[deliverable/linux.git] / drivers / md / linear.c

/*
   linear.c : Multiple Devices driver for Linux
	      Copyright (C) 1994-96 Marc ZYNGIER
	      <zyngier@ufr-info-p7.ibp.fr> or
	      <maz@gloups.fdn.fr>

   Linear mode 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/module.h>

#include <linux/raid/md.h>
#include <linux/slab.h>
#include <linux/raid/linear.h>

#define MAJOR_NR MD_MAJOR
#define MD_DRIVER
#define MD_PERSONALITY

/*
 * find which device holds a particular offset 
 */
static inline dev_info_t *which_dev(mddev_t *mddev, sector_t sector)
{
	dev_info_t *hash;
	linear_conf_t *conf = mddev_to_conf(mddev);
	sector_t block = sector >> 1;

	/*
	 * sector_div(a,b) returns the remainer and sets a to a/b
	 */
	block >>= conf->preshift;
	(void)sector_div(block, conf->hash_spacing);
	hash = conf->hash_table[block];

	while ((sector>>1) >= (hash->size + hash->offset))
		hash++;
	return hash;
}

/**
 *	linear_mergeable_bvec -- tell bio layer if two requests can be merged
 *	@q: request queue
 *	@bio: the buffer head that's been built up so far
 *	@biovec: the request that could be merged to it.
 *
 *	Return amount of bytes we can take at this offset
 */
static int linear_mergeable_bvec(request_queue_t *q, struct bio *bio, struct bio_vec *biovec)
{
	mddev_t *mddev = q->queuedata;
	dev_info_t *dev0;
	unsigned long maxsectors, bio_sectors = bio->bi_size >> 9;
	sector_t sector = bio->bi_sector + get_start_sect(bio->bi_bdev);

	dev0 = which_dev(mddev, sector);
	maxsectors = (dev0->size << 1) - (sector - (dev0->offset<<1));

	if (maxsectors < bio_sectors)
		maxsectors = 0;
	else
		maxsectors -= bio_sectors;

	if (maxsectors <= (PAGE_SIZE >> 9 ) && bio_sectors == 0)
		return biovec->bv_len;
	/* The bytes available at this offset could be really big,
	 * so we cap at 2^31 to avoid overflow */
	if (maxsectors > (1 << (31-9)))
		return 1<<31;
	return maxsectors << 9;
}

static void linear_unplug(request_queue_t *q)
{
	mddev_t *mddev = q->queuedata;
	linear_conf_t *conf = mddev_to_conf(mddev);
	int i;

	for (i=0; i < mddev->raid_disks; i++) {
		request_queue_t *r_queue = bdev_get_queue(conf->disks[i].rdev->bdev);
		if (r_queue->unplug_fn)
			r_queue->unplug_fn(r_queue);
	}
}

static int linear_issue_flush(request_queue_t *q, struct gendisk *disk,
			      sector_t *error_sector)
{
	mddev_t *mddev = q->queuedata;
	linear_conf_t *conf = mddev_to_conf(mddev);
	int i, ret = 0;

	for (i=0; i < mddev->raid_disks && ret == 0; i++) {
		struct block_device *bdev = conf->disks[i].rdev->bdev;
		request_queue_t *r_queue = bdev_get_queue(bdev);

		if (!r_queue->issue_flush_fn)
			ret = -EOPNOTSUPP;
		else
			ret = r_queue->issue_flush_fn(r_queue, bdev->bd_disk, error_sector);
	}
	return ret;
}

static int linear_run (mddev_t *mddev)
{
	linear_conf_t *conf;
	dev_info_t **table;
	mdk_rdev_t *rdev;
	int i, nb_zone, cnt;
	sector_t min_spacing;
	sector_t curr_offset;
	struct list_head *tmp;

	conf = kzalloc (sizeof (*conf) + mddev->raid_disks*sizeof(dev_info_t),
			GFP_KERNEL);
	if (!conf)
		goto out;
	mddev->private = conf;

	cnt = 0;
	mddev->array_size = 0;

	ITERATE_RDEV(mddev,rdev,tmp) {
		int j = rdev->raid_disk;
		dev_info_t *disk = conf->disks + j;

		if (j < 0 || j > mddev->raid_disks || disk->rdev) {
			printk("linear: disk numbering problem. Aborting!\n");
			goto out;
		}

		disk->rdev = rdev;

		blk_queue_stack_limits(mddev->queue,
				       rdev->bdev->bd_disk->queue);
		/* as we don't honour merge_bvec_fn, we must never risk
		 * violating it, so limit ->max_sector to one PAGE, as
		 * a one page request is never in violation.
		 */
		if (rdev->bdev->bd_disk->queue->merge_bvec_fn &&
		    mddev->queue->max_sectors > (PAGE_SIZE>>9))
			blk_queue_max_sectors(mddev->queue, PAGE_SIZE>>9);

		disk->size = rdev->size;
		mddev->array_size += rdev->size;

		cnt++;
	}
	if (cnt != mddev->raid_disks) {
		printk("linear: not enough drives present. Aborting!\n");
		goto out;
	}

	min_spacing = mddev->array_size;
	sector_div(min_spacing, PAGE_SIZE/sizeof(struct dev_info *));

	/* min_spacing is the minimum spacing that will fit the hash
	 * table in one PAGE.  This may be much smaller than needed.
	 * We find the smallest non-terminal set of consecutive devices
	 * that is larger than min_spacing as use the size of that as
	 * the actual spacing
	 */
	conf->hash_spacing = mddev->array_size;
	for (i=0; i < cnt-1 ; i++) {
		sector_t sz = 0;
		int j;
		for (j=i; i<cnt-1 && sz < min_spacing ; j++)
			sz += conf->disks[j].size;
		if (sz >= min_spacing && sz < conf->hash_spacing)
			conf->hash_spacing = sz;
	}

	/* hash_spacing may be too large for sector_div to work with,
	 * so we might need to pre-shift
	 */
	conf->preshift = 0;
	if (sizeof(sector_t) > sizeof(u32)) {
		sector_t space = conf->hash_spacing;
		while (space > (sector_t)(~(u32)0)) {
			space >>= 1;
			conf->preshift++;
		}
	}
	/*
	 * This code was restructured to work around a gcc-2.95.3 internal
	 * compiler error.  Alter it with care.
	 */
	{
		sector_t sz;
		unsigned round;
		unsigned long base;

		sz = mddev->array_size >> conf->preshift;
		sz += 1; /* force round-up */
		base = conf->hash_spacing >> conf->preshift;
		round = sector_div(sz, base);
		nb_zone = sz + (round ? 1 : 0);
	}
	BUG_ON(nb_zone > PAGE_SIZE / sizeof(struct dev_info *));

	conf->hash_table = kmalloc (sizeof (struct dev_info *) * nb_zone,
					GFP_KERNEL);
	if (!conf->hash_table)
		goto out;

	/*
	 * Here we generate the linear hash table
	 * First calculate the device offsets.
	 */
	conf->disks[0].offset = 0;
	for (i=1; i<mddev->raid_disks; i++)
		conf->disks[i].offset =
			conf->disks[i-1].offset +
			conf->disks[i-1].size;

	table = conf->hash_table;
	curr_offset = 0;
	i = 0;
	for (curr_offset = 0;
	     curr_offset < mddev->array_size;
	     curr_offset += conf->hash_spacing) {

		while (i < mddev->raid_disks-1 &&
		       curr_offset >= conf->disks[i+1].offset)
			i++;

		*table ++ = conf->disks + i;
	}

	if (conf->preshift) {
		conf->hash_spacing >>= conf->preshift;
		/* round hash_spacing up so that when we divide by it,
		 * we err on the side of "too-low", which is safest.
		 */
		conf->hash_spacing++;
	}

	BUG_ON(table - conf->hash_table > nb_zone);

	blk_queue_merge_bvec(mddev->queue, linear_mergeable_bvec);
	mddev->queue->unplug_fn = linear_unplug;
	mddev->queue->issue_flush_fn = linear_issue_flush;
	return 0;

out:
	kfree(conf);
	return 1;
}

static int linear_stop (mddev_t *mddev)
{
	linear_conf_t *conf = mddev_to_conf(mddev);
  
	blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/
	kfree(conf->hash_table);
	kfree(conf);

	return 0;
}

static int linear_make_request (request_queue_t *q, struct bio *bio)
{
	const int rw = bio_data_dir(bio);
	mddev_t *mddev = q->queuedata;
	dev_info_t *tmp_dev;
	sector_t block;

	if (unlikely(bio_barrier(bio))) {
		bio_endio(bio, bio->bi_size, -EOPNOTSUPP);
		return 0;
	}

	disk_stat_inc(mddev->gendisk, ios[rw]);
	disk_stat_add(mddev->gendisk, sectors[rw], bio_sectors(bio));

	tmp_dev = which_dev(mddev, bio->bi_sector);
	block = bio->bi_sector >> 1;
    
	if (unlikely(block >= (tmp_dev->size + tmp_dev->offset)
		     || block < tmp_dev->offset)) {
		char b[BDEVNAME_SIZE];

		printk("linear_make_request: Block %llu out of bounds on "
			"dev %s size %llu offset %llu\n",
			(unsigned long long)block,
			bdevname(tmp_dev->rdev->bdev, b),
			(unsigned long long)tmp_dev->size,
		        (unsigned long long)tmp_dev->offset);
		bio_io_error(bio, bio->bi_size);
		return 0;
	}
	if (unlikely(bio->bi_sector + (bio->bi_size >> 9) >
		     (tmp_dev->offset + tmp_dev->size)<<1)) {
		/* This bio crosses a device boundary, so we have to
		 * split it.
		 */
		struct bio_pair *bp;
		bp = bio_split(bio, bio_split_pool,
			       ((tmp_dev->offset + tmp_dev->size)<<1) - bio->bi_sector);
		if (linear_make_request(q, &bp->bio1))
			generic_make_request(&bp->bio1);
		if (linear_make_request(q, &bp->bio2))
			generic_make_request(&bp->bio2);
		bio_pair_release(bp);
		return 0;
	}
		    
	bio->bi_bdev = tmp_dev->rdev->bdev;
	bio->bi_sector = bio->bi_sector - (tmp_dev->offset << 1) + tmp_dev->rdev->data_offset;

	return 1;
}

static void linear_status (struct seq_file *seq, mddev_t *mddev)
{

#undef MD_DEBUG
#ifdef MD_DEBUG
	int j;
	linear_conf_t *conf = mddev_to_conf(mddev);
	sector_t s = 0;
  
	seq_printf(seq, "      ");
	for (j = 0; j < mddev->raid_disks; j++)
	{
		char b[BDEVNAME_SIZE];
		s += conf->smallest_size;
		seq_printf(seq, "[%s",
			   bdevname(conf->hash_table[j][0].rdev->bdev,b));

		while (s > conf->hash_table[j][0].offset +
		           conf->hash_table[j][0].size)
			seq_printf(seq, "/%s] ",
				   bdevname(conf->hash_table[j][1].rdev->bdev,b));
		else
			seq_printf(seq, "] ");
	}
	seq_printf(seq, "\n");
#endif
	seq_printf(seq, " %dk rounding", mddev->chunk_size/1024);
}


static struct mdk_personality linear_personality =
{
	.name		= "linear",
	.level		= LEVEL_LINEAR,
	.owner		= THIS_MODULE,
	.make_request	= linear_make_request,
	.run		= linear_run,
	.stop		= linear_stop,
	.status		= linear_status,
};

static int __init linear_init (void)
{
	return register_md_personality (&linear_personality);
}

static void linear_exit (void)
{
	unregister_md_personality (&linear_personality);
}


module_init(linear_init);
module_exit(linear_exit);
MODULE_LICENSE("GPL");
MODULE_ALIAS("md-personality-1"); /* LINEAR - deprecated*/
MODULE_ALIAS("md-linear");
MODULE_ALIAS("md-level--1");
Commit	Line	Data
1da177e4 LT	1	/*
	2	linear.c : Multiple Devices driver for Linux
	3	Copyright (C) 1994-96 Marc ZYNGIER
	4	<zyngier@ufr-info-p7.ibp.fr> or
	5	<maz@gloups.fdn.fr>
	6
	7	Linear mode management functions.
	8
	9	This program is free software; you can redistribute it and/or modify
	10	it under the terms of the GNU General Public License as published by
	11	the Free Software Foundation; either version 2, or (at your option)
	12	any later version.
	13
	14	You should have received a copy of the GNU General Public License
	15	(for example /usr/src/linux/COPYING); if not, write to the Free
	16	Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
	17	*/
	18
	19	#include <linux/module.h>
	20
	21	#include <linux/raid/md.h>
	22	#include <linux/slab.h>
	23	#include <linux/raid/linear.h>
	24
	25	#define MAJOR_NR MD_MAJOR
	26	#define MD_DRIVER
	27	#define MD_PERSONALITY
	28
	29	/*
	30	* find which device holds a particular offset
	31	*/
	32	static inline dev_info_t which_dev(mddev_t mddev, sector_t sector)
	33	{
	34	dev_info_t *hash;
	35	linear_conf_t *conf = mddev_to_conf(mddev);
	36	sector_t block = sector >> 1;
	37
	38	/*
	39	* sector_div(a,b) returns the remainer and sets a to a/b
	40	*/
15945fee N	41	block >>= conf->preshift;
15945fee N	42	(void)sector_div(block, conf->hash_spacing);
1da177e4 LT	43	hash = conf->hash_table[block];
	44
	45	while ((sector>>1) >= (hash->size + hash->offset))
	46	hash++;
	47	return hash;
	48	}
	49
	50	/**
15945fee	51	* linear_mergeable_bvec -- tell bio layer if two requests can be merged
1da177e4 LT	52	* @q: request queue
	53	* @bio: the buffer head that's been built up so far
	54	* @biovec: the request that could be merged to it.
	55	*
	56	* Return amount of bytes we can take at this offset
	57	*/
	58	static int linear_mergeable_bvec(request_queue_t q, struct bio bio, struct bio_vec *biovec)
	59	{
	60	mddev_t *mddev = q->queuedata;
	61	dev_info_t *dev0;
	62	unsigned long maxsectors, bio_sectors = bio->bi_size >> 9;
	63	sector_t sector = bio->bi_sector + get_start_sect(bio->bi_bdev);
	64
	65	dev0 = which_dev(mddev, sector);
	66	maxsectors = (dev0->size << 1) - (sector - (dev0->offset<<1));
	67
	68	if (maxsectors < bio_sectors)
	69	maxsectors = 0;
	70	else
	71	maxsectors -= bio_sectors;
	72
	73	if (maxsectors <= (PAGE_SIZE >> 9 ) && bio_sectors == 0)
	74	return biovec->bv_len;
	75	/* The bytes available at this offset could be really big,
	76	* so we cap at 2^31 to avoid overflow */
	77	if (maxsectors > (1 << (31-9)))
	78	return 1<<31;
	79	return maxsectors << 9;
	80	}
	81
	82	static void linear_unplug(request_queue_t *q)
	83	{
	84	mddev_t *mddev = q->queuedata;
	85	linear_conf_t *conf = mddev_to_conf(mddev);
	86	int i;
	87
	88	for (i=0; i < mddev->raid_disks; i++) {
	89	request_queue_t *r_queue = bdev_get_queue(conf->disks[i].rdev->bdev);
	90	if (r_queue->unplug_fn)
	91	r_queue->unplug_fn(r_queue);
	92	}
	93	}
	94
	95	static int linear_issue_flush(request_queue_t q, struct gendisk disk,
	96	sector_t *error_sector)
	97	{
	98	mddev_t *mddev = q->queuedata;
	99	linear_conf_t *conf = mddev_to_conf(mddev);
	100	int i, ret = 0;
	101
	102	for (i=0; i < mddev->raid_disks && ret == 0; i++) {
	103	struct block_device *bdev = conf->disks[i].rdev->bdev;
	104	request_queue_t *r_queue = bdev_get_queue(bdev);
	105
	106	if (!r_queue->issue_flush_fn)
	107	ret = -EOPNOTSUPP;
	108	else
	109	ret = r_queue->issue_flush_fn(r_queue, bdev->bd_disk, error_sector);
	110	}
	111	return ret;
	112	}
	113
	114	static int linear_run (mddev_t *mddev)
	115	{
116	linear_conf_t *conf;
117	dev_info_t **table;
118	mdk_rdev_t *rdev;
119	int i, nb_zone, cnt;
15945fee	120	sector_t min_spacing;
1da177e4 LT	121	sector_t curr_offset;
	122	struct list_head *tmp;
	123
9ffae0cf	124	conf = kzalloc (sizeof (conf) + mddev->raid_diskssizeof(dev_info_t),
1da177e4 LT	125	GFP_KERNEL);
	126	if (!conf)
	127	goto out;
1da177e4 LT	128	mddev->private = conf;
1da177e4 LT	129
1da177e4 LT	130	cnt = 0;
	131	mddev->array_size = 0;
	132
	133	ITERATE_RDEV(mddev,rdev,tmp) {
	134	int j = rdev->raid_disk;
	135	dev_info_t *disk = conf->disks + j;
	136
	137	if (j < 0 \|\| j > mddev->raid_disks \|\| disk->rdev) {
	138	printk("linear: disk numbering problem. Aborting!\n");
	139	goto out;
	140	}
	141
	142	disk->rdev = rdev;
	143
	144	blk_queue_stack_limits(mddev->queue,
	145	rdev->bdev->bd_disk->queue);
	146	/* as we don't honour merge_bvec_fn, we must never risk
	147	* violating it, so limit ->max_sector to one PAGE, as
	148	* a one page request is never in violation.
	149	*/
	150	if (rdev->bdev->bd_disk->queue->merge_bvec_fn &&
	151	mddev->queue->max_sectors > (PAGE_SIZE>>9))
	152	blk_queue_max_sectors(mddev->queue, PAGE_SIZE>>9);
	153
	154	disk->size = rdev->size;
	155	mddev->array_size += rdev->size;
	156
1da177e4 LT	157	cnt++;
	158	}
	159	if (cnt != mddev->raid_disks) {
	160	printk("linear: not enough drives present. Aborting!\n");
	161	goto out;
	162	}
	163
15945fee N	164	min_spacing = mddev->array_size;
	165	sector_div(min_spacing, PAGE_SIZE/sizeof(struct dev_info *));
	166
	167	/* min_spacing is the minimum spacing that will fit the hash
	168	* table in one PAGE. This may be much smaller than needed.
	169	* We find the smallest non-terminal set of consecutive devices
	170	* that is larger than min_spacing as use the size of that as
	171	* the actual spacing
	172	*/
	173	conf->hash_spacing = mddev->array_size;
	174	for (i=0; i < cnt-1 ; i++) {
	175	sector_t sz = 0;
	176	int j;
	177	for (j=i; i<cnt-1 && sz < min_spacing ; j++)
	178	sz += conf->disks[j].size;
	179	if (sz >= min_spacing && sz < conf->hash_spacing)
	180	conf->hash_spacing = sz;
	181	}
	182
	183	/* hash_spacing may be too large for sector_div to work with,
	184	* so we might need to pre-shift
	185	*/
	186	conf->preshift = 0;
	187	if (sizeof(sector_t) > sizeof(u32)) {
	188	sector_t space = conf->hash_spacing;
	189	while (space > (sector_t)(~(u32)0)) {
	190	space >>= 1;
	191	conf->preshift++;
	192	}
	193	}
1da177e4 LT	194	/*
	195	* This code was restructured to work around a gcc-2.95.3 internal
	196	* compiler error. Alter it with care.
	197	*/
	198	{
	199	sector_t sz;
	200	unsigned round;
	201	unsigned long base;
	202
15945fee N	203	sz = mddev->array_size >> conf->preshift;
	204	sz += 1; /* force round-up */
	205	base = conf->hash_spacing >> conf->preshift;
1da177e4	206	round = sector_div(sz, base);
15945fee	207	nb_zone = sz + (round ? 1 : 0);
1da177e4	208	}
15945fee N	209	BUG_ON(nb_zone > PAGE_SIZE / sizeof(struct dev_info *));
	210
	211	conf->hash_table = kmalloc (sizeof (struct dev_info ) nb_zone,
1da177e4 LT	212	GFP_KERNEL);
	213	if (!conf->hash_table)
	214	goto out;
	215
	216	/*
	217	* Here we generate the linear hash table
15945fee	218	* First calculate the device offsets.
1da177e4	219	*/
15945fee N	220	conf->disks[0].offset = 0;
	221	for (i=1; i<mddev->raid_disks; i++)
	222	conf->disks[i].offset =
	223	conf->disks[i-1].offset +
	224	conf->disks[i-1].size;
	225
1da177e4	226	table = conf->hash_table;
1da177e4	227	curr_offset = 0;
15945fee N	228	i = 0;
	229	for (curr_offset = 0;
	230	curr_offset < mddev->array_size;
	231	curr_offset += conf->hash_spacing) {
1da177e4	232
15945fee N	233	while (i < mddev->raid_disks-1 &&
	234	curr_offset >= conf->disks[i+1].offset)
	235	i++;
1da177e4	236
15945fee N	237	*table ++ = conf->disks + i;
	238	}
	239
	240	if (conf->preshift) {
	241	conf->hash_spacing >>= conf->preshift;
	242	/* round hash_spacing up so that when we divide by it,
	243	* we err on the side of "too-low", which is safest.
1da177e4	244	*/
15945fee	245	conf->hash_spacing++;
1da177e4	246	}
15945fee N	247
15945fee N	248	BUG_ON(table - conf->hash_table > nb_zone);
1da177e4 LT	249
	250	blk_queue_merge_bvec(mddev->queue, linear_mergeable_bvec);
	251	mddev->queue->unplug_fn = linear_unplug;
	252	mddev->queue->issue_flush_fn = linear_issue_flush;
	253	return 0;
	254
	255	out:
990a8baf	256	kfree(conf);
1da177e4 LT	257	return 1;
	258	}
	259
	260	static int linear_stop (mddev_t *mddev)
	261	{
	262	linear_conf_t *conf = mddev_to_conf(mddev);
	263
	264	blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/
	265	kfree(conf->hash_table);
	266	kfree(conf);
	267
	268	return 0;
	269	}
	270
	271	static int linear_make_request (request_queue_t q, struct bio bio)
	272	{
a362357b	273	const int rw = bio_data_dir(bio);
1da177e4 LT	274	mddev_t *mddev = q->queuedata;
	275	dev_info_t *tmp_dev;
	276	sector_t block;
	277
e5dcdd80 N	278	if (unlikely(bio_barrier(bio))) {
	279	bio_endio(bio, bio->bi_size, -EOPNOTSUPP);
	280	return 0;
	281	}
	282
a362357b JA	283	disk_stat_inc(mddev->gendisk, ios[rw]);
a362357b JA	284	disk_stat_add(mddev->gendisk, sectors[rw], bio_sectors(bio));
1da177e4 LT	285
	286	tmp_dev = which_dev(mddev, bio->bi_sector);
	287	block = bio->bi_sector >> 1;
	288
	289	if (unlikely(block >= (tmp_dev->size + tmp_dev->offset)
	290	\|\| block < tmp_dev->offset)) {
	291	char b[BDEVNAME_SIZE];
	292
	293	printk("linear_make_request: Block %llu out of bounds on "
	294	"dev %s size %llu offset %llu\n",
	295	(unsigned long long)block,
	296	bdevname(tmp_dev->rdev->bdev, b),
	297	(unsigned long long)tmp_dev->size,
	298	(unsigned long long)tmp_dev->offset);
	299	bio_io_error(bio, bio->bi_size);
	300	return 0;
	301	}
	302	if (unlikely(bio->bi_sector + (bio->bi_size >> 9) >
	303	(tmp_dev->offset + tmp_dev->size)<<1)) {
	304	/* This bio crosses a device boundary, so we have to
	305	* split it.
	306	*/
	307	struct bio_pair *bp;
29ac8e05 N	308	bp = bio_split(bio, bio_split_pool,
29ac8e05 N	309	((tmp_dev->offset + tmp_dev->size)<<1) - bio->bi_sector);
1da177e4 LT	310	if (linear_make_request(q, &bp->bio1))
	311	generic_make_request(&bp->bio1);
	312	if (linear_make_request(q, &bp->bio2))
	313	generic_make_request(&bp->bio2);
	314	bio_pair_release(bp);
	315	return 0;
	316	}
	317
	318	bio->bi_bdev = tmp_dev->rdev->bdev;
	319	bio->bi_sector = bio->bi_sector - (tmp_dev->offset << 1) + tmp_dev->rdev->data_offset;
	320
	321	return 1;
	322	}
	323
	324	static void linear_status (struct seq_file seq, mddev_t mddev)
	325	{
	326
	327	#undef MD_DEBUG
	328	#ifdef MD_DEBUG
	329	int j;
	330	linear_conf_t *conf = mddev_to_conf(mddev);
	331	sector_t s = 0;
	332
	333	seq_printf(seq, " ");
15945fee	334	for (j = 0; j < mddev->raid_disks; j++)
1da177e4 LT	335	{
	336	char b[BDEVNAME_SIZE];
	337	s += conf->smallest_size;
	338	seq_printf(seq, "[%s",
	339	bdevname(conf->hash_table[j][0].rdev->bdev,b));
	340
	341	while (s > conf->hash_table[j][0].offset +
	342	conf->hash_table[j][0].size)
	343	seq_printf(seq, "/%s] ",
	344	bdevname(conf->hash_table[j][1].rdev->bdev,b));
	345	else
	346	seq_printf(seq, "] ");
	347	}
	348	seq_printf(seq, "\n");
	349	#endif
	350	seq_printf(seq, " %dk rounding", mddev->chunk_size/1024);
	351	}
	352
	353
2604b703	354	static struct mdk_personality linear_personality =
1da177e4 LT	355	{
1da177e4 LT	356	.name = "linear",
2604b703	357	.level = LEVEL_LINEAR,
1da177e4 LT	358	.owner = THIS_MODULE,
	359	.make_request = linear_make_request,
	360	.run = linear_run,
	361	.stop = linear_stop,
	362	.status = linear_status,
	363	};
	364
	365	static int __init linear_init (void)
	366	{
2604b703	367	return register_md_personality (&linear_personality);
1da177e4 LT	368	}
	369
	370	static void linear_exit (void)
	371	{
2604b703	372	unregister_md_personality (&linear_personality);
1da177e4 LT	373	}
	374
	375
	376	module_init(linear_init);
	377	module_exit(linear_exit);
	378	MODULE_LICENSE("GPL");
d9d166c2 N	379	MODULE_ALIAS("md-personality-1"); /* LINEAR - deprecated*/
d9d166c2 N	380	MODULE_ALIAS("md-linear");
2604b703	381	MODULE_ALIAS("md-level--1");