[Xen-devel] Re: [PATCH 10/11] xen gntdev: use gnttab_map_refs and gnttab_unmap_refs

[Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>]

On Wed, Dec 15, 2010 at 01:40:45PM +0000, stefano.stabellini@xxxxxxxxxxxxx 
wrote:
> From: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
> 
> Use gnttab_map_refs and gnttab_unmap_refs to map and unmap the grant
> ref, so that we can have a corresponding struct page.
> 
> Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
> Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@xxxxxxxxxx>
> ---
>  drivers/xen/gntdev.c |   37 ++++++++++++++++++++++++++++++-------
>  1 files changed, 30 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c
> index fc5e420..35de6bb 100644
> --- a/drivers/xen/gntdev.c
> +++ b/drivers/xen/gntdev.c
> @@ -68,6 +68,7 @@ struct grant_map {
>       struct ioctl_gntdev_grant_ref *grants;
>       struct gnttab_map_grant_ref   *map_ops;
>       struct gnttab_unmap_grant_ref *unmap_ops;
> +     struct page **pages;
>  };
>  
>  /* ------------------------------------------------------------------ */
> @@ -88,6 +89,7 @@ static void gntdev_print_maps(struct gntdev_priv *priv,
>  static struct grant_map *gntdev_alloc_map(struct gntdev_priv *priv, int 
> count)
>  {
>       struct grant_map *add;
> +     int i;

So 'int' here.
>  
>       add = kzalloc(sizeof(struct grant_map), GFP_KERNEL);
>       if (NULL == add)
> @@ -96,11 +98,19 @@ static struct grant_map *gntdev_alloc_map(struct 
> gntdev_priv *priv, int count)
>       add->grants    = kzalloc(sizeof(add->grants[0])    * count, GFP_KERNEL);
>       add->map_ops   = kzalloc(sizeof(add->map_ops[0])   * count, GFP_KERNEL);
>       add->unmap_ops = kzalloc(sizeof(add->unmap_ops[0]) * count, GFP_KERNEL);
> -     if (NULL == add->grants  ||
> -         NULL == add->map_ops ||
> -         NULL == add->unmap_ops)
> +     add->pages     = kzalloc(sizeof(add->pages[0])     * count, GFP_KERNEL);
> +     if (NULL == add->grants    ||
> +         NULL == add->map_ops   ||
> +         NULL == add->unmap_ops ||
> +         NULL == add->pages)
>               goto err;
>  
> +     for (i = 0; i < count; i++) {
> +             add->pages[i] = alloc_page(GFP_KERNEL | __GFP_HIGHMEM);
> +             if (add->pages[i] == NULL)
> +                     goto err;
> +     }
> +
>       add->index = 0;
>       add->count = count;
>       add->priv  = priv;
> @@ -111,6 +121,12 @@ static struct grant_map *gntdev_alloc_map(struct 
> gntdev_priv *priv, int count)
>       return add;
>  
>  err:
> +     if (add->pages)
> +             for (i = 0; i < count; i++) {
> +                     if (add->pages[i])
> +                             __free_page(add->pages[i]);
> +             }
> +     kfree(add->pages);
>       kfree(add->grants);
>       kfree(add->map_ops);
>       kfree(add->unmap_ops);
> @@ -186,8 +202,17 @@ static int gntdev_del_map(struct grant_map *map)
>  
>  static void gntdev_free_map(struct grant_map *map)
>  {
> +     unsigned i;

But 'unsigned' here?

> +
>       if (!map)
>               return;
> +
> +     if (map->pages)
> +             for (i = 0; i < map->count; i++) {
> +                     if (map->pages[i])
> +                             __free_page(map->pages[i]);
> +             }
> +     kfree(map->pages);
>       kfree(map->grants);
>       kfree(map->map_ops);
>       kfree(map->unmap_ops);
> @@ -221,8 +246,7 @@ static int map_grant_pages(struct grant_map *map)
>  
>       if (debug)
>               printk("%s: map %d+%d\n", __FUNCTION__, map->index, map->count);
> -     err = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref,
> -                                     map->map_ops, map->count);
> +     err = gnttab_map_refs(map->map_ops, map->pages, map->count);
>       if (WARN_ON(err))
>               return err;
>  
> @@ -241,8 +265,7 @@ static int unmap_grant_pages(struct grant_map *map, int 
> offset, int pages)
>       if (debug)
>               printk("%s: map %d+%d [%d+%d]\n", __FUNCTION__,
>                      map->index, map->count, offset, pages);
> -     err = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref,
> -                                     map->unmap_ops + offset, pages);
> +     err = gnttab_unmap_refs(map->unmap_ops + offset, map->pages, pages);
>       if (WARN_ON(err))
>               return err;
>  
> -- 
> 1.5.6.5
> 
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