linux-kernel - Re: [PATCH v2 1/2] mm/mmap: pass vma to vma

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Message-ID: <20240126022501.juc5d7xpotjyying@revolver>
Date: Thu, 25 Jan 2024 21:25:01 -0500
From: "Liam R. Howlett" <Liam.Howlett@...cle.com>
To: Yajun Deng <yajun.deng@...ux.dev>
Cc: akpm@...ux-foundation.org, lstoakes@...il.com, viro@...iv.linux.org.uk,
        brauner@...nel.org, vbabka@...e.cz, willy@...radead.org,
        surenb@...gle.com, linux-mm@...ck.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 1/2] mm/mmap: pass vma to vma_merge()

* Yajun Deng <yajun.deng@...ux.dev> [240124 22:49]:
> These vma_merge() callers will pass mm, anon_vma and file, they all from
> the same vma. There is no need to pass three parameters at the same time.
> 
> Pass vma instead of mm, anon_vma and file to vma_merge(), so that it can
> save two parameters.
> 
> Signed-off-by: Yajun Deng <yajun.deng@...ux.dev>

Thanks for splitting these up.

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

> ---
>  mm/mmap.c | 27 +++++++++++++--------------
>  1 file changed, 13 insertions(+), 14 deletions(-)
> 
> diff --git a/mm/mmap.c b/mm/mmap.c
> index 49d25172eac8..f19bc53bc08e 100644
> --- a/mm/mmap.c
> +++ b/mm/mmap.c
> @@ -860,13 +860,15 @@ can_vma_merge_after(struct vm_area_struct *vma, unsigned long vm_flags,
>   *      area is returned, or the function will return NULL
>   */
>  static struct vm_area_struct
> -*vma_merge(struct vma_iterator *vmi, struct mm_struct *mm,
> -	   struct vm_area_struct *prev, unsigned long addr, unsigned long end,
> -	   unsigned long vm_flags, struct anon_vma *anon_vma, struct file *file,
> -	   pgoff_t pgoff, struct mempolicy *policy,
> +*vma_merge(struct vma_iterator *vmi, struct vm_area_struct *prev,
> +	   struct vm_area_struct *src, unsigned long addr, unsigned long end,
> +	   unsigned long vm_flags, pgoff_t pgoff, struct mempolicy *policy,
>  	   struct vm_userfaultfd_ctx vm_userfaultfd_ctx,
>  	   struct anon_vma_name *anon_name)
>  {
> +	struct mm_struct *mm = src->vm_mm;
> +	struct anon_vma *anon_vma = src->anon_vma;
> +	struct file *file = src->vm_file;
>  	struct vm_area_struct *curr, *next, *res;
>  	struct vm_area_struct *vma, *adjust, *remove, *remove2;
>  	struct vm_area_struct *anon_dup = NULL;
> @@ -2424,9 +2426,8 @@ struct vm_area_struct *vma_modify(struct vma_iterator *vmi,
>  	pgoff_t pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT);
>  	struct vm_area_struct *merged;
>  
> -	merged = vma_merge(vmi, vma->vm_mm, prev, start, end, vm_flags,
> -			   vma->anon_vma, vma->vm_file, pgoff, policy,
> -			   uffd_ctx, anon_name);
> +	merged = vma_merge(vmi, prev, vma, start, end, vm_flags,
> +			   pgoff, policy, uffd_ctx, anon_name);
>  	if (merged)
>  		return merged;
>  
> @@ -2456,9 +2457,8 @@ static struct vm_area_struct
>  		   struct vm_area_struct *vma, unsigned long start,
>  		   unsigned long end, pgoff_t pgoff)
>  {
> -	return vma_merge(vmi, vma->vm_mm, prev, start, end, vma->vm_flags,
> -			 vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma),
> -			 vma->vm_userfaultfd_ctx, anon_vma_name(vma));
> +	return vma_merge(vmi, prev, vma, start, end, vma->vm_flags, pgoff,
> +			 vma_policy(vma), vma->vm_userfaultfd_ctx, anon_vma_name(vma));
>  }
>  
>  /*
> @@ -2472,10 +2472,9 @@ struct vm_area_struct *vma_merge_extend(struct vma_iterator *vmi,
>  	pgoff_t pgoff = vma->vm_pgoff + vma_pages(vma);
>  
>  	/* vma is specified as prev, so case 1 or 2 will apply. */
> -	return vma_merge(vmi, vma->vm_mm, vma, vma->vm_end, vma->vm_end + delta,
> -			 vma->vm_flags, vma->anon_vma, vma->vm_file, pgoff,
> -			 vma_policy(vma), vma->vm_userfaultfd_ctx,
> -			 anon_vma_name(vma));
> +	return vma_merge(vmi, vma, vma, vma->vm_end, vma->vm_end + delta,
> +			 vma->vm_flags, pgoff, vma_policy(vma),
> +			 vma->vm_userfaultfd_ctx, anon_vma_name(vma));
>  }
>  
>  /*
> -- 
> 2.25.1
>