// 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(BIO_MAX_SIZE, 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;} void __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);}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 = 0; 	blk_start_plug(&plug);	__blkdev_issue_discard(bdev, sector, nr_sects, gfp_mask, &bio);	if (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), BIO_MAX_SECTORS & ~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) {		ret = bio_submit_or_kill(bio, flags);		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){	struct folio *zero_folio = largest_zero_folio(); 	while (nr_sects) {		unsigned int nr_vecs = __blkdev_sectors_to_bio_pages(nr_sects);		struct bio *bio; 		if ((flags & BLKDEV_ZERO_KILLABLE) &&		    fatal_signal_pending(current))			break; 		bio = bio_alloc(bdev, nr_vecs, REQ_OP_WRITE, gfp_mask);		bio->bi_iter.bi_sector = sector; 		do {			unsigned int len; 			len = min_t(sector_t, folio_size(zero_folio),				    nr_sects << SECTOR_SHIFT);			if (!bio_add_folio(bio, zero_folio, len, 0))				break;			nr_sects -= len >> SECTOR_SHIFT;			sector += len >> 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) {		ret = bio_submit_or_kill(bio, flags);		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 > BIO_MAX_SECTORS)		max_sectors = BIO_MAX_SECTORS;	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);