Subject: Re: [PATCH v18 15/17] of: fdt: Aggregate the processing of
 "linux,usable-memory-range"
To:     Dave Kleikamp <dave.kleikamp@oracle.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        <x86@kernel.org>, "H . Peter Anvin" <hpa@zytor.com>,
        <linux-kernel@vger.kernel.org>, Dave Young <dyoung@redhat.com>,
        Baoquan He <bhe@redhat.com>, Vivek Goyal <vgoyal@redhat.com>,
        Eric Biederman <ebiederm@xmission.com>,
        <kexec@lists.infradead.org>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will@kernel.org>,
        <linux-arm-kernel@lists.infradead.org>,
        Rob Herring <robh+dt@kernel.org>,
        Frank Rowand <frowand.list@gmail.com>,
        <devicetree@vger.kernel.org>, "Jonathan Corbet" <corbet@lwn.net>,
        <linux-doc@vger.kernel.org>
CC:     Randy Dunlap <rdunlap@infradead.org>,
        Feng Zhou <zhoufeng.zf@bytedance.com>,
        Kefeng Wang <wangkefeng.wang@huawei.com>,
        "Chen Zhou" <dingguo.cz@antgroup.com>,
        John Donnelly <John.p.donnelly@oracle.com>,
        Pingfan Liu <kernelfans@gmail.com>
References: <20211222130820.1754-1-thunder.leizhen@huawei.com>
 <20211222130820.1754-16-thunder.leizhen@huawei.com>
 <e9f66aca-f399-bf79-3e01-91d419442788@oracle.com>
From:   "Leizhen (ThunderTown)" <thunder.leizhen@huawei.com>
Message-ID: <de34f381-6165-7c30-b78d-e4b80479ca1d@huawei.com>
Date:   Fri, 24 Dec 2021 09:03:45 +0800
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On 2021/12/23 23:48, Dave Kleikamp wrote:
> On 12/22/21 7:08AM, 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.
> 
> Rob Herring is pushing a modified version of this patch (changes made by
> Pingfan Liu) to fix a regression. This will cause a conflict when it hits
> mainline.

Yes, I saw it yesterday, and I'll delete it in the next version. Thanks.

> 
> https://git.kernel.org/pub/scm/linux/kernel/git/robh/linux.git/log/?h=dt/linus
> 
> https://lore.kernel.org/linux-arm-kernel/20211214040157.27443-1-kernelfans@gmail.com/
> 
>>
>> Suggested-by: Rob Herring <robh@kernel.org>
>> Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
>> Reviewed-by: Rob Herring <robh@kernel.org>
>> Tested-by: Dave Kleikamp <dave.kleikamp@oracle.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)
> 
> .
>