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Re: [Xen-devel] [PATCH] skeleton frontend/backend examples and a deadloc

To: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
Subject: Re: [Xen-devel] [PATCH] skeleton frontend/backend examples and a deadlock
From: Harry Butterworth <harry@xxxxxxxxxxxxxxxxxxxxxxxxxxxxx>
Date: Wed, 02 Nov 2005 12:37:46 +0000
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On Wed, 2005-11-02 at 16:22 +1100, Rusty Russell wrote:
> Here are example frontend and backend driver skeletons.  They're
> *designed* to handle driver restart and module unloading.  However,
> device_unregister deadlocks.  I guess noone tried testing
> unregister_xenbus_watch when not called from a watch callback.

Thanks, that'll be useful for me to know when it comes to testing my
code.

For comparison, I've knocked up a skeleton FE/BE driver based on the
xenidc API that I'm using for my USB driver.

You'll see that my patch is smaller, simpler and provides significantly
more functionality: enough to send messages and transactions
bi-directionally between the FE and BE.  For a fair comparison, yours
would require interrupt handlers, use of the RING macros, correct memory
barriers etc.

Hopefully this helps to explain why I've split out the IDC functionality
from my USB driver into a generic service.

Harry.

Attachment: xenidc-skeleton-patch
Description: Text Data

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