linux-kernel - Re: [PATCH 1/2] splice: export do

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Date:   Mon, 4 May 2020 17:03:21 +0300
From:   Pavel Begunkov <asml.silence@...il.com>
To:     Jens Axboe <axboe@...nel.dk>, Jann Horn <jannh@...gle.com>
Cc:     io-uring <io-uring@...r.kernel.org>,
        kernel list <linux-kernel@...r.kernel.org>,
        Alexander Viro <viro@...iv.linux.org.uk>,
        linux-fsdevel <linux-fsdevel@...r.kernel.org>,
        Clay Harris <bugs@...ycon.org>
Subject: Re: [PATCH 1/2] splice: export do_tee()

On 04/05/2020 16:43, Jens Axboe wrote:
> On 5/4/20 6:31 AM, Pavel Begunkov wrote:
>> On 04/05/2020 14:09, Jann Horn wrote:
>>> On Sat, May 2, 2020 at 2:10 PM Pavel Begunkov <asml.silence@...il.com> wrote:
>>>> export do_tee() for use in io_uring
>>> [...]
>>>> diff --git a/fs/splice.c b/fs/splice.c
>>> [...]
>>>>   * The 'flags' used are the SPLICE_F_* variants, currently the only
>>>>   * applicable one is SPLICE_F_NONBLOCK.
>>>>   */
>>>> -static long do_tee(struct file *in, struct file *out, size_t len,
>>>> -                  unsigned int flags)
>>>> +long do_tee(struct file *in, struct file *out, size_t len, unsigned int flags)
>>>>  {
>>>>         struct pipe_inode_info *ipipe = get_pipe_info(in);
>>>>         struct pipe_inode_info *opipe = get_pipe_info(out);
>>>
>>> AFAICS do_tee() in its current form is not something you should be
>>> making available to anything else, because the file mode checks are
>>> performed in sys_tee() instead of in do_tee(). (And I don't see any
>>> check for file modes in your uring patch, but maybe I missed it?) If
>>> you want to make do_tee() available elsewhere, please refactor the
>>> file mode checks over into do_tee().
>>
>> Overlooked it indeed. Glad you found it
> 
> Yeah indeed, that's a glaring oversight on my part too. Will you send
> a patch for 5.7-rc as well for splice?

Absolutely

-- 
Pavel Begunkov