xen/gntalloc: release grant references on page free

gnttab_end_foreign_access_ref does not return the grant reference it is
passed to the free list; gnttab_free_grant_reference needs to be
explicitly called. While gnttab_end_foreign_access provides a wrapper
for this, it is unsuitable because it does not return errors.

Reported-by: Anil Madhavapeddy <anil@recoil.org>
Signed-off-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/drivers/xen/gntalloc.c b/drivers/xen/gntalloc.c
index c95181f43a6a..f330a4b8b685 100644
--- a/drivers/xen/gntalloc.c
+++ b/drivers/xen/gntalloc.c
@@ -191,6 +191,8 @@ static void __del_gref(struct gntalloc_gref *gref)
 
                 if (!gnttab_end_foreign_access_ref(gref->gref_id, 0))
                         return;
+
+                gnttab_free_grant_reference(gref->gref_id);
         }
 
         gref_size--;