commit beb9caac211c1be1bc118bb62d5cf09c4107e6a5
author Mike Snitzer <snitzer@redhat.com> Wed Oct 10 12:01:55 2018 -0400
committer Mike Snitzer <snitzer@redhat.com> Wed Oct 10 12:11:09 2018 -0400
tree 96442a261a24e3795cb1d3deecd3bdc3943dbc5b
parent 9864cd5dc54cade89fd4b0954c2e522841aa247c

dm linear: eliminate linear_end_io call if CONFIG_DM_ZONED disabled

It is best to avoid any extra overhead associated with bio completion.
DM core will indirectly call a DM target's .end_io if it is defined.
In the case of DM linear, there is no need to do so (for every bio that
completes) if CONFIG_DM_ZONED is not enabled.

Avoiding an extra indirect call for every bio completion is very
important for ensuring DM linear doesn't incur more overhead that
further widens the performance gap between dm-linear and raw block
devices.

Fixes: 0be12c1c7fce7 ("dm linear: add support for zoned block devices")
Cc: stable@vger.kernel.org
Signed-off-by: Mike Snitzer <snitzer@redhat.com>