vhost: correctly check the return value of translate_desc() in log_used()
authorJason Wang <jasowang@redhat.com>
Tue, 19 Feb 2019 06:53:44 +0000 (14:53 +0800)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Sat, 23 Feb 2019 08:07:25 +0000 (09:07 +0100)
[ Upstream commit 816db7663565cd23f74ed3d5c9240522e3fb0dda ]

When fail, translate_desc() returns negative value, otherwise the
number of iovs. So we should fail when the return value is negative
instead of a blindly check against zero.

Detected by CoverityScan, CID# 1442593:  Control flow issues  (DEADCODE)

Fixes: cc5e71075947 ("vhost: log dirty page correctly")
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Reported-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
drivers/vhost/vhost.c

index cf82e72..5eaeca8 100644 (file)
@@ -1784,7 +1784,7 @@ static int log_used(struct vhost_virtqueue *vq, u64 used_offset, u64 len)
 
        ret = translate_desc(vq, (uintptr_t)vq->used + used_offset,
                             len, iov, 64, VHOST_ACCESS_WO);
-       if (ret)
+       if (ret < 0)
                return ret;
 
        for (i = 0; i < ret; i++) {