[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/raid/linear.h>

/*
 * 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_div(a,b) returns the remainer and sets a to a/b
	 */
	sector >>= conf->sector_shift;
	(void)sector_div(sector, conf->spacing);
	hash = conf->hash_table[sector];

	while (sector >= hash->num_sectors + hash->start_sector)
		hash++;
	return hash;
}

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

	dev0 = which_dev(mddev, sector);
	maxsectors = dev0->num_sectors - (sector - dev0->start_sector);

	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(struct request_queue *q)
{
	mddev_t *mddev = q->queuedata;
	linear_conf_t *conf = mddev_to_conf(mddev);
	int i;

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

static int linear_congested(void *data, int bits)
{
	mddev_t *mddev = data;
	linear_conf_t *conf = mddev_to_conf(mddev);
	int i, ret = 0;

	for (i = 0; i < mddev->raid_disks && !ret ; i++) {
		struct request_queue *q = bdev_get_queue(conf->disks[i].rdev->bdev);
		ret |= bdi_congested(&q->backing_dev_info, bits);
	}
	return ret;
}

static linear_conf_t *linear_conf(mddev_t *mddev, int raid_disks)
{
	linear_conf_t *conf;
	dev_info_t **table;
	mdk_rdev_t *rdev;
	int i, nb_zone, cnt;
	sector_t min_sectors;
	sector_t curr_sector;
	struct list_head *tmp;

	conf = kzalloc (sizeof (*conf) + raid_disks*sizeof(dev_info_t),
			GFP_KERNEL);
	if (!conf)
		return NULL;

	cnt = 0;
	conf->array_sectors = 0;

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

		if (j < 0 || j >= 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->num_sectors = rdev->size * 2;
		conf->array_sectors += rdev->size * 2;

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

	min_sectors = conf->array_sectors;
	sector_div(min_sectors, PAGE_SIZE/sizeof(struct dev_info *));

	/* min_sectors 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_sectors and use the size of that as
	 * the actual spacing
	 */
	conf->spacing = conf->array_sectors;
	for (i=0; i < cnt-1 ; i++) {
		sector_t tmp = 0;
		int j;
		for (j = i; j < cnt - 1 && tmp < min_sectors; j++)
			tmp += conf->disks[j].num_sectors;
		if (tmp >= min_sectors && tmp < conf->spacing)
			conf->spacing = tmp;
	}

	/* spacing may be too large for sector_div to work with,
	 * so we might need to pre-shift
	 */
	conf->sector_shift = 0;
	if (sizeof(sector_t) > sizeof(u32)) {
		sector_t space = conf->spacing;
		while (space > (sector_t)(~(u32)0)) {
			space >>= 1;
			conf->sector_shift++;
		}
	}
	/*
	 * 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 = conf->array_sectors >> conf->sector_shift;
		sz += 1; /* force round-up */
		base = conf->spacing >> conf->sector_shift;
		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].start_sector = 0;
	for (i = 1; i < raid_disks; i++)
		conf->disks[i].start_sector =
			conf->disks[i-1].start_sector +
			conf->disks[i-1].num_sectors;

	table = conf->hash_table;
	i = 0;
	for (curr_sector = 0;
	     curr_sector < conf->array_sectors;
	     curr_sector += conf->spacing) {

		while (i < raid_disks-1 &&
		       curr_sector >= conf->disks[i+1].start_sector)
			i++;

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

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

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

	return conf;

out:
	kfree(conf);
	return NULL;
}

static int linear_run (mddev_t *mddev)
{
	linear_conf_t *conf;

	mddev->queue->queue_lock = &mddev->queue->__queue_lock;
	conf = linear_conf(mddev, mddev->raid_disks);

	if (!conf)
		return 1;
	mddev->private = conf;
	mddev->array_sectors = conf->array_sectors;

	blk_queue_merge_bvec(mddev->queue, linear_mergeable_bvec);
	mddev->queue->unplug_fn = linear_unplug;
	mddev->queue->backing_dev_info.congested_fn = linear_congested;
	mddev->queue->backing_dev_info.congested_data = mddev;
	return 0;
}

static int linear_add(mddev_t *mddev, mdk_rdev_t *rdev)
{
	/* Adding a drive to a linear array allows the array to grow.
	 * It is permitted if the new drive has a matching superblock
	 * already on it, with raid_disk equal to raid_disks.
	 * It is achieved by creating a new linear_private_data structure
	 * and swapping it in in-place of the current one.
	 * The current one is never freed until the array is stopped.
	 * This avoids races.
	 */
	linear_conf_t *newconf;

	if (rdev->saved_raid_disk != mddev->raid_disks)
		return -EINVAL;

	rdev->raid_disk = rdev->saved_raid_disk;

	newconf = linear_conf(mddev,mddev->raid_disks+1);

	if (!newconf)
		return -ENOMEM;

	newconf->prev = mddev_to_conf(mddev);
	mddev->private = newconf;
	mddev->raid_disks++;
	mddev->array_sectors = newconf->array_sectors;
	set_capacity(mddev->gendisk, mddev->array_sectors);
	return 0;
}

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'*/
	do {
		linear_conf_t *t = conf->prev;
		kfree(conf->hash_table);
		kfree(conf);
		conf = t;
	} while (conf);

	return 0;
}

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

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

	cpu = part_stat_lock();
	part_stat_inc(cpu, &mddev->gendisk->part0, ios[rw]);
	part_stat_add(cpu, &mddev->gendisk->part0, sectors[rw],
		      bio_sectors(bio));
	part_stat_unlock();

	tmp_dev = which_dev(mddev, bio->bi_sector);
    
	if (unlikely(bio->bi_sector >= (tmp_dev->num_sectors +
					tmp_dev->start_sector)
		     || (bio->bi_sector <
			 tmp_dev->start_sector))) {
		char b[BDEVNAME_SIZE];

		printk("linear_make_request: Sector %llu out of bounds on "
			"dev %s: %llu sectors, offset %llu\n",
			(unsigned long long)bio->bi_sector,
			bdevname(tmp_dev->rdev->bdev, b),
			(unsigned long long)tmp_dev->num_sectors,
			(unsigned long long)tmp_dev->start_sector);
		bio_io_error(bio);
		return 0;
	}
	if (unlikely(bio->bi_sector + (bio->bi_size >> 9) >
		     tmp_dev->start_sector + tmp_dev->num_sectors)) {
		/* This bio crosses a device boundary, so we have to
		 * split it.
		 */
		struct bio_pair *bp;

		bp = bio_split(bio,
			       tmp_dev->start_sector + tmp_dev->num_sectors
			       - 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->start_sector
		+ tmp_dev->rdev->data_offset;

	return 1;
}

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

	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,
	.hot_add_disk	= linear_add,
};

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
1da177e4 LT	19	#include <linux/raid/linear.h>
1da177e4 LT	20
1da177e4 LT	21	/*
	22	* find which device holds a particular offset
	23	*/
	24	static inline dev_info_t which_dev(mddev_t mddev, sector_t sector)
	25	{
	26	dev_info_t *hash;
	27	linear_conf_t *conf = mddev_to_conf(mddev);
1da177e4 LT	28
	29	/*
	30	* sector_div(a,b) returns the remainer and sets a to a/b
	31	*/
ab5bd5cb AN	32	sector >>= conf->sector_shift;
	33	(void)sector_div(sector, conf->spacing);
	34	hash = conf->hash_table[sector];
1da177e4	35
6283815d	36	while (sector >= hash->num_sectors + hash->start_sector)
1da177e4 LT	37	hash++;
	38	return hash;
	39	}
	40
	41	/**
15945fee	42	* linear_mergeable_bvec -- tell bio layer if two requests can be merged
1da177e4	43	* @q: request queue
cc371e66	44	* @bvm: properties of new bio
1da177e4 LT	45	* @biovec: the request that could be merged to it.
	46	*
	47	* Return amount of bytes we can take at this offset
	48	*/
cc371e66 AK	49	static int linear_mergeable_bvec(struct request_queue *q,
	50	struct bvec_merge_data *bvm,
	51	struct bio_vec *biovec)
1da177e4 LT	52	{
	53	mddev_t *mddev = q->queuedata;
	54	dev_info_t *dev0;
cc371e66 AK	55	unsigned long maxsectors, bio_sectors = bvm->bi_size >> 9;
cc371e66 AK	56	sector_t sector = bvm->bi_sector + get_start_sect(bvm->bi_bdev);
1da177e4 LT	57
1da177e4 LT	58	dev0 = which_dev(mddev, sector);
6283815d	59	maxsectors = dev0->num_sectors - (sector - dev0->start_sector);
1da177e4 LT	60
	61	if (maxsectors < bio_sectors)
	62	maxsectors = 0;
	63	else
	64	maxsectors -= bio_sectors;
	65
	66	if (maxsectors <= (PAGE_SIZE >> 9 ) && bio_sectors == 0)
	67	return biovec->bv_len;
	68	/* The bytes available at this offset could be really big,
	69	* so we cap at 2^31 to avoid overflow */
	70	if (maxsectors > (1 << (31-9)))
	71	return 1<<31;
	72	return maxsectors << 9;
	73	}
	74
165125e1	75	static void linear_unplug(struct request_queue *q)
1da177e4 LT	76	{
	77	mddev_t *mddev = q->queuedata;
	78	linear_conf_t *conf = mddev_to_conf(mddev);
	79	int i;
	80
	81	for (i=0; i < mddev->raid_disks; i++) {
165125e1	82	struct request_queue *r_queue = bdev_get_queue(conf->disks[i].rdev->bdev);
2ad8b1ef	83	blk_unplug(r_queue);
1da177e4 LT	84	}
	85	}
	86
26be34dc N	87	static int linear_congested(void *data, int bits)
	88	{
	89	mddev_t *mddev = data;
	90	linear_conf_t *conf = mddev_to_conf(mddev);
	91	int i, ret = 0;
	92
	93	for (i = 0; i < mddev->raid_disks && !ret ; i++) {
165125e1	94	struct request_queue *q = bdev_get_queue(conf->disks[i].rdev->bdev);
26be34dc N	95	ret \|= bdi_congested(&q->backing_dev_info, bits);
	96	}
	97	return ret;
	98	}
	99
7c7546cc	100	static linear_conf_t linear_conf(mddev_t mddev, int raid_disks)
1da177e4 LT	101	{
	102	linear_conf_t *conf;
	103	dev_info_t **table;
	104	mdk_rdev_t *rdev;
	105	int i, nb_zone, cnt;
23242fbb	106	sector_t min_sectors;
6283815d	107	sector_t curr_sector;
1da177e4 LT	108	struct list_head *tmp;
1da177e4 LT	109
7c7546cc	110	conf = kzalloc (sizeof (conf) + raid_diskssizeof(dev_info_t),
1da177e4 LT	111	GFP_KERNEL);
1da177e4 LT	112	if (!conf)
7c7546cc N	113	return NULL;
7c7546cc N	114
1da177e4	115	cnt = 0;
d6e22150	116	conf->array_sectors = 0;
1da177e4	117
d089c6af	118	rdev_for_each(rdev, tmp, mddev) {
1da177e4 LT	119	int j = rdev->raid_disk;
	120	dev_info_t *disk = conf->disks + j;
	121
13864515	122	if (j < 0 \|\| j >= raid_disks \|\| disk->rdev) {
1da177e4 LT	123	printk("linear: disk numbering problem. Aborting!\n");
	124	goto out;
	125	}
	126
	127	disk->rdev = rdev;
	128
	129	blk_queue_stack_limits(mddev->queue,
	130	rdev->bdev->bd_disk->queue);
	131	/* as we don't honour merge_bvec_fn, we must never risk
	132	* violating it, so limit ->max_sector to one PAGE, as
	133	* a one page request is never in violation.
	134	*/
	135	if (rdev->bdev->bd_disk->queue->merge_bvec_fn &&
	136	mddev->queue->max_sectors > (PAGE_SIZE>>9))
	137	blk_queue_max_sectors(mddev->queue, PAGE_SIZE>>9);
	138
6283815d	139	disk->num_sectors = rdev->size * 2;
d6e22150	140	conf->array_sectors += rdev->size * 2;
1da177e4	141
1da177e4 LT	142	cnt++;
1da177e4 LT	143	}
7c7546cc	144	if (cnt != raid_disks) {
1da177e4 LT	145	printk("linear: not enough drives present. Aborting!\n");
	146	goto out;
	147	}
	148
23242fbb AN	149	min_sectors = conf->array_sectors;
23242fbb AN	150	sector_div(min_sectors, PAGE_SIZE/sizeof(struct dev_info *));
15945fee	151
23242fbb	152	/* min_sectors is the minimum spacing that will fit the hash
15945fee N	153	* table in one PAGE. This may be much smaller than needed.
15945fee N	154	* We find the smallest non-terminal set of consecutive devices
23242fbb	155	* that is larger than min_sectors and use the size of that as
15945fee N	156	* the actual spacing
15945fee N	157	*/
ab5bd5cb	158	conf->spacing = conf->array_sectors;
15945fee	159	for (i=0; i < cnt-1 ; i++) {
23242fbb	160	sector_t tmp = 0;
15945fee	161	int j;
23242fbb AN	162	for (j = i; j < cnt - 1 && tmp < min_sectors; j++)
23242fbb AN	163	tmp += conf->disks[j].num_sectors;
ab5bd5cb AN	164	if (tmp >= min_sectors && tmp < conf->spacing)
ab5bd5cb AN	165	conf->spacing = tmp;
15945fee N	166	}
15945fee N	167
ab5bd5cb	168	/* spacing may be too large for sector_div to work with,
15945fee N	169	* so we might need to pre-shift
15945fee N	170	*/
ab5bd5cb	171	conf->sector_shift = 0;
15945fee	172	if (sizeof(sector_t) > sizeof(u32)) {
ab5bd5cb	173	sector_t space = conf->spacing;
15945fee N	174	while (space > (sector_t)(~(u32)0)) {
15945fee N	175	space >>= 1;
ab5bd5cb	176	conf->sector_shift++;
15945fee N	177	}
15945fee N	178	}
1da177e4 LT	179	/*
	180	* This code was restructured to work around a gcc-2.95.3 internal
	181	* compiler error. Alter it with care.
	182	*/
	183	{
	184	sector_t sz;
	185	unsigned round;
	186	unsigned long base;
	187
ab5bd5cb	188	sz = conf->array_sectors >> conf->sector_shift;
15945fee	189	sz += 1; /* force round-up */
ab5bd5cb	190	base = conf->spacing >> conf->sector_shift;
1da177e4	191	round = sector_div(sz, base);
15945fee	192	nb_zone = sz + (round ? 1 : 0);
1da177e4	193	}
15945fee N	194	BUG_ON(nb_zone > PAGE_SIZE / sizeof(struct dev_info *));
	195
	196	conf->hash_table = kmalloc (sizeof (struct dev_info ) nb_zone,
1da177e4 LT	197	GFP_KERNEL);
	198	if (!conf->hash_table)
	199	goto out;
	200
	201	/*
	202	* Here we generate the linear hash table
15945fee	203	* First calculate the device offsets.
1da177e4	204	*/
6283815d	205	conf->disks[0].start_sector = 0;
a778b73f	206	for (i = 1; i < raid_disks; i++)
6283815d AN	207	conf->disks[i].start_sector =
	208	conf->disks[i-1].start_sector +
	209	conf->disks[i-1].num_sectors;
15945fee	210
1da177e4	211	table = conf->hash_table;
15945fee	212	i = 0;
6283815d AN	213	for (curr_sector = 0;
6283815d AN	214	curr_sector < conf->array_sectors;
ab5bd5cb	215	curr_sector += conf->spacing) {
1da177e4	216
a778b73f	217	while (i < raid_disks-1 &&
6283815d	218	curr_sector >= conf->disks[i+1].start_sector)
15945fee	219	i++;
1da177e4	220
15945fee N	221	*table ++ = conf->disks + i;
	222	}
	223
ab5bd5cb AN	224	if (conf->sector_shift) {
	225	conf->spacing >>= conf->sector_shift;
	226	/* round spacing up so that when we divide by it,
15945fee	227	* we err on the side of "too-low", which is safest.
1da177e4	228	*/
ab5bd5cb	229	conf->spacing++;
1da177e4	230	}
15945fee N	231
15945fee N	232	BUG_ON(table - conf->hash_table > nb_zone);
1da177e4	233
7c7546cc N	234	return conf;
	235
	236	out:
	237	kfree(conf);
	238	return NULL;
	239	}
	240
	241	static int linear_run (mddev_t *mddev)
	242	{
	243	linear_conf_t *conf;
	244
e7e72bf6	245	mddev->queue->queue_lock = &mddev->queue->__queue_lock;
7c7546cc N	246	conf = linear_conf(mddev, mddev->raid_disks);
	247
	248	if (!conf)
	249	return 1;
	250	mddev->private = conf;
d6e22150	251	mddev->array_sectors = conf->array_sectors;
7c7546cc	252
1da177e4 LT	253	blk_queue_merge_bvec(mddev->queue, linear_mergeable_bvec);
1da177e4 LT	254	mddev->queue->unplug_fn = linear_unplug;
26be34dc N	255	mddev->queue->backing_dev_info.congested_fn = linear_congested;
26be34dc N	256	mddev->queue->backing_dev_info.congested_data = mddev;
1da177e4	257	return 0;
7c7546cc	258	}
1da177e4	259
7c7546cc N	260	static int linear_add(mddev_t mddev, mdk_rdev_t rdev)
	261	{
	262	/* Adding a drive to a linear array allows the array to grow.
	263	* It is permitted if the new drive has a matching superblock
	264	* already on it, with raid_disk equal to raid_disks.
	265	* It is achieved by creating a new linear_private_data structure
	266	* and swapping it in in-place of the current one.
	267	* The current one is never freed until the array is stopped.
	268	* This avoids races.
	269	*/
	270	linear_conf_t *newconf;
	271
a778b73f	272	if (rdev->saved_raid_disk != mddev->raid_disks)
7c7546cc N	273	return -EINVAL;
7c7546cc N	274
a778b73f N	275	rdev->raid_disk = rdev->saved_raid_disk;
a778b73f N	276
7c7546cc N	277	newconf = linear_conf(mddev,mddev->raid_disks+1);
	278
	279	if (!newconf)
	280	return -ENOMEM;
	281
	282	newconf->prev = mddev_to_conf(mddev);
	283	mddev->private = newconf;
	284	mddev->raid_disks++;
d6e22150	285	mddev->array_sectors = newconf->array_sectors;
f233ea5c	286	set_capacity(mddev->gendisk, mddev->array_sectors);
7c7546cc	287	return 0;
1da177e4 LT	288	}
	289
	290	static int linear_stop (mddev_t *mddev)
	291	{
	292	linear_conf_t *conf = mddev_to_conf(mddev);
	293
	294	blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/
7c7546cc N	295	do {
	296	linear_conf_t *t = conf->prev;
	297	kfree(conf->hash_table);
	298	kfree(conf);
	299	conf = t;
	300	} while (conf);
1da177e4 LT	301
	302	return 0;
	303	}
	304
165125e1	305	static int linear_make_request (struct request_queue q, struct bio bio)
1da177e4	306	{
a362357b	307	const int rw = bio_data_dir(bio);
1da177e4 LT	308	mddev_t *mddev = q->queuedata;
1da177e4 LT	309	dev_info_t *tmp_dev;
c9959059	310	int cpu;
1da177e4	311
e5dcdd80	312	if (unlikely(bio_barrier(bio))) {
6712ecf8	313	bio_endio(bio, -EOPNOTSUPP);
e5dcdd80 N	314	return 0;
	315	}
	316
074a7aca TH	317	cpu = part_stat_lock();
	318	part_stat_inc(cpu, &mddev->gendisk->part0, ios[rw]);
	319	part_stat_add(cpu, &mddev->gendisk->part0, sectors[rw],
	320	bio_sectors(bio));
	321	part_stat_unlock();
1da177e4 LT	322
1da177e4 LT	323	tmp_dev = which_dev(mddev, bio->bi_sector);
1da177e4	324
6283815d AN	325	if (unlikely(bio->bi_sector >= (tmp_dev->num_sectors +
	326	tmp_dev->start_sector)
	327	\|\| (bio->bi_sector <
	328	tmp_dev->start_sector))) {
1da177e4 LT	329	char b[BDEVNAME_SIZE];
1da177e4 LT	330
6283815d AN	331	printk("linear_make_request: Sector %llu out of bounds on "
	332	"dev %s: %llu sectors, offset %llu\n",
	333	(unsigned long long)bio->bi_sector,
1da177e4	334	bdevname(tmp_dev->rdev->bdev, b),
6283815d AN	335	(unsigned long long)tmp_dev->num_sectors,
6283815d AN	336	(unsigned long long)tmp_dev->start_sector);
6712ecf8	337	bio_io_error(bio);
1da177e4 LT	338	return 0;
	339	}
	340	if (unlikely(bio->bi_sector + (bio->bi_size >> 9) >
6283815d	341	tmp_dev->start_sector + tmp_dev->num_sectors)) {
1da177e4 LT	342	/* This bio crosses a device boundary, so we have to
	343	* split it.
	344	*/
	345	struct bio_pair *bp;
6283815d	346
6feef531	347	bp = bio_split(bio,
6283815d AN	348	tmp_dev->start_sector + tmp_dev->num_sectors
	349	- bio->bi_sector);
	350
1da177e4 LT	351	if (linear_make_request(q, &bp->bio1))
	352	generic_make_request(&bp->bio1);
	353	if (linear_make_request(q, &bp->bio2))
	354	generic_make_request(&bp->bio2);
	355	bio_pair_release(bp);
	356	return 0;
	357	}
	358
	359	bio->bi_bdev = tmp_dev->rdev->bdev;
6283815d AN	360	bio->bi_sector = bio->bi_sector - tmp_dev->start_sector
6283815d AN	361	+ tmp_dev->rdev->data_offset;
1da177e4 LT	362
	363	return 1;
	364	}
	365
	366	static void linear_status (struct seq_file seq, mddev_t mddev)
	367	{
	368
1da177e4 LT	369	seq_printf(seq, " %dk rounding", mddev->chunk_size/1024);
	370	}
	371
	372
2604b703	373	static struct mdk_personality linear_personality =
1da177e4 LT	374	{
1da177e4 LT	375	.name = "linear",
2604b703	376	.level = LEVEL_LINEAR,
1da177e4 LT	377	.owner = THIS_MODULE,
	378	.make_request = linear_make_request,
	379	.run = linear_run,
	380	.stop = linear_stop,
	381	.status = linear_status,
7c7546cc	382	.hot_add_disk = linear_add,
1da177e4 LT	383	};
	384
	385	static int __init linear_init (void)
	386	{
2604b703	387	return register_md_personality (&linear_personality);
1da177e4 LT	388	}
	389
	390	static void linear_exit (void)
	391	{
2604b703	392	unregister_md_personality (&linear_personality);
1da177e4 LT	393	}
	394
	395
	396	module_init(linear_init);
	397	module_exit(linear_exit);
	398	MODULE_LICENSE("GPL");
d9d166c2 N	399	MODULE_ALIAS("md-personality-1"); /* LINEAR - deprecated*/
d9d166c2 N	400	MODULE_ALIAS("md-linear");
2604b703	401	MODULE_ALIAS("md-level--1");