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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>
hifive-unleashed-5.1
Mike Snitzer 2010-08-12 04:14:24 +01:00 committed by Alasdair G Kergon
parent c96053b767
commit a79245b3e5
1 changed files with 23 additions and 24 deletions
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47
drivers/md/dm.c
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@ -1193,7 +1193,7 @@ static struct dm_target_io *alloc_tio(struct clone_info *ci,
}
static void __issue_target_request(struct clone_info *ci, struct dm_target *ti,
unsigned request_nr)
unsigned request_nr, sector_t len)
{
struct dm_target_io *tio = alloc_tio(ci, ti);
struct bio *clone;
@ -1208,17 +1208,21 @@ static void __issue_target_request(struct clone_info *ci, struct dm_target *ti,
clone = bio_alloc_bioset(GFP_NOIO, ci->bio->bi_max_vecs, ci->md->bs);
__bio_clone(clone, ci->bio);
clone->bi_destructor = dm_bio_destructor;
if (len) {
clone->bi_sector = ci->sector;
clone->bi_size = to_bytes(len);
}
__map_bio(ti, clone, tio);
}
static void __issue_target_requests(struct clone_info *ci, struct dm_target *ti,
unsigned num_requests)
unsigned num_requests, sector_t len)
{
unsigned request_nr;
for (request_nr = 0; request_nr < num_requests; request_nr++)
__issue_target_request(ci, ti, request_nr);
__issue_target_request(ci, ti, request_nr, len);
}
static int __clone_and_map_empty_barrier(struct clone_info *ci)
@ -1227,7 +1231,7 @@ static int __clone_and_map_empty_barrier(struct clone_info *ci)
struct dm_target *ti;
while ((ti = dm_table_get_target(ci->map, target_nr++)))
__issue_target_requests(ci, ti, ti->num_flush_requests);
__issue_target_requests(ci, ti, ti->num_flush_requests, 0);
ci->sector_count = 0;
@ -1253,32 +1257,27 @@ static void __clone_and_map_simple(struct clone_info *ci, struct dm_target *ti)
static int __clone_and_map_discard(struct clone_info *ci)
{
struct dm_target *ti;
sector_t max;
sector_t len;
ti = dm_table_find_target(ci->map, ci->sector);
if (!dm_target_is_valid(ti))
return -EIO;
do {
ti = dm_table_find_target(ci->map, ci->sector);
if (!dm_target_is_valid(ti))
return -EIO;
/*
* Even though the device advertised discard support,
* reconfiguration might have changed that since the
* check was performed.
*/
if (!ti->num_discard_requests)
return -EOPNOTSUPP;
max = max_io_len(ci->sector, ti);
if (ci->sector_count > max)
/*
* FIXME: Handle a discard that spans two or more targets.
* Even though the device advertised discard support,
* reconfiguration might have changed that since the
* check was performed.
*/
return -EOPNOTSUPP;
if (!ti->num_discard_requests)
return -EOPNOTSUPP;
__issue_target_requests(ci, ti, ti->num_discard_requests);
len = min(ci->sector_count, max_io_len_target_boundary(ci->sector, ti));
ci->sector_count = 0;
__issue_target_requests(ci, ti, ti->num_discard_requests, len);
ci->sector += len;
} while (ci->sector_count -= len);
return 0;
}