blk-ioprio: Convert from rqos policy to direct call

Convert blk-ioprio handling from a rqos policy to a direct call from
blk_mq_submit_bio(). Firstly, blk-ioprio is not much of a rqos policy
anyway, it just needs a hook in bio submission path to set the bio's IO
priority. Secondly, the rqos .track hook gets actually called too late
for blk-ioprio purposes and introducing a special rqos hook just for
blk-ioprio looks even weirder.

Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Tested-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20220623074840.5960-7-jack@suse.cz
Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 5 insertions, 45 deletions

diff --git a/block/blk-ioprio.c b/block/blk-ioprio.c
index 3f605583598b..c00060a02c6e 100644
--- a/block/blk-ioprio.c
+++ b/block/blk-ioprio.c
@@ -181,17 +181,12 @@ static struct blkcg_policy ioprio_policy = {
 	.pd_free_fn	= ioprio_free_pd,
 };
 
-struct blk_ioprio {
-	struct rq_qos rqos;
-};
-
-static void blkcg_ioprio_track(struct rq_qos *rqos, struct request *rq,
-			       struct bio *bio)
+void blkcg_set_ioprio(struct bio *bio)
 {
 	struct ioprio_blkcg *blkcg = ioprio_blkcg_from_bio(bio);
 	u16 prio;
 
-	if (blkcg->prio_policy == POLICY_NO_CHANGE)
+	if (!blkcg || blkcg->prio_policy == POLICY_NO_CHANGE)
 		return;
 
 	/*
@@ -207,49 +202,14 @@ static void blkcg_ioprio_track(struct rq_qos *rqos, struct request *rq,
 		bio->bi_ioprio = prio;
 }
 
-static void blkcg_ioprio_exit(struct rq_qos *rqos)
+void blk_ioprio_exit(struct request_queue *q)
 {
-	struct blk_ioprio *blkioprio_blkg =
-		container_of(rqos, typeof(*blkioprio_blkg), rqos);
-
-	blkcg_deactivate_policy(rqos->q, &ioprio_policy);
-	kfree(blkioprio_blkg);
+	blkcg_deactivate_policy(q, &ioprio_policy);
 }
 
-static struct rq_qos_ops blkcg_ioprio_ops = {
-	.track	= blkcg_ioprio_track,
-	.exit	= blkcg_ioprio_exit,
-};
-
 int blk_ioprio_init(struct request_queue *q)
 {
-	struct blk_ioprio *blkioprio_blkg;
-	struct rq_qos *rqos;
-	int ret;
-
-	blkioprio_blkg = kzalloc(sizeof(*blkioprio_blkg), GFP_KERNEL);
-	if (!blkioprio_blkg)
-		return -ENOMEM;
-
-	ret = blkcg_activate_policy(q, &ioprio_policy);
-	if (ret) {
-		kfree(blkioprio_blkg);
-		return ret;
-	}
-
-	rqos = &blkioprio_blkg->rqos;
-	rqos->id = RQ_QOS_IOPRIO;
-	rqos->ops = &blkcg_ioprio_ops;
-	rqos->q = q;
-
-	/*
-	 * Registering the rq-qos policy after activating the blk-cgroup
-	 * policy guarantees that ioprio_blkcg_from_bio(bio) != NULL in the
-	 * rq-qos callbacks.
-	 */
-	rq_qos_add(q, rqos);
-
-	return 0;
+	return blkcg_activate_policy(q, &ioprio_policy);
 }
 
 static int __init ioprio_init(void)