xen/gntdev: Fix off-by-one error when unmapping with holes

[ Upstream commit 951a010233625b77cde3430b4b8785a9a22968d1 ]

If the requested range has a hole, the calculation of the number of
pages to unmap is off by one. Fix it.

Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c
index 57efbd3..d3391a1 100644 (file)
--- a/drivers/xen/gntdev.c
+++ b/drivers/xen/gntdev.c
@@ -380,10 +380,8 @@ static int unmap_grant_pages(struct grant_map *map, int offset, int pages)
                }
                range = 0;
                while (range < pages) {
-                       if (map->unmap_ops[offset+range].handle == -1) {
-                               range--;
+                       if (map->unmap_ops[offset+range].handle == -1)
                                break;
-                       }
                        range++;
                }
                err = __unmap_grant_pages(map, offset, range);