linux-kernel - Re: [PATCH] mm/vmalloc: Refactoring function __vmalloc_node_range

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Message-ID: <Z8mr12PilC00Wcvg@pc636>
Date: Thu, 6 Mar 2025 15:06:15 +0100
From: Uladzislau Rezki <urezki@...il.com>
To: Liu Ye <liuye@...inos.cn>
Cc: akpm@...ux-foundation.org, urezki@...il.com, hch@...radead.org,
	linux-mm@...ck.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] mm/vmalloc: Refactoring function
 __vmalloc_node_range_noprof

On Thu, Mar 06, 2025 at 03:21:31PM +0800, Liu Ye wrote:
> According to the code logic, the first parameter of the sub-function
> __get_vm_area_node should be size instead of real_size.
> 
> Then in the function __get_vm_area_node, the size will be aligned,
> so the redundant alignment operation is deleted.
> 
> The use of the real_size variable causes code redundancy,
> so it is removed to simplify the code.
> 
> The real prefix is generally used to indicate the adjusted value of a
> parameter, but according to the code logic, it should indicate the
> original value, so it is recommended to rename it to original_align.
> 
> Signed-off-by: Liu Ye <liuye@...inos.cn>
> ---
>  mm/vmalloc.c | 20 ++++++++------------
>  1 file changed, 8 insertions(+), 12 deletions(-)
> 
> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
> index dc658d4af181..a8488452b70b 100644
> --- a/mm/vmalloc.c
> +++ b/mm/vmalloc.c
> @@ -3770,8 +3770,7 @@ void *__vmalloc_node_range_noprof(unsigned long size, unsigned long align,
>  	struct vm_struct *area;
>  	void *ret;
>  	kasan_vmalloc_flags_t kasan_flags = KASAN_VMALLOC_NONE;
> -	unsigned long real_size = size;
> -	unsigned long real_align = align;
> +	unsigned long original_align = align;
>  	unsigned int shift = PAGE_SHIFT;
>  
>  	if (WARN_ON_ONCE(!size))
> @@ -3780,7 +3779,7 @@ void *__vmalloc_node_range_noprof(unsigned long size, unsigned long align,
>  	if ((size >> PAGE_SHIFT) > totalram_pages()) {
>  		warn_alloc(gfp_mask, NULL,
>  			"vmalloc error: size %lu, exceeds total pages",
> -			real_size);
> +			size);
>  		return NULL;
>  	}
>  
> @@ -3797,19 +3796,18 @@ void *__vmalloc_node_range_noprof(unsigned long size, unsigned long align,
>  		else
>  			shift = arch_vmap_pte_supported_shift(size);
>  
> -		align = max(real_align, 1UL << shift);
> -		size = ALIGN(real_size, 1UL << shift);
> +		align = max(original_align, 1UL << shift);
>  	}
>  
>  again:
> -	area = __get_vm_area_node(real_size, align, shift, VM_ALLOC |
> +	area = __get_vm_area_node(size, align, shift, VM_ALLOC |
>  				  VM_UNINITIALIZED | vm_flags, start, end, node,
>  				  gfp_mask, caller);
>  	if (!area) {
>  		bool nofail = gfp_mask & __GFP_NOFAIL;
>  		warn_alloc(gfp_mask, NULL,
>  			"vmalloc error: size %lu, vm_struct allocation failed%s",
> -			real_size, (nofail) ? ". Retrying." : "");
> +			size, (nofail) ? ". Retrying." : "");
>  		if (nofail) {
>  			schedule_timeout_uninterruptible(1);
>  			goto again;
> @@ -3861,7 +3859,7 @@ void *__vmalloc_node_range_noprof(unsigned long size, unsigned long align,
>  	    (gfp_mask & __GFP_SKIP_ZERO))
>  		kasan_flags |= KASAN_VMALLOC_INIT;
>  	/* KASAN_VMALLOC_PROT_NORMAL already set if required. */
> -	area->addr = kasan_unpoison_vmalloc(area->addr, real_size, kasan_flags);
> +	area->addr = kasan_unpoison_vmalloc(area->addr, size, kasan_flags);
>  
>  	/*
>  	 * In this function, newly allocated vm_struct has VM_UNINITIALIZED
> @@ -3870,17 +3868,15 @@ void *__vmalloc_node_range_noprof(unsigned long size, unsigned long align,
>  	 */
>  	clear_vm_uninitialized_flag(area);
>  
> -	size = PAGE_ALIGN(size);
>  	if (!(vm_flags & VM_DEFER_KMEMLEAK))
> -		kmemleak_vmalloc(area, size, gfp_mask);
> +		kmemleak_vmalloc(area, PAGE_ALIGN(size), gfp_mask);
>  
>  	return area->addr;
>  
>  fail:
>  	if (shift > PAGE_SHIFT) {
>  		shift = PAGE_SHIFT;
> -		align = real_align;
> -		size = real_size;
> +		align = original_align;
>  		goto again;
>  	}
>  
> -- 
> 2.25.1
> 
This one looks good to me:

Reviewed-by: "Uladzislau Rezki (Sony)" <urezki@...il.com>

--
Uladzislau Rezki