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    SubjectRe: [PATCH v2] pstore: pass allocated memory region back to caller
    On Wed, Nov 16, 2011 at 2:20 PM, Don Zickus <> wrote:
    > This is an interesting approach.  But are we leaving psinfo data exposed
    > when you have a reader and writer at the same time?

    I look at this as the first step in separating the read & write paths.

    I started out with the (good) idea that the back end should allocate & own
    the buffer for the write path ... this means that the buffer is ready to use
    when an oops/panic happens - which is obviously a bad time to need to
    allocate memory :-)

    Then I reused the same buffer for read - in hindsight this was not such a
    good idea - it led to all the discussions we've had about how to guarantee
    that the dmesg data gets saved on panic - even in the cases where we
    can't get the locks (so proposals have been made to bust the locks).

    So Kees' patch is the functional equivalent of busting the spinlock.

    Next step would be to look at the back end drivers to see whether
    they can handle a simultaneous read & write in a graceful way.

    I've queued this for linux-next. Probably missed the snapshot today,
    but I expect it should show up in next-20111118
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      Last update: 2011-11-16 23:47    [W:0.020 / U:6.412 seconds]
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