drivers/net/macvtap: fix error check

'len' is unsigned of type size_t and can't be negative.

Signed-off-by: Nicolas Kaiser <nikai@nikai.net>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 1 deletions

diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c
index 5933621ac3ff..fc27a9926d9e 100644
--- a/drivers/net/macvtap.c
+++ b/drivers/net/macvtap.c
@@ -528,8 +528,9 @@ static ssize_t macvtap_get_user(struct macvtap_queue *q,
                 vnet_hdr_len = q->vnet_hdr_sz;
 
                 err = -EINVAL;
-                if ((len -= vnet_hdr_len) < 0)
+                if (len < vnet_hdr_len)
                         goto err;
+                len -= vnet_hdr_len;
 
                 err = memcpy_fromiovecend((void *)&vnet_hdr, iv, 0,
                                            sizeof(vnet_hdr));