blk-mq: remove the bio argument to ->prepare_request

None of the I/O schedulers actually needs it.

Signed-off-by: Christoph Hellwig <[e-mail]>
Reviewed-by: Ming Lei <[e-mail]>
Reviewed-by: Hannes Reinecke <[e-mail]>
Reviewed-by: Johannes Thumshirn <[e-mail]>
Reviewed-by: Bart Van Assche <[e-mail]>
Reviewed-by: Daniel Wagner <[e-mail]>
Signed-off-by: Jens Axboe <[e-mail]>

block/bfq-iosched.c

···
  * comments on bfq_init_rq for the reason behind this delayed
  * preparation.
  */
-static void bfq_prepare_request(struct request *rq, struct bio *bio)
+static void bfq_prepare_request(struct request *rq)
 {
 	/*
 	 * Regardless of whether we have an icq attached, we have to

block/blk-mq.c

···
 			if (e->type->icq_cache)
 				blk_mq_sched_assign_ioc(rq);
 
-			e->type->ops.prepare_request(rq, bio);
+			e->type->ops.prepare_request(rq);
 			rq->rq_flags |= RQF_ELVPRIV;
 		}
 	}

block/kyber-iosched.c

···
 	return merged;
 }
 
-static void kyber_prepare_request(struct request *rq, struct bio *bio)
+static void kyber_prepare_request(struct request *rq)
 {
 	rq_set_domain_token(rq, -1);
 }

block/mq-deadline.c

···
  * Nothing to do here. This is defined only to ensure that .finish_request
  * method is called upon request completion.
  */
-static void dd_prepare_request(struct request *rq, struct bio *bio)
+static void dd_prepare_request(struct request *rq)
 {
 }
 

include/linux/elevator.h

···
 	void (*request_merged)(struct request_queue *, struct request *, enum elv_merge);
 	void (*requests_merged)(struct request_queue *, struct request *, struct request *);
 	void (*limit_depth)(unsigned int, struct blk_mq_alloc_data *);
-	void (*prepare_request)(struct request *, struct bio *bio);
+	void (*prepare_request)(struct request *);
 	void (*finish_request)(struct request *);
 	void (*insert_requests)(struct blk_mq_hw_ctx *, struct list_head *, bool);
 	struct request *(*dispatch_request)(struct blk_mq_hw_ctx *);