linux-imx

/*

 * Copyright (C) 2006-2009 Red Hat, Inc.

 *

 * This file is released under the LGPL.

 */

​

#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/slab.h>

#include <net/sock.h>

#include <linux/workqueue.h>

#include <linux/connector.h>

#include <linux/device-mapper.h>

#include <linux/dm-log-userspace.h>

​

#include "dm-log-userspace-transfer.h"

​

static uint32_t dm_ulog_seq;

​

/*

 * Netlink/Connector is an unreliable protocol.  How long should

 * we wait for a response before assuming it was lost and retrying?

 * (If we do receive a response after this time, it will be discarded

 * and the response to the resent request will be waited for.

 */

#define DM_ULOG_RETRY_TIMEOUT (15 * HZ)

​

/*

 * Pre-allocated space for speed

 */

#define DM_ULOG_PREALLOCED_SIZE 512

static struct cn_msg *prealloced_cn_msg;

static struct dm_ulog_request *prealloced_ulog_tfr;

​

static struct cb_id ulog_cn_id = {

    .idx = CN_IDX_DM,

    .val = CN_VAL_DM_USERSPACE_LOG

};

​

static DEFINE_MUTEX(dm_ulog_lock);

​

struct receiving_pkg {

    struct list_head list;

    struct completion complete;

​

    uint32_t seq;

​

    int error;

    size_t *data_size;

    char *data;

};

​

static DEFINE_SPINLOCK(receiving_list_lock);

static struct list_head receiving_list;

​

static int dm_ulog_sendto_server(struct dm_ulog_request *tfr)

{

    int r;

    struct cn_msg *msg = prealloced_cn_msg;

​

    memset(msg, 0, sizeof(struct cn_msg));

​

    msg->id.idx = ulog_cn_id.idx;

    msg->id.val = ulog_cn_id.val;

    msg->ack = 0;

    msg->seq = tfr->seq;

    msg->len = sizeof(struct dm_ulog_request) + tfr->data_size;

​

    r = cn_netlink_send(msg, 0, 0, gfp_any());

​

    return r;

}

​

/*

 * Parameters for this function can be either msg or tfr, but not

 * both.  This function fills in the reply for a waiting request.

 * If just msg is given, then the reply is simply an ACK from userspace

 * that the request was received.

 *

 * Returns: 0 on success, -ENOENT on failure

 */

static int fill_pkg(struct cn_msg *msg, struct dm_ulog_request *tfr)

{

    uint32_t rtn_seq = (msg) ? msg->seq : (tfr) ? tfr->seq : 0;

    struct receiving_pkg *pkg;

​

    /*

     * The 'receiving_pkg' entries in this list are statically

     * allocated on the stack in 'dm_consult_userspace'.

     * Each process that is waiting for a reply from the user

     * space server will have an entry in this list.

     *