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linux-next/include/linux/ntb_transport.h
Dave Jiang e74bfeedad NTB: Add flow control to the ntb_netdev
Right now if we push the NTB really hard, we start dropping packets due
to not able to process the packets fast enough. We need to st:qop the
upper layer from flooding us when that happens.

A timer is necessary in order to restart the queue once the resource has
been processed on the receive side. Due to the way NTB is setup, the
resources on the tx side are tied to the processing of the rx side and
there's no async way to know when the rx side has released those
resources.

Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Jon Mason <jdmason@kudzu.us>
2015-09-07 15:17:08 -04:00

87 lines
3.8 KiB
C

/*
* This file is provided under a dual BSD/GPLv2 license. When using or
* redistributing this file, you may do so under either license.
*
* GPL LICENSE SUMMARY
*
* Copyright(c) 2012 Intel Corporation. All rights reserved.
* Copyright (C) 2015 EMC Corporation. All Rights Reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of version 2 of the GNU General Public License as
* published by the Free Software Foundation.
*
* BSD LICENSE
*
* Copyright(c) 2012 Intel Corporation. All rights reserved.
* Copyright (C) 2015 EMC Corporation. All Rights Reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copy
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* * Neither the name of Intel Corporation nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* PCIe NTB Transport Linux driver
*
* Contact Information:
* Jon Mason <jon.mason@intel.com>
*/
struct ntb_transport_qp;
struct ntb_transport_client {
struct device_driver driver;
int (*probe)(struct device *client_dev);
void (*remove)(struct device *client_dev);
};
int ntb_transport_register_client(struct ntb_transport_client *drvr);
void ntb_transport_unregister_client(struct ntb_transport_client *drvr);
int ntb_transport_register_client_dev(char *device_name);
void ntb_transport_unregister_client_dev(char *device_name);
struct ntb_queue_handlers {
void (*rx_handler)(struct ntb_transport_qp *qp, void *qp_data,
void *data, int len);
void (*tx_handler)(struct ntb_transport_qp *qp, void *qp_data,
void *data, int len);
void (*event_handler)(void *data, int status);
};
unsigned char ntb_transport_qp_num(struct ntb_transport_qp *qp);
unsigned int ntb_transport_max_size(struct ntb_transport_qp *qp);
struct ntb_transport_qp *
ntb_transport_create_queue(void *data, struct device *client_dev,
const struct ntb_queue_handlers *handlers);
void ntb_transport_free_queue(struct ntb_transport_qp *qp);
int ntb_transport_rx_enqueue(struct ntb_transport_qp *qp, void *cb, void *data,
unsigned int len);
int ntb_transport_tx_enqueue(struct ntb_transport_qp *qp, void *cb, void *data,
unsigned int len);
void *ntb_transport_rx_remove(struct ntb_transport_qp *qp, unsigned int *len);
void ntb_transport_link_up(struct ntb_transport_qp *qp);
void ntb_transport_link_down(struct ntb_transport_qp *qp);
bool ntb_transport_link_query(struct ntb_transport_qp *qp);
unsigned int ntb_transport_tx_free_entry(struct ntb_transport_qp *qp);