1 files changed, 47 insertions, 26 deletions

diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c
index ed93da2462ab..60a6835265fc 100644
--- a/block/bfq-iosched.c
+++ b/block/bfq-iosched.c
@@ -725,8 +725,12 @@ static void bfq_updated_next_req(struct bfq_data *bfqd,
 }
 
 static void
-bfq_bfqq_resume_state(struct bfq_queue *bfqq, struct bfq_io_cq *bic)
+bfq_bfqq_resume_state(struct bfq_queue *bfqq, struct bfq_data *bfqd,
+		      struct bfq_io_cq *bic, bool bfq_already_existing)
 {
+	unsigned int old_wr_coeff = bfqq->wr_coeff;
+	bool busy = bfq_already_existing && bfq_bfqq_busy(bfqq);
+
 	if (bic->saved_idle_window)
 		bfq_mark_bfqq_idle_window(bfqq);
 	else
@@ -754,6 +758,14 @@ bfq_bfqq_resume_state(struct bfq_queue *bfqq, struct bfq_io_cq *bic)
 
 	/* make sure weight will be updated, however we got here */
 	bfqq->entity.prio_changed = 1;
+
+	if (likely(!busy))
+		return;
+
+	if (old_wr_coeff == 1 && bfqq->wr_coeff > 1)
+		bfqd->wr_busy_queues++;
+	else if (old_wr_coeff > 1 && bfqq->wr_coeff == 1)
+		bfqd->wr_busy_queues--;
 }
 
 static int bfqq_process_refs(struct bfq_queue *bfqq)
@@ -3471,11 +3483,17 @@ static void bfq_update_wr_data(struct bfq_data *bfqd, struct bfq_queue *bfqq)
 			}
 		}
 	}
-	/* Update weight both if it must be raised and if it must be lowered */
+	/*
+	 * To improve latency (for this or other queues), immediately
+	 * update weight both if it must be raised and if it must be
+	 * lowered. Since, entity may be on some active tree here, and
+	 * might have a pending change of its ioprio class, invoke
+	 * next function with the last parameter unset (see the
+	 * comments on the function).
+	 */
 	if ((entity->weight > entity->orig_weight) != (bfqq->wr_coeff > 1))
-		__bfq_entity_update_weight_prio(
-			bfq_entity_service_tree(entity),
-			entity);
+		__bfq_entity_update_weight_prio(bfq_entity_service_tree(entity),
+						entity, false);
 }
 
 /*
@@ -4290,10 +4308,16 @@ static void bfq_put_rq_priv_body(struct bfq_queue *bfqq)
 	bfq_put_queue(bfqq);
 }
 
-static void bfq_put_rq_private(struct request_queue *q, struct request *rq)
+static void bfq_finish_request(struct request *rq)
 {
-	struct bfq_queue *bfqq = RQ_BFQQ(rq);
-	struct bfq_data *bfqd = bfqq->bfqd;
+	struct bfq_queue *bfqq;
+	struct bfq_data *bfqd;
+
+	if (!rq->elv.icq)
+		return;
+
+	bfqq = RQ_BFQQ(rq);
+	bfqd = bfqq->bfqd;
 
 	if (rq->rq_flags & RQF_STARTED)
 		bfqg_stats_update_completion(bfqq_group(bfqq),
@@ -4324,7 +4348,7 @@ static void bfq_put_rq_private(struct request_queue *q, struct request *rq)
 		 */
 
 		if (!RB_EMPTY_NODE(&rq->rb_node))
-			bfq_remove_request(q, rq);
+			bfq_remove_request(rq->q, rq);
 		bfq_put_rq_priv_body(bfqq);
 	}
 
@@ -4394,20 +4418,21 @@ static struct bfq_queue *bfq_get_bfqq_handle_split(struct bfq_data *bfqd,
 /*
  * Allocate bfq data structures associated with this request.
  */
-static int bfq_get_rq_private(struct request_queue *q, struct request *rq,
-			      struct bio *bio)
+static void bfq_prepare_request(struct request *rq, struct bio *bio)
 {
+	struct request_queue *q = rq->q;
 	struct bfq_data *bfqd = q->elevator->elevator_data;
-	struct bfq_io_cq *bic = icq_to_bic(rq->elv.icq);
+	struct bfq_io_cq *bic;
 	const int is_sync = rq_is_sync(rq);
 	struct bfq_queue *bfqq;
 	bool new_queue = false;
-	bool split = false;
+	bool bfqq_already_existing = false, split = false;
 
-	spin_lock_irq(&bfqd->lock);
+	if (!rq->elv.icq)
+		return;
+	bic = icq_to_bic(rq->elv.icq);
 
-	if (!bic)
-		goto queue_fail;
+	spin_lock_irq(&bfqd->lock);
 
 	bfq_check_ioprio_change(bic, bio);
 
@@ -4432,6 +4457,8 @@ static int bfq_get_rq_private(struct request_queue *q, struct request *rq,
 				bfqq = bfq_get_bfqq_handle_split(bfqd, bic, bio,
 								 true, is_sync,
 								 NULL);
+			else
+				bfqq_already_existing = true;
 		}
 	}
 
@@ -4457,7 +4484,8 @@ static int bfq_get_rq_private(struct request_queue *q, struct request *rq,
 			 * queue: restore the idle window and the
 			 * possible weight raising period.
 			 */
-			bfq_bfqq_resume_state(bfqq, bic);
+			bfq_bfqq_resume_state(bfqq, bfqd, bic,
+					      bfqq_already_existing);
 		}
 	}
 
@@ -4465,13 +4493,6 @@ static int bfq_get_rq_private(struct request_queue *q, struct request *rq,
 		bfq_handle_burst(bfqd, bfqq);
 
 	spin_unlock_irq(&bfqd->lock);
-
-	return 0;
-
-queue_fail:
-	spin_unlock_irq(&bfqd->lock);
-
-	return 1;
 }
 
 static void bfq_idle_slice_timer_body(struct bfq_queue *bfqq)
@@ -4950,8 +4971,8 @@ static struct elv_fs_entry bfq_attrs[] = {
 
 static struct elevator_type iosched_bfq_mq = {
 	.ops.mq = {
-		.get_rq_priv		= bfq_get_rq_private,
-		.put_rq_priv		= bfq_put_rq_private,
+		.prepare_request	= bfq_prepare_request,
+		.finish_request		= bfq_finish_request,
 		.exit_icq		= bfq_exit_icq,
 		.insert_requests	= bfq_insert_requests,
 		.dispatch_request	= bfq_dispatch_request,