[mirror_ubuntu-artful-kernel.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 <linux/slab.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(KERN_ERR "md/linear:%s: disk numbering problem. Aborting!\n",
			       mdname(mddev));
			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_segments to 1 lying within
		 * a single page.
		 */
		if (rdev->bdev->bd_disk->queue->merge_bvec_fn) {
			blk_queue_max_segments(mddev->queue, 1);
			blk_queue_segment_boundary(mddev->queue,
						   PAGE_CACHE_SIZE - 1);
		}

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

	}
	if (cnt != raid_disks) {
		printk(KERN_ERR "md/linear:%s: not enough drives present. Aborting!\n",
		       mdname(mddev));
		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);
	mddev->private = NULL;

	return 0;
}

static int linear_make_request (mddev_t *mddev, struct bio *bio)
{
	dev_info_t *tmp_dev;
	sector_t start_sector;

	if (unlikely(bio->bi_rw & REQ_FLUSH)) {
		md_flush_request(mddev, bio);
		return 0;
	}

	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(KERN_ERR
		       "md/linear:%s: make_request: Sector %llu out of bounds on "
		       "dev %s: %llu sectors, offset %llu\n",
		       mdname(mddev),
		       (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(mddev, &bp->bio1))
			generic_make_request(&bp->bio1);
		if (linear_make_request(mddev, &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>
5a0e3ad6	22	#include <linux/slab.h>
43b2e5d8	23	#include "md.h"
ef740c37	24	#include "linear.h"
1da177e4	25
1da177e4 LT	26	/*
	27	* find which device holds a particular offset
	28	*/
	29	static inline dev_info_t which_dev(mddev_t mddev, sector_t sector)
	30	{
aece3d1f	31	int lo, mid, hi;
af11c397	32	linear_conf_t *conf;
1da177e4	33
aece3d1f SS	34	lo = 0;
aece3d1f SS	35	hi = mddev->raid_disks - 1;
af11c397	36	conf = rcu_dereference(mddev->private);
1da177e4	37
aece3d1f SS	38	/*
	39	* Binary Search
	40	*/
	41
	42	while (hi > lo) {
	43
	44	mid = (hi + lo) / 2;
	45	if (sector < conf->disks[mid].end_sector)
	46	hi = mid;
	47	else
	48	lo = mid + 1;
	49	}
	50
	51	return conf->disks + lo;
1da177e4 LT	52	}
	53
	54	/**
15945fee	55	* linear_mergeable_bvec -- tell bio layer if two requests can be merged
1da177e4	56	* @q: request queue
cc371e66	57	* @bvm: properties of new bio
1da177e4 LT	58	* @biovec: the request that could be merged to it.
	59	*
	60	* Return amount of bytes we can take at this offset
	61	*/
cc371e66 AK	62	static int linear_mergeable_bvec(struct request_queue *q,
	63	struct bvec_merge_data *bvm,
	64	struct bio_vec *biovec)
1da177e4 LT	65	{
	66	mddev_t *mddev = q->queuedata;
	67	dev_info_t *dev0;
cc371e66 AK	68	unsigned long maxsectors, bio_sectors = bvm->bi_size >> 9;
cc371e66 AK	69	sector_t sector = bvm->bi_sector + get_start_sect(bvm->bi_bdev);
1da177e4	70
af11c397	71	rcu_read_lock();
1da177e4	72	dev0 = which_dev(mddev, sector);
4db7cdc8	73	maxsectors = dev0->end_sector - sector;
af11c397	74	rcu_read_unlock();
1da177e4 LT	75
	76	if (maxsectors < bio_sectors)
	77	maxsectors = 0;
	78	else
	79	maxsectors -= bio_sectors;
	80
	81	if (maxsectors <= (PAGE_SIZE >> 9 ) && bio_sectors == 0)
	82	return biovec->bv_len;
	83	/* The bytes available at this offset could be really big,
	84	* so we cap at 2^31 to avoid overflow */
	85	if (maxsectors > (1 << (31-9)))
	86	return 1<<31;
	87	return maxsectors << 9;
	88	}
	89
165125e1	90	static void linear_unplug(struct request_queue *q)
1da177e4 LT	91	{
1da177e4 LT	92	mddev_t *mddev = q->queuedata;
af11c397	93	linear_conf_t *conf;
1da177e4 LT	94	int i;
1da177e4 LT	95
af11c397 S	96	rcu_read_lock();
	97	conf = rcu_dereference(mddev->private);
	98
1da177e4	99	for (i=0; i < mddev->raid_disks; i++) {
165125e1	100	struct request_queue *r_queue = bdev_get_queue(conf->disks[i].rdev->bdev);
2ad8b1ef	101	blk_unplug(r_queue);
1da177e4	102	}
af11c397	103	rcu_read_unlock();
1da177e4 LT	104	}
1da177e4 LT	105
26be34dc N	106	static int linear_congested(void *data, int bits)
	107	{
	108	mddev_t *mddev = data;
af11c397	109	linear_conf_t *conf;
26be34dc N	110	int i, ret = 0;
26be34dc N	111
3fa841d7 N	112	if (mddev_congested(mddev, bits))
	113	return 1;
	114
af11c397 S	115	rcu_read_lock();
	116	conf = rcu_dereference(mddev->private);
	117
26be34dc	118	for (i = 0; i < mddev->raid_disks && !ret ; i++) {
165125e1	119	struct request_queue *q = bdev_get_queue(conf->disks[i].rdev->bdev);
26be34dc N	120	ret \|= bdi_congested(&q->backing_dev_info, bits);
26be34dc N	121	}
af11c397 S	122
af11c397 S	123	rcu_read_unlock();
26be34dc N	124	return ret;
	125	}
	126
80c3a6ce DW	127	static sector_t linear_size(mddev_t *mddev, sector_t sectors, int raid_disks)
80c3a6ce DW	128	{
af11c397 S	129	linear_conf_t *conf;
af11c397 S	130	sector_t array_sectors;
80c3a6ce	131
af11c397 S	132	rcu_read_lock();
af11c397 S	133	conf = rcu_dereference(mddev->private);
80c3a6ce DW	134	WARN_ONCE(sectors \|\| raid_disks,
80c3a6ce DW	135	"%s does not support generic reshape\n", __func__);
af11c397 S	136	array_sectors = conf->array_sectors;
af11c397 S	137	rcu_read_unlock();
80c3a6ce	138
af11c397	139	return array_sectors;
80c3a6ce DW	140	}
80c3a6ce DW	141
7c7546cc	142	static linear_conf_t linear_conf(mddev_t mddev, int raid_disks)
1da177e4 LT	143	{
1da177e4 LT	144	linear_conf_t *conf;
1da177e4	145	mdk_rdev_t *rdev;
45d4582f	146	int i, cnt;
1da177e4	147
7c7546cc	148	conf = kzalloc (sizeof (conf) + raid_diskssizeof(dev_info_t),
1da177e4 LT	149	GFP_KERNEL);
1da177e4 LT	150	if (!conf)
7c7546cc N	151	return NULL;
7c7546cc N	152
1da177e4	153	cnt = 0;
d6e22150	154	conf->array_sectors = 0;
1da177e4	155
159ec1fc	156	list_for_each_entry(rdev, &mddev->disks, same_set) {
1da177e4 LT	157	int j = rdev->raid_disk;
1da177e4 LT	158	dev_info_t *disk = conf->disks + j;
13f2682b	159	sector_t sectors;
1da177e4	160
13864515	161	if (j < 0 \|\| j >= raid_disks \|\| disk->rdev) {
2dc40f80 N	162	printk(KERN_ERR "md/linear:%s: disk numbering problem. Aborting!\n",
2dc40f80 N	163	mdname(mddev));
1da177e4 LT	164	goto out;
	165	}
	166
	167	disk->rdev = rdev;
13f2682b N	168	if (mddev->chunk_sectors) {
	169	sectors = rdev->sectors;
	170	sector_div(sectors, mddev->chunk_sectors);
	171	rdev->sectors = sectors * mddev->chunk_sectors;
	172	}
1da177e4	173
8f6c2e4b MP	174	disk_stack_limits(mddev->gendisk, rdev->bdev,
8f6c2e4b MP	175	rdev->data_offset << 9);
1da177e4	176	/* as we don't honour merge_bvec_fn, we must never risk
627a2d3c N	177	* violating it, so limit max_segments to 1 lying within
627a2d3c N	178	* a single page.
1da177e4	179	*/
627a2d3c N	180	if (rdev->bdev->bd_disk->queue->merge_bvec_fn) {
	181	blk_queue_max_segments(mddev->queue, 1);
	182	blk_queue_segment_boundary(mddev->queue,
	183	PAGE_CACHE_SIZE - 1);
	184	}
1da177e4	185
dd8ac336	186	conf->array_sectors += rdev->sectors;
1da177e4	187	cnt++;
4db7cdc8	188
1da177e4	189	}
7c7546cc	190	if (cnt != raid_disks) {
2dc40f80 N	191	printk(KERN_ERR "md/linear:%s: not enough drives present. Aborting!\n",
2dc40f80 N	192	mdname(mddev));
1da177e4 LT	193	goto out;
	194	}
	195
	196	/*
45d4582f	197	* Here we calculate the device offsets.
1da177e4	198	*/
4db7cdc8 SS	199	conf->disks[0].end_sector = conf->disks[0].rdev->sectors;
4db7cdc8 SS	200
a778b73f	201	for (i = 1; i < raid_disks; i++)
4db7cdc8 SS	202	conf->disks[i].end_sector =
	203	conf->disks[i-1].end_sector +
	204	conf->disks[i].rdev->sectors;
15945fee	205
7c7546cc N	206	return conf;
	207
	208	out:
	209	kfree(conf);
	210	return NULL;
	211	}
	212
	213	static int linear_run (mddev_t *mddev)
	214	{
	215	linear_conf_t *conf;
	216
0894cc30 AN	217	if (md_check_no_bitmap(mddev))
0894cc30 AN	218	return -EINVAL;
e7e72bf6	219	mddev->queue->queue_lock = &mddev->queue->__queue_lock;
7c7546cc N	220	conf = linear_conf(mddev, mddev->raid_disks);
	221
	222	if (!conf)
	223	return 1;
	224	mddev->private = conf;
1f403624	225	md_set_array_sectors(mddev, linear_size(mddev, 0, 0));
7c7546cc	226
1da177e4 LT	227	blk_queue_merge_bvec(mddev->queue, linear_mergeable_bvec);
1da177e4 LT	228	mddev->queue->unplug_fn = linear_unplug;
26be34dc N	229	mddev->queue->backing_dev_info.congested_fn = linear_congested;
26be34dc N	230	mddev->queue->backing_dev_info.congested_data = mddev;
ac5e7113	231	md_integrity_register(mddev);
1da177e4	232	return 0;
7c7546cc	233	}
1da177e4	234
495d3573 N	235	static void free_conf(struct rcu_head *head)
	236	{
	237	linear_conf_t *conf = container_of(head, linear_conf_t, rcu);
	238	kfree(conf);
	239	}
	240
7c7546cc N	241	static int linear_add(mddev_t mddev, mdk_rdev_t rdev)
	242	{
	243	/* Adding a drive to a linear array allows the array to grow.
	244	* It is permitted if the new drive has a matching superblock
	245	* already on it, with raid_disk equal to raid_disks.
	246	* It is achieved by creating a new linear_private_data structure
	247	* and swapping it in in-place of the current one.
	248	* The current one is never freed until the array is stopped.
	249	* This avoids races.
	250	*/
495d3573	251	linear_conf_t newconf, oldconf;
7c7546cc	252
a778b73f	253	if (rdev->saved_raid_disk != mddev->raid_disks)
7c7546cc N	254	return -EINVAL;
7c7546cc N	255
a778b73f N	256	rdev->raid_disk = rdev->saved_raid_disk;
a778b73f N	257
7c7546cc N	258	newconf = linear_conf(mddev,mddev->raid_disks+1);
	259
	260	if (!newconf)
	261	return -ENOMEM;
	262
495d3573	263	oldconf = rcu_dereference(mddev->private);
7c7546cc	264	mddev->raid_disks++;
af11c397	265	rcu_assign_pointer(mddev->private, newconf);
1f403624	266	md_set_array_sectors(mddev, linear_size(mddev, 0, 0));
f233ea5c	267	set_capacity(mddev->gendisk, mddev->array_sectors);
449aad3e	268	revalidate_disk(mddev->gendisk);
495d3573	269	call_rcu(&oldconf->rcu, free_conf);
7c7546cc	270	return 0;
1da177e4 LT	271	}
	272
	273	static int linear_stop (mddev_t *mddev)
	274	{
070ec55d	275	linear_conf_t *conf = mddev->private;
af11c397 S	276
	277	/*
	278	* We do not require rcu protection here since
	279	* we hold reconfig_mutex for both linear_add and
	280	* linear_stop, so they cannot race.
495d3573 N	281	* We should make sure any old 'conf's are properly
495d3573 N	282	* freed though.
af11c397	283	*/
495d3573	284	rcu_barrier();
1da177e4	285	blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/
495d3573	286	kfree(conf);
ef2f80ff	287	mddev->private = NULL;
1da177e4 LT	288
	289	return 0;
	290	}
	291
21a52c6d	292	static int linear_make_request (mddev_t mddev, struct bio bio)
1da177e4	293	{
1da177e4	294	dev_info_t *tmp_dev;
4db7cdc8	295	sector_t start_sector;
1da177e4	296
e9c7469b TH	297	if (unlikely(bio->bi_rw & REQ_FLUSH)) {
e9c7469b TH	298	md_flush_request(mddev, bio);
e5dcdd80 N	299	return 0;
	300	}
	301
af11c397	302	rcu_read_lock();
1da177e4	303	tmp_dev = which_dev(mddev, bio->bi_sector);
4db7cdc8 SS	304	start_sector = tmp_dev->end_sector - tmp_dev->rdev->sectors;
4db7cdc8 SS	305
af11c397	306
4db7cdc8 SS	307	if (unlikely(bio->bi_sector >= (tmp_dev->end_sector)
4db7cdc8 SS	308	\|\| (bio->bi_sector < start_sector))) {
1da177e4 LT	309	char b[BDEVNAME_SIZE];
1da177e4 LT	310
2dc40f80 N	311	printk(KERN_ERR
	312	"md/linear:%s: make_request: Sector %llu out of bounds on "
	313	"dev %s: %llu sectors, offset %llu\n",
	314	mdname(mddev),
	315	(unsigned long long)bio->bi_sector,
	316	bdevname(tmp_dev->rdev->bdev, b),
	317	(unsigned long long)tmp_dev->rdev->sectors,
	318	(unsigned long long)start_sector);
af11c397	319	rcu_read_unlock();
6712ecf8	320	bio_io_error(bio);
1da177e4 LT	321	return 0;
	322	}
	323	if (unlikely(bio->bi_sector + (bio->bi_size >> 9) >
4db7cdc8	324	tmp_dev->end_sector)) {
1da177e4 LT	325	/* This bio crosses a device boundary, so we have to
	326	* split it.
	327	*/
	328	struct bio_pair *bp;
af11c397 S	329	sector_t end_sector = tmp_dev->end_sector;
	330
	331	rcu_read_unlock();
6283815d	332
af11c397	333	bp = bio_split(bio, end_sector - bio->bi_sector);
6283815d	334
21a52c6d	335	if (linear_make_request(mddev, &bp->bio1))
1da177e4	336	generic_make_request(&bp->bio1);
21a52c6d	337	if (linear_make_request(mddev, &bp->bio2))
1da177e4 LT	338	generic_make_request(&bp->bio2);
	339	bio_pair_release(bp);
	340	return 0;
	341	}
	342
	343	bio->bi_bdev = tmp_dev->rdev->bdev;
4db7cdc8	344	bio->bi_sector = bio->bi_sector - start_sector
6283815d	345	+ tmp_dev->rdev->data_offset;
af11c397	346	rcu_read_unlock();
1da177e4 LT	347
	348	return 1;
	349	}
	350
	351	static void linear_status (struct seq_file seq, mddev_t mddev)
	352	{
	353
9d8f0363	354	seq_printf(seq, " %dk rounding", mddev->chunk_sectors / 2);
1da177e4 LT	355	}
	356
	357
2604b703	358	static struct mdk_personality linear_personality =
1da177e4 LT	359	{
1da177e4 LT	360	.name = "linear",
2604b703	361	.level = LEVEL_LINEAR,
1da177e4 LT	362	.owner = THIS_MODULE,
	363	.make_request = linear_make_request,
	364	.run = linear_run,
	365	.stop = linear_stop,
	366	.status = linear_status,
7c7546cc	367	.hot_add_disk = linear_add,
80c3a6ce	368	.size = linear_size,
1da177e4 LT	369	};
	370
	371	static int __init linear_init (void)
	372	{
2604b703	373	return register_md_personality (&linear_personality);
1da177e4 LT	374	}
	375
	376	static void linear_exit (void)
	377	{
2604b703	378	unregister_md_personality (&linear_personality);
1da177e4 LT	379	}
	380
	381
	382	module_init(linear_init);
	383	module_exit(linear_exit);
	384	MODULE_LICENSE("GPL");
0efb9e61	385	MODULE_DESCRIPTION("Linear device concatenation personality for MD");
d9d166c2 N	386	MODULE_ALIAS("md-personality-1"); /* LINEAR - deprecated*/
d9d166c2 N	387	MODULE_ALIAS("md-linear");
2604b703	388	MODULE_ALIAS("md-level--1");