vhost: handle error while adding split ranges to iotlb

mainline inclusion
from mainline-v5.18-rc1
commit 03a91c9a
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I5WXCZ
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=03a91c9af2c42ae14afafb829a4b7e6589ab5892

----------------------------------------------------------------------

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.
Signed-off-by: NAnirudh Rayabharam <mail@anirudhrb.com>
Link: https://lore.kernel.org/r/20220312141121.4981-1-mail@anirudhrb.comSigned-off-by: NMichael S. Tsirkin <mst@redhat.com>
Fixes: e2ae38cf ("vhost: fix hung thread due to erroneous iotlb entries")
Reviewed-by: NStefano Garzarella <sgarzare@redhat.com>
Signed-off-by: NPengyuan Zhao <zhaopengyuan@hisilicon.com>

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;
 	}