[PATCH v4 2/5] blk-iocost: don't allow to configure bio based device

[Yu Kuai]

From: Yu Kuai <yukuai3@xxxxxxxxxx>

iocost is based on rq_qos, which can only work for request based device,
thus it doesn't make sense to configure iocost for bio based device.

Signed-off-by: Yu Kuai <yukuai3@xxxxxxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
Acked-by: Tejun Heo <tj@xxxxxxxxxx>
---
 block/blk-iocost.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/block/blk-iocost.c b/block/blk-iocost.c
index f1166582fb64..d6256731cae4 100644
--- a/block/blk-iocost.c
+++ b/block/blk-iocost.c
@@ -3185,6 +3185,11 @@ static ssize_t ioc_qos_write(struct kernfs_open_file *of, char *input,
 		return PTR_ERR(bdev);
 
 	disk = bdev->bd_disk;
+	if (!queue_is_mq(disk->queue)) {
+		ret = -EOPNOTSUPP;
+		goto err;
+	}
+
 	ioc = q_to_ioc(disk->queue);
 	if (!ioc) {
 		ret = blk_iocost_init(disk);
@@ -3365,6 +3370,11 @@ static ssize_t ioc_cost_model_write(struct kernfs_open_file *of, char *input,
 		return PTR_ERR(bdev);
 
 	q = bdev_get_queue(bdev);
+	if (!queue_is_mq(q)) {
+		ret = -EOPNOTSUPP;
+		goto err;
+	}
+
 	ioc = q_to_ioc(q);
 	if (!ioc) {
 		ret = blk_iocost_init(bdev->bd_disk);
-- 
2.31.1