1 files changed, 23 insertions, 10 deletions

diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c
index 727955918563..dd13c2bbc29c 100644
--- a/block/bfq-iosched.c
+++ b/block/bfq-iosched.c
@@ -2361,6 +2361,9 @@ static int bfq_request_merge(struct request_queue *q, struct request **req,
 	__rq = bfq_find_rq_fmerge(bfqd, bio, q);
 	if (__rq && elv_bio_merge_ok(__rq, bio)) {
 		*req = __rq;
+
+		if (blk_discard_mergable(__rq))
+			return ELEVATOR_DISCARD_MERGE;
 		return ELEVATOR_FRONT_MERGE;
 	}
 
@@ -2505,7 +2508,7 @@ void bfq_end_wr_async_queues(struct bfq_data *bfqd,
 	int i, j;
 
 	for (i = 0; i < 2; i++)
-		for (j = 0; j < IOPRIO_BE_NR; j++)
+		for (j = 0; j < IOPRIO_NR_LEVELS; j++)
 			if (bfqg->async_bfqq[i][j])
 				bfq_bfqq_end_wr(bfqg->async_bfqq[i][j]);
 	if (bfqg->async_idle_bfqq)
@@ -2659,6 +2662,15 @@ bfq_setup_merge(struct bfq_queue *bfqq, struct bfq_queue *new_bfqq)
 	 * are likely to increase the throughput.
 	 */
 	bfqq->new_bfqq = new_bfqq;
+	/*
+	 * The above assignment schedules the following redirections:
+	 * each time some I/O for bfqq arrives, the process that
+	 * generated that I/O is disassociated from bfqq and
+	 * associated with new_bfqq. Here we increases new_bfqq->ref
+	 * in advance, adding the number of processes that are
+	 * expected to be associated with new_bfqq as they happen to
+	 * issue I/O.
+	 */
 	new_bfqq->ref += process_refs;
 	return new_bfqq;
 }
@@ -2721,6 +2733,10 @@ bfq_setup_cooperator(struct bfq_data *bfqd, struct bfq_queue *bfqq,
 {
 	struct bfq_queue *in_service_bfqq, *new_bfqq;
 
+	/* if a merge has already been setup, then proceed with that first */
+	if (bfqq->new_bfqq)
+		return bfqq->new_bfqq;
+
 	/*
 	 * Check delayed stable merge for rotational or non-queueing
 	 * devs. For this branch to be executed, bfqq must not be
@@ -2822,9 +2838,6 @@ bfq_setup_cooperator(struct bfq_data *bfqd, struct bfq_queue *bfqq,
 	if (bfq_too_late_for_merging(bfqq))
 		return NULL;
 
-	if (bfqq->new_bfqq)
-		return bfqq->new_bfqq;
-
 	if (!io_struct || unlikely(bfqq == &bfqd->oom_bfqq))
 		return NULL;
 
@@ -5266,8 +5279,8 @@ bfq_set_next_ioprio_data(struct bfq_queue *bfqq, struct bfq_io_cq *bic)
 	switch (ioprio_class) {
 	default:
 		pr_err("bdi %s: bfq: bad prio class %d\n",
-				bdi_dev_name(bfqq->bfqd->queue->backing_dev_info),
-				ioprio_class);
+			bdi_dev_name(bfqq->bfqd->queue->disk->bdi),
+			ioprio_class);
 		fallthrough;
 	case IOPRIO_CLASS_NONE:
 		/*
@@ -5290,10 +5303,10 @@ bfq_set_next_ioprio_data(struct bfq_queue *bfqq, struct bfq_io_cq *bic)
 		break;
 	}
 
-	if (bfqq->new_ioprio >= IOPRIO_BE_NR) {
+	if (bfqq->new_ioprio >= IOPRIO_NR_LEVELS) {
 		pr_crit("bfq_set_next_ioprio_data: new_ioprio %d\n",
 			bfqq->new_ioprio);
-		bfqq->new_ioprio = IOPRIO_BE_NR;
+		bfqq->new_ioprio = IOPRIO_NR_LEVELS - 1;
 	}
 
 	bfqq->entity.new_weight = bfq_ioprio_to_weight(bfqq->new_ioprio);
@@ -5408,7 +5421,7 @@ static struct bfq_queue **bfq_async_queue_prio(struct bfq_data *bfqd,
 	case IOPRIO_CLASS_RT:
 		return &bfqg->async_bfqq[0][ioprio];
 	case IOPRIO_CLASS_NONE:
-		ioprio = IOPRIO_NORM;
+		ioprio = IOPRIO_BE_NORM;
 		fallthrough;
 	case IOPRIO_CLASS_BE:
 		return &bfqg->async_bfqq[1][ioprio];
@@ -6822,7 +6835,7 @@ void bfq_put_async_queues(struct bfq_data *bfqd, struct bfq_group *bfqg)
 	int i, j;
 
 	for (i = 0; i < 2; i++)
-		for (j = 0; j < IOPRIO_BE_NR; j++)
+		for (j = 0; j < IOPRIO_NR_LEVELS; j++)
 			__bfq_put_async_bfqq(bfqd, &bfqg->async_bfqq[i][j]);
 
 	__bfq_put_async_bfqq(bfqd, &bfqg->async_idle_bfqq);