diff options
Diffstat (limited to '')
| -rw-r--r-- | block/blk-lib.c | 408 |
1 files changed, 408 insertions, 0 deletions
diff --git a/block/blk-lib.c b/block/blk-lib.c new file mode 100644 index 000000000..0dbc9e2ab --- /dev/null +++ b/block/blk-lib.c @@ -0,0 +1,408 @@ +// 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 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; +} + +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) { + sector_t req_sects = min_t(sector_t, nr_sects, + bio_allowed_max_sectors(q)); + + WARN_ON_ONCE((req_sects << 9) > UINT_MAX); + + bio = 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 = 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 = 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 = 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); |