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    SubjectRE: [PATCH] PCI: hv: Do not wait forever on a device that has disappeared
    Date
    > From: Andy Shevchenko <andy.shevchenko@gmail.com>
    > Sent: Tuesday, May 29, 2018 14:21
    > On Thu, May 24, 2018 at 12:12 AM, Dexuan Cui <decui@microsoft.com>
    > wrote:
    > >
    > > Before the guest finishes the device initialization, the device can be
    > > removed anytime by the host, and after that the host won't respond to
    > > the guest's request, so the guest should be prepared to handle this
    > > case.
    >
    > > + while (true) {
    > > + if (hdev->channel->rescind) {
    > > + dev_warn_once(&hdev->device, "The device is
    > gone.\n");
    > > + return -ENODEV;
    > > + }
    > > +
    > > + if (wait_for_completion_timeout(comp, HZ / 10))
    > > + break;
    > > + }
    >
    > Infinite loops are usually a red flags.
    >
    > What's wrong with simple:
    >
    > do {
    > ...
    > } while (wait_...(...) == 0);
    >
    > ?
    Thanks for the suggestion, Andy!
    The coding style you suggested looks better to me. :-)

    > > + if (!ret)
    > > + ret = wait_for_response(hdev, &comp);
    >
    > Better to use well established patterns, i.e.
    >
    > if (ret)
    > return ret;
    Agreed.

    >
    > > + if (!ret)
    > > + ret = wait_for_response(hdev,
    > &comp_pkt.host_event);
    >
    > Here it looks okay on the first glance, but better to think about it
    > again and refactor.

    > With Best Regards,
    > Andy Shevchenko

    I'll try to send out a patch to improve the coding style, after I address
    Michael Kelley's concern of a race.

    Thanks,
    -- Dexuan
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