Re: [PATCH v2 1/3] xen/privcmd: Corrected error handling path

[Jürgen Groß <jgross@xxxxxxxx>]

On 06.07.20 20:16, Souptick Joarder wrote:
> Previously, if lock_pages() end up partially mapping pages, it used
> to return -ERRNO due to which unlock_pages() have to go through
> each pages[i] till *nr_pages* to validate them. This can be avoided
> by passing correct number of partially mapped pages & -ERRNO separately,
> while returning from lock_pages() due to error.
>
> With this fix unlock_pages() doesn't need to validate pages[i] till
> *nr_pages* for error scenario and few condition checks can be ignored.
>
> Signed-off-by: Souptick Joarder <jrdr.linux@xxxxxxxxx>
> Cc: John Hubbard <jhubbard@xxxxxxxxxx>
> Cc: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
> Cc: Paul Durrant <xadimgnik@xxxxxxxxx>
> ---
>   drivers/xen/privcmd.c | 31 +++++++++++++++----------------
>   1 file changed, 15 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/xen/privcmd.c b/drivers/xen/privcmd.c
> index a250d11..33677ea 100644
> --- a/drivers/xen/privcmd.c
> +++ b/drivers/xen/privcmd.c
> @@ -580,13 +580,13 @@ static long privcmd_ioctl_mmap_batch(
>   
>   static int lock_pages(
>         struct privcmd_dm_op_buf kbufs[], unsigned int num,
> -       struct page *pages[], unsigned int nr_pages)
> +       struct page *pages[], unsigned int nr_pages, unsigned int *pinned)
>   {
>         unsigned int i;
> +       int page_count = 0;
Initial value shouldn't be needed, and ...

>   
>   	for (i = 0; i < num; i++) {
>                 unsigned int requested;
> -               int pinned;
... you could move the declaration here.

With that done you can add my

Reviewed-by: Juergen Gross <jgross@xxxxxxxx>


Juergen