[PATCH] mm/thp: Drop follow_devmap_pmd() default stub

[PATCH] mm/thp: Drop follow_devmap_pmd() default stub

[Anshuman Khandual]

follow_devmap_pmd() has already been dropped by the commit fd2825b0760a
("mm/gup: remove pXX_devmap usage from get_user_pages()"). The fallback
stub in the header which is now redundant, can be dropped off as well.

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: linux-mm@kvack.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
---
 include/linux/huge_mm.h | 6 ------
 1 file changed, 6 deletions(-)

diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
index 7748489fde1b..96ce0ca54e49 100644
--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h
@@ -652,12 +652,6 @@ static inline void mm_put_huge_zero_folio(struct mm_struct *mm)
 	return;
 }
 
-static inline struct page *follow_devmap_pmd(struct vm_area_struct *vma,
-	unsigned long addr, pmd_t *pmd, int flags, struct dev_pagemap **pgmap)
-{
-	return NULL;
-}
-
 static inline bool thp_migration_supported(void)
 {
 	return false;
-- 
2.30.2

Re: [PATCH] mm/thp: Drop follow_devmap_pmd() default stub

[David Hildenbrand]

On 29.09.25 12:46, Anshuman Khandual wrote:
> follow_devmap_pmd() has already been dropped by the commit fd2825b0760a
> ("mm/gup: remove pXX_devmap usage from get_user_pages()"). The fallback
> stub in the header which is now redundant, can be dropped off as well.
> 
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: David Hildenbrand <david@redhat.com>
> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
> Cc: Zi Yan <ziy@nvidia.com>
> Cc: linux-mm@kvack.org
> Cc: linux-kernel@vger.kernel.org
> Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
> ---
>   include/linux/huge_mm.h | 6 ------
>   1 file changed, 6 deletions(-)
> 
> diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
> index 7748489fde1b..96ce0ca54e49 100644
> --- a/include/linux/huge_mm.h
> +++ b/include/linux/huge_mm.h
> @@ -652,12 +652,6 @@ static inline void mm_put_huge_zero_folio(struct mm_struct *mm)
>   	return;
>   }
>   
> -static inline struct page *follow_devmap_pmd(struct vm_area_struct *vma,
> -	unsigned long addr, pmd_t *pmd, int flags, struct dev_pagemap **pgmap)
> -{
> -	return NULL;
> -}
> -
>   static inline bool thp_migration_supported(void)
>   {
>   	return false;

Acked-by: David Hildenbrand <david@redhat.com>

Documentation/mm/arch_pgtable_helpers.rst still mention devmap helpers, 
want to clean that up as well?

-- 
Cheers

David / dhildenb

Re: [PATCH] mm/thp: Drop follow_devmap_pmd() default stub

[Zi Yan]

On 29 Sep 2025, at 6:46, Anshuman Khandual wrote:

> follow_devmap_pmd() has already been dropped by the commit fd2825b0760a
> ("mm/gup: remove pXX_devmap usage from get_user_pages()"). The fallback
> stub in the header which is now redundant, can be dropped off as well.
>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: David Hildenbrand <david@redhat.com>
> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
> Cc: Zi Yan <ziy@nvidia.com>
> Cc: linux-mm@kvack.org
> Cc: linux-kernel@vger.kernel.org
> Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
> ---
>  include/linux/huge_mm.h | 6 ------
>  1 file changed, 6 deletions(-)
>

Reviewed-by: Zi Yan <ziy@nvidia.com>

Best Regards,
Yan, Zi

Re: [PATCH] mm/thp: Drop follow_devmap_pmd() default stub

[Dev Jain]

On 29/09/25 4:16 pm, Anshuman Khandual wrote:
> follow_devmap_pmd() has already been dropped by the commit fd2825b0760a
> ("mm/gup: remove pXX_devmap usage from get_user_pages()"). The fallback
> stub in the header which is now redundant, can be dropped off as well.
>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: David Hildenbrand <david@redhat.com>
> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
> Cc: Zi Yan <ziy@nvidia.com>
> Cc: linux-mm@kvack.org
> Cc: linux-kernel@vger.kernel.org
> Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
> ---
>   

Reviewed-by: Dev Jain <dev.jain@arm.com>

Re: [PATCH] mm/thp: Drop follow_devmap_pmd() default stub

[Alistair Popple]

On 2025-09-29 at 20:46 +1000, Anshuman Khandual <anshuman.khandual@arm.com> wrote...
> follow_devmap_pmd() has already been dropped by the commit fd2825b0760a
> ("mm/gup: remove pXX_devmap usage from get_user_pages()"). The fallback
> stub in the header which is now redundant, can be dropped off as well.

Looks good, thanks for the clean up.

Reviewed-by: Alistair Popple <apopple@nvidia.com>

> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: David Hildenbrand <david@redhat.com>
> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
> Cc: Zi Yan <ziy@nvidia.com>
> Cc: linux-mm@kvack.org
> Cc: linux-kernel@vger.kernel.org
> Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
> ---
>  include/linux/huge_mm.h | 6 ------
>  1 file changed, 6 deletions(-)
> 
> diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
> index 7748489fde1b..96ce0ca54e49 100644
> --- a/include/linux/huge_mm.h
> +++ b/include/linux/huge_mm.h
> @@ -652,12 +652,6 @@ static inline void mm_put_huge_zero_folio(struct mm_struct *mm)
>  	return;
>  }
>  
> -static inline struct page *follow_devmap_pmd(struct vm_area_struct *vma,
> -	unsigned long addr, pmd_t *pmd, int flags, struct dev_pagemap **pgmap)
> -{
> -	return NULL;
> -}
> -
>  static inline bool thp_migration_supported(void)
>  {
>  	return false;
> -- 
> 2.30.2
> 
> 

Re: [PATCH] mm/thp: Drop follow_devmap_pmd() default stub

[Wei Yang]

On Mon, Sep 29, 2025 at 11:46:43AM +0100, Anshuman Khandual wrote:
>follow_devmap_pmd() has already been dropped by the commit fd2825b0760a
>("mm/gup: remove pXX_devmap usage from get_user_pages()"). The fallback
>stub in the header which is now redundant, can be dropped off as well.
>
>Cc: Andrew Morton <akpm@linux-foundation.org>
>Cc: David Hildenbrand <david@redhat.com>
>Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
>Cc: Zi Yan <ziy@nvidia.com>
>Cc: linux-mm@kvack.org
>Cc: linux-kernel@vger.kernel.org
>Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>

Reviewed-by: Wei Yang <richard.weiyang@gmail.com>

-- 
Wei Yang
Help you, Help me