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Subject: Re: [PATCH v2] /dev/mem: nowait zero/null ops
To:     Pavel Begunkov <asml.silence@gmail.com>,
        Arnd Bergmann <arnd@arndb.de>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        linux-kernel@vger.kernel.org
Cc:     io-uring@vger.kernel.org
References: <f11090f97ddc2b2ce49ea1211258658ddfbc5563.1631127867.git.asml.silence@gmail.com>
From:   Jens Axboe <axboe@kernel.dk>
Message-ID: <9370d400-3944-b62a-65f6-5c31ac86ea35@kernel.dk>
Date:   Wed, 8 Sep 2021 13:15:27 -0600
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On 9/8/21 1:10 PM, Pavel Begunkov wrote:
> Make read_iter_zero() to honor IOCB_NOWAIT, so /dev/zero can be
> advertised as FMODE_NOWAIT. It's useful for io_uring, which needs it to
> apply certain optimisations when doing I/O against the device.
> 
> Set FMODE_NOWAIT for /dev/null as well, it never waits and therefore
> trivially meets the criteria.

Reviewed-by: Jens Axboe <axboe@kernel.dk>

-- 
Jens Axboe