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    SubjectRe: hw_random fixes
    [cc:ing to linux-kernel, finally]

    On Wed, 2009-11-25 at 10:16 +0000, Ian Molton wrote:
    > Rusty Russell wrote:
    > > Make that:
    > >
    > > ssize_t (*get_rng_data)(void *buf, size_t max, bool wait);
    > >
    > > Then, if driver supplies that hook, use it exclusively. Otherwise, use old
    > > ones. We can convert them gradually that way.
    > This doesn't quite solve things neatly, because it means one of:
    > 1) The core has to wait until there is nothing left before requesting
    > more data, because it doesnt know the alignment requirements of the driver.

    Hmm, this seems to imply you'd be calling get_rng_data multiple times
    with different offsets into buf to accumulate data. I think that's more
    complex than is needed. Just use buf as a nicely aligned scratch buffer
    and empty it completely into the final output buffer before the next
    driver request. If you end up with 1 byte of data hanging around until
    the next read, that's not a problem - the next read might be 5 bytes.

    You'll probably want to use cacheline alignment on buf to make Via
    Padlock happy, if anything needs larger alignment (ie page) it should
    handle it internally.

    -- : development and support for Mercurial and Linux

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