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From:   Linus Torvalds <torvalds@linux-foundation.org>
Date:   Sat, 26 Mar 2022 15:41:40 -0700
Message-ID: <CAHk-=wgqHqb_yaNUGwMfLJJw28VvauSB6sSMCi3Bu7Q0-N0GEQ@mail.gmail.com>
Subject: Re: [REGRESSION] Recent swiotlb DMA_FROM_DEVICE fixes break
 ath9k-based AP
To:     David Laight <David.Laight@aculab.com>
Cc:     =?UTF-8?B?VG9rZSBIw7hpbGFuZC1Kw7hyZ2Vuc2Vu?= <toke@toke.dk>,
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        Oleksandr Natalenko <oleksandr@natalenko.name>,
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On Sat, Mar 26, 2022 at 3:38 PM David Laight <David.Laight@aculab.com> wrote:
>
> Is the idea of 'buffer ownership' even a good one?

I do think it might be best to not think in those terms, but literally
just in data movement terms.

Because the "buffer ownership" mental model is clearly confused, when
data transfer might be ongoing, but the CPU might need to just look at
"what's going on right now" without actually taking any ownership of
the buffer.

                Linus