Re: [PATCH v2, part3 01/12] mm: enhance free_reserved_area() to supportpoisoning memory with zero

From: Jiang Liu
Date: Sat Mar 16 2013 - 13:48:25 EST


On 03/17/2013 01:37 AM, Geert Uytterhoeven wrote:
> On Sat, Mar 16, 2013 at 6:03 PM, Jiang Liu <liuj97@xxxxxxxxx> wrote:
>> --- a/mm/page_alloc.c
>> +++ b/mm/page_alloc.c
>> @@ -5130,13 +5130,13 @@ unsigned long free_reserved_area(unsigned long start, unsigned long end,
>> pos = start = PAGE_ALIGN(start);
>> end &= PAGE_MASK;
>> for (pages = 0; pos < end; pos += PAGE_SIZE, pages++) {
>> - if (poison)
>> + if ((unsigned int)poison <= 0xFF)
>
> "if (poison >= 0)"? No cast needed.
Hi Geert,
We constraints valid inputs as [0, UCHAR_MAX], so the code follows the comment as below.
/*
* Free reserved pages within range [PAGE_ALIGN(start), end & PAGE_MASK)
* into the buddy system. The freed pages will be poisoned with pattern
* "poison" if it's within range [0, UCHAR_MAX].
* Return pages freed into the buddy system.
*/

Regards!
Gerry

>
>> memset((void *)pos, poison, PAGE_SIZE);
>
> Gr{oetje,eeting}s,
>
> Geert
>
> --
> Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
>
> In personal conversations with technical people, I call myself a hacker. But
> when I'm talking to journalists I just say "programmer" or something like that.
> -- Linus Torvalds
>

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/