Re: [PATCH 1/9] mm: vmalloc: Add va_alloc() helper

[Lorenzo Stoakes <lstoakes@gmail.com>]

On Mon, May 22, 2023 at 01:08:41PM +0200, Uladzislau Rezki (Sony) wrote:
> Currently __alloc_vmap_area() function contains an open codded
> logic that finds and adjusts a VA based on allocation request.
>
> Introduce a va_alloc() helper that adjusts found VA only. It
> will be used later at least in two places.
>
> There is no a functional change as a result of this patch.
>
> Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
> ---
>  mm/vmalloc.c | 41 ++++++++++++++++++++++++++++-------------
>  1 file changed, 28 insertions(+), 13 deletions(-)
>
> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
> index 31ff782d368b..409285b68a67 100644
> --- a/mm/vmalloc.c
> +++ b/mm/vmalloc.c
> @@ -1482,6 +1482,32 @@ adjust_va_to_fit_type(struct rb_root *root, struct list_head *head,
>  	return 0;
>  }
>
> +static unsigned long
> +va_alloc(struct vmap_area *va,
> +	struct rb_root *root, struct list_head *head,
> +	unsigned long size, unsigned long align,
> +	unsigned long vstart, unsigned long vend)
> +{
> +	unsigned long nva_start_addr;
> +	int ret;
> +
> +	if (va->va_start > vstart)
> +		nva_start_addr = ALIGN(va->va_start, align);
> +	else
> +		nva_start_addr = ALIGN(vstart, align);
> +
> +	/* Check the "vend" restriction. */
> +	if (nva_start_addr + size > vend)
> +		return vend;
> +
> +	/* Update the free vmap_area. */
> +	ret = adjust_va_to_fit_type(root, head, va, nva_start_addr, size);
> +	if (WARN_ON_ONCE(ret))
> +		return vend;
> +
> +	return nva_start_addr;
> +}
> +
>  /*
>   * Returns a start address of the newly allocated area, if success.
>   * Otherwise a vend is returned that indicates failure.
> @@ -1494,7 +1520,6 @@ __alloc_vmap_area(struct rb_root *root, struct list_head *head,
>  	bool adjust_search_size = true;
>  	unsigned long nva_start_addr;
>  	struct vmap_area *va;
> -	int ret;
>
>  	/*
>  	 * Do not adjust when:
> @@ -1512,18 +1537,8 @@ __alloc_vmap_area(struct rb_root *root, struct list_head *head,
>  	if (unlikely(!va))
>  		return vend;
>
> -	if (va->va_start > vstart)
> -		nva_start_addr = ALIGN(va->va_start, align);
> -	else
> -		nva_start_addr = ALIGN(vstart, align);
> -
> -	/* Check the "vend" restriction. */
> -	if (nva_start_addr + size > vend)
> -		return vend;
> -
> -	/* Update the free vmap_area. */
> -	ret = adjust_va_to_fit_type(root, head, va, nva_start_addr, size);
> -	if (WARN_ON_ONCE(ret))
> +	nva_start_addr = va_alloc(va, root, head, size, align, vstart, vend);
> +	if (nva_start_addr == vend)
>  		return vend;
>
>  #if DEBUG_AUGMENT_LOWEST_MATCH_CHECK
> --
> 2.30.2
>

LGTM,

Reviewed-by: Lorenzo Stoakes <lstoakes@gmail.com>