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/block/kyber-iosched.c b/block/kyber-iosched.c
index 2557b39..a9f6fd3 100644
--- a/block/kyber-iosched.c
+++ b/block/kyber-iosched.c
@@ -426,24 +426,22 @@ static void rq_clear_domain_token(struct kyber_queue_data *kqd,
}
}
-static struct request *kyber_get_request(struct request_queue *q,
- unsigned int op,
- struct blk_mq_alloc_data *data)
+static void kyber_limit_depth(unsigned int op, struct blk_mq_alloc_data *data)
{
- struct kyber_queue_data *kqd = q->elevator->elevator_data;
- struct request *rq;
-
/*
* We use the scheduler tags as per-hardware queue queueing tokens.
* Async requests can be limited at this stage.
*/
- if (!op_is_sync(op))
- data->shallow_depth = kqd->async_depth;
+ if (!op_is_sync(op)) {
+ struct kyber_queue_data *kqd = data->q->elevator->elevator_data;
- rq = __blk_mq_alloc_request(data, op);
- if (rq)
- rq_set_domain_token(rq, -1);
- return rq;
+ data->shallow_depth = kqd->async_depth;
+ }
+}
+
+static void kyber_prepare_request(struct request *rq, struct bio *bio)
+{
+ rq_set_domain_token(rq, -1);
}
static void kyber_finish_request(struct request *rq)
@@ -813,7 +811,8 @@ static struct elevator_type kyber_sched = {
.exit_sched = kyber_exit_sched,
.init_hctx = kyber_init_hctx,
.exit_hctx = kyber_exit_hctx,
- .get_request = kyber_get_request,
+ .limit_depth = kyber_limit_depth,
+ .prepare_request = kyber_prepare_request,
.finish_request = kyber_finish_request,
.completed_request = kyber_completed_request,
.dispatch_request = kyber_dispatch_request,