Re: [Xen-devel] [RFC 02/23] xen/xenbus: client: Fix call of virt_to_mfn in xenbus_grant_ring

[David Vrabel <david.vrabel@xxxxxxxxxx>]

On 14/05/15 18:00, Julien Grall wrote:
> virt_to_mfn should take a void* rather an unsigned long. While it
> doesn't really matter now, it would throw a compiler warning later when
> virt_to_mfn will enforce the type.
> 
> At the same time, avoid to compute new virtual address every time in the
> loop and directly increment the parameter as we don't use it later.

Reviewed-by: David Vrabel <david.vrabel@xxxxxxxxxx>

But...

> --- a/drivers/xen/xenbus/xenbus_client.c
> +++ b/drivers/xen/xenbus/xenbus_client.c
> @@ -379,16 +379,16 @@ int xenbus_grant_ring(struct xenbus_device *dev, void 
> *vaddr,
>       int i, j;
>  
>       for (i = 0; i < nr_pages; i++) {
> -             unsigned long addr = (unsigned long)vaddr +
> -                     (PAGE_SIZE * i);
>               err = gnttab_grant_foreign_access(dev->otherend_id,
> -                                               virt_to_mfn(addr), 0);
> +                                               virt_to_mfn(vaddr), 0);
>               if (err < 0) {
>                       xenbus_dev_fatal(dev, err,
>                                        "granting access to ring page");
>                       goto fail;
>               }
>               grefs[i] = err;
> +
> +             vaddr = (char *)vaddr + PAGE_SIZE;

You don't need the cast here since vaddr is a void *.

David

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