Re: "usb_wwan: error case of resume" (16871dcac) is buggy

From: Oliver Neukum
Date: Mon Mar 21 2011 - 05:10:39 EST


Am Montag, 21. März 2011, 01:36:45 schrieb Jiri Kosina:
> Hi,
>
> the commit in subject make the kernel with CONFIG_PM_RUNTIME unset fail
> during compilation, as struct dev_pm_info doesn't have whole bunch of
> members in such case.
>
> The commit in question adds this code:
>
> /* we have to throw away the rest */
> do {
> unbusy_queued_urb(urb, portdata);
> //extremely dirty
> atomic_dec(&port->serial->interface->dev.power.usage_count);
> } while ((urb = usb_get_from_anchor(&portdata->delayed)));
>
> The 'extermely dirty' comment makes me a bit nervous whether the patch
> below is correct or some more thinking would be necessary.

I've since posted a clean patch, although your fix looks correct to me.
The problem was that I was unsure about the locking during resume().
I rather wrote a layering violation than risk a deadlock in an error path
hard to test. But I did not feel well doing it.

Regards
Oliver
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