[dm-devel] [PATCH 1/2] block: add resubmit_bio_noacct()

[Ming Lei]

Add block layer API of resubmit_bio_noacct() for handling blk-throttle
iops limit correctly. Typical use case is that bio split, and it isn't
good to export blk_throtl_charge_bio_split() for drivers, so add new API
for serving such purpose.

Cc: lining <lining2020x at 163.com>
Cc: Tejun Heo <tj at kernel.org>
Cc: Chunguang Xu <brookxu at tencent.com>
Signed-off-by: Ming Lei <ming.lei at redhat.com>
---
 block/blk-core.c       | 12 ++++++++++++
 block/blk-merge.c      |  4 +---
 include/linux/blkdev.h |  1 +
 3 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/block/blk-core.c b/block/blk-core.c
index fd029c86d6ac..733fec7dc5d6 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -910,6 +910,18 @@ void submit_bio_noacct(struct bio *bio)
 }
 EXPORT_SYMBOL(submit_bio_noacct);
 
+/*
+ * Usually for submitting one bio which has been checked by
+ * submit_bio_checks already. The typical use case is for handling
+ * blk-throttle iops limit correctly.
+ */
+void resubmit_bio_noacct(struct bio *bio)
+{
+	submit_bio_noacct(bio);
+	blk_throtl_charge_bio_split(bio);
+}
+EXPORT_SYMBOL(resubmit_bio_noacct);
+
 /**
  * submit_bio - submit a bio to the block device layer for I/O
  * @bio: The &struct bio which describes the I/O
diff --git a/block/blk-merge.c b/block/blk-merge.c
index 4de34a332c9f..acc786d872e6 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -366,10 +366,8 @@ void __blk_queue_split(struct request_queue *q, struct bio **bio,
 
 		bio_chain(split, *bio);
 		trace_block_split(split, (*bio)->bi_iter.bi_sector);
-		submit_bio_noacct(*bio);
+		resubmit_bio_noacct(*bio);
 		*bio = split;
-
-		blk_throtl_charge_bio_split(*bio);
 	}
 }
 
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 22746b2d6825..cce2db9fae1f 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -600,6 +600,7 @@ static inline unsigned int blk_queue_depth(struct request_queue *q)
 extern int blk_register_queue(struct gendisk *disk);
 extern void blk_unregister_queue(struct gendisk *disk);
 void submit_bio_noacct(struct bio *bio);
+void resubmit_bio_noacct(struct bio *bio);
 
 extern int blk_lld_busy(struct request_queue *q);
 extern void blk_queue_split(struct bio **);
-- 
2.31.1