[PATCH v2] vhost: handle error while adding split ranges to iotlb

[Anirudh Rayabharam <mail@anirudhrb.com>]

vhost_iotlb_add_range_ctx() handles the range [0, ULONG_MAX] by
splitting it into two ranges and adding them separately. The return
value of adding the first range to the iotlb is currently ignored.
Check the return value and bail out in case of an error.

Fixes: e2ae38cf3d91 ("vhost: fix hung thread due to erroneous iotlb entries")
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Anirudh Rayabharam <mail@anirudhrb.com>
---

v2:
- Add "Fixes:" tag and "Reviewed-by:".

v1:
https://lore.kernel.org/kvm/20220312141121.4981-1-mail@anirudhrb.com/

---
 drivers/vhost/iotlb.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/vhost/iotlb.c b/drivers/vhost/iotlb.c
index 40b098320b2a..5829cf2d0552 100644
--- a/drivers/vhost/iotlb.c
+++ b/drivers/vhost/iotlb.c
@@ -62,8 +62,12 @@ int vhost_iotlb_add_range_ctx(struct vhost_iotlb *iotlb,
 	 */
 	if (start == 0 && last == ULONG_MAX) {
 		u64 mid = last / 2;
+		int err = vhost_iotlb_add_range_ctx(iotlb, start, mid, addr,
+				perm, opaque);
+
+		if (err)
+			return err;
 
-		vhost_iotlb_add_range_ctx(iotlb, start, mid, addr, perm, opaque);
 		addr += mid + 1;
 		start = mid + 1;
 	}
-- 
2.35.1