Re: [PATCH] PCI: hv: Do not wait forever on a device that has disappeared
From: Andy Shevchenko
Date: Tue May 29 2018 - 17:21:09 EST
On Thu, May 24, 2018 at 12:12 AM, Dexuan Cui <decui@xxxxxxxxxxxxx> 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);
?
> + if (!ret)
> + ret = wait_for_response(hdev, &comp);
Better to use well established patterns, i.e.
if (ret)
return ret;
> + 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