author: Tejun Heo <tj@kernel.org> 2021-01-05 12:37:23 -0500
committer: Jens Axboe <axboe@kernel.dk> 2021-01-05 11:33:32 -0700
commit: d16baa3f1453c14d680c5fee01cd122a22d0e0ce
parent: 19cd3403cb0d522dd5e10188eef85817de29e26e
Commit Summary:
Diffstat:
1 file changed, 11 insertions, 5 deletions
diff --git a/block/blk-iocost.c b/block/blk-iocost.c
index ac6078a34939..98d656bdb42b 100644
--- a/block/blk-iocost.c
+++ b/block/blk-iocost.c
@@ -2551,8 +2551,8 @@ static void ioc_rqos_throttle(struct rq_qos *rqos, struct bio *bio)
bool use_debt, ioc_locked;
unsigned long flags;
- /* bypass IOs if disabled or for root cgroup */
- if (!ioc->enabled || !iocg->level)
+ /* bypass IOs if disabled, still initializing, or for root cgroup */
+ if (!ioc->enabled || !iocg || !iocg->level)
return;
/* calculate the absolute vtime cost */
@@ -2679,14 +2679,14 @@ static void ioc_rqos_merge(struct rq_qos *rqos, struct request *rq,
struct bio *bio)
{
struct ioc_gq *iocg = blkg_to_iocg(bio->bi_blkg);
- struct ioc *ioc = iocg->ioc;
+ struct ioc *ioc = rqos_to_ioc(rqos);
sector_t bio_end = bio_end_sector(bio);
struct ioc_now now;
u64 vtime, abs_cost, cost;
unsigned long flags;
- /* bypass if disabled or for root cgroup */
- if (!ioc->enabled || !iocg->level)
+ /* bypass if disabled, still initializing, or for root cgroup */
+ if (!ioc->enabled || !iocg || !iocg->level)
return;
abs_cost = calc_vtime_cost(bio, iocg, true);
@@ -2863,6 +2863,12 @@ static int blk_iocost_init(struct request_queue *q)
ioc_refresh_params(ioc, true);
spin_unlock_irq(&ioc->lock);
+ /*
+ * rqos must be added before activation to allow iocg_pd_init() to
+ * lookup the ioc from q. This means that the rqos methods may get
+ * called before policy activation completion, can't assume that the
+ * target bio has an iocg associated and need to test for NULL iocg.
+ */
rq_qos_add(q, rqos);
ret = blkcg_activate_policy(q, &blkcg_policy_iocost);
if (ret) {