Commit 3e49c1e4 authored by Bart Van Assche's avatar Bart Van Assche Committed by Jens Axboe
Browse files

block: BFQ: Add several invariant checks 



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@suse.cz>
Cc: Yu Kuai <yukuai3@huawei.com>
Signed-off-by: default avatarBart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20230516223853.1385255-1-bvanassche@acm.org


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent a036e698

block/bfq-iosched.c

+9 −0
Original line number Diff line number Diff line
@@ -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 */