[PATCH] fs-backend: fix gnttab unmap

[Stefano Stabellini <stefano.stabellini@eu.citrix.com>]

Hi all,
when a stubdom is destroyed, fs-backend does not correctly unmap all the
pages mapped for the shared ring.
This causes some pages not to be properly freed by xen, hence after a
cycle of 50 save\restore we don't have enough spare memory to start 2
VMs any more.
This patch fixes the issue properly unmapping all the pages needed by
the shared ring.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>

---

diff -r 633e08774dab tools/fs-back/fs-backend.c
--- a/tools/fs-back/fs-backend.c	Thu Mar 19 14:01:56 2009 +0000
+++ b/tools/fs-back/fs-backend.c	Thu Mar 19 16:33:34 2009 +0000
@@ -161,7 +161,7 @@
     while (!xenbus_frontend_state_changed(mount, STATE_CLOSING));
     xenbus_write_backend_state(mount, STATE_CLOSED);
 
-    xc_gnttab_munmap(mount->gnth, mount->ring.sring, 1);
+    xc_gnttab_munmap(mount->gnth, mount->ring.sring, mount->shared_ring_size);
     xc_gnttab_close(mount->gnth);
     xc_evtchn_unbind(mount->evth, mount->local_evtchn);
     xc_evtchn_close(mount->evth);