Re: [PATCH v6 03/16] dma-debug: refactor to use physical addresses for page mapping

Marek Szyprowski
2025-09-11T22:23:24Z

On 10.09.2025 07:26, Leon Romanovsky wrote:
> On Tue, Sep 09, 2025 at 10:37:48PM +0300, Leon Romanovsky wrote:
>> On Tue, Sep 09, 2025 at 04:27:31PM +0300, Leon Romanovsky wrote:
>>> From: Leon Romanovsky <leonro@nvidia.com>
>> <...>
>>
>>> include/linux/page-flags.h | 1 +
>> <...>
>>
>>> --- a/include/linux/page-flags.h
>>> +++ b/include/linux/page-flags.h
>>> @@ -614,6 +614,7 @@ FOLIO_FLAG(dropbehind, FOLIO_HEAD_PAGE)
>>> * available at this point.
>>> */
>>> #define PageHighMem(__p) is_highmem_idx(page_zonenum(__p))
>>> +#define PhysHighMem(__p) (PageHighMem(phys_to_page(__p)))
>> This was a not so great idea to add PhysHighMem() because of "else"
>> below which unfolds to maze of macros and automatically generated
>> functions with "static inline int Page##uname ..." signature.
>>
>>> #define folio_test_highmem(__f) is_highmem_idx(folio_zonenum(__f))
>>> #else
>>> PAGEFLAG_FALSE(HighMem, highmem)
> After sleeping over it, the following hunk will help:
>
> diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
> index dfbc4ba86bba2..2a1f346178024 100644
> --- a/include/linux/page-flags.h
> +++ b/include/linux/page-flags.h
> @@ -614,11 +614,11 @@ FOLIO_FLAG(dropbehind, FOLIO_HEAD_PAGE)
> * available at this point.
> */
> #define PageHighMem(__p) is_highmem_idx(page_zonenum(__p))
> -#define PhysHighMem(__p) (PageHighMem(phys_to_page(__p)))
> #define folio_test_highmem(__f) is_highmem_idx(folio_zonenum(__f))
> #else
> PAGEFLAG_FALSE(HighMem, highmem)
> #endif
> +#define PhysHighMem(__p) (PageHighMem(phys_to_page(__p)))
>
> /* Does kmap_local_folio() only allow access to one page of the folio? */
> #ifdef CONFIG_DEBUG_KMAP_LOCAL_FORCE_MAP

Okay, I will add this fixup while applying the patches.

Best regards
--
Marek Szyprowski, PhD
Samsung R&D Institute Poland