[linux.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"

static sector_t bio_discard_limit(struct block_device *bdev, sector_t sector)
{
	unsigned int discard_granularity = bdev_discard_granularity(bdev);
	sector_t granularity_aligned_sector;

	if (bdev_is_partition(bdev))
		sector += bdev->bd_start_sect;

	granularity_aligned_sector =
		round_up(sector, discard_granularity >> SECTOR_SHIFT);

	/*
	 * Make sure subsequent bios start aligned to the discard granularity if
	 * it needs to be split.
	 */
	if (granularity_aligned_sector != sector)
		return granularity_aligned_sector - sector;

	/*
	 * Align the bio size to the discard granularity to make splitting the bio
	 * at discard granularity boundaries easier in the driver if needed.
	 */
	return round_down(UINT_MAX, discard_granularity) >> SECTOR_SHIFT;
}

struct bio *blk_alloc_discard_bio(struct block_device *bdev,
		sector_t *sector, sector_t *nr_sects, gfp_t gfp_mask)
{
	sector_t bio_sects = min(*nr_sects, bio_discard_limit(bdev, *sector));
	struct bio *bio;

	if (!bio_sects)
		return NULL;

	bio = bio_alloc(bdev, 0, REQ_OP_DISCARD, gfp_mask);
	if (!bio)
		return NULL;
	bio->bi_iter.bi_sector = *sector;
	bio->bi_iter.bi_size = bio_sects << SECTOR_SHIFT;
	*sector += bio_sects;
	*nr_sects -= bio_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();
	return bio;
}

int __blkdev_issue_discard(struct block_device *bdev, sector_t sector,
		sector_t nr_sects, gfp_t gfp_mask, struct bio **biop)
{
	struct bio *bio;

	while ((bio = blk_alloc_discard_bio(bdev, &sector, &nr_sects,
			gfp_mask)))
		*biop = bio_chain_and_submit(*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)
 *
 * 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)
{
	struct bio *bio = NULL;
	struct blk_plug plug;
	int ret;

	blk_start_plug(&plug);
	ret = __blkdev_issue_discard(bdev, sector, nr_sects, gfp_mask, &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);

static sector_t bio_write_zeroes_limit(struct block_device *bdev)
{
	sector_t bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1;

	return min(bdev_write_zeroes_sectors(bdev),
		(UINT_MAX >> SECTOR_SHIFT) & ~bs_mask);
}

/*
 * There is no reliable way for the SCSI subsystem to determine whether a
 * device supports a WRITE SAME operation without actually performing a write
 * to media. As a result, write_zeroes is enabled by default and will be
 * disabled if a zeroing operation subsequently fails. This means that this
 * queue limit is likely to change at runtime.
 */
static void __blkdev_issue_write_zeroes(struct block_device *bdev,
		sector_t sector, sector_t nr_sects, gfp_t gfp_mask,
		struct bio **biop, unsigned flags, sector_t limit)
{

	while (nr_sects) {
		unsigned int len = min(nr_sects, limit);
		struct bio *bio;

		if ((flags & BLKDEV_ZERO_KILLABLE) &&
		    fatal_signal_pending(current))
			break;

		bio = bio_alloc(bdev, 0, REQ_OP_WRITE_ZEROES, gfp_mask);
		bio->bi_iter.bi_sector = sector;
		if (flags & BLKDEV_ZERO_NOUNMAP)
			bio->bi_opf |= REQ_NOUNMAP;

		bio->bi_iter.bi_size = len << SECTOR_SHIFT;
		*biop = bio_chain_and_submit(*biop, bio);

		nr_sects -= len;
		sector += len;
		cond_resched();
	}
}

static int blkdev_issue_write_zeroes(struct block_device *bdev, sector_t sector,
		sector_t nr_sects, gfp_t gfp, unsigned flags)
{
	sector_t limit = bio_write_zeroes_limit(bdev);
	struct bio *bio = NULL;
	struct blk_plug plug;
	int ret = 0;

	blk_start_plug(&plug);
	__blkdev_issue_write_zeroes(bdev, sector, nr_sects, gfp, &bio,
			flags, limit);
	if (bio) {
		if ((flags & BLKDEV_ZERO_KILLABLE) &&
		    fatal_signal_pending(current)) {
			bio_await_chain(bio);
			blk_finish_plug(&plug);
			return -EINTR;
		}
		ret = submit_bio_wait(bio);
		bio_put(bio);
	}
	blk_finish_plug(&plug);

	/*
	 * For some devices there is no non-destructive way to verify whether
	 * WRITE ZEROES is actually supported.  These will clear the capability
	 * on an I/O error, in which case we'll turn any error into
	 * "not supported" here.
	 */
	if (ret && !bdev_write_zeroes_sectors(bdev))
		return -EOPNOTSUPP;
	return ret;
}

/*
 * 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_VECS);
}

static void __blkdev_issue_zero_pages(struct block_device *bdev,
		sector_t sector, sector_t nr_sects, gfp_t gfp_mask,
		struct bio **biop, unsigned int flags)
{
	while (nr_sects) {
		unsigned int nr_vecs = __blkdev_sectors_to_bio_pages(nr_sects);
		struct bio *bio;

		bio = bio_alloc(bdev, nr_vecs, REQ_OP_WRITE, gfp_mask);
		bio->bi_iter.bi_sector = sector;

		if ((flags & BLKDEV_ZERO_KILLABLE) &&
		    fatal_signal_pending(current))
			break;

		do {
			unsigned int len, added;

			len = min_t(sector_t,
				PAGE_SIZE, nr_sects << SECTOR_SHIFT);
			added = bio_add_page(bio, ZERO_PAGE(0), len, 0);
			if (added < len)
				break;
			nr_sects -= added >> SECTOR_SHIFT;
			sector += added >> SECTOR_SHIFT;
		} while (nr_sects);

		*biop = bio_chain_and_submit(*biop, bio);
		cond_resched();
	}
}

static int blkdev_issue_zero_pages(struct block_device *bdev, sector_t sector,
		sector_t nr_sects, gfp_t gfp, unsigned flags)
{
	struct bio *bio = NULL;
	struct blk_plug plug;
	int ret = 0;

	if (flags & BLKDEV_ZERO_NOFALLBACK)
		return -EOPNOTSUPP;

	blk_start_plug(&plug);
	__blkdev_issue_zero_pages(bdev, sector, nr_sects, gfp, &bio, flags);
	if (bio) {
		if ((flags & BLKDEV_ZERO_KILLABLE) &&
		    fatal_signal_pending(current)) {
			bio_await_chain(bio);
			blk_finish_plug(&plug);
			return -EINTR;
		}
		ret = submit_bio_wait(bio);
		bio_put(bio);
	}
	blk_finish_plug(&plug);

	return ret;
}

/**
 * __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)
{
	sector_t limit = bio_write_zeroes_limit(bdev);

	if (bdev_read_only(bdev))
		return -EPERM;

	if (limit) {
		__blkdev_issue_write_zeroes(bdev, sector, nr_sects,
				gfp_mask, biop, flags, limit);
	} else {
		if (flags & BLKDEV_ZERO_NOFALLBACK)
			return -EOPNOTSUPP;
		__blkdev_issue_zero_pages(bdev, sector, nr_sects, gfp_mask,
				biop, flags);
	}
	return 0;
}
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;

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

	if (bdev_write_zeroes_sectors(bdev)) {
		ret = blkdev_issue_write_zeroes(bdev, sector, nr_sects,
				gfp_mask, flags);
		if (ret != -EOPNOTSUPP)
			return ret;
	}

	return blkdev_issue_zero_pages(bdev, sector, nr_sects, gfp_mask, flags);
}
EXPORT_SYMBOL(blkdev_issue_zeroout);

int blkdev_issue_secure_erase(struct block_device *bdev, sector_t sector,
		sector_t nr_sects, gfp_t gfp)
{
	sector_t bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1;
	unsigned int max_sectors = bdev_max_secure_erase_sectors(bdev);
	struct bio *bio = NULL;
	struct blk_plug plug;
	int ret = 0;

	/* make sure that "len << SECTOR_SHIFT" doesn't overflow */
	if (max_sectors > UINT_MAX >> SECTOR_SHIFT)
		max_sectors = UINT_MAX >> SECTOR_SHIFT;
	max_sectors &= ~bs_mask;

	if (max_sectors == 0)
		return -EOPNOTSUPP;
	if ((sector | nr_sects) & bs_mask)
		return -EINVAL;
	if (bdev_read_only(bdev))
		return -EPERM;

	blk_start_plug(&plug);
	while (nr_sects) {
		unsigned int len = min_t(sector_t, nr_sects, max_sectors);

		bio = blk_next_bio(bio, bdev, 0, REQ_OP_SECURE_ERASE, gfp);
		bio->bi_iter.bi_sector = sector;
		bio->bi_iter.bi_size = len << SECTOR_SHIFT;

		sector += len;
		nr_sects -= len;
		cond_resched();
	}
	if (bio) {
		ret = submit_bio_wait(bio);
		bio_put(bio);
	}
	blk_finish_plug(&plug);

	return ret;
}
EXPORT_SYMBOL(blkdev_issue_secure_erase);
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
e3cc28ea CH	13	static sector_t bio_discard_limit(struct block_device *bdev, sector_t sector)
e3cc28ea CH	14	{
7b47ef52	15	unsigned int discard_granularity = bdev_discard_granularity(bdev);
e3cc28ea CH	16	sector_t granularity_aligned_sector;
	17
	18	if (bdev_is_partition(bdev))
	19	sector += bdev->bd_start_sect;
	20
	21	granularity_aligned_sector =
	22	round_up(sector, discard_granularity >> SECTOR_SHIFT);
	23
	24	/*
	25	* Make sure subsequent bios start aligned to the discard granularity if
	26	* it needs to be split.
	27	*/
	28	if (granularity_aligned_sector != sector)
	29	return granularity_aligned_sector - sector;
	30
	31	/*
	32	* Align the bio size to the discard granularity to make splitting the bio
	33	* at discard granularity boundaries easier in the driver if needed.
	34	*/
	35	return round_down(UINT_MAX, discard_granularity) >> SECTOR_SHIFT;
	36	}
	37
e8b4869b CH	38	struct bio blk_alloc_discard_bio(struct block_device bdev,
e8b4869b CH	39	sector_t sector, sector_t nr_sects, gfp_t gfp_mask)
f31e7e40	40	{
e8b4869b CH	41	sector_t bio_sects = min(nr_sects, bio_discard_limit(bdev, sector));
e8b4869b CH	42	struct bio *bio;
a22c4d7e	43
e8b4869b CH	44	if (!bio_sects)
e8b4869b CH	45	return NULL;
4800bf7b	46
e8b4869b CH	47	bio = bio_alloc(bdev, 0, REQ_OP_DISCARD, gfp_mask);
	48	if (!bio)
	49	return NULL;
	50	bio->bi_iter.bi_sector = *sector;
	51	bio->bi_iter.bi_size = bio_sects << SECTOR_SHIFT;
	52	*sector += bio_sects;
	53	*nr_sects -= bio_sects;
	54	/*
	55	* We can loop for a long time in here if someone does full device
	56	* discards (like mkfs). Be nice and allow us to schedule out to avoid
	57	* softlocking if preempt is disabled.
	58	*/
	59	cond_resched();
	60	return bio;
	61	}
f31e7e40	62
e8b4869b CH	63	int __blkdev_issue_discard(struct block_device *bdev, sector_t sector,
	64	sector_t nr_sects, gfp_t gfp_mask, struct bio **biop)
	65	{
	66	struct bio *bio;
38f25255	67
e8b4869b CH	68	while ((bio = blk_alloc_discard_bio(bdev, &sector, &nr_sects,
	69	gfp_mask)))
	70	biop = bio_chain_and_submit(biop, bio);
38f25255 CH	71	return 0;
	72	}
	73	EXPORT_SYMBOL(__blkdev_issue_discard);
	74
	75	/**
	76	* blkdev_issue_discard - queue a discard
	77	* @bdev: blockdev to issue discard for
	78	* @sector: start sector
	79	* @nr_sects: number of sectors to discard
	80	* @gfp_mask: memory allocation flags (for bio_alloc)
38f25255 CH	81	*
	82	* Description:
	83	* Issue a discard request for the sectors in question.
	84	*/
	85	int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
44abff2c	86	sector_t nr_sects, gfp_t gfp_mask)
38f25255	87	{
38f25255 CH	88	struct bio *bio = NULL;
	89	struct blk_plug plug;
	90	int ret;
	91
38f25255	92	blk_start_plug(&plug);
44abff2c	93	ret = __blkdev_issue_discard(bdev, sector, nr_sects, gfp_mask, &bio);
bbd848e0	94	if (!ret && bio) {
4e49ea4a	95	ret = submit_bio_wait(bio);
48920ff2	96	if (ret == -EOPNOTSUPP)
bbd848e0	97	ret = 0;
05bd92dd	98	bio_put(bio);
bbd848e0	99	}
0cfbcafc	100	blk_finish_plug(&plug);
f31e7e40	101
bbd848e0	102	return ret;
f31e7e40 DM	103	}
f31e7e40 DM	104	EXPORT_SYMBOL(blkdev_issue_discard);
3f14d792	105
73a768d5 CH	106	static sector_t bio_write_zeroes_limit(struct block_device *bdev)
	107	{
	108	sector_t bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1;
	109
	110	return min(bdev_write_zeroes_sectors(bdev),
	111	(UINT_MAX >> SECTOR_SHIFT) & ~bs_mask);
	112	}
	113
64b582ca JG	114	/*
	115	* There is no reliable way for the SCSI subsystem to determine whether a
	116	* device supports a WRITE SAME operation without actually performing a write
	117	* to media. As a result, write_zeroes is enabled by default and will be
	118	* disabled if a zeroing operation subsequently fails. This means that this
	119	* queue limit is likely to change at runtime.
	120	*/
f6eacb26	121	static void __blkdev_issue_write_zeroes(struct block_device *bdev,
a6f0788e	122	sector_t sector, sector_t nr_sects, gfp_t gfp_mask,
64b582ca	123	struct bio **biop, unsigned flags, sector_t limit)
a6f0788e	124	{
64b582ca	125
a6f0788e	126	while (nr_sects) {
64b582ca	127	unsigned int len = min(nr_sects, limit);
bf86bcdb CH	128	struct bio *bio;
	129
	130	if ((flags & BLKDEV_ZERO_KILLABLE) &&
	131	fatal_signal_pending(current))
	132	break;
76a27e1b	133
bf86bcdb	134	bio = bio_alloc(bdev, 0, REQ_OP_WRITE_ZEROES, gfp_mask);
a6f0788e	135	bio->bi_iter.bi_sector = sector;
d928be9f CH	136	if (flags & BLKDEV_ZERO_NOUNMAP)
d928be9f CH	137	bio->bi_opf \|= REQ_NOUNMAP;
a6f0788e	138
76a27e1b	139	bio->bi_iter.bi_size = len << SECTOR_SHIFT;
bf86bcdb CH	140	biop = bio_chain_and_submit(biop, bio);
bf86bcdb CH	141
76a27e1b KB	142	nr_sects -= len;
76a27e1b KB	143	sector += len;
a6f0788e CK	144	cond_resched();
a6f0788e CK	145	}
a6f0788e CK	146	}
a6f0788e CK	147
99800ced CH	148	static int blkdev_issue_write_zeroes(struct block_device *bdev, sector_t sector,
	149	sector_t nr_sects, gfp_t gfp, unsigned flags)
	150	{
64b582ca	151	sector_t limit = bio_write_zeroes_limit(bdev);
99800ced CH	152	struct bio *bio = NULL;
	153	struct blk_plug plug;
	154	int ret = 0;
	155
	156	blk_start_plug(&plug);
64b582ca JG	157	__blkdev_issue_write_zeroes(bdev, sector, nr_sects, gfp, &bio,
64b582ca JG	158	flags, limit);
99800ced	159	if (bio) {
bf86bcdb CH	160	if ((flags & BLKDEV_ZERO_KILLABLE) &&
	161	fatal_signal_pending(current)) {
	162	bio_await_chain(bio);
	163	blk_finish_plug(&plug);
	164	return -EINTR;
	165	}
99800ced CH	166	ret = submit_bio_wait(bio);
	167	bio_put(bio);
	168	}
	169	blk_finish_plug(&plug);
	170
	171	/*
	172	* For some devices there is no non-destructive way to verify whether
	173	* WRITE ZEROES is actually supported. These will clear the capability
	174	* on an I/O error, in which case we'll turn any error into
	175	* "not supported" here.
	176	*/
e33a97a8	177	if (ret && !bdev_write_zeroes_sectors(bdev))
99800ced CH	178	return -EOPNOTSUPP;
	179	return ret;
	180	}
	181
615d22a5 DLM	182	/*
	183	* Convert a number of 512B sectors to a number of pages.
	184	* The result is limited to a number of pages that can fit into a BIO.
	185	* Also make sure that the result is always at least 1 (page) for the cases
	186	* where nr_sects is lower than the number of sectors in a page.
	187	*/
	188	static unsigned int __blkdev_sectors_to_bio_pages(sector_t nr_sects)
	189	{
09c2c359	190	sector_t pages = DIV_ROUND_UP_SECTOR_T(nr_sects, PAGE_SIZE / 512);
615d22a5	191
a8affc03	192	return min(pages, (sector_t)BIO_MAX_VECS);
615d22a5 DLM	193	}
615d22a5 DLM	194
f6eacb26	195	static void __blkdev_issue_zero_pages(struct block_device *bdev,
425a4dba	196	sector_t sector, sector_t nr_sects, gfp_t gfp_mask,
bf86bcdb	197	struct bio **biop, unsigned int flags)
425a4dba	198	{
bf86bcdb CH	199	while (nr_sects) {
	200	unsigned int nr_vecs = __blkdev_sectors_to_bio_pages(nr_sects);
	201	struct bio *bio;
425a4dba	202
bf86bcdb	203	bio = bio_alloc(bdev, nr_vecs, REQ_OP_WRITE, gfp_mask);
425a4dba	204	bio->bi_iter.bi_sector = sector;
425a4dba	205
bf86bcdb CH	206	if ((flags & BLKDEV_ZERO_KILLABLE) &&
	207	fatal_signal_pending(current))
	208	break;
	209
	210	do {
	211	unsigned int len, added;
	212
	213	len = min_t(sector_t,
	214	PAGE_SIZE, nr_sects << SECTOR_SHIFT);
	215	added = bio_add_page(bio, ZERO_PAGE(0), len, 0);
	216	if (added < len)
425a4dba	217	break;
bf86bcdb CH	218	nr_sects -= added >> SECTOR_SHIFT;
	219	sector += added >> SECTOR_SHIFT;
	220	} while (nr_sects);
	221
	222	biop = bio_chain_and_submit(biop, bio);
425a4dba ID	223	cond_resched();
425a4dba ID	224	}
425a4dba ID	225	}
425a4dba ID	226
99800ced CH	227	static int blkdev_issue_zero_pages(struct block_device *bdev, sector_t sector,
	228	sector_t nr_sects, gfp_t gfp, unsigned flags)
	229	{
	230	struct bio *bio = NULL;
	231	struct blk_plug plug;
	232	int ret = 0;
	233
	234	if (flags & BLKDEV_ZERO_NOFALLBACK)
	235	return -EOPNOTSUPP;
	236
	237	blk_start_plug(&plug);
bf86bcdb	238	__blkdev_issue_zero_pages(bdev, sector, nr_sects, gfp, &bio, flags);
99800ced	239	if (bio) {
bf86bcdb CH	240	if ((flags & BLKDEV_ZERO_KILLABLE) &&
	241	fatal_signal_pending(current)) {
	242	bio_await_chain(bio);
	243	blk_finish_plug(&plug);
	244	return -EINTR;
	245	}
99800ced CH	246	ret = submit_bio_wait(bio);
	247	bio_put(bio);
	248	}
	249	blk_finish_plug(&plug);
	250
	251	return ret;
	252	}
	253
3f14d792	254	/**
e73c23ff	255	* __blkdev_issue_zeroout - generate number of zero filed write bios
3f14d792 DM	256	* @bdev: blockdev to issue
	257	* @sector: start sector
	258	* @nr_sects: number of sectors to write
	259	* @gfp_mask: memory allocation flags (for bio_alloc)
e73c23ff	260	* @biop: pointer to anchor bio
ee472d83	261	* @flags: controls detailed behavior
3f14d792 DM	262	*
3f14d792 DM	263	* Description:
ee472d83 CH	264	* Zero-fill a block range, either using hardware offload or by explicitly
	265	* writing zeroes to the device.
	266	*
	267	* If a device is using logical block provisioning, the underlying space will
	268	* not be released if %flags contains BLKDEV_ZERO_NOUNMAP.
cb365b96 CH	269	*
	270	* If %flags contains BLKDEV_ZERO_NOFALLBACK, the function will return
	271	* -EOPNOTSUPP if no explicit hardware offload for zeroing is provided.
3f14d792	272	*/
e73c23ff CK	273	int __blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
e73c23ff CK	274	sector_t nr_sects, gfp_t gfp_mask, struct bio **biop,
ee472d83	275	unsigned flags)
3f14d792	276	{
64b582ca JG	277	sector_t limit = bio_write_zeroes_limit(bdev);
64b582ca JG	278
f6eacb26 CH	279	if (bdev_read_only(bdev))
f6eacb26 CH	280	return -EPERM;
3f14d792	281
64b582ca	282	if (limit) {
f6eacb26	283	__blkdev_issue_write_zeroes(bdev, sector, nr_sects,
64b582ca	284	gfp_mask, biop, flags, limit);
f6eacb26 CH	285	} else {
	286	if (flags & BLKDEV_ZERO_NOFALLBACK)
	287	return -EOPNOTSUPP;
	288	__blkdev_issue_zero_pages(bdev, sector, nr_sects, gfp_mask,
bf86bcdb	289	biop, flags);
f6eacb26 CH	290	}
f6eacb26 CH	291	return 0;
3f14d792	292	}
e73c23ff	293	EXPORT_SYMBOL(__blkdev_issue_zeroout);
579e8f3c MP	294
	295	/**
	296	* blkdev_issue_zeroout - zero-fill a block range
	297	* @bdev: blockdev to write
	298	* @sector: start sector
	299	* @nr_sects: number of sectors to write
	300	* @gfp_mask: memory allocation flags (for bio_alloc)
ee472d83	301	* @flags: controls detailed behavior
579e8f3c MP	302	*
579e8f3c MP	303	* Description:
ee472d83 CH	304	* Zero-fill a block range, either using hardware offload or by explicitly
	305	* writing zeroes to the device. See __blkdev_issue_zeroout() for the
	306	* valid values for %flags.
579e8f3c	307	*/
579e8f3c	308	int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
ee472d83	309	sector_t nr_sects, gfp_t gfp_mask, unsigned flags)
579e8f3c	310	{
99800ced	311	int ret;
d93ba7a5	312
99800ced	313	if ((sector \| nr_sects) & ((bdev_logical_block_size(bdev) >> 9) - 1))
d5ce4c31	314	return -EINVAL;
f6eacb26 CH	315	if (bdev_read_only(bdev))
f6eacb26 CH	316	return -EPERM;
d5ce4c31	317
99800ced CH	318	if (bdev_write_zeroes_sectors(bdev)) {
	319	ret = blkdev_issue_write_zeroes(bdev, sector, nr_sects,
	320	gfp_mask, flags);
39722a2f	321	if (ret != -EOPNOTSUPP)
99800ced	322	return ret;
d5ce4c31	323	}
579e8f3c	324
99800ced	325	return blkdev_issue_zero_pages(bdev, sector, nr_sects, gfp_mask, flags);
579e8f3c	326	}
3f14d792	327	EXPORT_SYMBOL(blkdev_issue_zeroout);
44abff2c CH	328
	329	int blkdev_issue_secure_erase(struct block_device *bdev, sector_t sector,
	330	sector_t nr_sects, gfp_t gfp)
	331	{
	332	sector_t bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1;
	333	unsigned int max_sectors = bdev_max_secure_erase_sectors(bdev);
	334	struct bio *bio = NULL;
	335	struct blk_plug plug;
	336	int ret = 0;
	337
c4fa3684 MP	338	/* make sure that "len << SECTOR_SHIFT" doesn't overflow */
	339	if (max_sectors > UINT_MAX >> SECTOR_SHIFT)
	340	max_sectors = UINT_MAX >> SECTOR_SHIFT;
	341	max_sectors &= ~bs_mask;
	342
44abff2c CH	343	if (max_sectors == 0)
	344	return -EOPNOTSUPP;
	345	if ((sector \| nr_sects) & bs_mask)
	346	return -EINVAL;
	347	if (bdev_read_only(bdev))
	348	return -EPERM;
	349
	350	blk_start_plug(&plug);
5affe497	351	while (nr_sects) {
44abff2c CH	352	unsigned int len = min_t(sector_t, nr_sects, max_sectors);
	353
	354	bio = blk_next_bio(bio, bdev, 0, REQ_OP_SECURE_ERASE, gfp);
	355	bio->bi_iter.bi_sector = sector;
c4fa3684	356	bio->bi_iter.bi_size = len << SECTOR_SHIFT;
44abff2c	357
c4fa3684 MP	358	sector += len;
c4fa3684 MP	359	nr_sects -= len;
44abff2c CH	360	cond_resched();
44abff2c CH	361	}
5affe497 KB	362	if (bio) {
	363	ret = submit_bio_wait(bio);
	364	bio_put(bio);
	365	}
44abff2c CH	366	blk_finish_plug(&plug);
	367
	368	return ret;
	369	}
	370	EXPORT_SYMBOL(blkdev_issue_secure_erase);