linux-imx

/*

 * Copyright (C) 2002 Sistina Software (UK) Limited.

 * Copyright (C) 2006 Red Hat GmbH

 *

 * This file is released under the GPL.

 *

 * Kcopyd provides a simple interface for copying an area of one

 * block-device to one or more other block-devices, with an asynchronous

 * completion notification.

 */

​

#include <linux/types.h>

#include <linux/atomic.h>

#include <linux/blkdev.h>

#include <linux/fs.h>

#include <linux/init.h>

#include <linux/list.h>

#include <linux/mempool.h>

#include <linux/module.h>

#include <linux/pagemap.h>

#include <linux/slab.h>

#include <linux/vmalloc.h>

#include <linux/workqueue.h>

#include <linux/mutex.h>

#include <linux/delay.h>

#include <linux/device-mapper.h>

#include <linux/dm-kcopyd.h>

​

#include "dm-core.h"

​

#define SUB_JOB_SIZE    128

#define SPLIT_COUNT 8

#define MIN_JOBS    8

#define RESERVE_PAGES   (DIV_ROUND_UP(SUB_JOB_SIZE << SECTOR_SHIFT, PAGE_SIZE))

​

/*-----------------------------------------------------------------

 * Each kcopyd client has its own little pool of preallocated

 * pages for kcopyd io.

 *---------------------------------------------------------------*/

struct dm_kcopyd_client {

    struct page_list *pages;

    unsigned nr_reserved_pages;

    unsigned nr_free_pages;

​

    struct dm_io_client *io_client;

​

    wait_queue_head_t destroyq;

​

    mempool_t job_pool;

​

    struct workqueue_struct *kcopyd_wq;

    struct work_struct kcopyd_work;

​

    struct dm_kcopyd_throttle *throttle;

​

    atomic_t nr_jobs;

​

/*

 * We maintain four lists of jobs:

 *

 * i)   jobs waiting for pages

 * ii)  jobs that have pages, and are waiting for the io to be issued.

 * iii) jobs that don't need to do any IO and just run a callback