[PATCH AUTOSEL 5.8 081/132] dm: change max_io_len() to use blk_max_size_offset()

Sasha Levin
2020-10-27T00:28:08Z

From: Mike Snitzer <snitzer@redhat.com>

[ Upstream commit 5091cdec56faeaefa79de4b6cb3c3c55e50d1ac3 ]

Using blk_max_size_offset() enables DM core's splitting to impose
ti->max_io_len (via q->limits.chunk_sectors) and also fallback to
respecting q->limits.max_sectors if chunk_sectors isn't set.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/md/dm.c | 20 ++++++++------------
1 file changed, 8 insertions(+), 12 deletions(-)

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 548ad06094e98..4cfd5c88113cb 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1051,22 +1051,18 @@ static sector_t max_io_len_target_boundary(sector_t sector, struct dm_target *ti
static sector_t max_io_len(sector_t sector, struct dm_target *ti)
{
sector_t len = max_io_len_target_boundary(sector, ti);
- sector_t offset, max_len;
+ sector_t max_len;

/*
* Does the target need to split even further?
+ * - q->limits.chunk_sectors reflects ti->max_io_len so
+ * blk_max_size_offset() provides required splitting.
+ * - blk_max_size_offset() also respects q->limits.max_sectors
*/
- if (ti->max_io_len) {
- offset = dm_target_offset(ti, sector);
- if (unlikely(ti->max_io_len & (ti->max_io_len - 1)))
- max_len = sector_div(offset, ti->max_io_len);
- else
- max_len = offset & (ti->max_io_len - 1);
- max_len = ti->max_io_len - max_len;
-
- if (len > max_len)
- len = max_len;
- }
+ max_len = blk_max_size_offset(dm_table_get_md(ti->table)->queue,
+ dm_target_offset(ti, sector));
+ if (len > max_len)
+ len = max_len;

return len;
}
--
2.25.1