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[PATCH] dm: bio split bvec fix
The code that handles bios that span table target boundaries by breaking them up into smaller bios will not split an individual struct bio_vec into more than two pieces. Sometimes more than that are required. This patch adds a loop to break the second piece up into as many pieces as are necessary. Cc: "Abhishek Gupta" <abhishekgupt@gmail.com> Cc: Dan Smith <danms@us.ibm.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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@ -533,30 +533,35 @@ static void __clone_and_map(struct clone_info *ci)
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} else {
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/*
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* Create two copy bios to deal with io that has
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* been split across a target.
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* Handle a bvec that must be split between two or more targets.
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*/
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struct bio_vec *bv = bio->bi_io_vec + ci->idx;
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sector_t remaining = to_sector(bv->bv_len);
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unsigned int offset = 0;
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clone = split_bvec(bio, ci->sector, ci->idx,
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bv->bv_offset, max);
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__map_bio(ti, clone, tio);
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do {
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if (offset) {
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ti = dm_table_find_target(ci->map, ci->sector);
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max = max_io_len(ci->md, ci->sector, ti);
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ci->sector += max;
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ci->sector_count -= max;
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ti = dm_table_find_target(ci->map, ci->sector);
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tio = alloc_tio(ci->md);
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tio->io = ci->io;
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tio->ti = ti;
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memset(&tio->info, 0, sizeof(tio->info));
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}
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len = to_sector(bv->bv_len) - max;
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clone = split_bvec(bio, ci->sector, ci->idx,
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bv->bv_offset + to_bytes(max), len);
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tio = alloc_tio(ci->md);
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tio->io = ci->io;
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tio->ti = ti;
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memset(&tio->info, 0, sizeof(tio->info));
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__map_bio(ti, clone, tio);
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len = min(remaining, max);
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clone = split_bvec(bio, ci->sector, ci->idx,
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bv->bv_offset + offset, len);
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__map_bio(ti, clone, tio);
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ci->sector += len;
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ci->sector_count -= len;
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offset += to_bytes(len);
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} while (remaining -= len);
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ci->sector += len;
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ci->sector_count -= len;
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ci->idx++;
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}
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}
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