On 3/7/23 4:49 AM, Shinichiro Kawasaki wrote:
> On Mar 07, 2023 / 18:28, Yu Kuai wrote:
>> Hi, Jan
>>
>> 在 2023/03/07 18:20, Jan Kara 写道:
>
> [...]
>
>>> So rather doing something like:
>>>
>>> bfqq_data->stable_merge_bfqq = NULL;
>>> new_bfqq = bfq_setup_stable_merge(bfqd, bfqq,
>>> stable_merge_bfqq, bfqq_data);
>>> bfq_put_stable_ref(stable_merge_bfqq);
>>> return new_bfqq;
>>>
>>> should work in bfq_setup_cooperator().
>>
>> Yes, this will work.
>
> Based on the description above, I quickly created the dirty patch below, and
> confirmed it avoids the BUG. Looks good. Jan, Yu, thanks for the quick actions.
> Let me wait for the formal patch.
>
> diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c
> index 8a8d4441519c..50eb435efed0 100644
> --- a/block/bfq-iosched.c
> +++ b/block/bfq-iosched.c
> @@ -2932,15 +2932,15 @@ bfq_setup_cooperator(struct bfq_data *bfqd, struct bfq_queue *bfqq,
> msecs_to_jiffies(bfq_late_stable_merging))) {
> struct bfq_queue *stable_merge_bfqq =
> bfqq_data->stable_merge_bfqq;
> + static struct bfq_queue *new_bfqq;
>
> /* deschedule stable merge, because done or aborted here */
> - bfq_put_stable_ref(stable_merge_bfqq);
> -
> bfqq_data->stable_merge_bfqq = NULL;
> -
> - return bfq_setup_stable_merge(bfqd, bfqq,
> - stable_merge_bfqq,
> - bfqq_data);
> + new_bfqq = bfq_setup_stable_merge(bfqd, bfqq,
> + stable_merge_bfqq,
> + bfqq_data);
> + bfq_put_stable_ref(stable_merge_bfqq);
> + return new_bfqq;
> }
> }
Can you or Jan post this as a real patch so we can get it queued
up?
--
Jens Axboe
