return 0;
peer_space = sizeof(struct gb_operation_msg_hdr) +
sizeof(struct gb_cport_shutdown_request);
if (connection->mode_switch)
peer_space += sizeof(struct gb_operation_msg_hdr);
ret = hd->driver->cport_quiesce(hd, connection->hd_cport_id,
peer_space,
GB_CONNECTION_CPORT_QUIESCE_TIMEOUT);
if (ret) {
dev_err(&hd->dev, "%s: failed to quiesce host cport: %d\n",
connection->name, ret);
return ret;
}
return 0;
}
static int gb_connection_hd_cport_clear(struct gb_connection *connection)
{
struct gb_host_device *hd = connection->hd;
int ret;
if (!hd->driver->cport_clear)
return 0;
ret = hd->driver->cport_clear(hd, connection->hd_cport_id);
if (ret) {
dev_err(&hd->dev, "%s: failed to clear host cport: %d\n",
connection->name, ret);
return ret;
}
return 0;
}
/*
* Request the SVC to create a connection from AP's cport to interface's
* cport.
*/
static int
gb_connection_svc_connection_create(struct gb_connection *connection)
{
struct gb_host_device *hd = connection->hd;
struct gb_interface *intf;
u8 cport_flags;
int ret;
if (gb_connection_is_static(connection))
return 0;
intf = connection->intf;
/*
* Enable either E2EFC or CSD, unless no flow control is requested.
*/
cport_flags = GB_SVC_CPORT_FLAG_CSV_N;
if (gb_connection_flow_control_disabled(connection)) {
cport_flags |= GB_SVC_CPORT_FLAG_CSD_N;
} else if (gb_connection_e2efc_enabled(connection)) {
cport_flags |= GB_SVC_CPORT_FLAG_CSD_N |
GB_SVC_CPORT_FLAG_E2EFC;
}
ret = gb_svc_connection_create(hd->svc,
hd->svc->ap_intf_id,
connection->hd_cport_id,
intf->interface_id,
connection->intf_cport_id,
cport_flags);
if (ret) {
dev_err(&connection->hd->dev,
"%s: failed to create svc connection: %d\n",
connection->name, ret);
return ret;
}
return 0;
}
static void
gb_connection_svc_connection_destroy(struct gb_connection *connection)
{
if (gb_connection_is_static(connection))
return;
gb_svc_connection_destroy(connection->hd->svc,
connection->hd->svc->ap_intf_id,
connection->hd_cport_id,
connection->intf->interface_id,
connection->intf_cport_id);
}
/* Inform Interface about active CPorts */
static int gb_connection_control_connected(struct gb_connection *connection)
{
struct gb_control *control;
u16 cport_id = connection->intf_cport_id;
int ret;
if (gb_connection_is_static(connection))
return 0;
if (gb_connection_is_control(connection))
return 0;
control = connection->intf->control;
ret = gb_control_connected_operation(control, cport_id);
if (ret) {
dev_err(&connection->bundle->dev,
"failed to connect cport: %d\n", ret);
return ret;
}
return 0;
}
static void
gb_connection_control_disconnecting(struct gb_connection *connection)
{
struct gb_control *control;
u16 cport_id = connection->intf_cport_id;
int ret;
if (gb_connection_is_static(connection))
return;
control = connection->intf->control;
ret = gb_control_disconnecting_operation(control, cport_id);
if (ret) {
dev_err(&connection->hd->dev,
"%s: failed to send disconnecting: %d\n",
connection->name, ret);
}
}
static void
gb_connection_control_disconnected(struct gb_connection *connection)
{
struct gb_control *control;
u16 cport_id = connection->intf_cport_id;
int ret;
if (gb_connection_is_static(connection))
return;
control = connection->intf->control;
if (gb_connection_is_control(connection)) {
if (connection->mode_switch) {
ret = gb_control_mode_switch_operation(control);
if (ret) {
/*
* Allow mode switch to time out waiting for
* mailbox event.
*/
return;
}
}
return;
}
ret = gb_control_disconnected_operation(control, cport_id);
if (ret) {
dev_warn(&connection->bundle->dev,
"failed to disconnect cport: %d\n", ret);
}
}
static int gb_connection_shutdown_operation(struct gb_connection *connection,
u8 phase)
{
struct gb_cport_shutdown_request *req;
struct gb_operation *operation;
int ret;
operation = gb_operation_create_core(connection,
GB_REQUEST_TYPE_CPORT_SHUTDOWN,
sizeof(*req), 0, 0,
GFP_KERNEL);
if (!operation)
return -ENOMEM;
req = operation->request->payload;
req->phase = phase;
ret = gb_operation_request_send_sync(operation);
gb_operation_put(operation);
return ret;
}
static int gb_connection_cport_shutdown(struct gb_connection *connection,
u8 phase)
{
struct gb_host_device *hd = connection->hd;
const struct gb_hd_driver *drv = hd->driver;
int ret;
if (gb_connection_is_static(connection))
return 0;
if (gb_connection_is_offloaded(connection)) {
if (!drv->cport_shutdown)
return 0;
ret = drv->cport_shutdown(hd, connection->hd_cport_id, phase,
GB_OPERATION_TIMEOUT_DEFAULT);
} else {
ret = gb_connection_shutdown_operation(connection, phase);
}
if (ret) {
dev_err(&hd->dev, "%s: failed to send cport shutdown (phase %d): %d\n",
connection->name, phase, ret);
return ret;
}
return 0;
}
static int
gb_connection_cport_shutdown_phase_1(struct gb_connection *connection)
{
return gb_connection_cport_shutdown(connection, 1);
}
static int
gb_connection_cport_shutdown_phase_2(struct gb_connection *connection)
{
return gb_connection_cport_shutdown(connection, 2);
}
/*
* Cancel all active operations on a connection.
*
* Locking: Called with connection lock held and state set to DISABLED or
* DISCONNECTING.
*/
static void gb_connection_cancel_operations(struct gb_connection *connection,
int errno)
__must_hold(&connection->lock)
{
struct gb_operation *operation;
while (!list_empty(&connection->operations)) {
operation = list_last_entry(&connection->operations,
struct gb_operation, links);
gb_operation_get(operation);
spin_unlock_irq(&connection->lock);
if (gb_operation_is_incoming(operation))
gb_operation_cancel_incoming(operation, errno);
else
gb_operation_cancel(operation, errno);
gb_operation_put(operation);
spin_lock_irq(&connection->lock);
}
}
/*
* Cancel all active incoming operations on a connection.
*
* Locking: Called with connection lock held and state set to ENABLED_TX.
*/
static void
gb_connection_flush_incoming_operations(struct gb_connection *connection,
int errno)
__must_hold(&connection->lock)
{
struct gb_operation *operation;
bool incoming;
while (!list_empty(&connection->operations)) {
incoming = false;
list_for_each_entry(operation, &connection->operations,
links) {
if (gb_operation_is_incoming(operation)) {
gb_operation_get(operation);
incoming = true;
break;
}
}
if (!incoming)
break;
spin_unlock_irq(&connection->lock);
/* FIXME: flush, not cancel? */
gb_operation_cancel_incoming(operation, errno);
gb_operation_put(operation);
spin_lock_irq(&connection->lock);
}
}
/*
* _gb_connection_enable() - enable a connection
* @connection: connection to enable
* @rx: whether to enable incoming requests
*
* Connection-enable helper for DISABLED->ENABLED, DISABLED->ENABLED_TX, and
* ENABLED_TX->ENABLED state transitions.
*
* Locking: Caller holds connection->mutex.
*/
static int _gb_connection_enable(struct gb_connection *connection, bool rx)
{
int ret;
/* Handle ENABLED_TX -> ENABLED transitions. */
if (connection->state == GB_CONNECTION_STATE_ENABLED_TX) {
if (!(connection->handler && rx))
return 0;
spin_lock_irq(&connection->lock);
connection->state = GB_CONNECTION_STATE_ENABLED;
spin_unlock_irq(&connection->lock);
return 0;
}
ret = gb_connection_hd_cport_enable(connection);
if (ret)
return ret;
ret = gb_connection_svc_connection_create(connection);
if (ret)
goto err_hd_cport_clear;
ret = gb_connection_hd_cport_connected(connection);
if (ret)
goto err_svc_connection_destroy;
spin_lock_irq(&connection->lock);
if (connection->handler && rx)
connection->state = GB_CONNECTION_STATE_ENABLED;
else
connection->state = GB_CONNECTION_STATE_ENABLED_TX;
spin_unlock_irq(&connection->lock);
ret = gb_connection_control_connected(connection);
if (ret)
goto err_control_disconnecting;
return 0;
err_control_disconnecting:
spin_lock_irq(&connection->lock);
connection->state = GB_CONNECTION_STATE_DISCONNECTING;
gb_connection_cancel_operations(connection, -ESHUTDOWN);
spin_unlock_irq(&connection->lock);
/* Transmit queue should already be empty. */
gb_connection_hd_cport_flush(connection);
gb_connection_control_disconnecting(connection);
gb_connection_cport_shutdown_phase_1(connection);
gb_connection_hd_cport_quiesce(connection);
gb_connection_cport_shutdown_phase_2(connection);
gb_connection_control_disconnected(connection);
connection->state = GB_CONNECTION_STATE_DISABLED;
err_svc_connection_destroy:
gb_connection_svc_connection_destroy(connection);
err_hd_cport_clear:
gb_connection_hd_cport_clear(connection);
gb_connection_hd_cport_disable(connection);
return ret;
}
int gb_connection_enable(struct gb_connection *connection)
{
int ret = 0;
mutex_lock(&connection->mutex);
if (connection->state == GB_CONNECTION_STATE_ENABLED)
goto out_unlock;
ret = _gb_connection_enable(connection, true);
if (!ret)
trace_gb_connection_enable(connection);
out_unlock:
mutex_unlock(&connection->mutex);
return ret;
}
EXPORT_SYMBOL_GPL(gb_connection_enable);
int gb_connection_enable_tx(struct gb_connection *connection)
{
int ret = 0;
mutex_lock(&connection->mutex);
if (connection->state == GB_CONNECTION_STATE_ENABLED) {
ret = -EINVAL;
goto out_unlock;
}
if (connection->state == GB_CONNECTION_STATE_ENABLED_TX)
goto out_unlock;
ret = _gb_connection_enable(connection, false);
if (!ret)
trace_gb_connection_enable(connection);
out_unlock:
mutex_unlock(&connection->mutex);
return ret;
}
EXPORT_SYMBOL_GPL(gb_connection_enable_tx);
void gb_connection_disable_rx(struct gb_connection *connection)
{
mutex_lock(&connection->mutex);
spin_lock_irq(&connection->lock);
if (connection->state != GB_CONNECTION_STATE_ENABLED) {
spin_unlock_irq(&connection->lock);
goto out_unlock;
}
connection->state = GB_CONNECTION_STATE_ENABLED_TX;
gb_connection_flush_incoming_operations(connection, -ESHUTDOWN);
spin_unlock_irq(&connection->lock);
trace_gb_connection_disable(connection);
out_unlock:
mutex_unlock(&connection->mutex);
}
EXPORT_SYMBOL_GPL(gb_connection_disable_rx);
void gb_connection_mode_switch_prepare(struct gb_connection *connection)
{
connection->mode_switch = true;
}
void gb_connection_mode_switch_complete(struct gb_connection *connection)
{
gb_connection_svc_connection_destroy(connection);
gb_connection_hd_cport_clear(connection);
gb_connection_hd_cport_disable(connection);
connection->mode_switch = false;
}
void gb_connection_disable(struct gb_connection *connection)
{
mutex_lock(&connection->mutex);
if (connection->state == GB_CONNECTION_STATE_DISABLED)
goto out_unlock;
trace_gb_connection_disable(connection);
spin_lock_irq(&connection->lock);
connection->state = GB_CONNECTION_STATE_DISCONNECTING;
gb_connection_cancel_operations(connection, -ESHUTDOWN);
spin_unlock_irq(&connection->lock);
gb_connection_hd_cport_flush(connection);
gb_connection_control_disconnecting(connection);
gb_connection_cport_shutdown_phase_1(connection);
gb_connection_hd_cport_quiesce(connection);
gb_connection_cport_shutdown_phase_2(connection);
gb_connection_control_disconnected(connection);
connection->state = GB_CONNECTION_STATE_DISABLED;
/* control-connection tear down is deferred when mode switching */
if (!connection->mode_switch) {
gb_connection_svc_connection_destroy(connection);
gb_connection_hd_cport_clear(connection);
gb_connection_hd_cport_disable(connection);
}
out_unlock:
mutex_unlock(&connection->mutex);
}
EXPORT_SYMBOL_GPL(gb_connection_disable);
/* Disable a connection without communicating with the remote end. */
void gb_connection_disable_forced(struct gb_connection *connection)
{
mutex_lock(&connection->mutex);
if (connection->state == GB_CONNECTION_STATE_DISABLED)
goto out_unlock;
trace_gb_connection_disable(connection);
spin_lock_irq(&connection->lock);
connection->state = GB_CONNECTION_STATE_DISABLED;
gb_connection_cancel_operations(connection, -ESHUTDOWN);
spin_unlock_irq(&connection->lock);
gb_connection_hd_cport_flush(connection);
gb_connection_svc_connection_destroy(connection);
gb_connection_hd_cport_clear(connection);
gb_connection_hd_cport_disable(connection);
out_unlock:
mutex_unlock(&connection->mutex);
}
EXPORT_SYMBOL_GPL(gb_connection_disable_forced);
/* Caller must have disabled the connection before destroying it. */
void gb_connection_destroy(struct gb_connection *connection)
{
if (!connection)
return;
if (WARN_ON(connection->state != GB_CONNECTION_STATE_DISABLED))
gb_connection_disable(connection);
mutex_lock(&gb_connection_mutex);
spin_lock_irq(&gb_connections_lock);
list_del(&connection->bundle_links);
list_del(&connection->hd_links);
spin_unlock_irq(&gb_connections_lock);
destroy_workqueue(connection->wq);
gb_hd_cport_release(connection->hd, connection->hd_cport_id);
connection->hd_cport_id = CPORT_ID_BAD;
mutex_unlock(&gb_connection_mutex);
gb_connection_put(connection);
}
EXPORT_SYMBOL_GPL(gb_connection_destroy);
void gb_connection_latency_tag_enable(struct gb_connection *connection)
{
struct gb_host_device *hd = connection->hd;
int ret;
if (!hd->driver->latency_tag_enable)
return;
ret = hd->driver->latency_tag_enable(hd, connection->hd_cport_id);
if (ret) {
dev_err(&connection->hd->dev,
"%s: failed to enable latency tag: %d\n",
connection->name, ret);
}
}
EXPORT_SYMBOL_GPL(gb_connection_latency_tag_enable);
void gb_connection_latency_tag_disable(struct gb_connection *connection)
{
struct gb_host_device *hd = connection->hd;
int ret;
if (!hd->driver->latency_tag_disable)
return;
ret = hd->driver->latency_tag_disable(hd, connection->hd_cport_id);
if (ret) {
dev_err(&connection->hd->dev,
"%s: failed to disable latency tag: %d\n",
connection->name, ret);
}
}
EXPORT_SYMBOL_GPL(gb_connection_latency_tag_disable);