From: Pavel Begunkov <asml.silence@gmail.com>
To: Jens Axboe <axboe@kernel.dk>, io-uring@vger.kernel.org
Subject: Re: [PATCH 7/8] io_uring: fix sequencing issues with linked timeouts
Date: Tue, 19 Nov 2019 23:51:35 +0300 [thread overview]
Message-ID: <ccf48def-1a4a-9cb1-aa9a-467294487856@gmail.com> (raw)
In-Reply-To: <20191116015314.24276-8-axboe@kernel.dk>
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On 16/11/2019 04:53, Jens Axboe wrote:
> We have an issue with timeout links that are deeper in the submit chain,
> because we only handle it upfront, not from later submissions. Move the
> prep + issue of the timeout link to the async work prep handler, and do
> it normally for non-async queue. If we validate and prepare the timeout
> links upfront when we first see them, there's nothing stopping us from
> supporting any sort of nesting.
>
> Fixes: 2665abfd757f ("io_uring: add support for linked SQE timeouts")
> Reported-by: Pavel Begunkov <asml.silence@gmail.com>
> Signed-off-by: Jens Axboe <axboe@kernel.dk>
> ---
> @@ -923,6 +942,7 @@ static void io_fail_links(struct io_kiocb *req)
> io_cqring_fill_event(link, -ECANCELED);
> __io_double_put_req(link);
> }
> + kfree(sqe_to_free);
> }
>
> io_commit_cqring(ctx);
> @@ -2668,8 +2688,12 @@ static void io_wq_submit_work(struct io_wq_work **workptr)
>
> /* if a dependent link is ready, pass it back */
> if (!ret && nxt) {
> - io_prep_async_work(nxt);
> + struct io_kiocb *link;
> +
> + io_prep_async_work(nxt, &link);
> *workptr = &nxt->work;
Are we safe here without synchronisation?
Probably io_link_timeout_fn() may miss the new value
(doing io-wq cancel).
> + if (link)
> + io_queue_linked_timeout(link);
> }
> }
>
--
Pavel Begunkov
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next prev parent reply other threads:[~2019-11-19 20:51 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-16 1:53 [PATCHSET] Pending io_uring items not yet queued up for 5.5 Jens Axboe
2019-11-16 1:53 ` [PATCH 1/8] io-wq: remove now redundant struct io_wq_nulls_list Jens Axboe
2019-11-16 1:53 ` [PATCH 2/8] io_uring: make POLL_ADD/POLL_REMOVE scale better Jens Axboe
2019-11-16 1:53 ` [PATCH 3/8] io_uring: io_async_cancel() should pass in 'nxt' request pointer Jens Axboe
2019-11-16 1:53 ` [PATCH 4/8] io_uring: cleanup return values from the queueing functions Jens Axboe
2019-11-16 1:53 ` [PATCH 5/8] io_uring: make io_double_put_req() use normal completion path Jens Axboe
2019-11-16 1:53 ` [PATCH 6/8] io_uring: make req->timeout be dynamically allocated Jens Axboe
2019-11-16 1:53 ` [PATCH 7/8] io_uring: fix sequencing issues with linked timeouts Jens Axboe
2019-11-19 20:51 ` Pavel Begunkov [this message]
2019-11-19 22:13 ` Jens Axboe
2019-11-20 12:42 ` Pavel Begunkov
2019-11-20 17:19 ` Jens Axboe
2019-11-20 18:15 ` Jens Axboe
2019-11-16 1:53 ` [PATCH 8/8] io_uring: remove dead REQ_F_SEQ_PREV flag Jens Axboe
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