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>

diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index 764e740..6906981 100644 (file)
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -1299,6 +1299,7 @@ int blkcg_init_queue(struct request_queue *q)
        ret = blk_iolatency_init(q);
        if (ret) {
                blk_throtl_exit(q);
+               blk_ioprio_exit(q);
                goto err_destroy_all;
        }
 

diff --git a/block/blk-ioprio.c b/block/blk-ioprio.c
index 3f60558..c00060a 100644 (file)
--- 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)

diff --git a/block/blk-ioprio.h b/block/blk-ioprio.h
index a7785c2..5a1eb55 100644 (file)
--- a/block/blk-ioprio.h
+++ b/block/blk-ioprio.h
@@ -6,14 +6,23 @@
 #include <linux/kconfig.h>
 
 struct request_queue;
+struct bio;
 
 #ifdef CONFIG_BLK_CGROUP_IOPRIO
 int blk_ioprio_init(struct request_queue *q);
+void blk_ioprio_exit(struct request_queue *q);
+void blkcg_set_ioprio(struct bio *bio);
 #else
 static inline int blk_ioprio_init(struct request_queue *q)
 {
        return 0;
 }
+static inline void blk_ioprio_exit(struct request_queue *q)
+{
+}
+static inline void blkcg_set_ioprio(struct bio *bio)
+{
+}
 #endif
 
 #endif /* _BLK_IOPRIO_H_ */

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 62b7025..4c4944b 100644 (file)
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -42,6 +42,7 @@
 #include "blk-stat.h"
 #include "blk-mq-sched.h"
 #include "blk-rq-qos.h"
+#include "blk-ioprio.h"
 
 static DEFINE_PER_CPU(struct llist_head, blk_cpu_done);
 
@@ -2779,6 +2780,11 @@ static inline struct request *blk_mq_get_cached_request(struct request_queue *q,
        return rq;
 }
 
+static void bio_set_ioprio(struct bio *bio)
+{
+       blkcg_set_ioprio(bio);
+}
+
 /**
  * blk_mq_submit_bio - Create and send a request to block device.
  * @bio: Bio pointer.
@@ -2819,6 +2825,8 @@ 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);