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Subject: Re: [git pull] iov_iter fixes
To:     Linus Torvalds <torvalds@linux-foundation.org>
Cc:     Al Viro <viro@zeniv.linux.org.uk>,
        Pavel Begunkov <asml.silence@gmail.com>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        linux-fsdevel <linux-fsdevel@vger.kernel.org>
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From:   Jens Axboe <axboe@kernel.dk>
Message-ID: <cfe9e6d6-dd1c-a500-b3b0-a92d0b66c3c0@kernel.dk>
Date:   Fri, 10 Sep 2021 11:32:24 -0600
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On 9/10/21 11:31 AM, Linus Torvalds wrote:
> On Fri, Sep 10, 2021 at 10:26 AM Jens Axboe <axboe@kernel.dk> wrote:
>>
>> On 9/10/21 10:58 AM, Linus Torvalds wrote:
>>> On Fri, Sep 10, 2021 at 9:56 AM Al Viro <viro@zeniv.linux.org.uk> wrote:
>>>>
>>>> What's the point of all those contortions, anyway?  You only need it for
>>>> iovec case; don't mix doing that and turning it into flavour-independent
>>>> primitive.
>>>
>>> Good point, making it specific to iovec only gets rid of a lot of
>>> special cases and worries.
>>>
>>> This is fairly specialized, no need to always cater to every possible case.
>>
>> Alright, split into three patches:
>>
>> https://git.kernel.dk/cgit/linux-block/log/?h=iov_iter
> 
> That looks sane to me.
> 
> Please add some comment about how that
> 
>         i->iov -= state->nr_segs - i->nr_segs;
> 
> actually is the right thing for all the three cases (iow how 'iov',
> 'kvec' and 'bvec' all end up having a union member that acts the same
> way).

Good idea, I'll add that right now.

> But yeah, I like how the io_uring.c code looks better this way too.

Me too :-)

-- 
Jens Axboe