linux-kernel - Re: [PATCH v2] mm/mmap: introduce vma_set

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Date: Thu, 25 Jan 2024 10:43:27 +0800
From: Yajun Deng <yajun.deng@...ux.dev>
To: "Liam R. Howlett" <Liam.Howlett@...cle.com>
Cc: akpm@...ux-foundation.org, linux-mm@...ck.org,
 linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] mm/mmap: introduce vma_set_range()


On 2024/1/24 23:47, Liam R. Howlett wrote:
> * Yajun Deng <yajun.deng@...ux.dev> [240123 22:57]:
>> There is a lot of code needs to set the range of vma in mmap.c,
>> introduce vma_set_range() to simplify the code.
>>
>> Signed-off-by: Yajun Deng <yajun.deng@...ux.dev>
> Thank you for making the suggested changes, I have one small comment but
> you don't need to re-spin the patch for it.  This looks good.
>
> Reviewed-by: Liam R. Howlett <Liam.Howlett@...cle.com>
>
>> ---
>> v2: use vma_set_range and put it to mm/internal.h.
>> v1: https://lore.kernel.org/all/20240111021526.3461825-1-yajun.deng@linux.dev/
>> ---
>>   mm/internal.h |  9 +++++++++
>>   mm/mmap.c     | 29 +++++++----------------------
>>   2 files changed, 16 insertions(+), 22 deletions(-)
>>
>> diff --git a/mm/internal.h b/mm/internal.h
>> index f309a010d50f..1e29c5821a1d 100644
>> --- a/mm/internal.h
>> +++ b/mm/internal.h
>> @@ -1114,6 +1114,15 @@ static inline bool gup_must_unshare(struct vm_area_struct *vma,
>>   extern bool mirrored_kernelcore;
>>   extern bool memblock_has_mirror(void);
>>   
>> +static __always_inline void vma_set_range(struct vm_area_struct *vma,
>> +					  unsigned long start, unsigned long end,
>> +					  pgoff_t pgoff)
> Nit: This isn't part of the style guide, but if you just indent with two
> tabs for arguments then it is easier to expand the list without more
> lines.  It also allows changing the function prototype without
> re-indenting all the other lines, so future changes can be smaller.  I
> think you would save a line here without affecting readability.

Thank you. I thought the parameters needed to be aligned.

>
>> +{
>> +	vma->vm_start = start;
>> +	vma->vm_end = end;
>> +	vma->vm_pgoff = pgoff;
>> +}
>> +
>>   static inline bool vma_soft_dirty_enabled(struct vm_area_struct *vma)
>>   {
>>   	/*
>> diff --git a/mm/mmap.c b/mm/mmap.c
>> index cf2f058bb3ae..7a9d2895a1bd 100644
>> --- a/mm/mmap.c
>> +++ b/mm/mmap.c
>> @@ -663,9 +663,7 @@ int vma_expand(struct vma_iterator *vmi, struct vm_area_struct *vma,
>>   
>>   	vma_prepare(&vp);
>>   	vma_adjust_trans_huge(vma, start, end, 0);
>> -	vma->vm_start = start;
>> -	vma->vm_end = end;
>> -	vma->vm_pgoff = pgoff;
>> +	vma_set_range(vma, start, end, pgoff);
>>   	vma_iter_store(vmi, vma);
>>   
>>   	vma_complete(&vp, vmi, vma->vm_mm);
>> @@ -708,9 +706,7 @@ int vma_shrink(struct vma_iterator *vmi, struct vm_area_struct *vma,
>>   	vma_adjust_trans_huge(vma, start, end, 0);
>>   
>>   	vma_iter_clear(vmi);
>> -	vma->vm_start = start;
>> -	vma->vm_end = end;
>> -	vma->vm_pgoff = pgoff;
>> +	vma_set_range(vma, start, end, pgoff);
>>   	vma_complete(&vp, vmi, vma->vm_mm);
>>   	return 0;
>>   }
>> @@ -1015,10 +1011,7 @@ static struct vm_area_struct
>>   
>>   	vma_prepare(&vp);
>>   	vma_adjust_trans_huge(vma, vma_start, vma_end, adj_start);
>> -
>> -	vma->vm_start = vma_start;
>> -	vma->vm_end = vma_end;
>> -	vma->vm_pgoff = vma_pgoff;
>> +	vma_set_range(vma, vma_start, vma_end, vma_pgoff);
>>   
>>   	if (vma_expanded)
>>   		vma_iter_store(vmi, vma);
>> @@ -2809,11 +2802,9 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
>>   	}
>>   
>>   	vma_iter_config(&vmi, addr, end);
>> -	vma->vm_start = addr;
>> -	vma->vm_end = end;
>> +	vma_set_range(vma, addr, end, pgoff);
>>   	vm_flags_init(vma, vm_flags);
>>   	vma->vm_page_prot = vm_get_page_prot(vm_flags);
>> -	vma->vm_pgoff = pgoff;
>>   
>>   	if (file) {
>>   		vma->vm_file = get_file(file);
>> @@ -3163,9 +3154,7 @@ static int do_brk_flags(struct vma_iterator *vmi, struct vm_area_struct *vma,
>>   		goto unacct_fail;
>>   
>>   	vma_set_anonymous(vma);
>> -	vma->vm_start = addr;
>> -	vma->vm_end = addr + len;
>> -	vma->vm_pgoff = addr >> PAGE_SHIFT;
>> +	vma_set_range(vma, addr, addr + len, addr >> PAGE_SHIFT);
>>   	vm_flags_init(vma, flags);
>>   	vma->vm_page_prot = vm_get_page_prot(flags);
>>   	vma_start_write(vma);
>> @@ -3402,9 +3391,7 @@ struct vm_area_struct *copy_vma(struct vm_area_struct **vmap,
>>   		new_vma = vm_area_dup(vma);
>>   		if (!new_vma)
>>   			goto out;
>> -		new_vma->vm_start = addr;
>> -		new_vma->vm_end = addr + len;
>> -		new_vma->vm_pgoff = pgoff;
>> +		vma_set_range(new_vma, addr, addr + len, pgoff);
>>   		if (vma_dup_policy(vma, new_vma))
>>   			goto out_free_vma;
>>   		if (anon_vma_clone(new_vma, vma))
>> @@ -3572,9 +3559,7 @@ static struct vm_area_struct *__install_special_mapping(
>>   	if (unlikely(vma == NULL))
>>   		return ERR_PTR(-ENOMEM);
>>   
>> -	vma->vm_start = addr;
>> -	vma->vm_end = addr + len;
>> -
>> +	vma_set_range(vma, addr, addr + len, 0);
>>   	vm_flags_init(vma, (vm_flags | mm->def_flags |
>>   		      VM_DONTEXPAND | VM_SOFTDIRTY) & ~VM_LOCKED_MASK);
>>   	vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
>> -- 
>> 2.25.1
>>