On Thu, 9 Jul 2015, Julien Grall wrote:
> The Xen interface is always using 4KB page. This means that a Linux page
> may be split across multiple Xen page when the page granularity is not
> the same.
>
> This helper will break down a Linux page into 4KB chunk and call the
> helper on each of them.
>
> Signed-off-by: Julien Grall <julien.gr...@citrix.com>
> Cc: Konrad Rzeszutek Wilk <konrad.w...@oracle.com>
> Cc: Boris Ostrovsky <boris.ostrov...@oracle.com>
> Cc: David Vrabel <david.vra...@citrix.com>
> ---
> Changes in v2:
> - Patch added
> ---
> include/xen/page.h | 20 ++++++++++++++++++++
> 1 file changed, 20 insertions(+)
>
> diff --git a/include/xen/page.h b/include/xen/page.h
> index 8ebd37b..b1f7722 100644
> --- a/include/xen/page.h
> +++ b/include/xen/page.h
> @@ -39,4 +39,24 @@ struct xen_memory_region
> xen_extra_mem[XEN_EXTRA_MEM_MAX_REGIONS];
>
> extern unsigned long xen_released_pages;
>
> +typedef int (*xen_pfn_fn_t)(struct page *page, unsigned long pfn, void
> *data);
> +/* Break down the page in 4KB granularity and call fn foreach xen pfn */
> +static inline int xen_apply_to_page(struct page *page, xen_pfn_fn_t fn,
> + void *data)
> +{
> + unsigned long pfn = xen_page_to_pfn(page);
> + int i;
> + int ret;
please initialize ret to 0
> + for (i = 0; i < XEN_PFN_PER_PAGE; i++, pfn++) {
> + ret = fn(page, pfn, data);
> + if (ret)
> + return ret;
> + }
> +
> + return ret;
> +}
> +
> +
> #endif /* _XEN_PAGE_H */
Reviewed-by: Stefano Stabellini <stefano.stabell...@eu.citrix.com>
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
