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Re: [Xen-devel] [PATCH] libxl: make libxl_wait_for_device_model not racy

To: Vincent Hanquez <Vincent.Hanquez@xxxxxxxxxxxxx>
Subject: Re: [Xen-devel] [PATCH] libxl: make libxl_wait_for_device_model not racy
From: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
Date: Wed, 23 Jun 2010 14:15:12 +0100
Cc: "xen-devel@xxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxx>, Stefano Stabellini <Stefano.Stabellini@xxxxxxxxxxxxx>
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On Wed, 23 Jun 2010, Vincent Hanquez wrote:
> On 23/06/10 12:15, Stefano Stabellini wrote:
> > Hi all,
> > at the moment libxl_wait_for_device_model waits on a xenstore watch
> > before checking the current value of the xenstore node, that might
> > contain already the value the function was looking for.
> > This patch changes libxl_wait_for_device_model so that it checks the
> > value of the xenstore node first, then waits for the watch.
> >
> > Signed-off-by: Stefano Stabellini<stefano.stabellini@xxxxxxxxxxxxx>
> >    
> xenstore watch automatically fire one time when you install them for 
> this exact same purpose. Is this patch actually solving any issue you saw ?

No, it was just refactoring.

Are you sure that both xenstore implementations always do that?
Is this a "feature" we can safely rely on?
If both answers are positive, then we can disregard this patch.

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