xen-blkfront: free allocated page

Free the page allocated for the persistent grant.
Signed-off-by: NRoger Pau Monné <roger.pau@citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

drivers/block/xen-blkfront.c

@@ -806,6 +806,7 @@ static void blkif_free(struct blkfront_info *info, int suspend)
 		all_gnts = llist_del_all(&info->persistent_gnts);
 		llist_for_each_entry(persistent_gnt, all_gnts, node) {
 			gnttab_end_foreign_access(persistent_gnt->gref, 0, 0UL);
+			__free_page(pfn_to_page(persistent_gnt->pfn));
 			kfree(persistent_gnt);
 		}
 		info->persistent_gnts_c = 0;