Re: [PATCH v2 1/2] arm64/mm: Allow __create_pgd_mapping() to propagate pgtable_alloc() errors

[Kevin Brodsky]

On 13/10/2025 10:02, Linu Cherian wrote:
> [...]
>
> @@ -1877,23 +1926,30 @@ int arch_add_memory(int nid, u64 start, u64 size,
>  	if (force_pte_mapping())
>  		flags |= NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS;
>  
> -	__create_pgd_mapping(swapper_pg_dir, start, __phys_to_virt(start),
> -			     size, params->pgprot, pgd_pgtable_alloc_init_mm,
> -			     flags);
> +	ret = __create_pgd_mapping(swapper_pg_dir, start, __phys_to_virt(start),
> +				   size, params->pgprot, pgd_pgtable_alloc_init_mm,
> +				   flags);
> +

Nit: usually no empty line between a call and a trivial if (ret).

> +	if (ret)
> +		goto out;
>  
>  	memblock_clear_nomap(start, size);
>  
>  	ret = __add_pages(nid, start >> PAGE_SHIFT, size >> PAGE_SHIFT,
>  			   params);
>  	if (ret)
> -		__remove_pgd_mapping(swapper_pg_dir,
> -				     __phys_to_virt(start), size);
> +		goto out;
>  	else {
>  		/* Address of hotplugged memory can be smaller */
>  		max_pfn = max(max_pfn, PFN_UP(start + size));
>  		max_low_pfn = max_pfn;
>  	}
>  
> +	return 0;
> +
> +out:

Nit: since this is an error path, it'd be clearer to call the label
"err" rather than "out".

- Kevin

> +	__remove_pgd_mapping(swapper_pg_dir,
> +			     __phys_to_virt(start), size);
>  	return ret;
>  }
>