diff options
| author | Mike Snitzer <snitzer@redhat.com> | 2012-12-21 21:23:37 +0100 |
|---|---|---|
| committer | Alasdair G Kergon <agk@redhat.com> | 2012-12-21 21:23:37 +0100 |
| commit | 23508a96cd2e857d57044a2ed7d305f2d9daf441 (patch) | |
| tree | 149ead46c45a0fdd159fb32a6bfb6439eae3d652 | |
| parent | dm: prepare to support WRITE SAME (diff) | |
| download | linux-23508a96cd2e857d57044a2ed7d305f2d9daf441.tar.xz linux-23508a96cd2e857d57044a2ed7d305f2d9daf441.zip | |
dm: add WRITE SAME support
WRITE SAME bios have a payload that contain a single page. When
cloning WRITE SAME bios DM has no need to modify the bi_io_vec
attributes (and doing so would be detrimental). DM need only alter the
start and end of the WRITE SAME bio accordingly.
Rather than duplicate __clone_and_map_discard, factor out a common
function that is also used by __clone_and_map_write_same.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
| -rw-r--r-- | drivers/md/dm.c | 44 |
1 files changed, 39 insertions, 5 deletions
diff --git a/drivers/md/dm.c b/drivers/md/dm.c index 77e6eff41cae..5401cdce0fc5 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -1174,7 +1174,28 @@ static void __clone_and_map_simple(struct clone_info *ci, struct dm_target *ti) ci->sector_count = 0; } -static int __clone_and_map_discard(struct clone_info *ci) +typedef unsigned (*get_num_requests_fn)(struct dm_target *ti); + +static unsigned get_num_discard_requests(struct dm_target *ti) +{ + return ti->num_discard_requests; +} + +static unsigned get_num_write_same_requests(struct dm_target *ti) +{ + return ti->num_write_same_requests; +} + +typedef bool (*is_split_required_fn)(struct dm_target *ti); + +static bool is_split_required_for_discard(struct dm_target *ti) +{ + return ti->split_discard_requests; +} + +static int __clone_and_map_changing_extent_only(struct clone_info *ci, + get_num_requests_fn get_num_requests, + is_split_required_fn is_split_required) { struct dm_target *ti; sector_t len; @@ -1185,15 +1206,15 @@ static int __clone_and_map_discard(struct clone_info *ci) return -EIO; /* - * Even though the device advertised discard support, - * that does not mean every target supports it, and + * Even though the device advertised support for this type of + * request, that does not mean every target supports it, and * reconfiguration might also have changed that since the * check was performed. */ - if (!ti->num_discard_requests) + if (!get_num_requests || !get_num_requests(ti)) return -EOPNOTSUPP; - if (!ti->split_discard_requests) + if (is_split_required && !is_split_required(ti)) len = min(ci->sector_count, max_io_len_target_boundary(ci->sector, ti)); else len = min(ci->sector_count, max_io_len(ci->sector, ti)); @@ -1206,6 +1227,17 @@ static int __clone_and_map_discard(struct clone_info *ci) return 0; } +static int __clone_and_map_discard(struct clone_info *ci) +{ + return __clone_and_map_changing_extent_only(ci, get_num_discard_requests, + is_split_required_for_discard); +} + +static int __clone_and_map_write_same(struct clone_info *ci) +{ + return __clone_and_map_changing_extent_only(ci, get_num_write_same_requests, NULL); +} + static int __clone_and_map(struct clone_info *ci) { struct bio *bio = ci->bio; @@ -1215,6 +1247,8 @@ static int __clone_and_map(struct clone_info *ci) if (unlikely(bio->bi_rw & REQ_DISCARD)) return __clone_and_map_discard(ci); + else if (unlikely(bio->bi_rw & REQ_WRITE_SAME)) + return __clone_and_map_write_same(ci); ti = dm_table_find_target(ci->map, ci->sector); if (!dm_target_is_valid(ti)) |