Re: [PATCH 27/30] mm/vma: correct incorrect vma.h inclusion

[Pedro Falcato]

On Mon, Jun 29, 2026 at 01:23:38PM +0100, Lorenzo Stoakes wrote:
> The only files which should be including vma.h are the implementation files
> for the core VMA logic - vma.c, vma_init.c, and vma_exec.c.
> 
> This is in order to allow for userland testing of core VMA logic. In this
> cases, vma_internal.h and vma.h are included, providing both the
> dependencies upon which the core VMA logic requires and its declarations.
> 
> Userland testable VMA logic is achieved by having separate vma_internal.h
> implementations for userland and kernel.
> 
> Callers other than the core VMA implementation should include internal.h
> instead. This header does not need to include vma_internal.h as it only
> contains the vma.h declarations, for which the includes already present
> suffice.
> 
> Update code to reflect this, update comments to reflect the fact there are
> 3 VMA implementation files and document things more clearly.
> 
> While we're here, slightly improve the language of the comment describing
> vma_exec.c.

Two random thoughts:
1) perhaps vma.h -> vma_private.h
2) https://lore.kernel.org/all/CAHk-=wghMm2c+AYEcwYY7drSVXB27DYqc-ZXpFiq=XFs-w59wA@xxxxxxxxxxxxxx/
   mm/vma/whatever.c :) would PROBABLY solve the issue of people snooping vma.h

> 
> No functional change intended.
> 
> Signed-off-by: Lorenzo Stoakes <ljs@xxxxxxxxxx>

Reviewed-by: Pedro Falcato <pfalcato@xxxxxxx>

> ---
>  mm/mmu_notifier.c | 2 +-
>  mm/nommu.c        | 1 -
>  mm/vma.c          | 4 ++++
>  mm/vma.h          | 9 ++++++++-
>  mm/vma_exec.c     | 8 ++++++--
>  mm/vma_init.c     | 4 ++++
>  mm/vma_internal.h | 4 ++--
>  7 files changed, 25 insertions(+), 7 deletions(-)
> 
> diff --git a/mm/mmu_notifier.c b/mm/mmu_notifier.c
> index 245b74f39f91..df69ba6e797f 100644
> --- a/mm/mmu_notifier.c
> +++ b/mm/mmu_notifier.c
> @@ -19,7 +19,7 @@
>  #include <linux/sched/mm.h>
>  #include <linux/slab.h>
>  
> -#include "vma.h"
> +#include "internal.h"
>  
>  /* global SRCU for all MMs */
>  DEFINE_STATIC_SRCU(srcu);
> diff --git a/mm/nommu.c b/mm/nommu.c
> index ba1c923c0942..4fef6fbbd6e9 100644
> --- a/mm/nommu.c
> +++ b/mm/nommu.c
> @@ -41,7 +41,6 @@
>  #include <asm/tlbflush.h>
>  #include <asm/mmu_context.h>
>  #include "internal.h"
> -#include "vma.h"
>  
>  unsigned long highest_memmap_pfn;
>  int heap_stack_gap = 0;
> diff --git a/mm/vma.c b/mm/vma.c
> index d727150e377a..5c3062e0e706 100644
> --- a/mm/vma.c
> +++ b/mm/vma.c
> @@ -4,6 +4,10 @@
>   * VMA-specific functions.
>   */
>  
> +/*
> + * To allow for userland testing we place internal dependencies in
> + * vma_internal.h and external VMA API declarations in vma.h.
> + */
>  #include "vma_internal.h"
>  #include "vma.h"
>  
> diff --git a/mm/vma.h b/mm/vma.h
> index 155eadda47aa..f4f885615a92 100644
> --- a/mm/vma.h
> +++ b/mm/vma.h
> @@ -2,7 +2,14 @@
>  /*
>   * vma.h
>   *
> - * Core VMA manipulation API implemented in vma.c.
> + * Core VMA manipulation API implemented in vma.c, vma_init.c and vma_exec.c.
> + *
> + * Note that, in order for VMA logic to be userland testable, this header
> + * intentionally includes no dependencies.
> + *
> + * This is specifically scoped to mm-only. Users of this functionality (other
> + * than the core VMA implementation itself) should not include this header
> + * directly, but rather include internal.h.
>   */
>  #ifndef __MM_VMA_H
>  #define __MM_VMA_H
> diff --git a/mm/vma_exec.c b/mm/vma_exec.c
> index 0107a6e3918c..c0f7ba2cfb27 100644
> --- a/mm/vma_exec.c
> +++ b/mm/vma_exec.c
> @@ -1,10 +1,14 @@
>  // SPDX-License-Identifier: GPL-2.0-only
>  
>  /*
> - * Functions explicitly implemented for exec functionality which however are
> - * explicitly VMA-only logic.
> + * Functions provided for exec functionality which however are
> + * specifically VMA-only logic.
>   */
>  
> +/*
> + * To allow for userland testing we place internal dependencies in
> + * vma_internal.h and external VMA API declarations in vma.h.
> + */
>  #include "vma_internal.h"
>  #include "vma.h"
>  
> diff --git a/mm/vma_init.c b/mm/vma_init.c
> index a459669a1654..715feee283f0 100644
> --- a/mm/vma_init.c
> +++ b/mm/vma_init.c
> @@ -5,6 +5,10 @@
>   * between CONFIG_MMU and non-CONFIG_MMU kernel configurations.
>   */
>  
> +/*
> + * To allow for userland testing we place internal dependencies in
> + * vma_internal.h and external VMA API declarations in vma.h.
> + */
>  #include "vma_internal.h"
>  #include "vma.h"
>  
> diff --git a/mm/vma_internal.h b/mm/vma_internal.h
> index 2da6d224c1a8..4d300e7bbaf4 100644
> --- a/mm/vma_internal.h
> +++ b/mm/vma_internal.h
> @@ -2,8 +2,8 @@
>  /*
>   * vma_internal.h
>   *
> - * Headers required by vma.c, which can be substituted accordingly when testing
> - * VMA functionality.
> + * Headers required by vma.c, vma_init.c and vma_exec.c, which can be
> + * substituted accordingly when testing VMA functionality.
>   */
>  
>  #ifndef __MM_VMA_INTERNAL_H
> -- 
> 2.54.0
> 

-- 
Pedro