blk-mq-sched: unify request prepare methods
This patch makes sure we always allocate requests in the core blk-mq
code and use a common prepare_request method to initialize them for
both mq I/O schedulers. For Kyber and additional limit_depth method
is added that is called before allocating the request.
Also because none of the intializations can really fail the new method
does not return an error - instead the bfq finish method is hardened
to deal with the no-IOC case.
Last but not least this removes the abuse of RQF_QUEUE by the blk-mq
scheduling code as RQF_ELFPRIV is all that is needed now.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/include/linux/elevator.h b/include/linux/elevator.h
index 4acea35..5bc8f86 100644
--- a/include/linux/elevator.h
+++ b/include/linux/elevator.h
@@ -104,7 +104,8 @@ struct elevator_mq_ops {
int (*request_merge)(struct request_queue *q, struct request **, struct bio *);
void (*request_merged)(struct request_queue *, struct request *, enum elv_merge);
void (*requests_merged)(struct request_queue *, struct request *, struct request *);
- struct request *(*get_request)(struct request_queue *, unsigned int, struct blk_mq_alloc_data *);
+ void (*limit_depth)(unsigned int, struct blk_mq_alloc_data *);
+ void (*prepare_request)(struct request *, struct bio *bio);
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 *);
@@ -114,7 +115,6 @@ struct elevator_mq_ops {
void (*requeue_request)(struct request *);
struct request *(*former_request)(struct request_queue *, struct request *);
struct request *(*next_request)(struct request_queue *, struct request *);
- int (*get_rq_priv)(struct request_queue *, struct request *, struct bio *);
void (*init_icq)(struct io_cq *);
void (*exit_icq)(struct io_cq *);
};