backend-track-pages-with-page-flags.patch

diff -r 7d1858b6cdbb drivers/xen/blkback/blkback.c
--- a/drivers/xen/blkback/blkback.c	Wed Jun 30 23:59:39 2010 -0700
+++ b/drivers/xen/blkback/blkback.c	Thu Jul 01 00:00:01 2010 -0700
@@ -637,6 +637,9 @@
 	if (!pending_reqs || !pending_grant_handles || !pending_pages)
 		goto out_of_memory;
 
+	for(i = 0; i < mmap_pages; i++)
+		SetPageBlkback(pending_pages[i]);
+
 	for (i = 0; i < mmap_pages; i++)
 		pending_grant_handles[i] = BLKBACK_INVALID_HANDLE;
 
diff -r 7d1858b6cdbb drivers/xen/core/gnttab.c
--- a/drivers/xen/core/gnttab.c	Wed Jun 30 23:59:39 2010 -0700
+++ b/drivers/xen/core/gnttab.c	Thu Jul 01 00:00:01 2010 -0700
@@ -598,6 +598,8 @@
 	*pagep = new_page;
 
 	SetPageForeign(page, gnttab_page_free);
+	ClearPageNetback(page);
+	ClearPageBlkback(page);
 	page->mapping = NULL;
 
 out:
diff -r 7d1858b6cdbb drivers/xen/netback/netback.c
--- a/drivers/xen/netback/netback.c	Wed Jun 30 23:59:39 2010 -0700
+++ b/drivers/xen/netback/netback.c	Thu Jul 01 00:00:01 2010 -0700
@@ -847,9 +847,14 @@
 static inline int copy_pending_req(struct xen_netbk *netbk,
 				   pending_ring_idx_t pending_idx)
 {
-	return gnttab_copy_grant_page(
+	int err = gnttab_copy_grant_page(
 			netbk->grant_tx_handle[pending_idx],
 			&netbk->mmap_pages[pending_idx]);
+
+	if (!err)
+		SetPageNetback(netbk->mmap_pages[pending_idx]);
+
+	return err;
 }
 
 static void permute_dealloc_ring(PEND_RING_IDX dc, PEND_RING_IDX dp)
@@ -1764,6 +1769,7 @@
 		for (i = 0; i < MAX_PENDING_REQS; i++) {
 			page = netbk->mmap_pages[i];
 			SetPageForeign(page, netif_page_release);
+			SetPageNetback(page);
 			netif_set_page_ext(page, group, i);
 			INIT_LIST_HEAD(&netbk->pending_inuse[i].list);
 		}
diff -r 7d1858b6cdbb include/linux/page-flags.h
--- a/include/linux/page-flags.h	Wed Jun 30 23:59:39 2010 -0700
+++ b/include/linux/page-flags.h	Thu Jul 01 00:00:01 2010 -0700
@@ -112,7 +112,7 @@
 #endif
 #ifdef CONFIG_XEN
 	PG_foreign,		/* Page is owned by foreign allocator. */
-	/* PG_netback,		   Page is owned by netback */
+	PG_netback,		/* Page is owned by netback */
 	PG_blkback,		/* Page is owned by blkback */
 #endif
 	__NR_PAGEFLAGS,
@@ -375,7 +375,7 @@
 {
 	((void (*)(struct page *, unsigned int))page->index)(page, order);
 }
-/*PAGEFLAG(Netback, netback)*/
+PAGEFLAG(Netback, netback)
 PAGEFLAG(Blkback, blkback)
 #endif