Re: [PATCH 1/4] mm: add is_highmem_addr() helper

From: Vignesh R
Date: Mon Apr 04 2016 - 04:16:10 EST


Hi,

On 03/31/2016 05:59 PM, Boris Brezillon wrote:
> Add an helper to check if a virtual address is in the highmem region.
>
> Signed-off-by: Boris Brezillon <boris.brezillon@xxxxxxxxxxxxxxxxxx>
> ---
> include/linux/highmem.h | 13 +++++++++++++
> 1 file changed, 13 insertions(+)
>
> diff --git a/include/linux/highmem.h b/include/linux/highmem.h
> index bb3f329..13dff37 100644
> --- a/include/linux/highmem.h
> +++ b/include/linux/highmem.h
> @@ -41,6 +41,14 @@ void kmap_flush_unused(void);
>
> struct page *kmap_to_page(void *addr);
>
> +static inline bool is_highmem_addr(const void *x)
> +{
> + unsigned long vaddr = (unsigned long)x;
> +
> + return vaddr >= PKMAP_BASE &&
> + vaddr < ((PKMAP_BASE + LAST_PKMAP) * PAGE_SIZE);


Shouldn't this be:
vaddr < (PKMAP_BASE + (LAST_PKMAP * PAGE_SIZE)) ?

--
Regards
Vignesh