[linux-2.6-block.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/blkdev.h>
#include <linux/raid/md_u.h>
#include <linux/seq_file.h>
#include "md.h"
#include "linear.h"

/*
 * find which device holds a particular offset 
 */
static inline dev_info_t *which_dev(mddev_t *mddev, sector_t sector)
{
	int lo, mid, hi;
	linear_conf_t *conf;

	lo = 0;
	hi = mddev->raid_disks - 1;
	conf = rcu_dereference(mddev->private);

	/*
	 * Binary Search
	 */

	while (hi > lo) {

		mid = (hi + lo) / 2;
		if (sector < conf->disks[mid].end_sector)
			hi = mid;
		else
			lo = mid + 1;
	}

	return conf->disks + lo;
}

/**
 *	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);

	rcu_read_lock();
	dev0 = which_dev(mddev, sector);
	maxsectors = dev0->end_sector - sector;
	rcu_read_unlock();

	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;
	int i;

	rcu_read_lock();
	conf = rcu_dereference(mddev->private);

	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);
	}
	rcu_read_unlock();
}

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

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

	rcu_read_lock();
	conf = rcu_dereference(mddev->private);

	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);
	}

	rcu_read_unlock();
	return ret;
}

static sector_t linear_size(mddev_t *mddev, sector_t sectors, int raid_disks)
{
	linear_conf_t *conf;
	sector_t array_sectors;

	rcu_read_lock();
	conf = rcu_dereference(mddev->private);
	WARN_ONCE(sectors || raid_disks,
		  "%s does not support generic reshape\n", __func__);
	array_sectors = conf->array_sectors;
	rcu_read_unlock();

	return array_sectors;
}

static linear_conf_t *linear_conf(mddev_t *mddev, int raid_disks)
{
	linear_conf_t *conf;
	mdk_rdev_t *rdev;
	int i, cnt;

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

	cnt = 0;
	conf->array_sectors = 0;

	list_for_each_entry(rdev, &mddev->disks, same_set) {
		int j = rdev->raid_disk;
		dev_info_t *disk = conf->disks + j;
		sector_t sectors;

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

		disk->rdev = rdev;
		if (mddev->chunk_sectors) {
			sectors = rdev->sectors;
			sector_div(sectors, mddev->chunk_sectors);
			rdev->sectors = sectors * mddev->chunk_sectors;
		}

		disk_stack_limits(mddev->gendisk, rdev->bdev,
				  rdev->data_offset << 9);
		/* 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 &&
		    queue_max_sectors(mddev->queue) > (PAGE_SIZE>>9))
			blk_queue_max_sectors(mddev->queue, PAGE_SIZE>>9);

		conf->array_sectors += rdev->sectors;
		cnt++;

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

	/*
	 * Here we calculate the device offsets.
	 */
	conf->disks[0].end_sector = conf->disks[0].rdev->sectors;

	for (i = 1; i < raid_disks; i++)
		conf->disks[i].end_sector =
			conf->disks[i-1].end_sector +
			conf->disks[i].rdev->sectors;

	return conf;

out:
	kfree(conf);
	return NULL;
}

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

	if (md_check_no_bitmap(mddev))
		return -EINVAL;
	mddev->queue->queue_lock = &mddev->queue->__queue_lock;
	conf = linear_conf(mddev, mddev->raid_disks);

	if (!conf)
		return 1;
	mddev->private = conf;
	md_set_array_sectors(mddev, linear_size(mddev, 0, 0));

	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;
	md_integrity_register(mddev);
	return 0;
}

static void free_conf(struct rcu_head *head)
{
	linear_conf_t *conf = container_of(head, linear_conf_t, rcu);
	kfree(conf);
}

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, *oldconf;

	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;

	oldconf = rcu_dereference(mddev->private);
	mddev->raid_disks++;
	rcu_assign_pointer(mddev->private, newconf);
	md_set_array_sectors(mddev, linear_size(mddev, 0, 0));
	set_capacity(mddev->gendisk, mddev->array_sectors);
	revalidate_disk(mddev->gendisk);
	call_rcu(&oldconf->rcu, free_conf);
	return 0;
}

static int linear_stop (mddev_t *mddev)
{
	linear_conf_t *conf = mddev->private;

	/*
	 * We do not require rcu protection here since
	 * we hold reconfig_mutex for both linear_add and
	 * linear_stop, so they cannot race.
	 * We should make sure any old 'conf's are properly
	 * freed though.
	 */
	rcu_barrier();
	blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/
	kfree(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;
	sector_t start_sector;
	int cpu;

	if (unlikely(bio_rw_flagged(bio, BIO_RW_BARRIER))) {
		md_barrier_request(mddev, bio);
		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();

	rcu_read_lock();
	tmp_dev = which_dev(mddev, bio->bi_sector);
	start_sector = tmp_dev->end_sector - tmp_dev->rdev->sectors;


	if (unlikely(bio->bi_sector >= (tmp_dev->end_sector)
		     || (bio->bi_sector < 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->rdev->sectors,
			(unsigned long long)start_sector);
		rcu_read_unlock();
		bio_io_error(bio);
		return 0;
	}
	if (unlikely(bio->bi_sector + (bio->bi_size >> 9) >
		     tmp_dev->end_sector)) {
		/* This bio crosses a device boundary, so we have to
		 * split it.
		 */
		struct bio_pair *bp;
		sector_t end_sector = tmp_dev->end_sector;

		rcu_read_unlock();

		bp = bio_split(bio, end_sector - 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 - start_sector
		+ tmp_dev->rdev->data_offset;
	rcu_read_unlock();

	return 1;
}

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

	seq_printf(seq, " %dk rounding", mddev->chunk_sectors / 2);
}


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,
	.size		= linear_size,
};

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_DESCRIPTION("Linear device concatenation personality for MD");
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
bff61975 N	19	#include <linux/blkdev.h>
bff61975 N	20	#include <linux/raid/md_u.h>
bff61975	21	#include <linux/seq_file.h>
43b2e5d8	22	#include "md.h"
ef740c37	23	#include "linear.h"
1da177e4	24
1da177e4 LT	25	/*
	26	* find which device holds a particular offset
	27	*/
	28	static inline dev_info_t which_dev(mddev_t mddev, sector_t sector)
	29	{
aece3d1f	30	int lo, mid, hi;
af11c397	31	linear_conf_t *conf;
1da177e4	32
aece3d1f SS	33	lo = 0;
aece3d1f SS	34	hi = mddev->raid_disks - 1;
af11c397	35	conf = rcu_dereference(mddev->private);
1da177e4	36
aece3d1f SS	37	/*
	38	* Binary Search
	39	*/
	40
	41	while (hi > lo) {
	42
	43	mid = (hi + lo) / 2;
	44	if (sector < conf->disks[mid].end_sector)
	45	hi = mid;
	46	else
	47	lo = mid + 1;
	48	}
	49
	50	return conf->disks + lo;
1da177e4 LT	51	}
	52
	53	/**
15945fee	54	* linear_mergeable_bvec -- tell bio layer if two requests can be merged
1da177e4	55	* @q: request queue
cc371e66	56	* @bvm: properties of new bio
1da177e4 LT	57	* @biovec: the request that could be merged to it.
	58	*
	59	* Return amount of bytes we can take at this offset
	60	*/
cc371e66 AK	61	static int linear_mergeable_bvec(struct request_queue *q,
	62	struct bvec_merge_data *bvm,
	63	struct bio_vec *biovec)
1da177e4 LT	64	{
	65	mddev_t *mddev = q->queuedata;
	66	dev_info_t *dev0;
cc371e66 AK	67	unsigned long maxsectors, bio_sectors = bvm->bi_size >> 9;
cc371e66 AK	68	sector_t sector = bvm->bi_sector + get_start_sect(bvm->bi_bdev);
1da177e4	69
af11c397	70	rcu_read_lock();
1da177e4	71	dev0 = which_dev(mddev, sector);
4db7cdc8	72	maxsectors = dev0->end_sector - sector;
af11c397	73	rcu_read_unlock();
1da177e4 LT	74
	75	if (maxsectors < bio_sectors)
	76	maxsectors = 0;
	77	else
	78	maxsectors -= bio_sectors;
	79
	80	if (maxsectors <= (PAGE_SIZE >> 9 ) && bio_sectors == 0)
	81	return biovec->bv_len;
	82	/* The bytes available at this offset could be really big,
	83	* so we cap at 2^31 to avoid overflow */
	84	if (maxsectors > (1 << (31-9)))
	85	return 1<<31;
	86	return maxsectors << 9;
	87	}
	88
165125e1	89	static void linear_unplug(struct request_queue *q)
1da177e4 LT	90	{
1da177e4 LT	91	mddev_t *mddev = q->queuedata;
af11c397	92	linear_conf_t *conf;
1da177e4 LT	93	int i;
1da177e4 LT	94
af11c397 S	95	rcu_read_lock();
	96	conf = rcu_dereference(mddev->private);
	97
1da177e4	98	for (i=0; i < mddev->raid_disks; i++) {
165125e1	99	struct request_queue *r_queue = bdev_get_queue(conf->disks[i].rdev->bdev);
2ad8b1ef	100	blk_unplug(r_queue);
1da177e4	101	}
af11c397	102	rcu_read_unlock();
1da177e4 LT	103	}
1da177e4 LT	104
26be34dc N	105	static int linear_congested(void *data, int bits)
	106	{
	107	mddev_t *mddev = data;
af11c397	108	linear_conf_t *conf;
26be34dc N	109	int i, ret = 0;
26be34dc N	110
3fa841d7 N	111	if (mddev_congested(mddev, bits))
	112	return 1;
	113
af11c397 S	114	rcu_read_lock();
	115	conf = rcu_dereference(mddev->private);
	116
26be34dc	117	for (i = 0; i < mddev->raid_disks && !ret ; i++) {
165125e1	118	struct request_queue *q = bdev_get_queue(conf->disks[i].rdev->bdev);
26be34dc N	119	ret \|= bdi_congested(&q->backing_dev_info, bits);
26be34dc N	120	}
af11c397 S	121
af11c397 S	122	rcu_read_unlock();
26be34dc N	123	return ret;
	124	}
	125
80c3a6ce DW	126	static sector_t linear_size(mddev_t *mddev, sector_t sectors, int raid_disks)
80c3a6ce DW	127	{
af11c397 S	128	linear_conf_t *conf;
af11c397 S	129	sector_t array_sectors;
80c3a6ce	130
af11c397 S	131	rcu_read_lock();
af11c397 S	132	conf = rcu_dereference(mddev->private);
80c3a6ce DW	133	WARN_ONCE(sectors \|\| raid_disks,
80c3a6ce DW	134	"%s does not support generic reshape\n", __func__);
af11c397 S	135	array_sectors = conf->array_sectors;
af11c397 S	136	rcu_read_unlock();
80c3a6ce	137
af11c397	138	return array_sectors;
80c3a6ce DW	139	}
80c3a6ce DW	140
7c7546cc	141	static linear_conf_t linear_conf(mddev_t mddev, int raid_disks)
1da177e4 LT	142	{
1da177e4 LT	143	linear_conf_t *conf;
1da177e4	144	mdk_rdev_t *rdev;
45d4582f	145	int i, cnt;
1da177e4	146
7c7546cc	147	conf = kzalloc (sizeof (conf) + raid_diskssizeof(dev_info_t),
1da177e4 LT	148	GFP_KERNEL);
1da177e4 LT	149	if (!conf)
7c7546cc N	150	return NULL;
7c7546cc N	151
1da177e4	152	cnt = 0;
d6e22150	153	conf->array_sectors = 0;
1da177e4	154
159ec1fc	155	list_for_each_entry(rdev, &mddev->disks, same_set) {
1da177e4 LT	156	int j = rdev->raid_disk;
1da177e4 LT	157	dev_info_t *disk = conf->disks + j;
13f2682b	158	sector_t sectors;
1da177e4	159
13864515	160	if (j < 0 \|\| j >= raid_disks \|\| disk->rdev) {
1da177e4 LT	161	printk("linear: disk numbering problem. Aborting!\n");
	162	goto out;
	163	}
	164
	165	disk->rdev = rdev;
13f2682b N	166	if (mddev->chunk_sectors) {
	167	sectors = rdev->sectors;
	168	sector_div(sectors, mddev->chunk_sectors);
	169	rdev->sectors = sectors * mddev->chunk_sectors;
	170	}
1da177e4	171
8f6c2e4b MP	172	disk_stack_limits(mddev->gendisk, rdev->bdev,
8f6c2e4b MP	173	rdev->data_offset << 9);
1da177e4 LT	174	/* as we don't honour merge_bvec_fn, we must never risk
	175	* violating it, so limit ->max_sector to one PAGE, as
	176	* a one page request is never in violation.
	177	*/
	178	if (rdev->bdev->bd_disk->queue->merge_bvec_fn &&
ae03bf63	179	queue_max_sectors(mddev->queue) > (PAGE_SIZE>>9))
1da177e4 LT	180	blk_queue_max_sectors(mddev->queue, PAGE_SIZE>>9);
1da177e4 LT	181
dd8ac336	182	conf->array_sectors += rdev->sectors;
1da177e4	183	cnt++;
4db7cdc8	184
1da177e4	185	}
7c7546cc	186	if (cnt != raid_disks) {
1da177e4 LT	187	printk("linear: not enough drives present. Aborting!\n");
	188	goto out;
	189	}
	190
	191	/*
45d4582f	192	* Here we calculate the device offsets.
1da177e4	193	*/
4db7cdc8 SS	194	conf->disks[0].end_sector = conf->disks[0].rdev->sectors;
4db7cdc8 SS	195
a778b73f	196	for (i = 1; i < raid_disks; i++)
4db7cdc8 SS	197	conf->disks[i].end_sector =
	198	conf->disks[i-1].end_sector +
	199	conf->disks[i].rdev->sectors;
15945fee	200
7c7546cc N	201	return conf;
	202
	203	out:
	204	kfree(conf);
	205	return NULL;
	206	}
	207
	208	static int linear_run (mddev_t *mddev)
	209	{
	210	linear_conf_t *conf;
	211
0894cc30 AN	212	if (md_check_no_bitmap(mddev))
0894cc30 AN	213	return -EINVAL;
e7e72bf6	214	mddev->queue->queue_lock = &mddev->queue->__queue_lock;
7c7546cc N	215	conf = linear_conf(mddev, mddev->raid_disks);
	216
	217	if (!conf)
	218	return 1;
	219	mddev->private = conf;
1f403624	220	md_set_array_sectors(mddev, linear_size(mddev, 0, 0));
7c7546cc	221
1da177e4 LT	222	blk_queue_merge_bvec(mddev->queue, linear_mergeable_bvec);
1da177e4 LT	223	mddev->queue->unplug_fn = linear_unplug;
26be34dc N	224	mddev->queue->backing_dev_info.congested_fn = linear_congested;
26be34dc N	225	mddev->queue->backing_dev_info.congested_data = mddev;
ac5e7113	226	md_integrity_register(mddev);
1da177e4	227	return 0;
7c7546cc	228	}
1da177e4	229
495d3573 N	230	static void free_conf(struct rcu_head *head)
	231	{
	232	linear_conf_t *conf = container_of(head, linear_conf_t, rcu);
	233	kfree(conf);
	234	}
	235
7c7546cc N	236	static int linear_add(mddev_t mddev, mdk_rdev_t rdev)
	237	{
	238	/* Adding a drive to a linear array allows the array to grow.
	239	* It is permitted if the new drive has a matching superblock
	240	* already on it, with raid_disk equal to raid_disks.
	241	* It is achieved by creating a new linear_private_data structure
	242	* and swapping it in in-place of the current one.
	243	* The current one is never freed until the array is stopped.
	244	* This avoids races.
	245	*/
495d3573	246	linear_conf_t newconf, oldconf;
7c7546cc	247
a778b73f	248	if (rdev->saved_raid_disk != mddev->raid_disks)
7c7546cc N	249	return -EINVAL;
7c7546cc N	250
a778b73f N	251	rdev->raid_disk = rdev->saved_raid_disk;
a778b73f N	252
7c7546cc N	253	newconf = linear_conf(mddev,mddev->raid_disks+1);
	254
	255	if (!newconf)
	256	return -ENOMEM;
	257
495d3573	258	oldconf = rcu_dereference(mddev->private);
7c7546cc	259	mddev->raid_disks++;
af11c397	260	rcu_assign_pointer(mddev->private, newconf);
1f403624	261	md_set_array_sectors(mddev, linear_size(mddev, 0, 0));
f233ea5c	262	set_capacity(mddev->gendisk, mddev->array_sectors);
449aad3e	263	revalidate_disk(mddev->gendisk);
495d3573	264	call_rcu(&oldconf->rcu, free_conf);
7c7546cc	265	return 0;
1da177e4 LT	266	}
	267
	268	static int linear_stop (mddev_t *mddev)
	269	{
070ec55d	270	linear_conf_t *conf = mddev->private;
af11c397 S	271
	272	/*
	273	* We do not require rcu protection here since
	274	* we hold reconfig_mutex for both linear_add and
	275	* linear_stop, so they cannot race.
495d3573 N	276	* We should make sure any old 'conf's are properly
495d3573 N	277	* freed though.
af11c397	278	*/
495d3573	279	rcu_barrier();
1da177e4	280	blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/
495d3573	281	kfree(conf);
1da177e4 LT	282
	283	return 0;
	284	}
	285
165125e1	286	static int linear_make_request (struct request_queue q, struct bio bio)
1da177e4	287	{
a362357b	288	const int rw = bio_data_dir(bio);
1da177e4 LT	289	mddev_t *mddev = q->queuedata;
1da177e4 LT	290	dev_info_t *tmp_dev;
4db7cdc8	291	sector_t start_sector;
c9959059	292	int cpu;
1da177e4	293
1f98a13f	294	if (unlikely(bio_rw_flagged(bio, BIO_RW_BARRIER))) {
a2826aa9	295	md_barrier_request(mddev, bio);
e5dcdd80 N	296	return 0;
	297	}
	298
074a7aca TH	299	cpu = part_stat_lock();
	300	part_stat_inc(cpu, &mddev->gendisk->part0, ios[rw]);
	301	part_stat_add(cpu, &mddev->gendisk->part0, sectors[rw],
	302	bio_sectors(bio));
	303	part_stat_unlock();
1da177e4	304
af11c397	305	rcu_read_lock();
1da177e4	306	tmp_dev = which_dev(mddev, bio->bi_sector);
4db7cdc8 SS	307	start_sector = tmp_dev->end_sector - tmp_dev->rdev->sectors;
4db7cdc8 SS	308
af11c397	309
4db7cdc8 SS	310	if (unlikely(bio->bi_sector >= (tmp_dev->end_sector)
4db7cdc8 SS	311	\|\| (bio->bi_sector < start_sector))) {
1da177e4 LT	312	char b[BDEVNAME_SIZE];
1da177e4 LT	313
6283815d AN	314	printk("linear_make_request: Sector %llu out of bounds on "
	315	"dev %s: %llu sectors, offset %llu\n",
	316	(unsigned long long)bio->bi_sector,
1da177e4	317	bdevname(tmp_dev->rdev->bdev, b),
4db7cdc8 SS	318	(unsigned long long)tmp_dev->rdev->sectors,
4db7cdc8 SS	319	(unsigned long long)start_sector);
af11c397	320	rcu_read_unlock();
6712ecf8	321	bio_io_error(bio);
1da177e4 LT	322	return 0;
	323	}
	324	if (unlikely(bio->bi_sector + (bio->bi_size >> 9) >
4db7cdc8	325	tmp_dev->end_sector)) {
1da177e4 LT	326	/* This bio crosses a device boundary, so we have to
	327	* split it.
	328	*/
	329	struct bio_pair *bp;
af11c397 S	330	sector_t end_sector = tmp_dev->end_sector;
	331
	332	rcu_read_unlock();
6283815d	333
af11c397	334	bp = bio_split(bio, end_sector - bio->bi_sector);
6283815d	335
1da177e4 LT	336	if (linear_make_request(q, &bp->bio1))
	337	generic_make_request(&bp->bio1);
	338	if (linear_make_request(q, &bp->bio2))
	339	generic_make_request(&bp->bio2);
	340	bio_pair_release(bp);
	341	return 0;
	342	}
	343
	344	bio->bi_bdev = tmp_dev->rdev->bdev;
4db7cdc8	345	bio->bi_sector = bio->bi_sector - start_sector
6283815d	346	+ tmp_dev->rdev->data_offset;
af11c397	347	rcu_read_unlock();
1da177e4 LT	348
	349	return 1;
	350	}
	351
	352	static void linear_status (struct seq_file seq, mddev_t mddev)
	353	{
	354
9d8f0363	355	seq_printf(seq, " %dk rounding", mddev->chunk_sectors / 2);
1da177e4 LT	356	}
	357
	358
2604b703	359	static struct mdk_personality linear_personality =
1da177e4 LT	360	{
1da177e4 LT	361	.name = "linear",
2604b703	362	.level = LEVEL_LINEAR,
1da177e4 LT	363	.owner = THIS_MODULE,
	364	.make_request = linear_make_request,
	365	.run = linear_run,
	366	.stop = linear_stop,
	367	.status = linear_status,
7c7546cc	368	.hot_add_disk = linear_add,
80c3a6ce	369	.size = linear_size,
1da177e4 LT	370	};
	371
	372	static int __init linear_init (void)
	373	{
2604b703	374	return register_md_personality (&linear_personality);
1da177e4 LT	375	}
	376
	377	static void linear_exit (void)
	378	{
2604b703	379	unregister_md_personality (&linear_personality);
1da177e4 LT	380	}
	381
	382
	383	module_init(linear_init);
	384	module_exit(linear_exit);
	385	MODULE_LICENSE("GPL");
0efb9e61	386	MODULE_DESCRIPTION("Linear device concatenation personality for MD");
d9d166c2 N	387	MODULE_ALIAS("md-personality-1"); /* LINEAR - deprecated*/
d9d166c2 N	388	MODULE_ALIAS("md-linear");
2604b703	389	MODULE_ALIAS("md-level--1");