net: ti: cpmac: Fix compiler warning due to type confusion

cpmac_start_xmit() used the max() macro on skb->len (an unsigned int)
and ETH_ZLEN (a signed int literal). This led to the following compiler
warning:

  In file included from include/linux/list.h:8:0,
                   from include/linux/module.h:9,
                   from drivers/net/ethernet/ti/cpmac.c:19:
  drivers/net/ethernet/ti/cpmac.c: In function 'cpmac_start_xmit':
  include/linux/kernel.h:748:17: warning: comparison of distinct pointer
  types lacks a cast
    (void) (&_max1 == &_max2);  \
                   ^
  drivers/net/ethernet/ti/cpmac.c:560:8: note: in expansion of macro 'max'
    len = max(skb->len, ETH_ZLEN);
          ^

On top of this, it assigned the result of the max() macro to a signed
integer whilst all further uses of it result in it being cast to varying
widths of unsigned integer.

Fix this up by using max_t to ensure the comparison is performed as
unsigned integers, and for consistency change the type of the len
variable to unsigned int.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 3 insertions, 2 deletions

diff --git a/drivers/net/ethernet/ti/cpmac.c b/drivers/net/ethernet/ti/cpmac.c
index d300d536d06f..fa0cfda24fd9 100644
--- a/drivers/net/ethernet/ti/cpmac.c
+++ b/drivers/net/ethernet/ti/cpmac.c
@@ -546,7 +546,8 @@ fatal_error:
 
 static int cpmac_start_xmit(struct sk_buff *skb, struct net_device *dev)
 {
-        int queue, len;
+        int queue;
+        unsigned int len;
         struct cpmac_desc *desc;
         struct cpmac_priv *priv = netdev_priv(dev);
 
@@ -556,7 +557,7 @@ static int cpmac_start_xmit(struct sk_buff *skb, struct net_device *dev)
         if (unlikely(skb_padto(skb, ETH_ZLEN)))
                 return NETDEV_TX_OK;
 
-        len = max(skb->len, ETH_ZLEN);
+        len = max_t(unsigned int, skb->len, ETH_ZLEN);
         queue = skb_get_queue_mapping(skb);
         netif_stop_subqueue(dev, queue);