[PATCH] block: Fix io statistics for cgroup in throttle path

[Jinke Han]

From: Jinke Han <hanjinke.666@xxxxxxxxxxxxx>

In the current code, io statistics are missing for cgroup when bio
was throttled by blk-throttle. Fix it by moving the unreaching code
to submit_bio_noacct_nocheck.

Fixes: 3f98c753717c ("block: don't check bio in blk_throtl_dispatch_work_fn")
Signed-off-by: Jinke Han <hanjinke.666@xxxxxxxxxxxxx>
---
 block/blk-core.c | 23 ++++++++++++-----------
 1 file changed, 12 insertions(+), 11 deletions(-)

diff --git a/block/blk-core.c b/block/blk-core.c
index 46d12b3344c9..82b5b2c53f1e 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -684,6 +684,18 @@ static void __submit_bio_noacct_mq(struct bio *bio)
 
 void submit_bio_noacct_nocheck(struct bio *bio)
 {
+	blk_cgroup_bio_start(bio);
+	blkcg_bio_issue_init(bio);
+
+	if (!bio_flagged(bio, BIO_TRACE_COMPLETION)) {
+		trace_block_bio_queue(bio);
+		/*
+		 * Now that enqueuing has been traced, we need to trace
+		 * completion as well.
+		 */
+		bio_set_flag(bio, BIO_TRACE_COMPLETION);
+	}
+
 	/*
 	 * We only want one ->submit_bio to be active at a time, else stack
 	 * usage with stacked devices could be a problem.  Use current->bio_list
@@ -792,17 +804,6 @@ void submit_bio_noacct(struct bio *bio)
 
 	if (blk_throtl_bio(bio))
 		return;
-
-	blk_cgroup_bio_start(bio);
-	blkcg_bio_issue_init(bio);
-
-	if (!bio_flagged(bio, BIO_TRACE_COMPLETION)) {
-		trace_block_bio_queue(bio);
-		/* Now that enqueuing has been traced, we need to trace
-		 * completion as well.
-		 */
-		bio_set_flag(bio, BIO_TRACE_COMPLETION);
-	}
 	submit_bio_noacct_nocheck(bio);
 	return;
 
-- 
2.20.1