linux-imx

/*

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

 *

 * This file is released under the LGPL.

 */

​

#include <linux/bio.h>

#include <linux/slab.h>

#include <linux/jiffies.h>

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

#include <linux/device-mapper.h>

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

#include <linux/module.h>

#include <linux/workqueue.h>

​

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

​

#define DM_LOG_USERSPACE_VSN "1.3.0"

​

#define FLUSH_ENTRY_POOL_SIZE 16

​

struct dm_dirty_log_flush_entry {

    int type;

    region_t region;

    struct list_head list;

};

​

/*

 * This limit on the number of mark and clear request is, to a degree,

 * arbitrary.  However, there is some basis for the choice in the limits

 * imposed on the size of data payload by dm-log-userspace-transfer.c:

 * dm_consult_userspace().

 */

#define MAX_FLUSH_GROUP_COUNT 32

​

struct log_c {

    struct dm_target *ti;

    struct dm_dev *log_dev;

​

    char *usr_argv_str;

    uint32_t usr_argc;

​

    uint32_t region_size;

    region_t region_count;

    uint64_t luid;

    char uuid[DM_UUID_LEN];

​

    /*

     * Mark and clear requests are held until a flush is issued

     * so that we can group, and thereby limit, the amount of

     * network traffic between kernel and userspace.  The 'flush_lock'

     * is used to protect these lists.

     */

    spinlock_t flush_lock;

    struct list_head mark_list;

    struct list_head clear_list;

​

    /*

     * in_sync_hint gets set when doing is_remote_recovering.  It

     * represents the first region that needs recovery.  IOW, the

     * first zero bit of sync_bits.  This can be useful for to limit

     * traffic for calls like is_remote_recovering and get_resync_work,

     * but be take care in its use for anything else.

     */

    uint64_t in_sync_hint;

​

    /*

     * Workqueue for flush of clear region requests.

     */

    struct workqueue_struct *dmlog_wq;

    struct delayed_work flush_log_work;

    atomic_t sched_flush;

​

    /*

     * Combine userspace flush and mark requests for efficiency.

     */

    uint32_t integrated_flush;

​

    mempool_t flush_entry_pool;

};

​

static struct kmem_cache *_flush_entry_cache;

​

static int userspace_do_request(struct log_c *lc, const char *uuid,

                int request_type, char *data, size_t data_size,

                char *rdata, size_t *rdata_size)

{

    int r;

​

    /*

     * If the server isn't there, -ESRCH is returned,

     * and we must keep trying until the server is