Re: [PATCH v3 0/2] blk-mq: fix update nr_requests regressions

[Jens Axboe <axboe@kernel.dk>]

On 9/5/25 1:20 AM, Yu Kuai wrote:
> Hi, Jens
> 
> ? 2025/08/26 14:27, Yu Kuai ??:
>> Hi, Jens
>>
>> ? 2025/08/21 14:06, Yu Kuai ??:
>>> From: Yu Kuai <yukuai3@huawei.com>
>>>
>>> Changes in v3:
>>>   - call depth_updated() directly in init_sched() method in patch 1;
>>>   - fix typos in patch 2;
>>>   - add review for patch 2;
>>> Changes in v2:
>>>   - instead of refactor and cleanups and fix updating nr_requests
>>>   thoroughly, fix the regression in patch 2 the easy way, and dealy
>>>   refactor and cleanups to next merge window.
>>>
>>> patch 1 fix regression that elevator async_depth is not updated correctly
>>> if nr_requests changes, first from error path and then for mq-deadline,
>>> and recently for bfq and kyber.
>>>
>>> patch 2 fix regression that if nr_requests grow, kernel will panic due
>>> to tags double free.
>>>
>>> Yu Kuai (2):
>>>    blk-mq: fix elevator depth_updated method
>>>    blk-mq: fix blk_mq_tags double free while nr_requests grown
>>>
>>>   block/bfq-iosched.c   | 22 +++++-----------------
>>>   block/blk-mq-sched.h  | 11 +++++++++++
>>>   block/blk-mq-tag.c    |  1 +
>>>   block/blk-mq.c        | 23 ++++++++++++-----------
>>>   block/elevator.h      |  2 +-
>>>   block/kyber-iosched.c | 19 +++++++++----------
>>>   block/mq-deadline.c   | 16 +++-------------
>>>   7 files changed, 42 insertions(+), 52 deletions(-)
>>>
>>
>> Friendly ping, please consider this set in this merge window.
>>
>> BTW, I see that for-6.18/block branch was created, however, I have
>> a pending set[1] for the next merge window that will have conflicts with
>> this set, not sure if you want to rebase for-6.18/block with block-6.17
>> or handle conflicts later for 6.18-rc1.

I think we're just a bit late on this one, given that they'd go into
-rc6 at this point. Going to queue this up for 6.18 and then we just get
it into stable instead, that gives us a lot more time to shake out any
potential issues.

-- 
Jens Axboe