Re: [PATCH] io_uring/io-wq: stop a single cancel after one running match

[Max Kellermann]

On Sun, Sep 13, 2026 at 12:30 PM Mark Amirkan via B4 Relay
<devnull+markdamirkan.gmail.com@xxxxxxxxxx> wrote:
> io_wq_worker_cancel() asks io_acct_for_each_worker() to stop after one
> match when cancel_all is clear.  io_acct_cancel_running_work() discards
> that result, so io_wq_cancel_running_work() continues into the other
> worker account with nr_running already set.
>
> If the first worker there also matches, one non-ALL cancel signals a
> request in both the bounded and unbounded accounts.
>
> Return the iterator result and stop scanning accounts after a match.
> IORING_ASYNC_CANCEL_ALL is unchanged because its callback does not stop
> the iteration.
>
> A test runs a blocking open in the bounded account and a blocking
> pipe-to-pipe splice in the unbounded account with the same user_data.
> Before this change both operations are interrupted by one cancel.  After
> the change only the open is interrupted, and the splice completes when
> input is supplied.
>
> Fixes: 751eedc4b4b7 ("io_uring/io-wq: move worker lists to struct io_wq_acct")

Thanks, that is indeed a detail that I have missed in my commit.
(Bonus points for documenting the new io_acct_cancel_running_work()
return value. That's missing too often in the kernel, even in my own
commit.)

Reviewed-by: Max Kellermann <max.kellermann@xxxxxxxxx>

-- 
Max Kellermann
Principal Architect
Hosting Technology

cm4all | Im Mediapark 6a | 50670 Köln | Germany
General information about the company can be found here:
https://www.cm4all.com/impressum
A member of the IONOS Group