From: Jens Axboe <axboe@kernel.dk>
To: Pavel Begunkov <asml.silence@gmail.com>, io-uring@vger.kernel.org
Subject: Re: [PATCH 8/8] io_uring: keep interrupts on on submit completion
Date: Mon, 25 Jan 2021 09:02:35 -0700 [thread overview]
Message-ID: <6fd689bd-a34c-21e8-6175-83f4ca0c7eb2@kernel.dk> (raw)
In-Reply-To: <1645f7f935aa833231ebaad974bc37890ad9a2e3.1611573970.git.asml.silence@gmail.com>
On 1/25/21 4:42 AM, Pavel Begunkov wrote:
> We don't call io_submit_flush_completions() in interrupt context, no
> need to use irq* versions of spinlock.
_irq() isn't safe to use from IRQ context, it would have to be
_irqsave() for that. So the point here isn't to ensure that we work from
IRQ context, it's to protect against a deadlock when the lock is _also_
grabbed from IRQ context. And for that, we need to make sure that IRQs
are disabled, if this lock is already grabbed from IRQ context.
So this patch is wrong, the code is correct as-is.
--
Jens Axboe
next prev parent reply other threads:[~2021-01-25 16:05 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-25 11:42 [PATCH 0/8] second part of 5.12 patches Pavel Begunkov
2021-01-25 11:42 ` [PATCH 1/8] io_uring: ensure only sqo_task has file notes Pavel Begunkov
2021-01-25 11:42 ` [PATCH 2/8] io_uring: consolidate putting reqs task Pavel Begunkov
2021-01-25 11:42 ` [PATCH 3/8] io_uring: don't keep submit_state on stack Pavel Begunkov
2021-01-25 16:00 ` Jens Axboe
2021-01-25 16:25 ` Pavel Begunkov
2021-01-25 16:31 ` Jens Axboe
2021-01-25 16:52 ` Pavel Begunkov
2021-01-25 11:42 ` [PATCH 4/8] io_uring: remove ctx from comp_state Pavel Begunkov
2021-01-25 11:42 ` [PATCH 5/8] io_uring: don't reinit submit state every time Pavel Begunkov
2021-01-25 11:42 ` [PATCH 6/8] io_uring: replace list with array for compl batch Pavel Begunkov
2021-01-25 11:42 ` [PATCH 7/8] io_uring: submit-completion free batching Pavel Begunkov
2021-01-25 11:42 ` [PATCH 8/8] io_uring: keep interrupts on on submit completion Pavel Begunkov
2021-01-25 16:02 ` Jens Axboe [this message]
2021-01-25 16:08 ` [PATCH 0/8] second part of 5.12 patches Jens Axboe
2021-01-25 16:56 ` Pavel Begunkov
2021-01-25 17:04 ` Jens Axboe
2021-01-25 17:05 ` Pavel Begunkov
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