linux-kernel - Re: [PATCH v3 1/7] mm: Move can_modify

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Message-ID: <fp2z3jevyvhpjqutv4a6aziws7bittmz3imelu4eh3eyp7niie@hnyca5qt6nmm>
Date: Mon, 19 Aug 2024 16:15:07 -0400
From: "Liam R. Howlett" <Liam.Howlett@...cle.com>
To: Pedro Falcato <pedro.falcato@...il.com>
Cc: Andrew Morton <akpm@...ux-foundation.org>,
        Vlastimil Babka <vbabka@...e.cz>,
        Lorenzo Stoakes <lorenzo.stoakes@...cle.com>,
        Shuah Khan <shuah@...nel.org>, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org, linux-kselftest@...r.kernel.org,
        jeffxu@...omium.org, oliver.sang@...el.com,
        torvalds@...ux-foundation.org, Michael Ellerman <mpe@...erman.id.au>,
        Kees Cook <kees@...nel.org>
Subject: Re: [PATCH v3 1/7] mm: Move can_modify_vma to mm/vma.h

* Pedro Falcato <pedro.falcato@...il.com> [240816 20:18]:
> Move can_modify_vma to vma.h so it can be inlined properly (with
> the intent to remove can_modify_mm callsites).
> 
> Signed-off-by: Pedro Falcato <pedro.falcato@...il.com>
> ---
>  mm/mseal.c | 17 -----------------
>  mm/vma.h   | 28 ++++++++++++++++++++++++++++
>  2 files changed, 28 insertions(+), 17 deletions(-)
> 
> diff --git a/mm/mseal.c b/mm/mseal.c
> index 15bba28acc00..2170e2139ca0 100644
> --- a/mm/mseal.c
> +++ b/mm/mseal.c
> @@ -16,28 +16,11 @@
>  #include <linux/sched.h>
>  #include "internal.h"
>  
> -static inline bool vma_is_sealed(struct vm_area_struct *vma)
> -{
> -	return (vma->vm_flags & VM_SEALED);
> -}
> -
>  static inline void set_vma_sealed(struct vm_area_struct *vma)
>  {
>  	vm_flags_set(vma, VM_SEALED);
>  }
>  
> -/*
> - * check if a vma is sealed for modification.
> - * return true, if modification is allowed.
> - */
> -static bool can_modify_vma(struct vm_area_struct *vma)
> -{
> -	if (unlikely(vma_is_sealed(vma)))
> -		return false;
> -
> -	return true;
> -}
> -
>  static bool is_madv_discard(int behavior)
>  {
>  	switch (behavior) {
> diff --git a/mm/vma.h b/mm/vma.h
> index 6efdf1768a0a..e979015cc7fc 100644
> --- a/mm/vma.h
> +++ b/mm/vma.h
> @@ -361,4 +361,32 @@ struct vm_area_struct *vma_iter_prev_range(struct vma_iterator *vmi)
>  	return mas_prev_range(&vmi->mas, 0);
>  }
>  
> +#ifdef CONFIG_64BIT
> +
> +static inline bool vma_is_sealed(struct vm_area_struct *vma)
> +{
> +	return (vma->vm_flags & VM_SEALED);
> +}

If you respin, I'd support dropping this entirely as it seems
unnecessary.

Either way,
Reviewed-by: Liam R. Howlett <Liam.Howlett@...cle.com>


> +
> +/*
> + * check if a vma is sealed for modification.
> + * return true, if modification is allowed.
> + */
> +static inline bool can_modify_vma(struct vm_area_struct *vma)
> +{
> +	if (unlikely(vma_is_sealed(vma)))
> +		return false;
> +
> +	return true;
> +}
> +
> +#else
> +
> +static inline bool can_modify_vma(struct vm_area_struct *vma)
> +{
> +	return true;
> +}
> +
> +#endif
> +
>  #endif	/* __MM_VMA_H */
> 
> -- 
> 2.46.0
>