[linux-2.6-block.git] / block / blk-lib.c

// SPDX-License-Identifier: GPL-2.0
/*
 * 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"

struct bio *blk_next_bio(struct bio *bio, unsigned int nr_pages, gfp_t gfp)
{
	struct bio *new = bio_alloc(gfp, nr_pages);

	if (bio) {
		bio_chain(bio, new);
		submit_bio(bio);
	}

	return new;
}

int __blkdev_issue_discard(struct block_device *bdev, sector_t sector,
		sector_t nr_sects, gfp_t gfp_mask, int flags,
		struct bio **biop)
{
	struct request_queue *q = bdev_get_queue(bdev);
	struct bio *bio = *biop;
	unsigned int op;
	sector_t bs_mask;

	if (!q)
		return -ENXIO;

	if (bdev_read_only(bdev))
		return -EPERM;

	if (flags & BLKDEV_DISCARD_SECURE) {
		if (!blk_queue_secure_erase(q))
			return -EOPNOTSUPP;
		op = REQ_OP_SECURE_ERASE;
	} else {
		if (!blk_queue_discard(q))
			return -EOPNOTSUPP;
		op = REQ_OP_DISCARD;
	}

	bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1;
	if ((sector | nr_sects) & bs_mask)
		return -EINVAL;

	if (!nr_sects)
		return -EINVAL;

	while (nr_sects) {
		unsigned int req_sects = min_t(unsigned int, nr_sects,
				bio_allowed_max_sectors(q));

		bio = blk_next_bio(bio, 0, gfp_mask);
		bio->bi_iter.bi_sector = sector;
		bio_set_dev(bio, bdev);
		bio_set_op_attrs(bio, op, 0);

		bio->bi_iter.bi_size = req_sects << 9;
		sector += req_sects;
		nr_sects -= req_sects;

		/*
		 * We can loop for a long time in here, if someone does
		 * full device discards (like mkfs). Be nice and allow
		 * us to schedule out to avoid softlocking if preempt
		 * is disabled.
		 */
		cond_resched();
	}

	*biop = bio;
	return 0;
}
EXPORT_SYMBOL(__blkdev_issue_discard);

/**
 * 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_DISCARD_* 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)
{
	struct bio *bio = NULL;
	struct blk_plug plug;
	int ret;

	blk_start_plug(&plug);
	ret = __blkdev_issue_discard(bdev, sector, nr_sects, gfp_mask, flags,
			&bio);
	if (!ret && bio) {
		ret = submit_bio_wait(bio);
		if (ret == -EOPNOTSUPP)
			ret = 0;
		bio_put(bio);
	}
	blk_finish_plug(&plug);

	return ret;
}
EXPORT_SYMBOL(blkdev_issue_discard);

/**
 * __blkdev_issue_write_same - generate number of bios with same page
 * @bdev:	target blockdev
 * @sector:	start sector
 * @nr_sects:	number of sectors to write
 * @gfp_mask:	memory allocation flags (for bio_alloc)
 * @page:	page containing data to write
 * @biop:	pointer to anchor bio
 *
 * Description:
 *  Generate and issue number of bios(REQ_OP_WRITE_SAME) with same page.
 */
static int __blkdev_issue_write_same(struct block_device *bdev, sector_t sector,
		sector_t nr_sects, gfp_t gfp_mask, struct page *page,
		struct bio **biop)
{
	struct request_queue *q = bdev_get_queue(bdev);
	unsigned int max_write_same_sectors;
	struct bio *bio = *biop;
	sector_t bs_mask;

	if (!q)
		return -ENXIO;

	if (bdev_read_only(bdev))
		return -EPERM;

	bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1;
	if ((sector | nr_sects) & bs_mask)
		return -EINVAL;

	if (!bdev_write_same(bdev))
		return -EOPNOTSUPP;

	/* Ensure that max_write_same_sectors doesn't overflow bi_size */
	max_write_same_sectors = bio_allowed_max_sectors(q);

	while (nr_sects) {
		bio = blk_next_bio(bio, 1, gfp_mask);
		bio->bi_iter.bi_sector = sector;
		bio_set_dev(bio, bdev);
		bio->bi_vcnt = 1;
		bio->bi_io_vec->bv_page = page;
		bio->bi_io_vec->bv_offset = 0;
		bio->bi_io_vec->bv_len = bdev_logical_block_size(bdev);
		bio_set_op_attrs(bio, REQ_OP_WRITE_SAME, 0);

		if (nr_sects > max_write_same_sectors) {
			bio->bi_iter.bi_size = max_write_same_sectors << 9;
			nr_sects -= max_write_same_sectors;
			sector += max_write_same_sectors;
		} else {
			bio->bi_iter.bi_size = nr_sects << 9;
			nr_sects = 0;
		}
		cond_resched();
	}

	*biop = bio;
	return 0;
}

/**
 * blkdev_issue_write_same - queue a write same operation
 * @bdev:	target blockdev
 * @sector:	start sector
 * @nr_sects:	number of sectors to write
 * @gfp_mask:	memory allocation flags (for bio_alloc)
 * @page:	page containing data
 *
 * Description:
 *    Issue a write same request for the sectors in question.
 */
int blkdev_issue_write_same(struct block_device *bdev, sector_t sector,
				sector_t nr_sects, gfp_t gfp_mask,
				struct page *page)
{
	struct bio *bio = NULL;
	struct blk_plug plug;
	int ret;

	blk_start_plug(&plug);
	ret = __blkdev_issue_write_same(bdev, sector, nr_sects, gfp_mask, page,
			&bio);
	if (ret == 0 && bio) {
		ret = submit_bio_wait(bio);
		bio_put(bio);
	}
	blk_finish_plug(&plug);
	return ret;
}
EXPORT_SYMBOL(blkdev_issue_write_same);

static int __blkdev_issue_write_zeroes(struct block_device *bdev,
		sector_t sector, sector_t nr_sects, gfp_t gfp_mask,
		struct bio **biop, unsigned flags)
{
	struct bio *bio = *biop;
	unsigned int max_write_zeroes_sectors;
	struct request_queue *q = bdev_get_queue(bdev);

	if (!q)
		return -ENXIO;

	if (bdev_read_only(bdev))
		return -EPERM;

	/* Ensure that max_write_zeroes_sectors doesn't overflow bi_size */
	max_write_zeroes_sectors = bdev_write_zeroes_sectors(bdev);

	if (max_write_zeroes_sectors == 0)
		return -EOPNOTSUPP;

	while (nr_sects) {
		bio = blk_next_bio(bio, 0, gfp_mask);
		bio->bi_iter.bi_sector = sector;
		bio_set_dev(bio, bdev);
		bio->bi_opf = REQ_OP_WRITE_ZEROES;
		if (flags & BLKDEV_ZERO_NOUNMAP)
			bio->bi_opf |= REQ_NOUNMAP;

		if (nr_sects > max_write_zeroes_sectors) {
			bio->bi_iter.bi_size = max_write_zeroes_sectors << 9;
			nr_sects -= max_write_zeroes_sectors;
			sector += max_write_zeroes_sectors;
		} else {
			bio->bi_iter.bi_size = nr_sects << 9;
			nr_sects = 0;
		}
		cond_resched();
	}

	*biop = bio;
	return 0;
}

/*
 * Convert a number of 512B sectors to a number of pages.
 * The result is limited to a number of pages that can fit into a BIO.
 * Also make sure that the result is always at least 1 (page) for the cases
 * where nr_sects is lower than the number of sectors in a page.
 */
static unsigned int __blkdev_sectors_to_bio_pages(sector_t nr_sects)
{
	sector_t pages = DIV_ROUND_UP_SECTOR_T(nr_sects, PAGE_SIZE / 512);

	return min(pages, (sector_t)BIO_MAX_PAGES);
}

static int __blkdev_issue_zero_pages(struct block_device *bdev,
		sector_t sector, sector_t nr_sects, gfp_t gfp_mask,
		struct bio **biop)
{
	struct request_queue *q = bdev_get_queue(bdev);
	struct bio *bio = *biop;
	int bi_size = 0;
	unsigned int sz;

	if (!q)
		return -ENXIO;

	if (bdev_read_only(bdev))
		return -EPERM;

	while (nr_sects != 0) {
		bio = blk_next_bio(bio, __blkdev_sectors_to_bio_pages(nr_sects),
				   gfp_mask);
		bio->bi_iter.bi_sector = sector;
		bio_set_dev(bio, bdev);
		bio_set_op_attrs(bio, REQ_OP_WRITE, 0);

		while (nr_sects != 0) {
			sz = min((sector_t) PAGE_SIZE, nr_sects << 9);
			bi_size = bio_add_page(bio, ZERO_PAGE(0), sz, 0);
			nr_sects -= bi_size >> 9;
			sector += bi_size >> 9;
			if (bi_size < sz)
				break;
		}
		cond_resched();
	}

	*biop = bio;
	return 0;
}

/**
 * __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)
 * @biop:	pointer to anchor bio
 * @flags:	controls detailed behavior
 *
 * Description:
 *  Zero-fill a block range, either using hardware offload or by explicitly
 *  writing zeroes to the device.
 *
 *  If a device is using logical block provisioning, the underlying space will
 *  not be released if %flags contains BLKDEV_ZERO_NOUNMAP.
 *
 *  If %flags contains BLKDEV_ZERO_NOFALLBACK, the function will return
 *  -EOPNOTSUPP if no explicit hardware offload for zeroing is provided.
 */
int __blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
		sector_t nr_sects, gfp_t gfp_mask, struct bio **biop,
		unsigned flags)
{
	int ret;
	sector_t bs_mask;

	bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1;
	if ((sector | nr_sects) & bs_mask)
		return -EINVAL;

	ret = __blkdev_issue_write_zeroes(bdev, sector, nr_sects, gfp_mask,
			biop, flags);
	if (ret != -EOPNOTSUPP || (flags & BLKDEV_ZERO_NOFALLBACK))
		return ret;

	return __blkdev_issue_zero_pages(bdev, sector, nr_sects, gfp_mask,
					 biop);
}
EXPORT_SYMBOL(__blkdev_issue_zeroout);

/**
 * blkdev_issue_zeroout - zero-fill a block range
 * @bdev:	blockdev to write
 * @sector:	start sector
 * @nr_sects:	number of sectors to write
 * @gfp_mask:	memory allocation flags (for bio_alloc)
 * @flags:	controls detailed behavior
 *
 * Description:
 *  Zero-fill a block range, either using hardware offload or by explicitly
 *  writing zeroes to the device.  See __blkdev_issue_zeroout() for the
 *  valid values for %flags.
 */
int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
		sector_t nr_sects, gfp_t gfp_mask, unsigned flags)
{
	int ret = 0;
	sector_t bs_mask;
	struct bio *bio;
	struct blk_plug plug;
	bool try_write_zeroes = !!bdev_write_zeroes_sectors(bdev);

	bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1;
	if ((sector | nr_sects) & bs_mask)
		return -EINVAL;

retry:
	bio = NULL;
	blk_start_plug(&plug);
	if (try_write_zeroes) {
		ret = __blkdev_issue_write_zeroes(bdev, sector, nr_sects,
						  gfp_mask, &bio, flags);
	} else if (!(flags & BLKDEV_ZERO_NOFALLBACK)) {
		ret = __blkdev_issue_zero_pages(bdev, sector, nr_sects,
						gfp_mask, &bio);
	} else {
		/* No zeroing offload support */
		ret = -EOPNOTSUPP;
	}
	if (ret == 0 && bio) {
		ret = submit_bio_wait(bio);
		bio_put(bio);
	}
	blk_finish_plug(&plug);
	if (ret && try_write_zeroes) {
		if (!(flags & BLKDEV_ZERO_NOFALLBACK)) {
			try_write_zeroes = false;
			goto retry;
		}
		if (!bdev_write_zeroes_sectors(bdev)) {
			/*
			 * Zeroing offload support was indicated, but the
			 * device reported ILLEGAL REQUEST (for some devices
			 * there is no non-destructive way to verify whether
			 * WRITE ZEROES is actually supported).
			 */
			ret = -EOPNOTSUPP;
		}
	}

	return ret;
}
EXPORT_SYMBOL(blkdev_issue_zeroout);
Commit	Line	Data
b2441318	1	// SPDX-License-Identifier: GPL-2.0
f31e7e40 DM	2	/*
	3	* Functions related to generic helpers functions
	4	*/
	5	#include <linux/kernel.h>
	6	#include <linux/module.h>
	7	#include <linux/bio.h>
	8	#include <linux/blkdev.h>
	9	#include <linux/scatterlist.h>
	10
	11	#include "blk.h"
	12
a2d6b3a2	13	struct bio blk_next_bio(struct bio bio, unsigned int nr_pages, gfp_t gfp)
f31e7e40	14	{
9082e87b CH	15	struct bio *new = bio_alloc(gfp, nr_pages);
	16
	17	if (bio) {
	18	bio_chain(bio, new);
4e49ea4a	19	submit_bio(bio);
9082e87b	20	}
5dba3089	21
9082e87b	22	return new;
f31e7e40 DM	23	}
f31e7e40 DM	24
38f25255	25	int __blkdev_issue_discard(struct block_device *bdev, sector_t sector,
288dab8a	26	sector_t nr_sects, gfp_t gfp_mask, int flags,
469e3216	27	struct bio **biop)
f31e7e40	28	{
f31e7e40	29	struct request_queue *q = bdev_get_queue(bdev);
38f25255	30	struct bio bio = biop;
ef295ecf	31	unsigned int op;
28b2be20	32	sector_t bs_mask;
f31e7e40 DM	33
	34	if (!q)
	35	return -ENXIO;
288dab8a	36
a13553c7 ID	37	if (bdev_read_only(bdev))
	38	return -EPERM;
	39
288dab8a CH	40	if (flags & BLKDEV_DISCARD_SECURE) {
	41	if (!blk_queue_secure_erase(q))
	42	return -EOPNOTSUPP;
	43	op = REQ_OP_SECURE_ERASE;
	44	} else {
	45	if (!blk_queue_discard(q))
	46	return -EOPNOTSUPP;
	47	op = REQ_OP_DISCARD;
	48	}
f31e7e40	49
28b2be20 DW	50	bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1;
	51	if ((sector \| nr_sects) & bs_mask)
	52	return -EINVAL;
	53
ba5d7385 ML	54	if (!nr_sects)
ba5d7385 ML	55	return -EINVAL;
a22c4d7e	56
ba5d7385 ML	57	while (nr_sects) {
	58	unsigned int req_sects = min_t(unsigned int, nr_sects,
	59	bio_allowed_max_sectors(q));
c6e66634	60
a2d6b3a2	61	bio = blk_next_bio(bio, 0, gfp_mask);
4f024f37	62	bio->bi_iter.bi_sector = sector;
74d46992	63	bio_set_dev(bio, bdev);
288dab8a	64	bio_set_op_attrs(bio, op, 0);
f31e7e40	65
4f024f37	66	bio->bi_iter.bi_size = req_sects << 9;
ba5d7385	67	sector += req_sects;
c6e66634	68	nr_sects -= req_sects;
f31e7e40	69
c8123f8c JA	70	/*
	71	* We can loop for a long time in here, if someone does
	72	* full device discards (like mkfs). Be nice and allow
	73	* us to schedule out to avoid softlocking if preempt
	74	* is disabled.
	75	*/
	76	cond_resched();
5dba3089	77	}
38f25255 CH	78
	79	*biop = bio;
	80	return 0;
	81	}
	82	EXPORT_SYMBOL(__blkdev_issue_discard);
	83
	84	/**
	85	* blkdev_issue_discard - queue a discard
	86	* @bdev: blockdev to issue discard for
	87	* @sector: start sector
	88	* @nr_sects: number of sectors to discard
	89	* @gfp_mask: memory allocation flags (for bio_alloc)
e554911c	90	* @flags: BLKDEV_DISCARD_* flags to control behaviour
38f25255 CH	91	*
	92	* Description:
	93	* Issue a discard request for the sectors in question.
	94	*/
	95	int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
	96	sector_t nr_sects, gfp_t gfp_mask, unsigned long flags)
	97	{
38f25255 CH	98	struct bio *bio = NULL;
	99	struct blk_plug plug;
	100	int ret;
	101
38f25255	102	blk_start_plug(&plug);
288dab8a	103	ret = __blkdev_issue_discard(bdev, sector, nr_sects, gfp_mask, flags,
38f25255	104	&bio);
bbd848e0	105	if (!ret && bio) {
4e49ea4a	106	ret = submit_bio_wait(bio);
48920ff2	107	if (ret == -EOPNOTSUPP)
bbd848e0	108	ret = 0;
05bd92dd	109	bio_put(bio);
bbd848e0	110	}
0cfbcafc	111	blk_finish_plug(&plug);
f31e7e40	112
bbd848e0	113	return ret;
f31e7e40 DM	114	}
f31e7e40 DM	115	EXPORT_SYMBOL(blkdev_issue_discard);
3f14d792	116
4363ac7c	117	/**
e73c23ff	118	* __blkdev_issue_write_same - generate number of bios with same page
4363ac7c MP	119	* @bdev: target blockdev
	120	* @sector: start sector
	121	* @nr_sects: number of sectors to write
	122	* @gfp_mask: memory allocation flags (for bio_alloc)
	123	* @page: page containing data to write
e73c23ff	124	* @biop: pointer to anchor bio
4363ac7c MP	125	*
4363ac7c MP	126	* Description:
e73c23ff	127	* Generate and issue number of bios(REQ_OP_WRITE_SAME) with same page.
4363ac7c	128	*/
e73c23ff CK	129	static int __blkdev_issue_write_same(struct block_device *bdev, sector_t sector,
	130	sector_t nr_sects, gfp_t gfp_mask, struct page *page,
	131	struct bio **biop)
4363ac7c	132	{
4363ac7c MP	133	struct request_queue *q = bdev_get_queue(bdev);
4363ac7c MP	134	unsigned int max_write_same_sectors;
e73c23ff	135	struct bio bio = biop;
28b2be20	136	sector_t bs_mask;
4363ac7c MP	137
	138	if (!q)
	139	return -ENXIO;
	140
a13553c7 ID	141	if (bdev_read_only(bdev))
	142	return -EPERM;
	143
28b2be20 DW	144	bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1;
	145	if ((sector \| nr_sects) & bs_mask)
	146	return -EINVAL;
	147
e73c23ff CK	148	if (!bdev_write_same(bdev))
	149	return -EOPNOTSUPP;
	150
b49a0871	151	/* Ensure that max_write_same_sectors doesn't overflow bi_size */
34ffec60	152	max_write_same_sectors = bio_allowed_max_sectors(q);
4363ac7c	153
4363ac7c	154	while (nr_sects) {
a2d6b3a2	155	bio = blk_next_bio(bio, 1, gfp_mask);
4f024f37	156	bio->bi_iter.bi_sector = sector;
74d46992	157	bio_set_dev(bio, bdev);
4363ac7c MP	158	bio->bi_vcnt = 1;
	159	bio->bi_io_vec->bv_page = page;
	160	bio->bi_io_vec->bv_offset = 0;
	161	bio->bi_io_vec->bv_len = bdev_logical_block_size(bdev);
95fe6c1a	162	bio_set_op_attrs(bio, REQ_OP_WRITE_SAME, 0);
4363ac7c MP	163
4363ac7c MP	164	if (nr_sects > max_write_same_sectors) {
4f024f37	165	bio->bi_iter.bi_size = max_write_same_sectors << 9;
4363ac7c MP	166	nr_sects -= max_write_same_sectors;
	167	sector += max_write_same_sectors;
	168	} else {
4f024f37	169	bio->bi_iter.bi_size = nr_sects << 9;
4363ac7c MP	170	nr_sects = 0;
4363ac7c MP	171	}
e73c23ff	172	cond_resched();
4363ac7c MP	173	}
4363ac7c MP	174
e73c23ff CK	175	*biop = bio;
	176	return 0;
	177	}
	178
	179	/**
	180	* blkdev_issue_write_same - queue a write same operation
	181	* @bdev: target blockdev
	182	* @sector: start sector
	183	* @nr_sects: number of sectors to write
	184	* @gfp_mask: memory allocation flags (for bio_alloc)
	185	* @page: page containing data
	186	*
	187	* Description:
	188	* Issue a write same request for the sectors in question.
	189	*/
	190	int blkdev_issue_write_same(struct block_device *bdev, sector_t sector,
	191	sector_t nr_sects, gfp_t gfp_mask,
	192	struct page *page)
	193	{
	194	struct bio *bio = NULL;
	195	struct blk_plug plug;
	196	int ret;
	197
	198	blk_start_plug(&plug);
	199	ret = __blkdev_issue_write_same(bdev, sector, nr_sects, gfp_mask, page,
	200	&bio);
	201	if (ret == 0 && bio) {
4e49ea4a	202	ret = submit_bio_wait(bio);
05bd92dd ST	203	bio_put(bio);
05bd92dd ST	204	}
e73c23ff	205	blk_finish_plug(&plug);
3f40bf2c	206	return ret;
4363ac7c MP	207	}
	208	EXPORT_SYMBOL(blkdev_issue_write_same);
	209
a6f0788e CK	210	static int __blkdev_issue_write_zeroes(struct block_device *bdev,
a6f0788e CK	211	sector_t sector, sector_t nr_sects, gfp_t gfp_mask,
d928be9f	212	struct bio **biop, unsigned flags)
a6f0788e CK	213	{
	214	struct bio bio = biop;
	215	unsigned int max_write_zeroes_sectors;
	216	struct request_queue *q = bdev_get_queue(bdev);
	217
	218	if (!q)
	219	return -ENXIO;
	220
a13553c7 ID	221	if (bdev_read_only(bdev))
	222	return -EPERM;
	223
a6f0788e CK	224	/* Ensure that max_write_zeroes_sectors doesn't overflow bi_size */
	225	max_write_zeroes_sectors = bdev_write_zeroes_sectors(bdev);
	226
	227	if (max_write_zeroes_sectors == 0)
	228	return -EOPNOTSUPP;
	229
	230	while (nr_sects) {
a2d6b3a2	231	bio = blk_next_bio(bio, 0, gfp_mask);
a6f0788e	232	bio->bi_iter.bi_sector = sector;
74d46992	233	bio_set_dev(bio, bdev);
d928be9f CH	234	bio->bi_opf = REQ_OP_WRITE_ZEROES;
	235	if (flags & BLKDEV_ZERO_NOUNMAP)
	236	bio->bi_opf \|= REQ_NOUNMAP;
a6f0788e CK	237
	238	if (nr_sects > max_write_zeroes_sectors) {
	239	bio->bi_iter.bi_size = max_write_zeroes_sectors << 9;
	240	nr_sects -= max_write_zeroes_sectors;
	241	sector += max_write_zeroes_sectors;
	242	} else {
	243	bio->bi_iter.bi_size = nr_sects << 9;
	244	nr_sects = 0;
	245	}
	246	cond_resched();
	247	}
	248
	249	*biop = bio;
	250	return 0;
	251	}
	252
615d22a5 DLM	253	/*
	254	* Convert a number of 512B sectors to a number of pages.
	255	* The result is limited to a number of pages that can fit into a BIO.
	256	* Also make sure that the result is always at least 1 (page) for the cases
	257	* where nr_sects is lower than the number of sectors in a page.
	258	*/
	259	static unsigned int __blkdev_sectors_to_bio_pages(sector_t nr_sects)
	260	{
09c2c359	261	sector_t pages = DIV_ROUND_UP_SECTOR_T(nr_sects, PAGE_SIZE / 512);
615d22a5	262
09c2c359	263	return min(pages, (sector_t)BIO_MAX_PAGES);
615d22a5 DLM	264	}
615d22a5 DLM	265
425a4dba ID	266	static int __blkdev_issue_zero_pages(struct block_device *bdev,
	267	sector_t sector, sector_t nr_sects, gfp_t gfp_mask,
	268	struct bio **biop)
	269	{
	270	struct request_queue *q = bdev_get_queue(bdev);
	271	struct bio bio = biop;
	272	int bi_size = 0;
	273	unsigned int sz;
	274
	275	if (!q)
	276	return -ENXIO;
	277
a13553c7 ID	278	if (bdev_read_only(bdev))
	279	return -EPERM;
	280
425a4dba	281	while (nr_sects != 0) {
a2d6b3a2 DLM	282	bio = blk_next_bio(bio, __blkdev_sectors_to_bio_pages(nr_sects),
a2d6b3a2 DLM	283	gfp_mask);
425a4dba ID	284	bio->bi_iter.bi_sector = sector;
	285	bio_set_dev(bio, bdev);
	286	bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
	287
	288	while (nr_sects != 0) {
	289	sz = min((sector_t) PAGE_SIZE, nr_sects << 9);
	290	bi_size = bio_add_page(bio, ZERO_PAGE(0), sz, 0);
	291	nr_sects -= bi_size >> 9;
	292	sector += bi_size >> 9;
	293	if (bi_size < sz)
	294	break;
	295	}
	296	cond_resched();
	297	}
	298
	299	*biop = bio;
	300	return 0;
	301	}
	302
3f14d792	303	/**
e73c23ff	304	* __blkdev_issue_zeroout - generate number of zero filed write bios
3f14d792 DM	305	* @bdev: blockdev to issue
	306	* @sector: start sector
	307	* @nr_sects: number of sectors to write
	308	* @gfp_mask: memory allocation flags (for bio_alloc)
e73c23ff	309	* @biop: pointer to anchor bio
ee472d83	310	* @flags: controls detailed behavior
3f14d792 DM	311	*
3f14d792 DM	312	* Description:
ee472d83 CH	313	* Zero-fill a block range, either using hardware offload or by explicitly
	314	* writing zeroes to the device.
	315	*
	316	* If a device is using logical block provisioning, the underlying space will
	317	* not be released if %flags contains BLKDEV_ZERO_NOUNMAP.
cb365b96 CH	318	*
	319	* If %flags contains BLKDEV_ZERO_NOFALLBACK, the function will return
	320	* -EOPNOTSUPP if no explicit hardware offload for zeroing is provided.
3f14d792	321	*/
e73c23ff CK	322	int __blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
e73c23ff CK	323	sector_t nr_sects, gfp_t gfp_mask, struct bio **biop,
ee472d83	324	unsigned flags)
3f14d792	325	{
18edc8ea	326	int ret;
28b2be20 DW	327	sector_t bs_mask;
	328
	329	bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1;
	330	if ((sector \| nr_sects) & bs_mask)
	331	return -EINVAL;
3f14d792	332
a6f0788e	333	ret = __blkdev_issue_write_zeroes(bdev, sector, nr_sects, gfp_mask,
d928be9f	334	biop, flags);
cb365b96	335	if (ret != -EOPNOTSUPP \|\| (flags & BLKDEV_ZERO_NOFALLBACK))
425a4dba	336	return ret;
3f14d792	337
425a4dba ID	338	return __blkdev_issue_zero_pages(bdev, sector, nr_sects, gfp_mask,
425a4dba ID	339	biop);
3f14d792	340	}
e73c23ff	341	EXPORT_SYMBOL(__blkdev_issue_zeroout);
579e8f3c MP	342
	343	/**
	344	* blkdev_issue_zeroout - zero-fill a block range
	345	* @bdev: blockdev to write
	346	* @sector: start sector
	347	* @nr_sects: number of sectors to write
	348	* @gfp_mask: memory allocation flags (for bio_alloc)
ee472d83	349	* @flags: controls detailed behavior
579e8f3c MP	350	*
579e8f3c MP	351	* Description:
ee472d83 CH	352	* Zero-fill a block range, either using hardware offload or by explicitly
	353	* writing zeroes to the device. See __blkdev_issue_zeroout() for the
	354	* valid values for %flags.
579e8f3c	355	*/
579e8f3c	356	int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
ee472d83	357	sector_t nr_sects, gfp_t gfp_mask, unsigned flags)
579e8f3c	358	{
d5ce4c31 ID	359	int ret = 0;
	360	sector_t bs_mask;
	361	struct bio *bio;
e73c23ff	362	struct blk_plug plug;
d5ce4c31	363	bool try_write_zeroes = !!bdev_write_zeroes_sectors(bdev);
d93ba7a5	364
d5ce4c31 ID	365	bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1;
	366	if ((sector \| nr_sects) & bs_mask)
	367	return -EINVAL;
	368
	369	retry:
	370	bio = NULL;
e73c23ff	371	blk_start_plug(&plug);
d5ce4c31 ID	372	if (try_write_zeroes) {
	373	ret = __blkdev_issue_write_zeroes(bdev, sector, nr_sects,
	374	gfp_mask, &bio, flags);
	375	} else if (!(flags & BLKDEV_ZERO_NOFALLBACK)) {
	376	ret = __blkdev_issue_zero_pages(bdev, sector, nr_sects,
	377	gfp_mask, &bio);
	378	} else {
	379	/* No zeroing offload support */
	380	ret = -EOPNOTSUPP;
	381	}
e73c23ff CK	382	if (ret == 0 && bio) {
	383	ret = submit_bio_wait(bio);
	384	bio_put(bio);
	385	}
	386	blk_finish_plug(&plug);
d5ce4c31 ID	387	if (ret && try_write_zeroes) {
	388	if (!(flags & BLKDEV_ZERO_NOFALLBACK)) {
	389	try_write_zeroes = false;
	390	goto retry;
	391	}
	392	if (!bdev_write_zeroes_sectors(bdev)) {
	393	/*
	394	* Zeroing offload support was indicated, but the
	395	* device reported ILLEGAL REQUEST (for some devices
	396	* there is no non-destructive way to verify whether
	397	* WRITE ZEROES is actually supported).
	398	*/
	399	ret = -EOPNOTSUPP;
	400	}
	401	}
579e8f3c	402
e73c23ff	403	return ret;
579e8f3c	404	}
3f14d792	405	EXPORT_SYMBOL(blkdev_issue_zeroout);