block: Initialize bio priority earlier

Bio's IO priority needs to be initialized before we try to merge the bio
with other bios. Otherwise we could merge bios which would otherwise
receive different IO priorities leading to possible QoS issues.
Reviewed-by: NDamien Le Moal <damien.lemoal@opensource.wdc.com>
Tested-by: NDamien Le Moal <damien.lemoal@opensource.wdc.com>
Signed-off-by: NJan Kara <jack@suse.cz>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20220623074840.5960-8-jack@suse.czSigned-off-by: NJens Axboe <axboe@kernel.dk>

block/blk-mq.c

@@ -2814,6 +2814,8 @@ void blk_mq_submit_bio(struct bio *bio)
 	if (!bio_integrity_prep(bio))
 		return;
 
+	bio_set_ioprio(bio);
+
 	rq = blk_mq_get_cached_request(q, plug, &bio, nr_segs);
 	if (!rq) {
 		if (!bio)
@@ -2825,8 +2827,6 @@ void blk_mq_submit_bio(struct bio *bio)
 
 	trace_block_getrq(bio);
 
-	bio_set_ioprio(bio);
-
 	rq_qos_track(q, rq, bio);
 
 	blk_mq_bio_to_request(rq, bio, nr_segs);