dm: split discard requests on target boundaries
Update __clone_and_map_discard to loop across all targets in a DM device's table when it processes a discard bio. If a discard crosses a target boundary it must be split accordingly. Update __issue_target_requests and __issue_target_request to allow a cloned discard bio to have a custom start sector and size. Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
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@ -1193,7 +1193,7 @@ static struct dm_target_io *alloc_tio(struct clone_info *ci,
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}
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static void __issue_target_request(struct clone_info *ci, struct dm_target *ti,
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unsigned request_nr)
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unsigned request_nr, sector_t len)
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{
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struct dm_target_io *tio = alloc_tio(ci, ti);
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struct bio *clone;
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@ -1208,17 +1208,21 @@ static void __issue_target_request(struct clone_info *ci, struct dm_target *ti,
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clone = bio_alloc_bioset(GFP_NOIO, ci->bio->bi_max_vecs, ci->md->bs);
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__bio_clone(clone, ci->bio);
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clone->bi_destructor = dm_bio_destructor;
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if (len) {
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clone->bi_sector = ci->sector;
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clone->bi_size = to_bytes(len);
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}
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__map_bio(ti, clone, tio);
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}
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static void __issue_target_requests(struct clone_info *ci, struct dm_target *ti,
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unsigned num_requests)
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unsigned num_requests, sector_t len)
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{
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unsigned request_nr;
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for (request_nr = 0; request_nr < num_requests; request_nr++)
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__issue_target_request(ci, ti, request_nr);
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__issue_target_request(ci, ti, request_nr, len);
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}
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static int __clone_and_map_empty_barrier(struct clone_info *ci)
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@ -1227,7 +1231,7 @@ static int __clone_and_map_empty_barrier(struct clone_info *ci)
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struct dm_target *ti;
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while ((ti = dm_table_get_target(ci->map, target_nr++)))
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__issue_target_requests(ci, ti, ti->num_flush_requests);
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__issue_target_requests(ci, ti, ti->num_flush_requests, 0);
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ci->sector_count = 0;
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@ -1253,32 +1257,27 @@ static void __clone_and_map_simple(struct clone_info *ci, struct dm_target *ti)
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static int __clone_and_map_discard(struct clone_info *ci)
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{
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struct dm_target *ti;
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sector_t max;
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sector_t len;
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ti = dm_table_find_target(ci->map, ci->sector);
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if (!dm_target_is_valid(ti))
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return -EIO;
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do {
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ti = dm_table_find_target(ci->map, ci->sector);
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if (!dm_target_is_valid(ti))
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return -EIO;
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/*
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* Even though the device advertised discard support,
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* reconfiguration might have changed that since the
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* check was performed.
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*/
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if (!ti->num_discard_requests)
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return -EOPNOTSUPP;
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max = max_io_len(ci->sector, ti);
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if (ci->sector_count > max)
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/*
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* FIXME: Handle a discard that spans two or more targets.
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* Even though the device advertised discard support,
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* reconfiguration might have changed that since the
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* check was performed.
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*/
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return -EOPNOTSUPP;
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if (!ti->num_discard_requests)
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return -EOPNOTSUPP;
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__issue_target_requests(ci, ti, ti->num_discard_requests);
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len = min(ci->sector_count, max_io_len_target_boundary(ci->sector, ti));
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ci->sector_count = 0;
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__issue_target_requests(ci, ti, ti->num_discard_requests, len);
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ci->sector += len;
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} while (ci->sector_count -= len);
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return 0;
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}
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