/* * 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 void blkdev_discard_end_io(struct bio *bio, int err) { if (err) { if (err == -EOPNOTSUPP) set_bit(BIO_EOPNOTSUPP, &bio->bi_flags); clear_bit(BIO_UPTODATE, &bio->bi_flags); } if (bio->bi_private) complete(bio->bi_private); 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 *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 (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; } while (nr_sects && !ret) { bio = bio_alloc(gfp_mask, 1); if (!bio) { ret = -ENOMEM; break; } bio->bi_sector = sector; bio->bi_end_io = blkdev_discard_end_io; bio->bi_bdev = bdev; bio->bi_private = &wait; 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; } bio_get(bio); submit_bio(type, bio); wait_for_completion(&wait); if (bio_flagged(bio, BIO_EOPNOTSUPP)) ret = -EOPNOTSUPP; else if (!bio_flagged(bio, BIO_UPTODATE)) ret = -EIO; bio_put(bio); } return ret; } EXPORT_SYMBOL(blkdev_issue_discard); struct bio_batch { atomic_t done; unsigned long flags; struct completion *wait; bio_end_io_t *end_io; }; static void bio_batch_end_io(struct bio *bio, int err) { struct bio_batch *bb = bio->bi_private; if (err) { if (err == -EOPNOTSUPP) set_bit(BIO_EOPNOTSUPP, &bb->flags); else clear_bit(BIO_UPTODATE, &bb->flags); } if (bb) { if (bb->end_io) bb->end_io(bio, err); atomic_inc(&bb->done); complete(bb->wait); } bio_put(bio); } /** * 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. * Send barrier at the beginning and at the end if requested. This guarantie * correct request ordering. Empty barrier allow us to avoid post queue flush. */ 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, issued = 0; DECLARE_COMPLETION_ONSTACK(wait); atomic_set(&bb.done, 0); bb.flags = 1 << BIO_UPTODATE; bb.wait = &wait; bb.end_io = NULL; submit: 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); if (sz == 0) /* bio has maximum size possible */ break; 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; issued++; submit_bio(WRITE, bio); } /* Wait for bios in-flight */ while (issued != atomic_read(&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; if (ret) goto out; if (test_bit(BIO_EOPNOTSUPP, &bb.flags)) { ret = -EOPNOTSUPP; goto out; } if (nr_sects != 0) goto submit; out: return ret; } EXPORT_SYMBOL(blkdev_issue_zeroout);