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?
>
> Otherwise, feel free to add:
>
> Reviewed-by: Ming Lei <ming.lei@xxxxxxxxxx>
>
Thanks,
--Nilay
