linux-imx

/*

 * (c) 2017 Stefano Stabellini <stefano@aporeto.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.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 */

​

#include <linux/module.h>

#include <linux/net.h>

#include <linux/socket.h>

​

#include <net/sock.h>

​

#include <xen/events.h>

#include <xen/grant_table.h>

#include <xen/xen.h>

#include <xen/xenbus.h>

#include <xen/interface/io/pvcalls.h>

​

#include "pvcalls-front.h"

​

#define PVCALLS_INVALID_ID UINT_MAX

#define PVCALLS_RING_ORDER XENBUS_MAX_RING_GRANT_ORDER

#define PVCALLS_NR_RSP_PER_RING __CONST_RING_SIZE(xen_pvcalls, XEN_PAGE_SIZE)

#define PVCALLS_FRONT_MAX_SPIN 5000

​

static struct proto pvcalls_proto = {

    .name   = "PVCalls",

    .owner  = THIS_MODULE,

    .obj_size = sizeof(struct sock),

};

​

struct pvcalls_bedata {

    struct xen_pvcalls_front_ring ring;

    grant_ref_t ref;

    int irq;

​

    struct list_head socket_mappings;

    spinlock_t socket_lock;

​

    wait_queue_head_t inflight_req;

    struct xen_pvcalls_response rsp[PVCALLS_NR_RSP_PER_RING];

};

/* Only one front/back connection supported. */

static struct xenbus_device *pvcalls_front_dev;

static atomic_t pvcalls_refcount;

​

/* first increment refcount, then proceed */

#define pvcalls_enter() {               \

    atomic_inc(&pvcalls_refcount);      \

}

​

/* first complete other operations, then decrement refcount */

#define pvcalls_exit() {                \

    atomic_dec(&pvcalls_refcount);      \

}