queue-4.20/vhost-correctly-check-the-return-value-of-translate_.patch

   1 From 3e7aa46811cd9f98621d6c9d46bda275d52eb12d Mon Sep 17 00:00:00 2001
   2 From: Jason Wang <jasowang@redhat.com>
   3 Date: Tue, 19 Feb 2019 14:53:44 +0800
   4 Subject: vhost: correctly check the return value of translate_desc() in
   5  log_used()
   6
   7 [ Upstream commit 816db7663565cd23f74ed3d5c9240522e3fb0dda ]
   8
   9 When fail, translate_desc() returns negative value, otherwise the
  10 number of iovs. So we should fail when the return value is negative
  11 instead of a blindly check against zero.
  12
  13 Detected by CoverityScan, CID# 1442593:  Control flow issues  (DEADCODE)
  14
  15 Fixes: cc5e71075947 ("vhost: log dirty page correctly")
  16 Acked-by: Michael S. Tsirkin <mst@redhat.com>
  17 Reported-by: Stephen Hemminger <stephen@networkplumber.org>
  18 Signed-off-by: Jason Wang <jasowang@redhat.com>
  19 Signed-off-by: David S. Miller <davem@davemloft.net>
  20 Signed-off-by: Sasha Levin <sashal@kernel.org>
  21 ---
  22  drivers/vhost/vhost.c | 2 +-
  23  1 file changed, 1 insertion(+), 1 deletion(-)
  24
  25 diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
  26 index cf82e72663976..5eaeca805c95c 100644
  27 --- a/drivers/vhost/vhost.c
  28 +++ b/drivers/vhost/vhost.c
  29 @@ -1784,7 +1784,7 @@ static int log_used(struct vhost_virtqueue *vq, u64 used_offset, u64 len)
  30
  31         ret = translate_desc(vq, (uintptr_t)vq->used + used_offset,
  32                              len, iov, 64, VHOST_ACCESS_WO);
  33 -       if (ret)
  34 +       if (ret < 0)
  35                 return ret;
  36
  37         for (i = 0; i < ret; i++) {
  38 --
  39 2.19.1
  40