[PATCH 2/3] block: Fix __blk_mq_update_nr_hw_queues() queue freeze and limits lock order

[Christoph Hellwig]

On Mon, Jan 06, 2025 at 06:58:00PM +0900, Damien Le Moal wrote:
> Ah, yes, that would potentially be an issue... Hmmm... Maybe a better solution
> would be to move the start update out of the main loop and do it first, before
> the freeze. What I do not fully understand with the code of this function is
> that it does freeze and limit update for each tag list of the tag set, but
> there is only a single request queue for all of them. So I am confused. Why
> does the blk_mq_freeze_queue and poll limit setting have to be done in the loop
> multiple times for each tag list ? I do not see it... If we can move these out
> of the tag list loops, then correcting the ordering becomes easy.

I've come up with a version that simply never updates the flag. About
to send it out.