From: Liu Bo Date: Fri, 25 Jan 2019 00:12:48 +0000 (+0800) Subject: Blk-iolatency: warn on negative inflight IO counter X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=391f552af213985d3d324c60004475759a7030c5;p=linux.git Blk-iolatency: warn on negative inflight IO counter This is to catch any unexpected negative value of inflight IO counter. Signed-off-by: Liu Bo Signed-off-by: Jens Axboe --- diff --git a/block/blk-iolatency.c b/block/blk-iolatency.c index 1893686a9c1f3..2620baa1f6993 100644 --- a/block/blk-iolatency.c +++ b/block/blk-iolatency.c @@ -592,6 +592,7 @@ static void blkcg_iolatency_done_bio(struct rq_qos *rqos, struct bio *bio) u64 now = ktime_to_ns(ktime_get()); bool issue_as_root = bio_issue_as_root_blkg(bio); bool enabled = false; + int inflight = 0; blkg = bio->bi_blkg; if (!blkg || !bio_flagged(bio, BIO_TRACKED)) @@ -613,7 +614,8 @@ static void blkcg_iolatency_done_bio(struct rq_qos *rqos, struct bio *bio) } rqw = &iolat->rq_wait; - atomic_dec(&rqw->inflight); + inflight = atomic_dec_return(&rqw->inflight); + WARN_ON_ONCE(inflight < 0); if (iolat->min_lat_nsec == 0) goto next; iolatency_record_time(iolat, &bio->bi_issue, now,