linux-kernel - Re: [PATCH v17 08/10] of: fdt: Aggregate the processing of "linux,usable-memory-range"

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Message-ID: <c99abca7-8c3f-94da-3f0e-e4b9872d2db0@oracle.com>
Date:   Mon, 13 Dec 2021 08:34:03 -0600
From:   john.p.donnelly@...cle.com
To:     Zhen Lei <thunder.leizhen@...wei.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        x86@...nel.org, "H . Peter Anvin" <hpa@...or.com>,
        linux-kernel@...r.kernel.org, Dave Young <dyoung@...hat.com>,
        Baoquan He <bhe@...hat.com>, Vivek Goyal <vgoyal@...hat.com>,
        Eric Biederman <ebiederm@...ssion.com>,
        kexec@...ts.infradead.org,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will@...nel.org>,
        linux-arm-kernel@...ts.infradead.org,
        Rob Herring <robh+dt@...nel.org>,
        Frank Rowand <frowand.list@...il.com>,
        devicetree@...r.kernel.org, Jonathan Corbet <corbet@....net>,
        linux-doc@...r.kernel.org
Cc:     Randy Dunlap <rdunlap@...radead.org>,
        Feng Zhou <zhoufeng.zf@...edance.com>,
        Kefeng Wang <wangkefeng.wang@...wei.com>,
        Chen Zhou <dingguo.cz@...group.com>
Subject: Re: [PATCH v17 08/10] of: fdt: Aggregate the processing of
 "linux,usable-memory-range"

On 12/10/21 12:55 AM, Zhen Lei wrote:
> Currently, we parse the "linux,usable-memory-range" property in
> early_init_dt_scan_chosen(), to obtain the specified memory range of the
> crash kernel. We then reserve the required memory after
> early_init_dt_scan_memory() has identified all available physical memory.
> Because the two pieces of code are separated far, the readability and
> maintainability are reduced. So bring them together.
> 
> Suggested-by: Rob Herring <robh@...nel.org>
> Signed-off-by: Zhen Lei <thunder.leizhen@...wei.com>
> Tested-by: Dave Kleikamp <dave.kleikamp@...cle.com>

  Acked-by: John Donnelly <john.p.donnelly@...cle.com>

> ---
>   drivers/of/fdt.c | 15 +++++++++++----
>   1 file changed, 11 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
> index bdca35284cebd56..37b477a51175359 100644
> --- a/drivers/of/fdt.c
> +++ b/drivers/of/fdt.c
> @@ -965,8 +965,7 @@ static void __init early_init_dt_check_for_elfcorehdr(unsigned long node)
>   		 elfcorehdr_addr, elfcorehdr_size);
>   }
>   
> -static phys_addr_t cap_mem_addr;
> -static phys_addr_t cap_mem_size;
> +static unsigned long chosen_node_offset = -FDT_ERR_NOTFOUND;
>   
>   /**
>    * early_init_dt_check_for_usable_mem_range - Decode usable memory range
> @@ -977,6 +976,11 @@ static void __init early_init_dt_check_for_usable_mem_range(unsigned long node)
>   {
>   	const __be32 *prop;
>   	int len;
> +	phys_addr_t cap_mem_addr;
> +	phys_addr_t cap_mem_size;
> +
> +	if ((long)node < 0)
> +		return;
>   
>   	pr_debug("Looking for usable-memory-range property... ");
>   
> @@ -989,6 +993,8 @@ static void __init early_init_dt_check_for_usable_mem_range(unsigned long node)
>   
>   	pr_debug("cap_mem_start=%pa cap_mem_size=%pa\n", &cap_mem_addr,
>   		 &cap_mem_size);
> +
> +	memblock_cap_memory_range(cap_mem_addr, cap_mem_size);
>   }
>   
>   #ifdef CONFIG_SERIAL_EARLYCON
> @@ -1137,9 +1143,10 @@ int __init early_init_dt_scan_chosen(unsigned long node, const char *uname,
>   	    (strcmp(uname, "chosen") != 0 && strcmp(uname, "chosen@0") != 0))
>   		return 0;
>   
> +	chosen_node_offset = node;
> +
>   	early_init_dt_check_for_initrd(node);
>   	early_init_dt_check_for_elfcorehdr(node);
> -	early_init_dt_check_for_usable_mem_range(node);
>   
>   	/* Retrieve command line */
>   	p = of_get_flat_dt_prop(node, "bootargs", &l);
> @@ -1275,7 +1282,7 @@ void __init early_init_dt_scan_nodes(void)
>   	of_scan_flat_dt(early_init_dt_scan_memory, NULL);
>   
>   	/* Handle linux,usable-memory-range property */
> -	memblock_cap_memory_range(cap_mem_addr, cap_mem_size);
> +	early_init_dt_check_for_usable_mem_range(chosen_node_offset);
>   }
>   
>   bool __init early_init_dt_scan(void *params)