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From:   Dan Williams <dan.j.williams@intel.com>
Date:   Mon, 22 Mar 2021 09:11:14 -0700
Message-ID: <CAPcyv4ijmTQgPwD+mS4JfSC-=1dLM6jhMqt6vL8TJd-_FbZa+g@mail.gmail.com>
Subject: Re: [PATCH v1 2/3] kernel/resource: make walk_mem_res() find all busy
 IORESOURCE_MEM resources
To:     David Hildenbrand <david@redhat.com>
Cc:     Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Linux MM <linux-mm@kvack.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Daniel Vetter <daniel.vetter@ffwll.ch>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Mauro Carvalho Chehab <mchehab+huawei@kernel.org>,
        Dave Young <dyoung@redhat.com>, Baoquan He <bhe@redhat.com>,
        Vivek Goyal <vgoyal@redhat.com>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        Keith Busch <keith.busch@intel.com>,
        Michal Hocko <mhocko@suse.com>, Qian Cai <cai@lca.pw>,
        Oscar Salvador <osalvador@suse.de>,
        Eric Biederman <ebiederm@xmission.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        "H. Peter Anvin" <hpa@zytor.com>,
        Tom Lendacky <thomas.lendacky@amd.com>,
        Brijesh Singh <brijesh.singh@amd.com>, X86 ML <x86@kernel.org>,
        Kexec Mailing List <kexec@lists.infradead.org>
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On Mon, Mar 22, 2021 at 9:02 AM David Hildenbrand <david@redhat.com> wrote:
>
> It used to be true that we can have system RAM only on the first level
> in the resourc tree. However, this is no longer holds for driver-managed
> system RAM (i.e., dax/kmem and virtio-mem).
>
> The function walk_mem_res() only consideres the first level and is
> used in arch/x86/mm/ioremap.c:__ioremap_check_mem() only. We currently
> fail to identify System RAM added by dax/kmem and virtio-mem as
> "IORES_MAP_SYSTEM_RAM", for example, allowing for remapping of such
> "normal RAM" in __ioremap_caller().
>
> Let's find all busy IORESOURCE_MEM resources, making the function
> behave similar to walk_system_ram_res().

Looks good,

Reviewed-by: Dan Williams <dan.j.williams@intel.com>