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

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Message-ID: <b62d84b0-c5a8-402f-d62e-e0b8d41221bb@kernel.dk>
Date:   Mon, 4 May 2020 07:43:09 -0600
From:   Jens Axboe <axboe@...nel.dk>
To:     Pavel Begunkov <asml.silence@...il.com>,
        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 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?

-- 
Jens Axboe