| /* |
| * 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 granularity; |
| unsigned int op; |
| int alignment; |
| sector_t bs_mask; |
| |
| if (!q) |
| return -ENXIO; |
| |
| if (flags & BLKDEV_DISCARD_SECURE) { |
| if (flags & BLKDEV_DISCARD_ZERO) |
| return -EOPNOTSUPP; |
| if (!blk_queue_secure_erase(q)) |
| return -EOPNOTSUPP; |
| op = REQ_OP_SECURE_ERASE; |
| } else { |
| if (!blk_queue_discard(q)) |
| return -EOPNOTSUPP; |
| if ((flags & BLKDEV_DISCARD_ZERO) && |
| !q->limits.discard_zeroes_data) |
| return -EOPNOTSUPP; |
| op = REQ_OP_DISCARD; |
| } |
| |
| bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1; |
| if ((sector | nr_sects) & bs_mask) |
| return -EINVAL; |
| |
| /* 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; |
| |
| while (nr_sects) { |
| unsigned int req_sects; |
| sector_t end_sect, tmp; |
| |
| /* 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 = next_bio(bio, 1, gfp_mask); |
| bio->bi_iter.bi_sector = sector; |
| bio->bi_bdev = bdev; |
| bio_set_op_attrs(bio, op, 0); |
| |
| bio->bi_iter.bi_size = req_sects << 9; |
| nr_sects -= req_sects; |
| sector = end_sect; |
| |
| /* |
| * 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_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) |
| { |
| 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 && !(flags & BLKDEV_DISCARD_ZERO)) |
| ret = 0; |
| bio_put(bio); |
| } |
| blk_finish_plug(&plug); |
| |
| 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) |
| { |
| struct request_queue *q = bdev_get_queue(bdev); |
| unsigned int max_write_same_sectors; |
| struct bio *bio = NULL; |
| int ret = 0; |
| sector_t bs_mask; |
| |
| if (!q) |
| return -ENXIO; |
| |
| bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1; |
| if ((sector | nr_sects) & bs_mask) |
| return -EINVAL; |
| |
| /* Ensure that max_write_same_sectors doesn't overflow bi_size */ |
| max_write_same_sectors = UINT_MAX >> 9; |
| |
| while (nr_sects) { |
| bio = next_bio(bio, 1, gfp_mask); |
| bio->bi_iter.bi_sector = sector; |
| bio->bi_bdev = 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; |
| } |
| } |
| |
| if (bio) { |
| ret = submit_bio_wait(bio); |
| bio_put(bio); |
| } |
| 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 = NULL; |
| unsigned int sz; |
| sector_t bs_mask; |
| |
| bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1; |
| if ((sector | nr_sects) & bs_mask) |
| return -EINVAL; |
| |
| while (nr_sects != 0) { |
| bio = next_bio(bio, min(nr_sects, (sector_t)BIO_MAX_PAGES), |
| gfp_mask); |
| bio->bi_iter.bi_sector = sector; |
| bio->bi_bdev = bdev; |
| bio_set_op_attrs(bio, REQ_OP_WRITE, 0); |
| |
| 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; |
| } |
| } |
| |
| if (bio) { |
| ret = submit_bio_wait(bio); |
| bio_put(bio); |
| return ret; |
| } |
| return 0; |
| } |
| |
| /** |
| * 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) |
| { |
| if (discard) { |
| if (!blkdev_issue_discard(bdev, sector, nr_sects, gfp_mask, |
| BLKDEV_DISCARD_ZERO)) |
| 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); |