[PATCH v9 1/5] block: Fix where bio IO priority gets set

[Mike Snitzer <snitzer@kernel.org>]

From: Hongyu Jin <hongyu.jin@unisoc.com>

Commit 82b74cac2849 ("blk-ioprio: Convert from rqos policy to direct
call") pushed setting bio I/O priority down into blk_mq_submit_bio()
-- which is too low within block core's submit_bio() because it
skips setting I/O priority for block drivers that implement
fops->submit_bio() (e.g. DM, MD, etc).

Fix this by moving bio_set_ioprio() up from blk-mq.c to blk-core.c and
call it from submit_bio().  This ensures all block drivers call
bio_set_ioprio() during initial bio submission.

Fixes: a78418e6a04c ("block: Always initialize bio IO priority on submit")
Co-developed-by: Yibin Ding <yibin.ding@unisoc.com>
Signed-off-by: Yibin Ding <yibin.ding@unisoc.com>
Signed-off-by: Hongyu Jin <hongyu.jin@unisoc.com>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Mikulas Patocka <mpatocka@redhat.com>
[snitzer: revised commit header]
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
---
 block/blk-core.c | 10 ++++++++++
 block/blk-mq.c   | 10 ----------
 2 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/block/blk-core.c b/block/blk-core.c
index 11342af420d0..de771093b526 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -49,6 +49,7 @@
 #include "blk-pm.h"
 #include "blk-cgroup.h"
 #include "blk-throttle.h"
+#include "blk-ioprio.h"
 
 struct dentry *blk_debugfs_root;
 
@@ -833,6 +834,14 @@ void submit_bio_noacct(struct bio *bio)
 }
 EXPORT_SYMBOL(submit_bio_noacct);
 
+static void bio_set_ioprio(struct bio *bio)
+{
+	/* Nobody set ioprio so far? Initialize it based on task's nice value */
+	if (IOPRIO_PRIO_CLASS(bio->bi_ioprio) == IOPRIO_CLASS_NONE)
+		bio->bi_ioprio = get_current_ioprio();
+	blkcg_set_ioprio(bio);
+}
+
 /**
  * submit_bio - submit a bio to the block device layer for I/O
  * @bio: The &struct bio which describes the I/O
@@ -855,6 +864,7 @@ void submit_bio(struct bio *bio)
 		count_vm_events(PGPGOUT, bio_sectors(bio));
 	}
 
+	bio_set_ioprio(bio);
 	submit_bio_noacct(bio);
 }
 EXPORT_SYMBOL(submit_bio);
diff --git a/block/blk-mq.c b/block/blk-mq.c
index aa87fcfda1ec..2dc01551e27c 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -40,7 +40,6 @@
 #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);
 static DEFINE_PER_CPU(call_single_data_t, blk_cpu_csd);
@@ -2944,14 +2943,6 @@ static bool blk_mq_use_cached_rq(struct request *rq, struct blk_plug *plug,
 	return true;
 }
 
-static void bio_set_ioprio(struct bio *bio)
-{
-	/* Nobody set ioprio so far? Initialize it based on task's nice value */
-	if (IOPRIO_PRIO_CLASS(bio->bi_ioprio) == IOPRIO_CLASS_NONE)
-		bio->bi_ioprio = get_current_ioprio();
-	blkcg_set_ioprio(bio);
-}
-
 /**
  * blk_mq_submit_bio - Create and send a request to block device.
  * @bio: Bio pointer.
@@ -2976,7 +2967,6 @@ void blk_mq_submit_bio(struct bio *bio)
 	blk_status_t ret;
 
 	bio = blk_queue_bounce(bio, q);
-	bio_set_ioprio(bio);
 
 	if (plug) {
 		rq = rq_list_peek(&plug->cached_rq);
-- 
2.40.0