This is to catch any unexpected negative value of inflight IO counter. Signed-off-by: Liu Bo <bo.liu@xxxxxxxxxxxxxxxxx> --- block/blk-iolatency.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/block/blk-iolatency.c b/block/blk-iolatency.c index fc714ef402a6..7200f3189a84 100644 --- a/block/blk-iolatency.c +++ b/block/blk-iolatency.c @@ -591,6 +591,7 @@ 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)) @@ -609,7 +610,8 @@ 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 (!enabled || iolat->min_lat_nsec == 0) goto next; iolatency_record_time(iolat, &bio->bi_issue, now, -- 2.20.1.2.gb21ebb6
