Re: [PATCH] x86/kaslr: simplify the code in mem_avoid_memmap()

[Baoquan He]

On 08/22/19 at 10:26am, Qian Cai wrote:
> If "i >= MAX_MEMMAP_REGIONS" already when entering mem_avoid_memmap(),
> even without the return statement the loop will not run anyway. The only
> time it needs to set "memmap_too_large = true" in this situation is
> "memmap_too_large" is "false" currently. Hence, the code could be
> simplified.

It seems not improved much. If far more than MAX_MEMMAP_REGIONS 'memmap='
specified, the if condition checking looks more straightforward. Anyway,
it's not simplifying much, in my opinion.

Thanks
Baoquan

> 
> Signed-off-by: Qian Cai <cai@xxxxxx>
> ---
>  arch/x86/boot/compressed/kaslr.c | 5 +----
>  1 file changed, 1 insertion(+), 4 deletions(-)
> 
> diff --git a/arch/x86/boot/compressed/kaslr.c b/arch/x86/boot/compressed/kaslr.c
> index 2e53c056ba20..35c6942fb95b 100644
> --- a/arch/x86/boot/compressed/kaslr.c
> +++ b/arch/x86/boot/compressed/kaslr.c
> @@ -176,9 +176,6 @@ static void mem_avoid_memmap(char *str)
>  {
>  	static int i;
>  
> -	if (i >= MAX_MEMMAP_REGIONS)
> -		return;
> -
>  	while (str && (i < MAX_MEMMAP_REGIONS)) {
>  		int rc;
>  		unsigned long long start, size;
> @@ -206,7 +203,7 @@ static void mem_avoid_memmap(char *str)
>  	}
>  
>  	/* More than 4 memmaps, fail kaslr */
> -	if ((i >= MAX_MEMMAP_REGIONS) && str)
> +	if (i >= MAX_MEMMAP_REGIONS && !memmap_too_large)
>  		memmap_too_large = true;
>  }
>  
> -- 
> 1.8.3.1
>