DM reuses the request queue when swapping in a new device table
Introduce blk_set_default_limits() which can be used to reset the the
queue_limits prior to stacking devices.
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>
Acked-by: NAlasdair G Kergon <agk@redhat.com>
Acked-by: NMike Snitzer <snitzer@redhat.com>
Signed-off-by: NJens Axboe <jens.axboe@oracle.com>