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From:   Dan Williams <dan.j.williams@intel.com>
Date:   Thu, 29 Aug 2019 14:04:49 -0700
Message-ID: <CAPcyv4jEgk3Nsax0_KxDEsOPY91_py5NTyh2F58zVcoxaO0_Tw@mail.gmail.com>
Subject: Re: [PATCH] libnvdimm, region: Use struct_size() in kzalloc()
To:     "Verma, Vishal L" <vishal.l.verma@intel.com>
Cc:     "Jiang, Dave" <dave.jiang@intel.com>,
        "gustavo@embeddedor.com" <gustavo@embeddedor.com>,
        "Busch, Keith" <keith.busch@intel.com>,
        "Weiny, Ira" <ira.weiny@intel.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "linux-nvdimm@lists.01.org" <linux-nvdimm@lists.01.org>
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On Wed, Aug 28, 2019 at 1:24 PM Verma, Vishal L
<vishal.l.verma@intel.com> wrote:
>
> On Wed, 2019-08-28 at 14:36 -0500, Gustavo A. R. Silva wrote:
>
> > struct_size() does not apply to those scenarios. See below...
> >
> > > [1]:
> > > https://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm.git/tree/drivers/nvdimm/region_devs.c#n1030
> >
> > struct_size() only applies to structures of the following kind:
> >
> > struct foo {
> >    int stuff;
> >    struct boo entry[];
> > };
> >
> > and this scenario includes two different structures:
> >
> > struct nd_region {
> >       ...
> >         struct nd_mapping mapping[0];
> > };
> >
> > struct nd_blk_region {
> >       ...
> >         struct nd_region nd_region;
> > };
>
> Yep - I neglected to actually look at the structures involved - you're
> right, it doesn't apply here.
>
> >
> > > [2]:
> > > https://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm.git/tree/drivers/nvdimm/region_devs.c#n96
> > >
> >
> > In this scenario struct_size() does not apply directly because of the
> > following
> > logic before the call to devm_kzalloc():
>
> Agreed, I missed that the calculation was more involved here.
>
> Thanks for the clarifications, you can add:
> Reviewed-by: Vishal Verma <vishal.l.verma@intel.com>

Thanks, applied.