[PATCH v4 1/5] block: Fix bio IO priority setting

[Hongyu Jin]

From: Hongyu Jin <hongyu.jin@xxxxxxxxxx>

Move bio_set_ioprio() into submit_bio():
1. Only call bio_set_ioprio() once to set the priority of original bio,
   the bio that cloned and splited from original bio will auto inherit
   the priority of original bio in clone process.

2. The IO priority can be passed to module that implement
   struct gendisk::fops::submit_bio, help resolve some
   of the IO priority loss issues.

This patch depends on commit 82b74cac2849 ("blk-ioprio: Convert from
rqos policy to direct call")

Fixes: a78418e6a04c ("block: Always initialize bio IO priority on submit")

Co-developed-by: Yibin Ding <yibin.ding@xxxxxxxxxx>
Signed-off-by: Yibin Ding <yibin.ding@xxxxxxxxxx>
Signed-off-by: Hongyu Jin <hongyu.jin@xxxxxxxxxx>
---
 block/blk-core.c | 10 ++++++++++
 block/blk-mq.c   | 11 -----------
 2 files changed, 10 insertions(+), 11 deletions(-)

diff --git a/block/blk-core.c b/block/blk-core.c
index fdf25b8d6e78..68158c327aea 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;
 
@@ -809,6 +810,14 @@ 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
@@ -831,6 +840,7 @@ 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 e2d11183f62e..a6e2609df9c9 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);
@@ -2922,14 +2921,6 @@ static inline struct request *blk_mq_get_cached_request(struct request_queue *q,
 	return rq;
 }
 
-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.
@@ -2963,8 +2954,6 @@ 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)
-- 
2.34.1