If anything goes wrong with the counters that track the number of
requests, I/O locks up. Make such scenarios easier to debug by adding
invariant checks for the request counters. Additionally, check that
BFQ queues are empty before these are freed.
Cc: Jan Kara <jack@xxxxxxx>
Cc: Yu Kuai <yukuai3@xxxxxxxxxx>
Signed-off-by: Bart Van Assche <bvanassche@xxxxxxx>
---
block/bfq-iosched.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c
index 3164e3177965..c5727afad159 100644
--- a/block/bfq-iosched.c
+++ b/block/bfq-iosched.c
@@ -5403,6 +5403,9 @@ void bfq_put_queue(struct bfq_queue *bfqq)
if (bfqq->bfqd->last_completed_rq_bfqq == bfqq)
bfqq->bfqd->last_completed_rq_bfqq = NULL;
+ WARN_ON_ONCE(!list_empty(&bfqq->fifo));
+ WARN_ON_ONCE(!RB_EMPTY_ROOT(&bfqq->sort_list));
+
kmem_cache_free(bfq_pool, bfqq);
bfqg_and_blkg_put(bfqg);
}
@@ -7135,6 +7138,7 @@ static void bfq_exit_queue(struct elevator_queue *e)
{
struct bfq_data *bfqd = e->elevator_data;
struct bfq_queue *bfqq, *n;
+ unsigned int actuator;
hrtimer_cancel(&bfqd->idle_slice_timer);
@@ -7143,6 +7147,11 @@ static void bfq_exit_queue(struct elevator_queue *e)
bfq_deactivate_bfqq(bfqd, bfqq, false, false);
spin_unlock_irq(&bfqd->lock);
+ for (actuator = 0; actuator < bfqd->num_actuators; actuator++)
+ WARN_ON_ONCE(bfqd->rq_in_driver[actuator]);
+ WARN_ON_ONCE(bfqd->tot_rq_in_driver);
+ WARN_ON_ONCE(bfqq->dispatched);
+
hrtimer_cancel(&bfqd->idle_slice_timer);
/* release oom-queue reference to root group */
