Re: [Xen-devel] [PATCH 06/17] xen/x86: mm: Fix the comment on top put_page_from_l2e() to use 'mfn'

[Jan Beulich <jbeulich@xxxxxxxx>]

On 22.03.2020 17:14, julien@xxxxxxx wrote:
> From: Julien Grall <jgrall@xxxxxxxxxx>
> 
> We are using the 'mfn' to refer to machine frame. As this function deal
> with 'mfn', replace 'pfn' with 'mfn'.
> 
> Signed-off-by: Julien Grall <jgrall@xxxxxxxxxx>
> 
> ---
> 
> I am not entirely sure to understand the comment on top of the
> function, so this change may be wrong.

Looking at the history of the function, ...

> --- a/xen/arch/x86/mm.c
> +++ b/xen/arch/x86/mm.c
> @@ -1321,7 +1321,7 @@ static int put_data_pages(struct page_info *page, bool 
> writeable, int pt_shift)
>  }
>  
>  /*
> - * NB. Virtual address 'l2e' maps to a machine address within frame 'pfn'.
> + * NB. Virtual address 'l2e' maps to a machine address within frame 'mfn'.
>   * Note also that this automatically deals correctly with linear p.t.'s.
>   */
>  static int put_page_from_l2e(l2_pgentry_t l2e, mfn_t l2mfn, unsigned int 
> flags)

... it used to be

static int put_page_from_l2e(l2_pgentry_t l2e, unsigned long pfn)

When the rename occurred (in the context of or as a follow-up to an
XSA iirc), the comment adjustment was apparently missed. With the
referenced name matching that of the function argument (l2mfn)
Acked-by: Jan Beulich <jbeulich@xxxxxxxx>

Jan