I'll look again (just did).
But I think you found a bug.
On Tue, Feb 22, 2011 at 4:10 PM, <r...@hemiola.co.uk> wrote:
> I'm struggling to understand the ins and outs of the usb ohci driver
> (usbohci.c) and have a question (well, several).
>
> If one writes to an endpoint, then "epio" gets called. This in turn
> does ilock(ctrl) which disables interrupts on my single-processor
> machine. Then "epgettd" is called several times to allocate transfer
> descriptors. Each call to epgettd copies a portion from the user space
> buffer which was passed as a parameter to "epio".
>
> What happens here if the user space buffer is in a page which is not
> present? Is it possible for a page-in to happen even when interrupts
> are disabled by the ilock?
>
> Thanks for any insight.
>
> rod
>
>
