Re: [PATCH] 9p/xen: fix init sequence

From: Juergen Gross
Date: Thu Nov 21 2024 - 07:28:08 EST


On 21.11.24 13:23, Dominique Martinet wrote:
Alexander Merritt wrote on Tue, Nov 19, 2024 at 09:16:33PM +0000:
From: Alex Zenla <alex@xxxxxxxxx>

Large amount of mount hangs observed during hotplugging of 9pfs devices. The
9pfs Xen driver attempts to initialize itself more than once, causing the
frontend and backend to disagree: the backend listens on a channel that the
frontend does not send on, resulting in stalled processing.

Only allow initialization of 9p frontend once.

I'm not familiar with the xen bringup so I don't understand how the
patch guarantees this -- otherend_changed calls are guaranted to be
seralized for a given frontend?

Yes. They are all executed by a single kernel thread.


Juergen

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