Patch "net: ti: cpmac: Fix compiler warning due to type confusion" has been added to the 4.4-stable tree

This is a note to let you know that I've just added the patch titled

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

to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
net-ti-cpmac-fix-compiler-warning-due-to-type-confusion.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Paul Burton <[email protected]>
Date: Fri, 2 Sep 2016 15:22:48 +0100
Subject: net: ti: cpmac: Fix compiler warning due to type confusion

From: Paul Burton <[email protected]>

commit 2f5281ba2a8feaf6f0aee93356f350855bb530fc upstream.

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.

---
 drivers/net/ethernet/ti/cpmac.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

@@ -549,7 +549,8 @@ 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);
 

@@ -559,7 +560,7 @@ static int cpmac_start_xmit(struct sk_bu
 	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);
 

Patches currently in stable-queue which might be from [email protected] are

queue-4.4/net-ti-cpmac-fix-compiler-warning-due-to-type-confusion.patch