linux-kernel - Re: [PATCH v2 2/9] xen/grant-table: Make set/clear page private code shared

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Date:   Fri, 1 Jun 2018 14:44:38 +0300
From:   Oleksandr Andrushchenko <andr2000@...il.com>
To:     xen-devel@...ts.xenproject.org, linux-kernel@...r.kernel.org,
        dri-devel@...ts.freedesktop.org, linux-media@...r.kernel.org,
        jgross@...e.com, boris.ostrovsky@...cle.com, konrad.wilk@...cle.com
Cc:     daniel.vetter@...el.com, dongwon.kim@...el.com,
        matthew.d.roper@...el.com,
        Oleksandr Andrushchenko <oleksandr_andrushchenko@...m.com>
Subject: Re: [PATCH v2 2/9] xen/grant-table: Make set/clear page private code
 shared

Boris, I dropped your r-b for this patch as I changed

EXPORT_SYMBOL to EXPORT_SYMBOL_GPL as Juergen requested

On 06/01/2018 02:41 PM, Oleksandr Andrushchenko wrote:
> From: Oleksandr Andrushchenko <oleksandr_andrushchenko@...m.com>
>
> Make set/clear page private code shared and accessible to
> other kernel modules which can re-use these instead of open-coding.
>
> Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@...m.com>
> ---
>   drivers/xen/grant-table.c | 54 +++++++++++++++++++++++++--------------
>   include/xen/grant_table.h |  3 +++
>   2 files changed, 38 insertions(+), 19 deletions(-)
>
> diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c
> index ba36ff3e4903..dbb48a89e987 100644
> --- a/drivers/xen/grant-table.c
> +++ b/drivers/xen/grant-table.c
> @@ -769,29 +769,18 @@ void gnttab_free_auto_xlat_frames(void)
>   }
>   EXPORT_SYMBOL_GPL(gnttab_free_auto_xlat_frames);
>   
> -/**
> - * gnttab_alloc_pages - alloc pages suitable for grant mapping into
> - * @nr_pages: number of pages to alloc
> - * @pages: returns the pages
> - */
> -int gnttab_alloc_pages(int nr_pages, struct page **pages)
> +int gnttab_pages_set_private(int nr_pages, struct page **pages)
>   {
>   	int i;
> -	int ret;
> -
> -	ret = alloc_xenballooned_pages(nr_pages, pages);
> -	if (ret < 0)
> -		return ret;
>   
>   	for (i = 0; i < nr_pages; i++) {
>   #if BITS_PER_LONG < 64
>   		struct xen_page_foreign *foreign;
>   
>   		foreign = kzalloc(sizeof(*foreign), GFP_KERNEL);
> -		if (!foreign) {
> -			gnttab_free_pages(nr_pages, pages);
> +		if (!foreign)
>   			return -ENOMEM;
> -		}
> +
>   		set_page_private(pages[i], (unsigned long)foreign);
>   #endif
>   		SetPagePrivate(pages[i]);
> @@ -799,14 +788,30 @@ int gnttab_alloc_pages(int nr_pages, struct page **pages)
>   
>   	return 0;
>   }
> -EXPORT_SYMBOL_GPL(gnttab_alloc_pages);
> +EXPORT_SYMBOL_GPL(gnttab_pages_set_private);
>   
>   /**
> - * gnttab_free_pages - free pages allocated by gnttab_alloc_pages()
> - * @nr_pages; number of pages to free
> - * @pages: the pages
> + * gnttab_alloc_pages - alloc pages suitable for grant mapping into
> + * @nr_pages: number of pages to alloc
> + * @pages: returns the pages
>    */
> -void gnttab_free_pages(int nr_pages, struct page **pages)
> +int gnttab_alloc_pages(int nr_pages, struct page **pages)
> +{
> +	int ret;
> +
> +	ret = alloc_xenballooned_pages(nr_pages, pages);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = gnttab_pages_set_private(nr_pages, pages);
> +	if (ret < 0)
> +		gnttab_free_pages(nr_pages, pages);
> +
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(gnttab_alloc_pages);
> +
> +void gnttab_pages_clear_private(int nr_pages, struct page **pages)
>   {
>   	int i;
>   
> @@ -818,6 +823,17 @@ void gnttab_free_pages(int nr_pages, struct page **pages)
>   			ClearPagePrivate(pages[i]);
>   		}
>   	}
> +}
> +EXPORT_SYMBOL_GPL(gnttab_pages_clear_private);
> +
> +/**
> + * gnttab_free_pages - free pages allocated by gnttab_alloc_pages()
> + * @nr_pages; number of pages to free
> + * @pages: the pages
> + */
> +void gnttab_free_pages(int nr_pages, struct page **pages)
> +{
> +	gnttab_pages_clear_private(nr_pages, pages);
>   	free_xenballooned_pages(nr_pages, pages);
>   }
>   EXPORT_SYMBOL_GPL(gnttab_free_pages);
> diff --git a/include/xen/grant_table.h b/include/xen/grant_table.h
> index 2e37741f6b8d..de03f2542bb7 100644
> --- a/include/xen/grant_table.h
> +++ b/include/xen/grant_table.h
> @@ -198,6 +198,9 @@ void gnttab_free_auto_xlat_frames(void);
>   int gnttab_alloc_pages(int nr_pages, struct page **pages);
>   void gnttab_free_pages(int nr_pages, struct page **pages);
>   
> +int gnttab_pages_set_private(int nr_pages, struct page **pages);
> +void gnttab_pages_clear_private(int nr_pages, struct page **pages);
> +
>   int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
>   		    struct gnttab_map_grant_ref *kmap_ops,
>   		    struct page **pages, unsigned int count);