Re: [Xen-devel] [PATCH v8 21/21] libxl: add support for migrating HVM guests without a device model

[Ian Jackson <Ian.Jackson@xxxxxxxxxxxxx>]

Wei Liu writes ("Re: [PATCH v8 21/21] libxl: add support for migrating HVM 
guests without a device model"):
> On Fri, Nov 06, 2015 at 05:05:55PM +0100, Roger Pau Monne wrote:
> > @@ -387,6 +396,7 @@ static void emulator_xenstore_record_done(libxl__egc 
> > *egc,
> >                                            libxl__stream_write_state 
> > *stream)
> >  {
> >      libxl__domain_suspend_state *dss = stream->dss;
> > +    STATE_AO_GC(stream->ao);
> >  
> 
> This is redundant.

`Unneeded' calls to STATE_AO_GC (ie ones in functions which do not
actually use anything from ao or gc) are at worst harmless.

In fact, such uses of STATE_AO_GC provide additional safety, because
they call libxl__ao_inprogress_gc which checks that the ao is in the
right state.

So I think there is nothing wrong with adding this call here (even if
it is a left-over addition from a previous version or draft of this
patch, or from wanting to add some calls to LOG* for debugging).

There would also be nothing wrong with not adding it.

Ian.

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