Re: [RFC PATCH v3 3/3] blk-mq: Lockout tagset iterator when exiting elevator

From: John Garry
Date: Wed Mar 10 2021 - 03:55:14 EST


On 09/03/2021 19:21, Bart Van Assche wrote:
On 3/9/21 9:47 AM, John Garry wrote:
This does fall over if some tags are allocated without associated
request queue, which I do not know exists.


Hi Bart,

The only tag allocation mechanism I know of is blk_mq_get_tag(). The
only blk_mq_get_tag() callers I know of are __blk_mq_alloc_request() and
blk_mq_alloc_request_hctx(). So I think all allocated tags are
associated with a request queue.


ok, good.

Regarding this patch series, I have shared the feedback I wanted to
share so I would appreciate it if someone else could also take a look.


So I can incorporate any changes and suggestions so far and send a non-RFC version - that may get more attention if none extra comes.

As mentioned on the cover letter, if patch 2+3/3 are accepted, then patch 1/3 could be simplified. But I plan to leave as is.

BTW, any issue with putting your suggested-by on patch 2/3?

Thanks,
John