linux-kernel - Re: [PATCH v5 06/11] powerpc/pseries/iommu: Add ddw_property_create() and refactor enable

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Message-ID: <1cf050db5d37f6e515cd25e26f4e8940960c12d0.camel@gmail.com>
Date:   Tue, 17 Aug 2021 02:59:14 -0300
From:   Leonardo Brás <leobras.c@...il.com>
To:     Frederic Barrat <fbarrat@...ux.ibm.com>,
        Michael Ellerman <mpe@...erman.id.au>,
        Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Paul Mackerras <paulus@...ba.org>,
        Alexey Kardashevskiy <aik@...abs.ru>,
        David Gibson <david@...son.dropbear.id.au>,
        kernel test robot <lkp@...el.com>,
        Nicolin Chen <nicoleotsuka@...il.com>
Cc:     linuxppc-dev@...ts.ozlabs.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v5 06/11] powerpc/pseries/iommu: Add
 ddw_property_create() and refactor enable_ddw()

Hello Fred, thanks for this feedback!

On Tue, 2021-07-20 at 19:49 +0200, Frederic Barrat wrote:
> 
> >         kfree(window);
> >   
> > -out_clear_window:
> > -       remove_ddw(pdn, true);
> > +out_del_prop:
> > +       of_remove_property(pdn, win64);
> >   
> >   out_free_prop:
> >         kfree(win64->name);
> >         kfree(win64->value);
> >         kfree(win64);
> >   
> > +out_remove_win:
> > +       remove_ddw(pdn, true);
> 
> 
> I believe there's a small problem here. We jump directly to 
> out_remove_win if allocating the property failed. Yet, the first
> thing 
> remove_ddw() does is look for the property. So it will never find it
> and 
> the window is never removed by the hypervisor.
> 
>    Fred

That makes sense, thanks for catching this one!

What I intended here was just removing the DDW, so I think it should be
ok replacing remove_ddw() by a new helper that only does the rtas-call.

I will send a v6 with this change soon.

> 
> 
> > +
> >   out_failed:
> >         if (default_win_removed)
> >                 reset_dma_window(dev, pdn);
> >