From 57f0f512b273f60d52568b8c6b77e17f5636edc0 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Andr=C3=A9=20Fabian=20Silva=20Delgado?= Date: Wed, 5 Aug 2015 17:04:01 -0300 Subject: Initial import --- block/blk-lib.c | 317 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 317 insertions(+) create mode 100644 block/blk-lib.c (limited to 'block/blk-lib.c') diff --git a/block/blk-lib.c b/block/blk-lib.c new file mode 100644 index 000000000..7688ee3f5 --- /dev/null +++ b/block/blk-lib.c @@ -0,0 +1,317 @@ +/* + * Functions related to generic helpers functions + */ +#include +#include +#include +#include +#include + +#include "blk.h" + +struct bio_batch { + atomic_t done; + unsigned long flags; + struct completion *wait; +}; + +static void bio_batch_end_io(struct bio *bio, int err) +{ + struct bio_batch *bb = bio->bi_private; + + if (err && (err != -EOPNOTSUPP)) + clear_bit(BIO_UPTODATE, &bb->flags); + if (atomic_dec_and_test(&bb->done)) + complete(bb->wait); + bio_put(bio); +} + +/** + * 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_IFL_* 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) +{ + DECLARE_COMPLETION_ONSTACK(wait); + struct request_queue *q = bdev_get_queue(bdev); + int type = REQ_WRITE | REQ_DISCARD; + unsigned int max_discard_sectors, granularity; + int alignment; + struct bio_batch bb; + struct bio *bio; + int ret = 0; + struct blk_plug plug; + + if (!q) + return -ENXIO; + + if (!blk_queue_discard(q)) + return -EOPNOTSUPP; + + /* 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; + + /* + * Ensure that max_discard_sectors is of the proper + * granularity, so that requests stay aligned after a split. + */ + max_discard_sectors = min(q->limits.max_discard_sectors, UINT_MAX >> 9); + max_discard_sectors -= max_discard_sectors % granularity; + if (unlikely(!max_discard_sectors)) { + /* Avoid infinite loop below. Being cautious never hurts. */ + return -EOPNOTSUPP; + } + + if (flags & BLKDEV_DISCARD_SECURE) { + if (!blk_queue_secdiscard(q)) + return -EOPNOTSUPP; + type |= REQ_SECURE; + } + + atomic_set(&bb.done, 1); + bb.flags = 1 << BIO_UPTODATE; + bb.wait = &wait; + + blk_start_plug(&plug); + while (nr_sects) { + unsigned int req_sects; + sector_t end_sect, tmp; + + bio = bio_alloc(gfp_mask, 1); + if (!bio) { + ret = -ENOMEM; + break; + } + + req_sects = min_t(sector_t, nr_sects, max_discard_sectors); + + /* + * 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->bi_iter.bi_sector = sector; + bio->bi_end_io = bio_batch_end_io; + bio->bi_bdev = bdev; + bio->bi_private = &bb; + + bio->bi_iter.bi_size = req_sects << 9; + nr_sects -= req_sects; + sector = end_sect; + + atomic_inc(&bb.done); + submit_bio(type, bio); + + /* + * 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(); + } + blk_finish_plug(&plug); + + /* Wait for bios in-flight */ + if (!atomic_dec_and_test(&bb.done)) + wait_for_completion_io(&wait); + + if (!test_bit(BIO_UPTODATE, &bb.flags)) + ret = -EIO; + + return ret; +} +EXPORT_SYMBOL(blkdev_issue_discard); + +/** + * 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 to write + * + * 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) +{ + DECLARE_COMPLETION_ONSTACK(wait); + struct request_queue *q = bdev_get_queue(bdev); + unsigned int max_write_same_sectors; + struct bio_batch bb; + struct bio *bio; + int ret = 0; + + if (!q) + return -ENXIO; + + max_write_same_sectors = q->limits.max_write_same_sectors; + + if (max_write_same_sectors == 0) + return -EOPNOTSUPP; + + atomic_set(&bb.done, 1); + bb.flags = 1 << BIO_UPTODATE; + bb.wait = &wait; + + while (nr_sects) { + bio = bio_alloc(gfp_mask, 1); + if (!bio) { + ret = -ENOMEM; + break; + } + + bio->bi_iter.bi_sector = sector; + bio->bi_end_io = bio_batch_end_io; + bio->bi_bdev = bdev; + bio->bi_private = &bb; + 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); + + 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; + } + + atomic_inc(&bb.done); + submit_bio(REQ_WRITE | REQ_WRITE_SAME, bio); + } + + /* Wait for bios in-flight */ + if (!atomic_dec_and_test(&bb.done)) + wait_for_completion_io(&wait); + + if (!test_bit(BIO_UPTODATE, &bb.flags)) + ret = -ENOTSUPP; + + return ret; +} +EXPORT_SYMBOL(blkdev_issue_write_same); + +/** + * 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) + * + * Description: + * Generate and issue number of bios with zerofiled pages. + */ + +static int __blkdev_issue_zeroout(struct block_device *bdev, sector_t sector, + sector_t nr_sects, gfp_t gfp_mask) +{ + int ret; + struct bio *bio; + struct bio_batch bb; + unsigned int sz; + DECLARE_COMPLETION_ONSTACK(wait); + + atomic_set(&bb.done, 1); + bb.flags = 1 << BIO_UPTODATE; + bb.wait = &wait; + + ret = 0; + while (nr_sects != 0) { + bio = bio_alloc(gfp_mask, + min(nr_sects, (sector_t)BIO_MAX_PAGES)); + if (!bio) { + ret = -ENOMEM; + break; + } + + bio->bi_iter.bi_sector = sector; + bio->bi_bdev = bdev; + bio->bi_end_io = bio_batch_end_io; + bio->bi_private = &bb; + + while (nr_sects != 0) { + sz = min((sector_t) PAGE_SIZE >> 9 , nr_sects); + ret = bio_add_page(bio, ZERO_PAGE(0), sz << 9, 0); + nr_sects -= ret >> 9; + sector += ret >> 9; + if (ret < (sz << 9)) + break; + } + ret = 0; + atomic_inc(&bb.done); + submit_bio(WRITE, bio); + } + + /* Wait for bios in-flight */ + if (!atomic_dec_and_test(&bb.done)) + wait_for_completion_io(&wait); + + if (!test_bit(BIO_UPTODATE, &bb.flags)) + /* One of bios in the batch was completed with error.*/ + ret = -EIO; + + return ret; +} + +/** + * 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) + * @discard: whether to discard the block range + * + * Description: + * Zero-fill a block range. If the discard flag is set and the block + * device guarantees that subsequent READ operations to the block range + * in question will return zeroes, the blocks will be discarded. Should + * the discard request fail, if the discard flag is not set, or if + * discard_zeroes_data is not supported, this function will resort to + * zeroing the blocks manually, thus provisioning (allocating, + * anchoring) them. If the block device supports the WRITE SAME command + * blkdev_issue_zeroout() will use it to optimize the process of + * clearing the block range. Otherwise the zeroing will be performed + * using regular WRITE calls. + */ + +int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector, + sector_t nr_sects, gfp_t gfp_mask, bool discard) +{ + struct request_queue *q = bdev_get_queue(bdev); + + if (discard && blk_queue_discard(q) && q->limits.discard_zeroes_data && + blkdev_issue_discard(bdev, sector, nr_sects, gfp_mask, 0) == 0) + return 0; + + if (bdev_write_same(bdev) && + blkdev_issue_write_same(bdev, sector, nr_sects, gfp_mask, + ZERO_PAGE(0)) == 0) + return 0; + + return __blkdev_issue_zeroout(bdev, sector, nr_sects, gfp_mask); +} +EXPORT_SYMBOL(blkdev_issue_zeroout); -- cgit v1.2.3