Re: [PATCH] mm/pgtable: convert pgtable_t to ptdesc pointer

[Alex Shi <seakeel@gmail.com>]

On 2026/1/7 17:05, Mike Rapoport wrote:
> On Wed, Jan 07, 2026 at 02:46:35PM +0800,alexs@kernel.org wrote:
>> From: Alex Shi<alexs@kernel.org>
>>
>> After struct ptdesc introduced, pgtable_t should used it instead of old
>> struct page pointer. The only thing in the way for this change is just
>> pgtable->lru in pgtable_trans_huge_deposit/withdraw.
>>
>> Let's convert them into ptdesc and use struct ptdesc* as pgtable_t.
>> Thanks testing support from kernel test robot<lkp@intel.com>
>>
>> Signed-off-by: Alex Shi<alexs@kernel.org>
>> ---
> ...
> 
>> diff --git a/arch/arm/include/asm/pgalloc.h b/arch/arm/include/asm/pgalloc.h
>> index a17f01235c29..1a3484c2df4c 100644
>> --- a/arch/arm/include/asm/pgalloc.h
>> +++ b/arch/arm/include/asm/pgalloc.h
>> @@ -96,12 +96,12 @@ pte_alloc_one(struct mm_struct *mm)
>>   {
>>   	struct page *pte;
>>   
>> -	pte = __pte_alloc_one(mm, GFP_PGTABLE_USER | PGTABLE_HIGHMEM);
>> +	pte = ptdesc_page(__pte_alloc_one(mm, GFP_PGTABLE_USER | PGTABLE_HIGHMEM));
> When ptdesc will be separated from struct page, ptdesc_page() would fail if the
> allocation failed. This line should be split into something like
> 
> 	struct ptdesc *ptdesc = __pte_alloc_one(...);
> 	if (!ptesc)
> 		return NULL;
> 	pte = ptdesc_page(ptdesc);
> 
> 

Right, I will fix this. and sent the 2nd version.
Thanks a lot!

>>   	if (!pte)
>>   		return NULL;
>>   	if (!PageHighMem(pte))
>>   		clean_pte_table(page_address(pte));
>> -	return pte;
>> +	return page_ptdesc(pte);
>>   }
>>   
>>   static inline void __pmd_populate(pmd_t *pmdp, phys_addr_t pte,
> -- Sincerely yours, Mike.
>