raid0.c

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/*
   raid0.c : Multiple Devices driver for Linux
             Copyright (C) 1994-96 Marc ZYNGIER
         <[email protected]> or
         <[email protected]>
             Copyright (C) 1999, 2000 Ingo Molnar, Red Hat


   RAID-0 management functions.

   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, or (at your option)
   any later version.
   
   You should have received a copy of the GNU General Public License
   (for example /usr/src/linux/COPYING); if not, write to the Free
   Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  
*/

#include <linux/blkdev.h>
#include <linux/seq_file.h>
#include <linux/module.h>
#include <linux/slab.h>
#include "md.h"
#include "raid0.h"
#include "raid5.h"

static int raid0_congested(void *data, int bits)
{
    struct mddev *mddev = data;
    struct r0conf *conf = mddev->private;
    struct md_rdev **devlist = conf->devlist;
    int raid_disks = conf->strip_zone[0].nb_dev;
    int i, ret = 0;

    if (mddev_congested(mddev, bits))
        return 1;

    for (i = 0; i < raid_disks && !ret ; i++) {
        struct request_queue *q = bdev_get_queue(devlist[i]->bdev);

        ret |= bdi_congested(&q->backing_dev_info, bits);
    }
    return ret;
}

/*
 * inform the user of the raid configuration
*/
static void dump_zones(struct mddev *mddev)
{
    int j, k;
    sector_t zone_size = 0;
    sector_t zone_start = 0;
    char b[BDEVNAME_SIZE];
    struct r0conf *conf = mddev->private;
    int raid_disks = conf->strip_zone[0].nb_dev;
    printk(KERN_INFO "md: RAID0 configuration for %s - %d zone%s\n",
           mdname(mddev),
           conf->nr_strip_zones, conf->nr_strip_zones==1?"":"s");
    for (j = 0; j < conf->nr_strip_zones; j++) {
        printk(KERN_INFO "md: zone%d=[", j);
        for (k = 0; k < conf->strip_zone[j].nb_dev; k++)
            printk(KERN_CONT "%s%s", k?"/":"",
            bdevname(conf->devlist[j*raid_disks
                        + k]->bdev, b));
        printk(KERN_CONT "]\n");

        zone_size  = conf->strip_zone[j].zone_end - zone_start;
        printk(KERN_INFO "      zone-offset=%10lluKB, "
                "device-offset=%10lluKB, size=%10lluKB\n",
            (unsigned long long)zone_start>>1,
            (unsigned long long)conf->strip_zone[j].dev_start>>1,
            (unsigned long long)zone_size>>1);
        zone_start = conf->strip_zone[j].zone_end;
    }
    printk(KERN_INFO "\n");
}

static int create_strip_zones(struct mddev *mddev, struct r0conf **private_conf)
{
    int i, c, err;
    sector_t curr_zone_end, sectors;
    struct md_rdev *smallest, *rdev1, *rdev2, *rdev, **dev;
    struct strip_zone *zone;
    int cnt;
    char b[BDEVNAME_SIZE];
    char b2[BDEVNAME_SIZE];
    struct r0conf *conf = kzalloc(sizeof(*conf), GFP_KERNEL);
    bool discard_supported = false;

    if (!conf)
        return -ENOMEM;
    rdev_for_each(rdev1, mddev) {
        pr_debug("md/raid0:%s: looking at %s\n",
             mdname(mddev),
             bdevname(rdev1->bdev, b));
        c = 0;

        /* round size to chunk_size */
        sectors = rdev1->sectors;
        sector_div(sectors, mddev->chunk_sectors);
        rdev1->sectors = sectors * mddev->chunk_sectors;

        rdev_for_each(rdev2, mddev) {
            pr_debug("md/raid0:%s:   comparing %s(%llu)"
                 " with %s(%llu)\n",
                 mdname(mddev),
                 bdevname(rdev1->bdev,b),
                 (unsigned long long)rdev1->sectors,
                 bdevname(rdev2->bdev,b2),
                 (unsigned long long)rdev2->sectors);
            if (rdev2 == rdev1) {
                pr_debug("md/raid0:%s:   END\n",
                     mdname(mddev));
                break;
            }
            if (rdev2->sectors == rdev1->sectors) {
                /*
                 * Not unique, don't count it as a new
                 * group
                 */
                pr_debug("md/raid0:%s:   EQUAL\n",
                     mdname(mddev));
                c = 1;
                break;
            }
            pr_debug("md/raid0:%s:   NOT EQUAL\n",
                 mdname(mddev));
        }
        if (!c) {
            pr_debug("md/raid0:%s:   ==> UNIQUE\n",
                 mdname(mddev));
            conf->nr_strip_zones++;
            pr_debug("md/raid0:%s: %d zones\n",
                 mdname(mddev), conf->nr_strip_zones);
        }
    }
    pr_debug("md/raid0:%s: FINAL %d zones\n",
         mdname(mddev), conf->nr_strip_zones);
    err = -ENOMEM;
    conf->strip_zone = kzalloc(sizeof(struct strip_zone)*
                conf->nr_strip_zones, GFP_KERNEL);
    if (!conf->strip_zone)
        goto abort;
    conf->devlist = kzalloc(sizeof(struct md_rdev*)*
                conf->nr_strip_zones*mddev->raid_disks,
                GFP_KERNEL);
    if (!conf->devlist)
        goto abort;

    /* The first zone must contain all devices, so here we check that
     * there is a proper alignment of slots to devices and find them all
     */
    zone = &conf->strip_zone[0];
    cnt = 0;
    smallest = NULL;
    dev = conf->devlist;
    err = -EINVAL;
    rdev_for_each(rdev1, mddev) {
        int j = rdev1->raid_disk;

        if (mddev->level == 10) {
            /* taking over a raid10-n2 array */
            j /= 2;
            rdev1->new_raid_disk = j;
        }

        if (mddev->level == 1) {
            /* taiking over a raid1 array-
             * we have only one active disk
             */
            j = 0;
            rdev1->new_raid_disk = j;
        }

        if (j < 0 || j >= mddev->raid_disks) {
            printk(KERN_ERR "md/raid0:%s: bad disk number %d - "
                   "aborting!\n", mdname(mddev), j);
            goto abort;
        }
        if (dev[j]) {
            printk(KERN_ERR "md/raid0:%s: multiple devices for %d - "
                   "aborting!\n", mdname(mddev), j);
            goto abort;
        }
        dev[j] = rdev1;

        disk_stack_limits(mddev->gendisk, rdev1->bdev,
                  rdev1->data_offset << 9);

        if (rdev1->bdev->bd_disk->queue->merge_bvec_fn)
            conf->has_merge_bvec = 1;

        if (!smallest || (rdev1->sectors < smallest->sectors))
            smallest = rdev1;
        cnt++;

        if (blk_queue_discard(bdev_get_queue(rdev1->bdev)))
            discard_supported = true;
    }
    if (cnt != mddev->raid_disks) {
        printk(KERN_ERR "md/raid0:%s: too few disks (%d of %d) - "
               "aborting!\n", mdname(mddev), cnt, mddev->raid_disks);
        goto abort;
    }
    zone->nb_dev = cnt;
    zone->zone_end = smallest->sectors * cnt;

    curr_zone_end = zone->zone_end;

    /* now do the other zones */
    for (i = 1; i < conf->nr_strip_zones; i++)
    {
        int j;

        zone = conf->strip_zone + i;
        dev = conf->devlist + i * mddev->raid_disks;

        pr_debug("md/raid0:%s: zone %d\n", mdname(mddev), i);
        zone->dev_start = smallest->sectors;
        smallest = NULL;
        c = 0;

        for (j=0; j<cnt; j++) {
            rdev = conf->devlist[j];
            if (rdev->sectors <= zone->dev_start) {
                pr_debug("md/raid0:%s: checking %s ... nope\n",
                     mdname(mddev),
                     bdevname(rdev->bdev, b));
                continue;
            }
            pr_debug("md/raid0:%s: checking %s ..."
                 " contained as device %d\n",
                 mdname(mddev),
                 bdevname(rdev->bdev, b), c);
            dev[c] = rdev;
            c++;
            if (!smallest || rdev->sectors < smallest->sectors) {
                smallest = rdev;
                pr_debug("md/raid0:%s:  (%llu) is smallest!.\n",
                     mdname(mddev),
                     (unsigned long long)rdev->sectors);
            }
        }

        zone->nb_dev = c;
        sectors = (smallest->sectors - zone->dev_start) * c;
        pr_debug("md/raid0:%s: zone->nb_dev: %d, sectors: %llu\n",
             mdname(mddev),
             zone->nb_dev, (unsigned long long)sectors);

        curr_zone_end += sectors;
        zone->zone_end = curr_zone_end;

        pr_debug("md/raid0:%s: current zone start: %llu\n",
             mdname(mddev),
             (unsigned long long)smallest->sectors);
    }
    mddev->queue->backing_dev_info.congested_fn = raid0_congested;
    mddev->queue->backing_dev_info.congested_data = mddev;

    /*
     * now since we have the hard sector sizes, we can make sure
     * chunk size is a multiple of that sector size
     */
    if ((mddev->chunk_sectors << 9) % queue_logical_block_size(mddev->queue)) {
        printk(KERN_ERR "md/raid0:%s: chunk_size of %d not valid\n",
               mdname(mddev),
               mddev->chunk_sectors << 9);
        goto abort;
    }

    blk_queue_io_min(mddev->queue, mddev->chunk_sectors << 9);
    blk_queue_io_opt(mddev->queue,
             (mddev->chunk_sectors << 9) * mddev->raid_disks);

    if (!discard_supported)
        queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, mddev->queue);
    else
        queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, mddev->queue);

    pr_debug("md/raid0:%s: done.\n", mdname(mddev));
    *private_conf = conf;

    return 0;
abort:
    kfree(conf->strip_zone);
    kfree(conf->devlist);
    kfree(conf);
    *private_conf = NULL;
    return err;
}

/* Find the zone which holds a particular offset
 * Update *sectorp to be an offset in that zone
 */
static struct strip_zone *find_zone(struct r0conf *conf,
                    sector_t *sectorp)
{
    int i;
    struct strip_zone *z = conf->strip_zone;
    sector_t sector = *sectorp;

    for (i = 0; i < conf->nr_strip_zones; i++)
        if (sector < z[i].zone_end) {
            if (i)
                *sectorp = sector - z[i-1].zone_end;
            return z + i;
        }
    BUG();
}

/*
 * remaps the bio to the target device. we separate two flows.
 * power 2 flow and a general flow for the sake of perfromance
*/
static struct md_rdev *map_sector(struct mddev *mddev, struct strip_zone *zone,
                sector_t sector, sector_t *sector_offset)
{
    unsigned int sect_in_chunk;
    sector_t chunk;
    struct r0conf *conf = mddev->private;
    int raid_disks = conf->strip_zone[0].nb_dev;
    unsigned int chunk_sects = mddev->chunk_sectors;

    if (is_power_of_2(chunk_sects)) {
        int chunksect_bits = ffz(~chunk_sects);
        /* find the sector offset inside the chunk */
        sect_in_chunk  = sector & (chunk_sects - 1);
        sector >>= chunksect_bits;
        /* chunk in zone */
        chunk = *sector_offset;
        /* quotient is the chunk in real device*/
        sector_div(chunk, zone->nb_dev << chunksect_bits);
    } else{
        sect_in_chunk = sector_div(sector, chunk_sects);
        chunk = *sector_offset;
        sector_div(chunk, chunk_sects * zone->nb_dev);
    }
    /*
    *  position the bio over the real device
    *  real sector = chunk in device + starting of zone
    *   + the position in the chunk
    */
    *sector_offset = (chunk * chunk_sects) + sect_in_chunk;
    return conf->devlist[(zone - conf->strip_zone)*raid_disks
                 + sector_div(sector, zone->nb_dev)];
}

static int raid0_mergeable_bvec(struct request_queue *q,
                struct bvec_merge_data *bvm,
                struct bio_vec *biovec)
{
    struct mddev *mddev = q->queuedata;
    struct r0conf *conf = mddev->private;
    sector_t sector = bvm->bi_sector + get_start_sect(bvm->bi_bdev);
    sector_t sector_offset = sector;
    int max;
    unsigned int chunk_sectors = mddev->chunk_sectors;
    unsigned int bio_sectors = bvm->bi_size >> 9;
    struct strip_zone *zone;
    struct md_rdev *rdev;
    struct request_queue *subq;

    if (is_power_of_2(chunk_sectors))
        max =  (chunk_sectors - ((sector & (chunk_sectors-1))
                        + bio_sectors)) << 9;
    else
        max =  (chunk_sectors - (sector_div(sector, chunk_sectors)
                        + bio_sectors)) << 9;
    if (max < 0)
        max = 0; /* bio_add cannot handle a negative return */
    if (max <= biovec->bv_len && bio_sectors == 0)
        return biovec->bv_len;
    if (max < biovec->bv_len)
        /* too small already, no need to check further */
        return max;
    if (!conf->has_merge_bvec)
        return max;

    /* May need to check subordinate device */
    sector = sector_offset;
    zone = find_zone(mddev->private, &sector_offset);
    rdev = map_sector(mddev, zone, sector, &sector_offset);
    subq = bdev_get_queue(rdev->bdev);
    if (subq->merge_bvec_fn) {
        bvm->bi_bdev = rdev->bdev;
        bvm->bi_sector = sector_offset + zone->dev_start +
            rdev->data_offset;
        return min(max, subq->merge_bvec_fn(subq, bvm, biovec));
    } else
        return max;
}

static sector_t raid0_size(struct mddev *mddev, sector_t sectors, int raid_disks)
{
    sector_t array_sectors = 0;
    struct md_rdev *rdev;

    WARN_ONCE(sectors || raid_disks,
          "%s does not support generic reshape\n", __func__);

    rdev_for_each(rdev, mddev)
        array_sectors += rdev->sectors;

    return array_sectors;
}

static int raid0_stop(struct mddev *mddev);

static int raid0_run(struct mddev *mddev)
{
    struct r0conf *conf;
    int ret;

    if (mddev->chunk_sectors == 0) {
        printk(KERN_ERR "md/raid0:%s: chunk size must be set.\n",
               mdname(mddev));
        return -EINVAL;
    }
    if (md_check_no_bitmap(mddev))
        return -EINVAL;
    blk_queue_max_hw_sectors(mddev->queue, mddev->chunk_sectors);
    blk_queue_max_write_same_sectors(mddev->queue, mddev->chunk_sectors);
    blk_queue_max_discard_sectors(mddev->queue, mddev->chunk_sectors);

    /* if private is not null, we are here after takeover */
    if (mddev->private == NULL) {
        ret = create_strip_zones(mddev, &conf);
        if (ret < 0)
            return ret;
        mddev->private = conf;
    }
    conf = mddev->private;

    /* calculate array device size */
    md_set_array_sectors(mddev, raid0_size(mddev, 0, 0));

    printk(KERN_INFO "md/raid0:%s: md_size is %llu sectors.\n",
           mdname(mddev),
           (unsigned long long)mddev->array_sectors);
    /* calculate the max read-ahead size.
     * For read-ahead of large files to be effective, we need to
     * readahead at least twice a whole stripe. i.e. number of devices
     * multiplied by chunk size times 2.
     * If an individual device has an ra_pages greater than the
     * chunk size, then we will not drive that device as hard as it
     * wants.  We consider this a configuration error: a larger
     * chunksize should be used in that case.
     */
    {
        int stripe = mddev->raid_disks *
            (mddev->chunk_sectors << 9) / PAGE_SIZE;
        if (mddev->queue->backing_dev_info.ra_pages < 2* stripe)
            mddev->queue->backing_dev_info.ra_pages = 2* stripe;
    }

    blk_queue_merge_bvec(mddev->queue, raid0_mergeable_bvec);
    dump_zones(mddev);

    ret = md_integrity_register(mddev);
    if (ret)
        raid0_stop(mddev);

    return ret;
}

static int raid0_stop(struct mddev *mddev)
{
    struct r0conf *conf = mddev->private;

    blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/
    kfree(conf->strip_zone);
    kfree(conf->devlist);
    kfree(conf);
    mddev->private = NULL;
    return 0;
}

/*
 * Is io distribute over 1 or more chunks ?
*/
static inline int is_io_in_chunk_boundary(struct mddev *mddev,
            unsigned int chunk_sects, struct bio *bio)
{
    if (likely(is_power_of_2(chunk_sects))) {
        return chunk_sects >= ((bio->bi_sector & (chunk_sects-1))
                    + (bio->bi_size >> 9));
    } else{
        sector_t sector = bio->bi_sector;
        return chunk_sects >= (sector_div(sector, chunk_sects)
                        + (bio->bi_size >> 9));
    }
}

static void raid0_make_request(struct mddev *mddev, struct bio *bio)
{
    unsigned int chunk_sects;
    sector_t sector_offset;
    struct strip_zone *zone;
    struct md_rdev *tmp_dev;

    if (unlikely(bio->bi_rw & REQ_FLUSH)) {
        md_flush_request(mddev, bio);
        return;
    }

    chunk_sects = mddev->chunk_sectors;
    if (unlikely(!is_io_in_chunk_boundary(mddev, chunk_sects, bio))) {
        sector_t sector = bio->bi_sector;
        struct bio_pair *bp;
        /* Sanity check -- queue functions should prevent this happening */
        if ((bio->bi_vcnt != 1 && bio->bi_vcnt != 0) ||
            bio->bi_idx != 0)
            goto bad_map;
        /* This is a one page bio that upper layers
         * refuse to split for us, so we need to split it.
         */
        if (likely(is_power_of_2(chunk_sects)))
            bp = bio_split(bio, chunk_sects - (sector &
                               (chunk_sects-1)));
        else
            bp = bio_split(bio, chunk_sects -
                       sector_div(sector, chunk_sects));
        raid0_make_request(mddev, &bp->bio1);
        raid0_make_request(mddev, &bp->bio2);
        bio_pair_release(bp);
        return;
    }

    sector_offset = bio->bi_sector;
    zone = find_zone(mddev->private, &sector_offset);
    tmp_dev = map_sector(mddev, zone, bio->bi_sector,
                 &sector_offset);
    bio->bi_bdev = tmp_dev->bdev;
    bio->bi_sector = sector_offset + zone->dev_start +
        tmp_dev->data_offset;

    if (unlikely((bio->bi_rw & REQ_DISCARD) &&
             !blk_queue_discard(bdev_get_queue(bio->bi_bdev)))) {
        /* Just ignore it */
        bio_endio(bio, 0);
        return;
    }

    generic_make_request(bio);
    return;

bad_map:
    printk("md/raid0:%s: make_request bug: can't convert block across chunks"
           " or bigger than %dk %llu %d\n",
           mdname(mddev), chunk_sects / 2,
           (unsigned long long)bio->bi_sector, bio->bi_size >> 10);

    bio_io_error(bio);
    return;
}

static void raid0_status(struct seq_file *seq, struct mddev *mddev)
{
    seq_printf(seq, " %dk chunks", mddev->chunk_sectors / 2);
    return;
}

static void *raid0_takeover_raid45(struct mddev *mddev)
{
    struct md_rdev *rdev;
    struct r0conf *priv_conf;

    if (mddev->degraded != 1) {
        printk(KERN_ERR "md/raid0:%s: raid5 must be degraded! Degraded disks: %d\n",
               mdname(mddev),
               mddev->degraded);
        return ERR_PTR(-EINVAL);
    }

    rdev_for_each(rdev, mddev) {
        /* check slot number for a disk */
        if (rdev->raid_disk == mddev->raid_disks-1) {
            printk(KERN_ERR "md/raid0:%s: raid5 must have missing parity disk!\n",
                   mdname(mddev));
            return ERR_PTR(-EINVAL);
        }
    }

    /* Set new parameters */
    mddev->new_level = 0;
    mddev->new_layout = 0;
    mddev->new_chunk_sectors = mddev->chunk_sectors;
    mddev->raid_disks--;
    mddev->delta_disks = -1;
    /* make sure it will be not marked as dirty */
    mddev->recovery_cp = MaxSector;

    create_strip_zones(mddev, &priv_conf);
    return priv_conf;
}

static void *raid0_takeover_raid10(struct mddev *mddev)
{
    struct r0conf *priv_conf;

    /* Check layout:
     *  - far_copies must be 1
     *  - near_copies must be 2
     *  - disks number must be even
     *  - all mirrors must be already degraded
     */
    if (mddev->layout != ((1 << 8) + 2)) {
        printk(KERN_ERR "md/raid0:%s:: Raid0 cannot takover layout: 0x%x\n",
               mdname(mddev),
               mddev->layout);
        return ERR_PTR(-EINVAL);
    }
    if (mddev->raid_disks & 1) {
        printk(KERN_ERR "md/raid0:%s: Raid0 cannot takover Raid10 with odd disk number.\n",
               mdname(mddev));
        return ERR_PTR(-EINVAL);
    }
    if (mddev->degraded != (mddev->raid_disks>>1)) {
        printk(KERN_ERR "md/raid0:%s: All mirrors must be already degraded!\n",
               mdname(mddev));
        return ERR_PTR(-EINVAL);
    }

    /* Set new parameters */
    mddev->new_level = 0;
    mddev->new_layout = 0;
    mddev->new_chunk_sectors = mddev->chunk_sectors;
    mddev->delta_disks = - mddev->raid_disks / 2;
    mddev->raid_disks += mddev->delta_disks;
    mddev->degraded = 0;
    /* make sure it will be not marked as dirty */
    mddev->recovery_cp = MaxSector;

    create_strip_zones(mddev, &priv_conf);
    return priv_conf;
}

static void *raid0_takeover_raid1(struct mddev *mddev)
{
    struct r0conf *priv_conf;
    int chunksect;

    /* Check layout:
     *  - (N - 1) mirror drives must be already faulty
     */
    if ((mddev->raid_disks - 1) != mddev->degraded) {
        printk(KERN_ERR "md/raid0:%s: (N - 1) mirrors drives must be already faulty!\n",
               mdname(mddev));
        return ERR_PTR(-EINVAL);
    }

    /*
     * a raid1 doesn't have the notion of chunk size, so
     * figure out the largest suitable size we can use.
     */
    chunksect = 64 * 2; /* 64K by default */

    /* The array must be an exact multiple of chunksize */
    while (chunksect && (mddev->array_sectors & (chunksect - 1)))
        chunksect >>= 1;

    if ((chunksect << 9) < PAGE_SIZE)
        /* array size does not allow a suitable chunk size */
        return ERR_PTR(-EINVAL);

    /* Set new parameters */
    mddev->new_level = 0;
    mddev->new_layout = 0;
    mddev->new_chunk_sectors = chunksect;
    mddev->chunk_sectors = chunksect;
    mddev->delta_disks = 1 - mddev->raid_disks;
    mddev->raid_disks = 1;
    /* make sure it will be not marked as dirty */
    mddev->recovery_cp = MaxSector;

    create_strip_zones(mddev, &priv_conf);
    return priv_conf;
}

static void *raid0_takeover(struct mddev *mddev)
{
    /* raid0 can take over:
     *  raid4 - if all data disks are active.
     *  raid5 - providing it is Raid4 layout and one disk is faulty
     *  raid10 - assuming we have all necessary active disks
     *  raid1 - with (N -1) mirror drives faulty
     */
    if (mddev->level == 4)
        return raid0_takeover_raid45(mddev);

    if (mddev->level == 5) {
        if (mddev->layout == ALGORITHM_PARITY_N)
            return raid0_takeover_raid45(mddev);

        printk(KERN_ERR "md/raid0:%s: Raid can only takeover Raid5 with layout: %d\n",
               mdname(mddev), ALGORITHM_PARITY_N);
    }

    if (mddev->level == 10)
        return raid0_takeover_raid10(mddev);

    if (mddev->level == 1)
        return raid0_takeover_raid1(mddev);

    printk(KERN_ERR "Takeover from raid%i to raid0 not supported\n",
        mddev->level);

    return ERR_PTR(-EINVAL);
}

static void raid0_quiesce(struct mddev *mddev, int state)
{
}

static struct md_personality raid0_personality=
{
    .name       = "raid0",
    .level      = 0,
    .owner      = THIS_MODULE,
    .make_request   = raid0_make_request,
    .run        = raid0_run,
    .stop       = raid0_stop,
    .status     = raid0_status,
    .size       = raid0_size,
    .takeover   = raid0_takeover,
    .quiesce    = raid0_quiesce,
};

static int __init raid0_init (void)
{
    return register_md_personality (&raid0_personality);
}

static void raid0_exit (void)
{
    unregister_md_personality (&raid0_personality);
}

module_init(raid0_init);
module_exit(raid0_exit);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("RAID0 (striping) personality for MD");
MODULE_ALIAS("md-personality-2"); /* RAID0 */
MODULE_ALIAS("md-raid0");
MODULE_ALIAS("md-level-0");