linux-kernel - Re: [PATCH v2 3/4] mm, madvise: move madvise_set_anon

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Message-ID: <c6240a90-e02a-4ae2-b144-4fbf82aca6ce@redhat.com>
Date: Tue, 24 Jun 2025 16:05:26 +0200
From: David Hildenbrand <david@...hat.com>
To: Vlastimil Babka <vbabka@...e.cz>,
 Andrew Morton <akpm@...ux-foundation.org>,
 "Liam R. Howlett" <Liam.Howlett@...cle.com>,
 Lorenzo Stoakes <lorenzo.stoakes@...cle.com>, Jann Horn <jannh@...gle.com>,
 Mike Rapoport <rppt@...nel.org>, Suren Baghdasaryan <surenb@...gle.com>,
 Michal Hocko <mhocko@...e.com>, Colin Cross <ccross@...gle.com>
Cc: linux-mm@...ck.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 3/4] mm, madvise: move madvise_set_anon_name() down the
 file

On 24.06.25 15:03, Vlastimil Babka wrote:
> Preparatory change so that we can use madvise_lock()/unlock() in the
> function without forward declarations or more thorough shuffling.
> 
> Signed-off-by: Vlastimil Babka <vbabka@...e.cz>
> ---
>   mm/madvise.c | 64 ++++++++++++++++++++++++++++++------------------------------
>   1 file changed, 32 insertions(+), 32 deletions(-)
> 
> diff --git a/mm/madvise.c b/mm/madvise.c
> index 7e8819b5e9a0f183213ffe19d7e52bd5fda5f49d..cae064479cdf908707c45b941bd03d43d095eab6 100644
> --- a/mm/madvise.c
> +++ b/mm/madvise.c
> @@ -133,38 +133,6 @@ static int replace_anon_vma_name(struct vm_area_struct *vma,
>   
>   	return 0;
>   }
> -
> -static int madvise_set_anon_name(struct mm_struct *mm, unsigned long start,
> -		unsigned long len_in, struct anon_vma_name *anon_name)
> -{
> -	unsigned long end;
> -	unsigned long len;
> -	struct madvise_behavior madv_behavior = {
> -		.mm = mm,
> -		.behavior = __MADV_SET_ANON_VMA_NAME,
> -		.lock_mode = MADVISE_MMAP_WRITE_LOCK,
> -		.anon_name = anon_name,
> -	};
> -
> -	if (start & ~PAGE_MASK)
> -		return -EINVAL;
> -	len = (len_in + ~PAGE_MASK) & PAGE_MASK;
> -
> -	/* Check to see whether len was rounded up from small -ve to zero */
> -	if (len_in && !len)
> -		return -EINVAL;
> -
> -	end = start + len;
> -	if (end < start)
> -		return -EINVAL;
> -
> -	if (end == start)
> -		return 0;
> -
> -	madv_behavior.range.start = start;
> -	madv_behavior.range.end = end;
> -	return madvise_walk_vmas(&madv_behavior);
> -}
>   #else /* CONFIG_ANON_VMA_NAME */
>   static int replace_anon_vma_name(struct vm_area_struct *vma,
>   				 struct anon_vma_name *anon_name)
> @@ -2109,6 +2077,38 @@ static inline bool is_valid_name_char(char ch)
>   		!strchr(ANON_VMA_NAME_INVALID_CHARS, ch);
>   }
>   
> +static int madvise_set_anon_name(struct mm_struct *mm, unsigned long start,
> +		unsigned long len_in, struct anon_vma_name *anon_name)
> +{
> +	unsigned long end;
> +	unsigned long len;
> +	struct madvise_behavior madv_behavior = {
> +		.mm = mm,
> +		.behavior = __MADV_SET_ANON_VMA_NAME,
> +		.lock_mode = MADVISE_MMAP_WRITE_LOCK,
> +		.anon_name = anon_name,
> +	};
> +
> +	if (start & ~PAGE_MASK)
> +		return -EINVAL;
> +	len = (len_in + ~PAGE_MASK) & PAGE_MASK;
> +
> +	/* Check to see whether len was rounded up from small -ve to zero */
> +	if (len_in && !len)
> +		return -EINVAL;
> +
> +	end = start + len;
> +	if (end < start)
> +		return -EINVAL;
> +
> +	if (end == start)
> +		return 0;
> +
> +	madv_behavior.range.start = start;
> +	madv_behavior.range.end = end;
> +	return madvise_walk_vmas(&madv_behavior);
> +}
> +
>   int set_anon_vma_name(unsigned long addr, unsigned long size,
>   		      const char __user *uname)
>   {
> 

Personally, I would squash that into #4, given that #4 is pretty small ;)

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

-- 
Cheers,

David / dhildenb