Release 4.13 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 struct bio *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;
}

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Christoph Hellwig
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19
35.85%
1
25.00%
Lukas Czerner
4
7.55%
1
25.00%
Total
53
100.00%
4
100.00%



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 granularity;
	unsigned int op;
	int alignment;
	sector_t bs_mask;

	if (!q)
		return -ENXIO;

	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;

	/* Zero-sector (unknown) and one-sector granularities are the same.  */
	granularity = max(q->limits.discard_granularity >> 9, 1U);
	alignment = (bdev_discard_alignment(bdev) >> 9) % granularity;

	while (nr_sects) {
		unsigned int req_sects;
		sector_t end_sect, tmp;

		/* Make sure bi_size doesn't overflow */
		req_sects = min_t(sector_t, nr_sects, UINT_MAX >> 9);

		/**
                 * If splitting a request, and the next starting sector would be
                 * misaligned, stop the discard at the previous aligned sector.
                 */
		end_sect = sector + req_sects;
		tmp = end_sect;
		if (req_sects < nr_sects &&
		    sector_div(tmp, granularity) != alignment) {
			end_sect = end_sect - alignment;
			sector_div(end_sect, granularity);
			end_sect = end_sect * granularity + alignment;
			req_sects = end_sect - sector;
		}

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

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

		/*
                 * 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;
}
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Ming Lin
83
26.27%
1
6.25%
Christoph Hellwig
65
20.57%
5
31.25%
Darrick J. Wong
30
9.49%
1
6.25%
Paolo Bonzini
26
8.23%
1
6.25%
Jens Axboe
9
2.85%
2
12.50%
Michael Christie
6
1.90%
2
12.50%
Kent Overstreet
4
1.27%
1
6.25%
Shaohua Li
1
0.32%
1
6.25%
Lukas Czerner
1
0.32%
1
6.25%
Total
316
100.00%
16
100.00%


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;
}
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Christoph Hellwig
74
72.55%
3
42.86%
Mike Snitzer
13
12.75%
1
14.29%
Dmitriy Monakhov
8
7.84%
1
14.29%
Shaun Tancheff
5
4.90%
1
14.29%
Lukas Czerner
2
1.96%
1
14.29%
Total
102
100.00%
7
100.00%


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;

	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 = UINT_MAX >> 9;

	while (nr_sects) {
		bio = next_bio(bio, 1, gfp_mask);
		bio->bi_iter.bi_sector = sector;
		bio->bi_bdev = 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;
}

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Chaitanya Kulkarni
34
14.29%
1
12.50%
Darrick J. Wong
30
12.61%
1
12.50%
Michael Christie
9
3.78%
2
25.00%
Christoph Hellwig
7
2.94%
1
12.50%
Kent Overstreet
6
2.52%
1
12.50%
Ming Lin
4
1.68%
1
12.50%
Total
238
100.00%
8
100.00%

/**
 * 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;
}
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Chaitanya Kulkarni
71
76.34%
1
25.00%
Martin K. Petersen
8
8.60%
1
25.00%
Christoph Hellwig
7
7.53%
1
25.00%
Shaun Tancheff
7
7.53%
1
25.00%
Total
93
100.00%
4
100.00%


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;

	/* 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 = next_bio(bio, 0, gfp_mask);
		bio->bi_iter.bi_sector = sector;
		bio->bi_bdev = 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;
}

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Chaitanya Kulkarni
163
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Christoph Hellwig
18
9.94%
1
50.00%
Total
181
100.00%
2
100.00%

/*
 * 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 bytes = (nr_sects << 9) + PAGE_SIZE - 1;

	return min(bytes >> PAGE_SHIFT, (sector_t)BIO_MAX_PAGES);
}

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1
100.00%

/**
 * __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.
 *
 *  Note that this function may fail with -EOPNOTSUPP if the driver signals
 *  zeroing offload support, but the device fails to process the command (for
 *  some devices there is no non-destructive way to verify whether this
 *  operation is actually supported).  In this case the caller should call
 *  retry the call to blkdev_issue_zeroout() and the fallback path will be used.
 *
 *  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;
	int bi_size = 0;
	struct bio *bio = *biop;
	unsigned int sz;
	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))
		goto out;

	ret = 0;
	while (nr_sects != 0) {
		bio = next_bio(bio, __blkdev_sectors_to_bio_pages(nr_sects),
			       gfp_mask);
		bio->bi_iter.bi_sector = sector;
		bio->bi_bdev   = 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;
out:
	return ret;
}
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Dmitriy Monakhov
105
45.65%
1
6.25%
Chaitanya Kulkarni
55
23.91%
2
12.50%
Darrick J. Wong
30
13.04%
1
6.25%
Christoph Hellwig
17
7.39%
5
31.25%
Michael Christie
9
3.91%
2
12.50%
Shaun Tancheff
5
2.17%
1
6.25%
Damien Le Moal
3
1.30%
1
6.25%
Jens Axboe
3
1.30%
1
6.25%
Kent Overstreet
2
0.87%
1
6.25%
Martin K. Petersen
1
0.43%
1
6.25%
Total
230
100.00%
16
100.00%


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;
	struct bio *bio = NULL;
	struct blk_plug plug;

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

	return ret;
}
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Chaitanya Kulkarni
49
53.85%
1
20.00%
Martin K. Petersen
39
42.86%
3
60.00%
Christoph Hellwig
3
3.30%
1
20.00%
Total
91
100.00%
5
100.00%


EXPORT_SYMBOL(blkdev_issue_zeroout);
Overall Contributors
Person
Tokens
Prop
Commits
CommitProp
Chaitanya Kulkarni
379
27.27%
2
5.71%
Dmitriy Monakhov
252
18.13%
2
5.71%
Christoph Hellwig
228
16.40%
10
28.57%
Martin K. Petersen
201
14.46%
4
11.43%
Darrick J. Wong
90
6.47%
1
2.86%
Ming Lin
87
6.26%
2
5.71%
Damien Le Moal
40
2.88%
1
2.86%
Paolo Bonzini
26
1.87%
1
2.86%
Michael Christie
24
1.73%
3
8.57%
Shaun Tancheff
17
1.22%
1
2.86%
Mike Snitzer
13
0.94%
1
2.86%
Kent Overstreet
12
0.86%
1
2.86%
Jens Axboe
12
0.86%
3
8.57%
Lukas Czerner
7
0.50%
1
2.86%
Shaohua Li
1
0.07%
1
2.86%
Eric Biggers
1
0.07%
1
2.86%
Total
1390
100.00%
35
100.00%
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