Re: [PATCH 07/10] mm: use remove_vm_area in __vunmap

[Uladzislau Rezki <urezki@gmail.com>]

On Thu, Jan 19, 2023 at 11:02:23AM +0100, Christoph Hellwig wrote:
> Use the common helper to find and remove a vmap_area instead of open
> coding it.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>  mm/vmalloc.c | 33 ++++++++++++---------------------
>  1 file changed, 12 insertions(+), 21 deletions(-)
> 
> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
> index 09c6fcfdaeb7c9..096633ba89965a 100644
> --- a/mm/vmalloc.c
> +++ b/mm/vmalloc.c
> @@ -2571,20 +2571,6 @@ struct vm_struct *find_vm_area(const void *addr)
>  	return va->vm;
>  }
>  
> -static struct vm_struct *__remove_vm_area(struct vmap_area *va)
> -{
> -	struct vm_struct *vm;
> -
> -	if (!va || !va->vm)
> -		return NULL;
> -
> -	vm = va->vm;
> -	kasan_free_module_shadow(vm);
> -	free_unmap_vmap_area(va);
> -
> -	return vm;
> -}
> -
>  /**
>   * remove_vm_area - find and remove a continuous kernel virtual area
>   * @addr:	    base address
> @@ -2597,10 +2583,18 @@ static struct vm_struct *__remove_vm_area(struct vmap_area *va)
>   */
>  struct vm_struct *remove_vm_area(const void *addr)
>  {
> +	struct vmap_area *va;
> +	struct vm_struct *vm;
> +
>  	might_sleep();
>  
> -	return __remove_vm_area(
> -		find_unlink_vmap_area((unsigned long) addr));
> +	va = find_unlink_vmap_area((unsigned long)addr);
> +	if (!va || !va->vm)
> +		return NULL;
> +	vm = va->vm;
> +	kasan_free_module_shadow(vm);
> +	free_unmap_vmap_area(va);
> +	return vm;
>  }
>  
>  static inline void set_area_direct_map(const struct vm_struct *area,
> @@ -2666,7 +2660,6 @@ static void va_remove_mappings(struct vm_struct *area, int deallocate_pages)
>  static void __vunmap(const void *addr, int deallocate_pages)
>  {
>  	struct vm_struct *area;
> -	struct vmap_area *va;
>  
>  	if (!addr)
>  		return;
> @@ -2675,20 +2668,18 @@ static void __vunmap(const void *addr, int deallocate_pages)
>  			addr))
>  		return;
>  
> -	va = find_unlink_vmap_area((unsigned long)addr);
> -	if (unlikely(!va)) {
> +	area = remove_vm_area(addr);
> +	if (unlikely(!area)) {
>  		WARN(1, KERN_ERR "Trying to vfree() nonexistent vm area (%p)\n",
>  				addr);
>  		return;
>  	}
>  
> -	area = va->vm;
>  	debug_check_no_locks_freed(area->addr, get_vm_area_size(area));
>  	debug_check_no_obj_freed(area->addr, get_vm_area_size(area));
>  
>  	kasan_poison_vmalloc(area->addr, get_vm_area_size(area));
>  
> -	__remove_vm_area(va);
>  	va_remove_mappings(area, deallocate_pages);
>  
>  	if (deallocate_pages) {
> -- 
> 2.39.0
> 
Reviewed-by: Uladzislau Rezki (Sony) <urezki@gmail.com>

--
Uladzislau Rezki