On Wed, May 31, 2017 at 03:52:36PM -0700, Bart Van Assche wrote:

Several block drivers need to initialize the driver-private data
after having called blk_get_request() and before .prep_rq_fn() is
called, e.g. when submitting a REQ_OP_SCSI_* request. Avoid that
that initialization code has to be repeated after every
blk_get_request() call by adding a new callback function to struct
request_queue.

Can we please still have a initialize_rq mq_op for the blk-mq path
to avoid using the operation vectors directly in the requeuest_queue
for blk-mq?