[PATCH 5.10 031/306] block: bfq: fix bfq_set_next_ioprio_data()

[Greg Kroah-Hartman]

From: Damien Le Moal <damien.lemoal@xxxxxxx>

commit a680dd72ec336b81511e3bff48efac6dbfa563e7 upstream.

For a request that has a priority level equal to or larger than
IOPRIO_BE_NR, bfq_set_next_ioprio_data() prints a critical warning but
defaults to setting the request new_ioprio field to IOPRIO_BE_NR. This
is not consistent with the warning and the allowed values for priority
levels. Fix this by setting the request new_ioprio field to
IOPRIO_BE_NR - 1, the lowest priority level allowed.

Cc: <stable@xxxxxxxxxxxxxxx>
Fixes: aee69d78dec0 ("block, bfq: introduce the BFQ-v0 I/O scheduler as an extra scheduler")
Signed-off-by: Damien Le Moal <damien.lemoal@xxxxxxx>
Reviewed-by: Hannes Reinecke <hare@xxxxxxx>
Link: https://lore.kernel.org/r/20210811033702.368488-2-damien.lemoal@xxxxxxx
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 block/bfq-iosched.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/block/bfq-iosched.c
+++ b/block/bfq-iosched.c
@@ -5011,7 +5011,7 @@ bfq_set_next_ioprio_data(struct bfq_queu
 	if (bfqq->new_ioprio >= IOPRIO_BE_NR) {
 		pr_crit("bfq_set_next_ioprio_data: new_ioprio %d\n",
 			bfqq->new_ioprio);
-		bfqq->new_ioprio = IOPRIO_BE_NR;
+		bfqq->new_ioprio = IOPRIO_BE_NR - 1;
 	}
 
 	bfqq->entity.new_weight = bfq_ioprio_to_weight(bfqq->new_ioprio);