Re: [PATCH v5 1/9] MIPS: Avoid future duplicate elf core header reservation

[Mike Rapoport]

Hi Geert,

On Wed, Aug 11, 2021 at 10:50:59AM +0200, Geert Uytterhoeven wrote:
> Prepare for early_init_fdt_scan_reserved_mem() reserving the memory
> occupied by an elf core header described in the device tree.
> As arch_mem_init() calls early_init_fdt_scan_reserved_mem() before
> mips_reserve_vmcore(), the latter needs to check if the memory has
> already been reserved before.

Doing memblock_reserve() for the same region is usually fine, did you
encounter any issues without this patch?
 
> Note that mips_reserve_vmcore() cannot just be removed, as not all MIPS
> systems use DT.
> 
> Signed-off-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
> ---
> v5:
>   - New.
> ---
>  arch/mips/kernel/setup.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c
> index 23a140327a0bac1b..4693add05743d78b 100644
> --- a/arch/mips/kernel/setup.c
> +++ b/arch/mips/kernel/setup.c
> @@ -429,7 +429,8 @@ static void __init mips_reserve_vmcore(void)
>  	pr_info("Reserving %ldKB of memory at %ldKB for kdump\n",
>  		(unsigned long)elfcorehdr_size >> 10, (unsigned long)elfcorehdr_addr >> 10);
>  
> -	memblock_reserve(elfcorehdr_addr, elfcorehdr_size);
> +	if (!memblock_is_region_reserved(elfcorehdr_addr, elfcorehdr_size)
> +		memblock_reserve(elfcorehdr_addr, elfcorehdr_size);
>  #endif
>  }
>  
> -- 
> 2.25.1
> 

-- 
Sincerely yours,
Mike.