[PATCH 1/2] vringh: fix range used in iotlb_translate()

[Stefano Garzarella <sgarzare@redhat.com>]

vhost_iotlb_itree_first() requires `start` and `last` parameters
to search for a mapping that overlaps the range.

In iotlb_translate() we cyclically call vhost_iotlb_itree_first(),
incrementing `addr` by the amount already translated, so rightly
we move the `start` parameter passed to vhost_iotlb_itree_first(),
but we should hold the `last` parameter constant.

Let's fix it by saving the `last` parameter value before incrementing
`addr` in the loop.

Fixes: 9ad9c49cfe97 ("vringh: IOTLB support")
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
---
 drivers/vhost/vringh.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/vhost/vringh.c b/drivers/vhost/vringh.c
index 11f59dd06a74..828c29306565 100644
--- a/drivers/vhost/vringh.c
+++ b/drivers/vhost/vringh.c
@@ -1102,7 +1102,7 @@ static int iotlb_translate(const struct vringh *vrh,
 	struct vhost_iotlb_map *map;
 	struct vhost_iotlb *iotlb = vrh->iotlb;
 	int ret = 0;
-	u64 s = 0;
+	u64 s = 0, last = addr + len - 1;
 
 	spin_lock(vrh->iotlb_lock);
 
@@ -1114,8 +1114,7 @@ static int iotlb_translate(const struct vringh *vrh,
 			break;
 		}
 
-		map = vhost_iotlb_itree_first(iotlb, addr,
-					      addr + len - 1);
+		map = vhost_iotlb_itree_first(iotlb, addr, last);
 		if (!map || map->start > addr) {
 			ret = -EINVAL;
 			break;
-- 
2.38.1