linux-kernel - Re: [PATCH 2/2] of: of_reserved_mem: mark nomap memory instead of removing

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Message-ID: <CAL_JsqJMyY4iEcJi1z0o7pZdCASYHjnVjf6+fQDqa_ucb-M-MA@mail.gmail.com>
Date:   Fri, 11 Jun 2021 11:10:36 -0600
From:   Rob Herring <robh+dt@...nel.org>
To:     Dong Aisheng <aisheng.dong@....com>,
        Quentin Perret <qperret@...gle.com>,
        Stephen Boyd <sboyd@...nel.org>,
        Nicolas Boichat <drinkcat@...omium.org>,
        KarimAllah Ahmed <karahmed@...zon.de>
Cc:     linux-mm <linux-mm@...ck.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Dong Aisheng <dongas86@...il.com>,
        linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>,
        devicetree@...r.kernel.org
Subject: Re: [PATCH 2/2] of: of_reserved_mem: mark nomap memory instead of removing

On Fri, Jun 11, 2021 at 7:13 AM Dong Aisheng <aisheng.dong@....com> wrote:
>
> Since commit 86588296acbf ("fdt: Properly handle "no-map" field in the memory region"),
> nomap memory is changed to call memblock_mark_nomap() instead of
> memblock_remove(). But it only changed the reserved memory with fixed
> addr and size case in early_init_dt_reserve_memory_arch(), not
> including the dynamical allocation by size case in
> early_init_dt_alloc_reserved_memory_arch().
>
> Cc: Rob Herring <robh+dt@...nel.org>
> Cc: devicetree@...r.kernel.org

Good practice is to Cc the people involved in referenced commits.
Adding them now. This code is a minefield so I'd like other eyes on
it.

> Signed-off-by: Dong Aisheng <aisheng.dong@....com>
> ---
>  drivers/of/of_reserved_mem.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/of/of_reserved_mem.c b/drivers/of/of_reserved_mem.c
> index 367f298a83b2..ebba88395bf8 100644
> --- a/drivers/of/of_reserved_mem.c
> +++ b/drivers/of/of_reserved_mem.c
> @@ -42,7 +42,7 @@ static int __init early_init_dt_alloc_reserved_memory_arch(phys_addr_t size,
>
>         *res_base = base;
>         if (nomap)
> -               return memblock_remove(base, size);
> +               return memblock_mark_nomap(base, size);
>
>         return memblock_reserve(base, size);
>  }
> @@ -276,7 +276,7 @@ void __init fdt_init_reserved_mem(void)
>                                 pr_info("node %s compatible matching fail\n",
>                                         rmem->name);
>                                 if (nomap)
> -                                       memblock_add(rmem->base, rmem->size);
> +                                       memblock_clear_nomap(rmem->base, rmem->size);
>                                 else
>                                         memblock_free(rmem->base, rmem->size);
>                         }
> --
> 2.25.1
>