block/blk-lib.c - linux - Git at Google

 // 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 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_sectors;

 	if (bdev_read_only(bdev))
 		return -EPERM;

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

 	if (max_sectors == 0)
 		return -EOPNOTSUPP;

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

 		bio = blk_next_bio(bio, 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;
 		nr_sects -= len;
 		sector += len;
 		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_VECS);
 }

 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 bio *bio = *biop;
 	int bi_size = 0;
 	unsigned int sz;

 	if (bdev_read_only(bdev))
 		return -EPERM;

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

 		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);

 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);
	// 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 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_sectors;

	if (bdev_read_only(bdev))
	return -EPERM;

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

	if (max_sectors == 0)
	return -EOPNOTSUPP;

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

	bio = blk_next_bio(bio, 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;
	nr_sects -= len;
	sector += len;
	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_VECS);
	}

	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 bio bio = biop;
	int bi_size = 0;
	unsigned int sz;

	if (bdev_read_only(bdev))
	return -EPERM;

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

	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);

	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);