On 6/20/25 8:47 PM, Ming Lei wrote:
> On Fri, Jun 20, 2025 at 08:09:01PM +0530, Nilay Shroff wrote:
>>
>>
>> On 6/17/25 8:37 PM, Ming Lei wrote:
>>> On Mon, Jun 16, 2025 at 11:02:25PM +0530, Nilay Shroff wrote:
>>>> In preparation for allocating sched_tags before freezing the request
>>>> queue and acquiring ->elevator_lock, move the elevator queue allocation
>>>> logic from the elevator ops ->init_sched callback into blk_mq_init_sched.
>>>>
>>>> This refactoring provides a centralized location for elevator queue
>>>> initialization, which makes it easier to store pre-allocated sched_tags
>>>> in the struct elevator_queue during later changes.
>>>>
>>>> Signed-off-by: Nilay Shroff <nilay@xxxxxxxxxxxxx>
>>>> ---
>>
>> [...]
>>
>>>> diff --git a/block/blk-mq-sched.c b/block/blk-mq-sched.c
>>>> index 55a0fd105147..d914eb9d61a6 100644
>>>> --- a/block/blk-mq-sched.c
>>>> +++ b/block/blk-mq-sched.c
>>>> @@ -475,6 +475,10 @@ int blk_mq_init_sched(struct request_queue *q, struct elevator_type *e)
>>>> q->nr_requests = 2 * min_t(unsigned int, q->tag_set->queue_depth,
>>>> BLKDEV_DEFAULT_RQ);
>>>>
>>>> + eq = elevator_alloc(q, e);
>>>> + if (!eq)
>>>> + return -ENOMEM;
>>>> +
>>>> if (blk_mq_is_shared_tags(flags)) {
>>>> ret = blk_mq_init_sched_shared_tags(q);
>>>> if (ret)
>>>
>>> The above failure needs to be handled by kobject_put(&eq->kobj).
>>
>> I think here the elevator_alloc() failure occurs before we initialize
>> eq->kobj. So we don't need to handle it with kobject_put(&eq->kobj)
>> and instead simply returning -ENOMEM should be sufficient. Agree?
>
> I meant the failure from blk_mq_init_sched_shared_tags(), which has to
> call kobject_put() for correct cleanup.
>
Oh I see... yes we need to call kobject_put() here.
Will do it in the next series.
Thanks,
--Nilay
