[PATCH AUTOSEL for 4.9 49/52] xen/gntdev: Fix off-by-one error when unmapping with holes

Sasha Levin
2018-02-03T18:07:17Z

From: Ross Lagerwall <ross.lagerwall@citrix.com>

[ 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@microsoft.com>
---
drivers/xen/gntdev.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c
index 79b8ab4c6663..54c4c4183fbe 100644
--- a/drivers/xen/gntdev.c
+++ b/drivers/xen/gntdev.c
@@ -378,10 +378,8 @@ 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);
--
2.11.0