Re: [PATCH] blk-mq: take quiesce_lock when removing a queue from the tag set

[Mani Tofigh]

On 11/4/26 8:19 AM, Nilay Shroff wrote:
> Now that set->quiesce_lock serializes both traversal of set->tag_list
> in blk_mq_[un]quiesce_tagset() as well as modifications in
> blk_mq_[add|del]_queue_tag_set(), do we still need RCU protection for
> this list?


I don't think so.  The quiesce walks are the only users that don't
hold tag_list_lock and I didn't find any other reader of the list in
block or drivers.


I'd like to keep this fix minimal for stable though.  I'll drop the RCU
and add the __guarded_by() annotations as a separate cleanup.


Thanks!
Mani