[net-next-2.6.git] / block / blk-lib.c

/*
 * Functions related to generic helpers functions
 */
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/bio.h>
#include <linux/blkdev.h>
#include <linux/scatterlist.h>

#include "blk.h"

static void blkdev_discard_end_io(struct bio *bio, int err)
{
	if (err) {
		if (err == -EOPNOTSUPP)
			set_bit(BIO_EOPNOTSUPP, &bio->bi_flags);
		clear_bit(BIO_UPTODATE, &bio->bi_flags);
	}

	if (bio->bi_private)
		complete(bio->bi_private);

	bio_put(bio);
}

/**
 * blkdev_issue_discard - queue a discard
 * @bdev:	blockdev to issue discard for
 * @sector:	start sector
 * @nr_sects:	number of sectors to discard
 * @gfp_mask:	memory allocation flags (for bio_alloc)
 * @flags:	BLKDEV_IFL_* flags to control behaviour
 *
 * Description:
 *    Issue a discard request for the sectors in question.
 */
int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
		sector_t nr_sects, gfp_t gfp_mask, unsigned long flags)
{
	DECLARE_COMPLETION_ONSTACK(wait);
	struct request_queue *q = bdev_get_queue(bdev);
	int type = flags & BLKDEV_IFL_BARRIER ?
		DISCARD_BARRIER : DISCARD_NOBARRIER;
	unsigned int max_discard_sectors;
	struct bio *bio;
	int ret = 0;

	if (!q)
		return -ENXIO;

	if (!blk_queue_discard(q))
		return -EOPNOTSUPP;

	/*
	 * Ensure that max_discard_sectors is of the proper
	 * granularity
	 */
	max_discard_sectors = min(q->limits.max_discard_sectors, UINT_MAX >> 9);
	if (q->limits.discard_granularity) {
		unsigned int disc_sects = q->limits.discard_granularity >> 9;

		max_discard_sectors &= ~(disc_sects - 1);
	}

	while (nr_sects && !ret) {
		bio = bio_alloc(gfp_mask, 1);
		if (!bio) {
			ret = -ENOMEM;
			break;
		}

		bio->bi_sector = sector;
		bio->bi_end_io = blkdev_discard_end_io;
		bio->bi_bdev = bdev;
		if (flags & BLKDEV_IFL_WAIT)
			bio->bi_private = &wait;

		if (nr_sects > max_discard_sectors) {
			bio->bi_size = max_discard_sectors << 9;
			nr_sects -= max_discard_sectors;
			sector += max_discard_sectors;
		} else {
			bio->bi_size = nr_sects << 9;
			nr_sects = 0;
		}

		bio_get(bio);
		submit_bio(type, bio);

		if (flags & BLKDEV_IFL_WAIT)
			wait_for_completion(&wait);

		if (bio_flagged(bio, BIO_EOPNOTSUPP))
			ret = -EOPNOTSUPP;
		else if (!bio_flagged(bio, BIO_UPTODATE))
			ret = -EIO;
		bio_put(bio);
	}

	return ret;
}
EXPORT_SYMBOL(blkdev_issue_discard);

struct bio_batch
{
	atomic_t 		done;
	unsigned long 		flags;
	struct completion 	*wait;
	bio_end_io_t		*end_io;
};

static void bio_batch_end_io(struct bio *bio, int err)
{
	struct bio_batch *bb = bio->bi_private;

	if (err) {
		if (err == -EOPNOTSUPP)
			set_bit(BIO_EOPNOTSUPP, &bb->flags);
		else
			clear_bit(BIO_UPTODATE, &bb->flags);
	}
	if (bb) {
		if (bb->end_io)
			bb->end_io(bio, err);
		atomic_inc(&bb->done);
		complete(bb->wait);
	}
	bio_put(bio);
}

/**
 * blkdev_issue_zeroout generate number of zero filed write bios
 * @bdev:	blockdev to issue
 * @sector:	start sector
 * @nr_sects:	number of sectors to write
 * @gfp_mask:	memory allocation flags (for bio_alloc)
 * @flags:	BLKDEV_IFL_* flags to control behaviour
 *
 * Description:
 *  Generate and issue number of bios with zerofiled pages.
 *  Send barrier at the beginning and at the end if requested. This guarantie
 *  correct request ordering. Empty barrier allow us to avoid post queue flush.
 */

int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
			sector_t nr_sects, gfp_t gfp_mask, unsigned long flags)
{
	int ret = 0;
	struct bio *bio;
	struct bio_batch bb;
	unsigned int sz, issued = 0;
	DECLARE_COMPLETION_ONSTACK(wait);

	atomic_set(&bb.done, 0);
	bb.flags = 1 << BIO_UPTODATE;
	bb.wait = &wait;
	bb.end_io = NULL;

	if (flags & BLKDEV_IFL_BARRIER) {
		/* issue async barrier before the data */
		ret = blkdev_issue_flush(bdev, gfp_mask, NULL, 0);
		if (ret)
			return ret;
	}
submit:
	while (nr_sects != 0) {
		bio = bio_alloc(gfp_mask,
				min(nr_sects, (sector_t)BIO_MAX_PAGES));
		if (!bio)
			break;

		bio->bi_sector = sector;
		bio->bi_bdev   = bdev;
		bio->bi_end_io = bio_batch_end_io;
		if (flags & BLKDEV_IFL_WAIT)
			bio->bi_private = &bb;

		while (nr_sects != 0) {
			sz = min((sector_t) PAGE_SIZE >> 9 , nr_sects);
			if (sz == 0)
				/* bio has maximum size possible */
				break;
			ret = bio_add_page(bio, ZERO_PAGE(0), sz << 9, 0);
			nr_sects -= ret >> 9;
			sector += ret >> 9;
			if (ret < (sz << 9))
				break;
		}
		issued++;
		submit_bio(WRITE, bio);
	}
	/*
	 * When all data bios are in flight. Send final barrier if requeted.
	 */
	if (nr_sects == 0 && flags & BLKDEV_IFL_BARRIER)
		ret = blkdev_issue_flush(bdev, gfp_mask, NULL,
					flags & BLKDEV_IFL_WAIT);


	if (flags & BLKDEV_IFL_WAIT)
		/* Wait for bios in-flight */
		while ( issued != atomic_read(&bb.done))
			wait_for_completion(&wait);

	if (!test_bit(BIO_UPTODATE, &bb.flags))
		/* One of bios in the batch was completed with error.*/
		ret = -EIO;

	if (ret)
		goto out;

	if (test_bit(BIO_EOPNOTSUPP, &bb.flags)) {
		ret = -EOPNOTSUPP;
		goto out;
	}
	if (nr_sects != 0)
		goto submit;
out:
	return ret;
}
EXPORT_SYMBOL(blkdev_issue_zeroout);
Commit	Line	Data
f31e7e40 DM	1	/*
	2	* Functions related to generic helpers functions
	3	*/
	4	#include <linux/kernel.h>
	5	#include <linux/module.h>
	6	#include <linux/bio.h>
	7	#include <linux/blkdev.h>
	8	#include <linux/scatterlist.h>
	9
	10	#include "blk.h"
	11
	12	static void blkdev_discard_end_io(struct bio *bio, int err)
	13	{
	14	if (err) {
	15	if (err == -EOPNOTSUPP)
	16	set_bit(BIO_EOPNOTSUPP, &bio->bi_flags);
	17	clear_bit(BIO_UPTODATE, &bio->bi_flags);
	18	}
	19
	20	if (bio->bi_private)
	21	complete(bio->bi_private);
f31e7e40 DM	22
	23	bio_put(bio);
	24	}
	25
	26	/**
	27	* blkdev_issue_discard - queue a discard
	28	* @bdev: blockdev to issue discard for
	29	* @sector: start sector
	30	* @nr_sects: number of sectors to discard
	31	* @gfp_mask: memory allocation flags (for bio_alloc)
	32	* @flags: BLKDEV_IFL_* flags to control behaviour
	33	*
	34	* Description:
	35	* Issue a discard request for the sectors in question.
	36	*/
	37	int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
	38	sector_t nr_sects, gfp_t gfp_mask, unsigned long flags)
	39	{
	40	DECLARE_COMPLETION_ONSTACK(wait);
	41	struct request_queue *q = bdev_get_queue(bdev);
	42	int type = flags & BLKDEV_IFL_BARRIER ?
	43	DISCARD_BARRIER : DISCARD_NOBARRIER;
10d1f9e2	44	unsigned int max_discard_sectors;
f31e7e40	45	struct bio *bio;
f31e7e40 DM	46	int ret = 0;
	47
	48	if (!q)
	49	return -ENXIO;
	50
	51	if (!blk_queue_discard(q))
	52	return -EOPNOTSUPP;
	53
10d1f9e2 JA	54	/*
	55	* Ensure that max_discard_sectors is of the proper
	56	* granularity
	57	*/
	58	max_discard_sectors = min(q->limits.max_discard_sectors, UINT_MAX >> 9);
	59	if (q->limits.discard_granularity) {
	60	unsigned int disc_sects = q->limits.discard_granularity >> 9;
	61
	62	max_discard_sectors &= ~(disc_sects - 1);
	63	}
f31e7e40	64
10d1f9e2	65	while (nr_sects && !ret) {
f31e7e40	66	bio = bio_alloc(gfp_mask, 1);
66ac0280 CH	67	if (!bio) {
	68	ret = -ENOMEM;
	69	break;
	70	}
	71
f31e7e40 DM	72	bio->bi_sector = sector;
	73	bio->bi_end_io = blkdev_discard_end_io;
	74	bio->bi_bdev = bdev;
	75	if (flags & BLKDEV_IFL_WAIT)
	76	bio->bi_private = &wait;
	77
f31e7e40 DM	78	if (nr_sects > max_discard_sectors) {
	79	bio->bi_size = max_discard_sectors << 9;
	80	nr_sects -= max_discard_sectors;
	81	sector += max_discard_sectors;
	82	} else {
	83	bio->bi_size = nr_sects << 9;
	84	nr_sects = 0;
	85	}
	86
	87	bio_get(bio);
	88	submit_bio(type, bio);
	89
	90	if (flags & BLKDEV_IFL_WAIT)
	91	wait_for_completion(&wait);
	92
	93	if (bio_flagged(bio, BIO_EOPNOTSUPP))
	94	ret = -EOPNOTSUPP;
	95	else if (!bio_flagged(bio, BIO_UPTODATE))
	96	ret = -EIO;
	97	bio_put(bio);
	98	}
66ac0280	99
f31e7e40	100	return ret;
f31e7e40 DM	101	}
f31e7e40 DM	102	EXPORT_SYMBOL(blkdev_issue_discard);
3f14d792 DM	103
	104	struct bio_batch
	105	{
	106	atomic_t done;
	107	unsigned long flags;
	108	struct completion *wait;
	109	bio_end_io_t *end_io;
	110	};
	111
	112	static void bio_batch_end_io(struct bio *bio, int err)
	113	{
	114	struct bio_batch *bb = bio->bi_private;
0341aafb	115
3f14d792 DM	116	if (err) {
	117	if (err == -EOPNOTSUPP)
	118	set_bit(BIO_EOPNOTSUPP, &bb->flags);
	119	else
	120	clear_bit(BIO_UPTODATE, &bb->flags);
	121	}
	122	if (bb) {
	123	if (bb->end_io)
	124	bb->end_io(bio, err);
	125	atomic_inc(&bb->done);
	126	complete(bb->wait);
	127	}
	128	bio_put(bio);
	129	}
	130
	131	/**
	132	* blkdev_issue_zeroout generate number of zero filed write bios
	133	* @bdev: blockdev to issue
	134	* @sector: start sector
	135	* @nr_sects: number of sectors to write
	136	* @gfp_mask: memory allocation flags (for bio_alloc)
	137	* @flags: BLKDEV_IFL_* flags to control behaviour
	138	*
	139	* Description:
	140	* Generate and issue number of bios with zerofiled pages.
	141	* Send barrier at the beginning and at the end if requested. This guarantie
	142	* correct request ordering. Empty barrier allow us to avoid post queue flush.
	143	*/
	144
	145	int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
	146	sector_t nr_sects, gfp_t gfp_mask, unsigned long flags)
	147	{
	148	int ret = 0;
	149	struct bio *bio;
	150	struct bio_batch bb;
	151	unsigned int sz, issued = 0;
	152	DECLARE_COMPLETION_ONSTACK(wait);
	153
	154	atomic_set(&bb.done, 0);
	155	bb.flags = 1 << BIO_UPTODATE;
	156	bb.wait = &wait;
	157	bb.end_io = NULL;
	158
	159	if (flags & BLKDEV_IFL_BARRIER) {
	160	/* issue async barrier before the data */
	161	ret = blkdev_issue_flush(bdev, gfp_mask, NULL, 0);
	162	if (ret)
	163	return ret;
	164	}
	165	submit:
	166	while (nr_sects != 0) {
	167	bio = bio_alloc(gfp_mask,
	168	min(nr_sects, (sector_t)BIO_MAX_PAGES));
	169	if (!bio)
	170	break;
	171
	172	bio->bi_sector = sector;
	173	bio->bi_bdev = bdev;
	174	bio->bi_end_io = bio_batch_end_io;
	175	if (flags & BLKDEV_IFL_WAIT)
	176	bio->bi_private = &bb;
	177
0341aafb JA	178	while (nr_sects != 0) {
0341aafb JA	179	sz = min((sector_t) PAGE_SIZE >> 9 , nr_sects);
3f14d792 DM	180	if (sz == 0)
	181	/* bio has maximum size possible */
	182	break;
	183	ret = bio_add_page(bio, ZERO_PAGE(0), sz << 9, 0);
	184	nr_sects -= ret >> 9;
	185	sector += ret >> 9;
	186	if (ret < (sz << 9))
	187	break;
	188	}
	189	issued++;
	190	submit_bio(WRITE, bio);
	191	}
	192	/*
	193	* When all data bios are in flight. Send final barrier if requeted.
	194	*/
	195	if (nr_sects == 0 && flags & BLKDEV_IFL_BARRIER)
	196	ret = blkdev_issue_flush(bdev, gfp_mask, NULL,
	197	flags & BLKDEV_IFL_WAIT);
	198
	199
	200	if (flags & BLKDEV_IFL_WAIT)
	201	/* Wait for bios in-flight */
	202	while ( issued != atomic_read(&bb.done))
	203	wait_for_completion(&wait);
	204
	205	if (!test_bit(BIO_UPTODATE, &bb.flags))
	206	/* One of bios in the batch was completed with error.*/
	207	ret = -EIO;
	208
	209	if (ret)
	210	goto out;
	211
	212	if (test_bit(BIO_EOPNOTSUPP, &bb.flags)) {
	213	ret = -EOPNOTSUPP;
	214	goto out;
	215	}
	216	if (nr_sects != 0)
	217	goto submit;
	218	out:
	219	return ret;
	220	}
	221	EXPORT_SYMBOL(blkdev_issue_zeroout);