x86/xen: require ballooned pages for grant maps

Ballooned pages are always used for grant maps which means the
original frame does not need to be saved in page->index nor restored
after the grant unmap.

This allows the workaround in netback for the conflicting use of the
(unionized) page->index and page->pfmemalloc to be removed.

Signed-off-by: Jennifer Herbert <jennifer.herbert@citrix.com>
Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>

1 files changed, 0 insertions, 6 deletions

diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
index 908e65e9b821..64413189ad06 100644
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -1241,12 +1241,6 @@ static void xenvif_fill_frags(struct xenvif_queue *queue, struct sk_buff *skb)
                 /* Take an extra reference to offset network stack's put_page */
                 get_page(queue->mmap_pages[pending_idx]);
         }
-        /* FIXME: __skb_fill_page_desc set this to true because page->pfmemalloc
-         * overlaps with "index", and "mapping" is not set. I think mapping
-         * should be set. If delivered to local stack, it would drop this
-         * skb in sk_filter unless the socket has the right to use it.
-         */
-        skb->pfmemalloc = false;
 }
 
 static int xenvif_get_extras(struct xenvif_queue *queue,