diff options
Diffstat (limited to 'block/blk-lib.c')
| -rw-r--r-- | block/blk-lib.c | 178 |
1 files changed, 178 insertions, 0 deletions
diff --git a/block/blk-lib.c b/block/blk-lib.c new file mode 100644 index 00000000..2b461b49 --- /dev/null +++ b/block/blk-lib.c @@ -0,0 +1,178 @@ +/* + * 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" + +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; + struct bio_batch bb; + struct bio *bio; + int ret = 0; + + if (!q) + return -ENXIO; + + if (!blk_queue_discard(q)) + return -EOPNOTSUPP; + + /* + * Ensure that max_discard_sectors is of the proper + * granularity + */ + max_discard_sectors = min(q->limits.max_discard_sectors, UINT_MAX >> 9); + if (unlikely(!max_discard_sectors)) { + /* Avoid infinite loop below. Being cautious never hurts. */ + return -EOPNOTSUPP; + } else if (q->limits.discard_granularity) { + unsigned int disc_sects = q->limits.discard_granularity >> 9; + + max_discard_sectors &= ~(disc_sects - 1); + } + + 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; + + while (nr_sects) { + bio = bio_alloc(gfp_mask, 1); + if (!bio) { + ret = -ENOMEM; + break; + } + + bio->bi_sector = sector; + bio->bi_end_io = bio_batch_end_io; + bio->bi_bdev = bdev; + bio->bi_private = &bb; + + if (nr_sects > max_discard_sectors) { + bio->bi_size = max_discard_sectors << 9; + nr_sects -= max_discard_sectors; + sector += max_discard_sectors; + } else { + bio->bi_size = nr_sects << 9; + nr_sects = 0; + } + + atomic_inc(&bb.done); + submit_bio(type, bio); + } + + /* Wait for bios in-flight */ + if (!atomic_dec_and_test(&bb.done)) + wait_for_completion(&wait); + + if (!test_bit(BIO_UPTODATE, &bb.flags)) + ret = -EIO; + + return ret; +} +EXPORT_SYMBOL(blkdev_issue_discard); + +/** + * 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. + */ + +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_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(&wait); + + if (!test_bit(BIO_UPTODATE, &bb.flags)) + /* One of bios in the batch was completed with error.*/ + ret = -EIO; + + return ret; +} +EXPORT_SYMBOL(blkdev_issue_zeroout); |