Re: [PATCH v2 7/7] virtio_balloon: Stop calling page_address() in free_pages()

[David Hildenbrand <david@redhat.com>]

On 26.08.25 22:56, Vishal Moola (Oracle) wrote:
> free_pages() should be used when we only have a virtual address. We
> should call __free_pages() directly on our page instead.
> 
> Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
> ---
>   drivers/virtio/virtio_balloon.c | 3 +--
>   1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
> index eae65136cdfb..d4e6865ce355 100644
> --- a/drivers/virtio/virtio_balloon.c
> +++ b/drivers/virtio/virtio_balloon.c
> @@ -488,8 +488,7 @@ static unsigned long return_free_pages_to_mm(struct virtio_balloon *vb,
>   		page = balloon_page_pop(&vb->free_page_list);
>   		if (!page)
>   			break;
> -		free_pages((unsigned long)page_address(page),
> -			   VIRTIO_BALLOON_HINT_BLOCK_ORDER);
> +		__free_pages(page, VIRTIO_BALLOON_HINT_BLOCK_ORDER);
>   	}
>   	vb->num_free_page_blocks -= num_returned;
>   	spin_unlock_irq(&vb->free_page_list_lock);

I think you missed another nastiness of similar kind in 
get_free_page_and_send() where we do

	p = page_address(page);

Just to call

	free_pages((unsigned long)p, VIRTIO_BALLOON_HINT_BLOCK_ORDER);

-- 
Cheers

David / dhildenb