| /* |
| * 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; |
| sector_t max_discard_sectors; |
| sector_t granularity, 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; |
| alignment = sector_div(alignment, 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); |
| sector_div(max_discard_sectors, granularity); |
| 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_sector = sector; |
| bio->bi_end_io = bio_batch_end_io; |
| bio->bi_bdev = bdev; |
| bio->bi_private = &bb; |
| |
| bio->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_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_size = max_write_same_sectors << 9; |
| nr_sects -= max_write_same_sectors; |
| sector += max_write_same_sectors; |
| } else { |
| bio->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. |
| */ |
| |
| 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_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) |
| * |
| * 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) |
| { |
| if (bdev_write_same(bdev)) { |
| unsigned char bdn[BDEVNAME_SIZE]; |
| |
| if (!blkdev_issue_write_same(bdev, sector, nr_sects, gfp_mask, |
| ZERO_PAGE(0))) |
| return 0; |
| |
| bdevname(bdev, bdn); |
| pr_err("%s: WRITE SAME failed. Manually zeroing.\n", bdn); |
| } |
| |
| return __blkdev_issue_zeroout(bdev, sector, nr_sects, gfp_mask); |
| } |
| EXPORT_SYMBOL(blkdev_issue_zeroout); |