Re: [Xen-devel] [PATCH] libxc: make unlock_page return error

[Ian Campbell <Ian.Campbell@xxxxxxxxxxxxx>]

On Thu, 2010-08-19 at 16:39 +0100, Christoph Egger wrote:
> On Thursday 19 August 2010 16:57:21 Ian Campbell wrote:
> > On Thu, 2010-08-19 at 15:46 +0100, Ian Jackson wrote:
> > > Christoph Egger writes ("[Xen-devel] [PATCH] libxc: make unlock_page 
> return error"):
> > > > As a result of debugging 'xend segfaults when starting',
> > > > the attached patch makes unlock_pages return an error.
> > >
> > > Having read this in more detail, it seems that you're making
> > > {lock,unlock}_pages return errno values on error.  That's fine but
> > > it's quite unusual in libxc; all libxc functions normally return -1 on
> > > error and set errno.
> > >
> > > So I think the unusual return value convention is worth a comment in
> > > xc_private.h.  Can you please resubmit with such a comment ?
> >
> > I think it should just follow the normal libxc convention instead of
> > commenting on the use of an unusual return value convention.
> >
> > I also think that such a patch must include (or be part of a series
> > which) updates the callers to actually do something with the new return
> > value, or else it is somewhat pointless.
> >
> > Given that this patch was only for debugging purposes for an issue which
> > is now resolved is there any need?
> 
> The need I see for now is a future regression.

But if nothing checks the return value what use is it?

If it's just for your debug patch you can always apply this same thing
as part of that debug patch, there's no need for it to be upstream.

Ian.

> 
> Christoph
> 
> 
> 



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