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    SubjectRe: [PATCH 0/4] Rework NVMe abort handling
    On Thu, Jul 19, 2018 at 04:10:25PM +0200, Johannes Thumshirn wrote:
    > The problem I'm trying to solve here is really just single commands
    > timing out because of i.e. a bad switch in between which causes frame
    > loss somewhere.

    And that is exactly the case where NVMe abort does not actually work
    in any sensible way.

    Remember that while NVMe guarantes ordered delivery inside a given
    queue it does not guarantee anything between multiple queues.

    So now you have your buggy FC setup where an I/O command times out
    because your switch delayed it for two hours due to a firmware bug.

    After 30 seconds we send an abort over the admin queue, which happens
    to pass through just fine. The controller will tell you: no command
    found as it has never seen it.

    No with the the code following what we have in PCIe that just means
    we'll eventually controller reset after the I/O command times out
    the second time as we still won't have seen a completion for it.

    If you incorrectly just continue and resend the command we'll actually
    get the command sent twice and thus a potential bug once the original
    command just gets sent along.

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