Subject: [PATCH 14/20] vhost: correctly check the return value of translate_desc() in log_used()

From: Jason Wang <[email-masked]>
Date: Tue, 19 Feb 2019 14:53:44 +0800

[ 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 <[email-masked]>
Reported-by: Stephen Hemminger <[email-masked]>
Signed-off-by: Jason Wang <[email-masked]>
Signed-off-by: David S. Miller <[email-masked]>
---
 drivers/vhost/vhost.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index cf82e7266397..5eaeca805c95 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -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++) {
-- 
2.20.1