/* * 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; int error; struct completion *wait; }; static void bio_batch_end_io(struct bio *bio) { struct bio_batch *bb = bio->bi_private; if (bio->bi_error && bio->bi_error != -EOPNOTSUPP) bb->error = bio->bi_error; 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 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; if (flags & BLKDEV_DISCARD_SECURE) { if (!blk_queue_secdiscard(q)) return -EOPNOTSUPP; type |= REQ_SECURE; } atomic_set(&bb.done, 1); bb.error = 0; 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; } /* Make sure bi_size doesn't overflow */ req_sects = min_t(sector_t, nr_sects, UINT_MAX >> 9); /* * 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 (bb.error) return bb.error; 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; /* Ensure that max_write_same_sectors doesn't overflow bi_size */ max_write_same_sectors = UINT_MAX >> 9; atomic_set(&bb.done, 1); bb.error = 0; 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 (bb.error) return bb.error; 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.error = 0; 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 (bb.error) return bb.error; 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);