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yaml --- r: 196822 b: refs/heads/master c: f31e7e4 h: refs/heads/master v: v3
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Dmitry Monakhov
authored and
Jens Axboe
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Apr 28, 2010
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -1,2 +1,2 @@ | ||
| --- | ||
| refs/heads/master: f17e232e9237c231daf9f0f4b177c61218bcb2e4 | ||
| refs/heads/master: f31e7e4022841c43c53b847b86b1bf97a08b2c94 |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,114 @@ | ||
| /* | ||
| * 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); | ||
| __free_page(bio_page(bio)); | ||
|
|
||
| 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 = flags & BLKDEV_IFL_BARRIER ? | ||
| DISCARD_BARRIER : DISCARD_NOBARRIER; | ||
| struct bio *bio; | ||
| struct page *page; | ||
| int ret = 0; | ||
|
|
||
| if (!q) | ||
| return -ENXIO; | ||
|
|
||
| if (!blk_queue_discard(q)) | ||
| return -EOPNOTSUPP; | ||
|
|
||
| while (nr_sects && !ret) { | ||
| unsigned int sector_size = q->limits.logical_block_size; | ||
| unsigned int max_discard_sectors = | ||
| min(q->limits.max_discard_sectors, UINT_MAX >> 9); | ||
|
|
||
| bio = bio_alloc(gfp_mask, 1); | ||
| if (!bio) | ||
| goto out; | ||
| bio->bi_sector = sector; | ||
| bio->bi_end_io = blkdev_discard_end_io; | ||
| bio->bi_bdev = bdev; | ||
| if (flags & BLKDEV_IFL_WAIT) | ||
| bio->bi_private = &wait; | ||
|
|
||
| /* | ||
| * Add a zeroed one-sector payload as that's what | ||
| * our current implementations need. If we'll ever need | ||
| * more the interface will need revisiting. | ||
| */ | ||
| page = alloc_page(gfp_mask | __GFP_ZERO); | ||
| if (!page) | ||
| goto out_free_bio; | ||
| if (bio_add_pc_page(q, bio, page, sector_size, 0) < sector_size) | ||
| goto out_free_page; | ||
|
|
||
| /* | ||
| * And override the bio size - the way discard works we | ||
| * touch many more blocks on disk than the actual payload | ||
| * length. | ||
| */ | ||
| 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); | ||
|
|
||
| if (flags & BLKDEV_IFL_WAIT) | ||
| 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; | ||
| out_free_page: | ||
| __free_page(page); | ||
| out_free_bio: | ||
| bio_put(bio); | ||
| out: | ||
| return -ENOMEM; | ||
| } | ||
| EXPORT_SYMBOL(blkdev_issue_discard); |