block: Introduce request_queue.initialize_rq_fn()
Several block drivers need to initialize the driver-private request
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 new callback functions to struct
request_queue and to struct blk_mq_ops.
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.com>
Cc: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index 3077714..366b83c 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -144,6 +144,8 @@ struct blk_mq_ops {
init_request_fn *init_request;
exit_request_fn *exit_request;
reinit_request_fn *reinit_request;
+ /* Called from inside blk_get_request() */
+ void (*initialize_rq_fn)(struct request *rq);
map_queues_fn *map_queues;