From: Dennis Zhou <dennis@kernel.org>
Date: Thu, 23 May 2019 20:10:18 +0000 (-0400)
Subject: blk-iolatency: only account submitted bios
X-Git-Tag: v5.3-rc1~164^2~98
X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=a3fb01ba5af0;p=linux.git

blk-iolatency: only account submitted bios

As is, iolatency recognizes done_bio and cleanup as ending paths. If a
request is marked REQ_NOWAIT and fails to get a request, the bio is
cleaned up via rq_qos_cleanup() and ended in bio_wouldblock_error().
This results in underflowing the inflight counter. Fix this by only
accounting bios that were actually submitted.

Signed-off-by: Dennis Zhou <dennis@kernel.org>
Cc: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
---

diff --git a/block/blk-iolatency.c b/block/blk-iolatency.c
index 17896bb3aaf2..e8859350ab6e 100644
--- a/block/blk-iolatency.c
+++ b/block/blk-iolatency.c
@@ -600,6 +600,10 @@ static void blkcg_iolatency_done_bio(struct rq_qos *rqos, struct bio *bio)
 	if (!blkg || !bio_flagged(bio, BIO_TRACKED))
 		return;
 
+	/* We didn't actually submit this bio, don't account it. */
+	if (bio->bi_status == BLK_STS_AGAIN)
+		return;
+
 	iolat = blkg_to_lat(bio->bi_blkg);
 	if (!iolat)
 		return;