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From:   Arnd Bergmann <arnd@arndb.de>
Date:   Tue, 5 May 2020 22:57:15 +0200
Message-ID: <CAK8P3a2_7+_a_cwDK1cwfrJX4azQJhd_Y0xB18cCUn6=p7fVsg@mail.gmail.com>
Subject: Re: [PATCH] xenbus: avoid stack overflow warning
To:     =?UTF-8?B?SsO8cmdlbiBHcm/Dnw==?= <jgross@suse.com>
Cc:     Boris Ostrovsky <boris.ostrovsky@oracle.com>,
        Stefano Stabellini <sstabellini@kernel.org>,
        Yan Yankovskyi <yyankovskyi@gmail.com>, Wei Liu <wl@xen.org>,
        xen-devel <xen-devel@lists.xenproject.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        clang-built-linux <clang-built-linux@googlegroups.com>
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On Tue, May 5, 2020 at 6:02 PM Jürgen Groß <jgross@suse.com> wrote:
> On 05.05.20 17:01, Arnd Bergmann wrote:
> > On Tue, May 5, 2020 at 4:34 PM Jürgen Groß <jgross@suse.com> wrote:
> >> On 05.05.20 16:15, Arnd Bergmann wrote:
> >
> > I considered that as well, and don't really mind either way. I think it does
> > get a bit ugly whatever we do. If you prefer the union, I can respin the
> > patch that way.
>
> Hmm, thinking more about it I think the real clean solution would be to
> extend struct map_ring_valloc_hvm to cover the pv case, too, to add the
> map and unmap arrays (possibly as a union) to it and to allocate it
> dynamically instead of having it on the stack.
>
> Would you be fine doing this?

This is a little more complex than I'd want to do without doing any testing
(and no, I don't want to do the testing either) ;-)

It does sound like a better approach though.

      Arnd