[PATCH 5.15 688/913] block/bfq_wf2q: correct weight to ioprio

[Greg Kroah-Hartman]

From: Yahu Gao <gaoyahu19@xxxxxxxxx>

[ Upstream commit bcd2be763252f3a4d5fc4d6008d4d96c601ee74b ]

The return value is ioprio * BFQ_WEIGHT_CONVERSION_COEFF or 0.
What we want is ioprio or 0.
Correct this by changing the calculation.

Signed-off-by: Yahu Gao <gaoyahu19@xxxxxxxxx>
Acked-by: Paolo Valente <paolo.valente@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20220107065859.25689-1-gaoyahu19@xxxxxxxxx
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 block/bfq-wf2q.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/block/bfq-wf2q.c b/block/bfq-wf2q.c
index b74cc0da118e..709b901de3ca 100644
--- a/block/bfq-wf2q.c
+++ b/block/bfq-wf2q.c
@@ -519,7 +519,7 @@ unsigned short bfq_ioprio_to_weight(int ioprio)
 static unsigned short bfq_weight_to_ioprio(int weight)
 {
 	return max_t(int, 0,
-		     IOPRIO_NR_LEVELS * BFQ_WEIGHT_CONVERSION_COEFF - weight);
+		     IOPRIO_NR_LEVELS - weight / BFQ_WEIGHT_CONVERSION_COEFF);
 }
 
 static void bfq_get_entity(struct bfq_entity *entity)
-- 
2.34.1