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    Subject[PATCH 3.16 291/294] net: ti: cpmac: Fix compiler warning due to type confusion
    3.16.50-rc1 review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Paul Burton <paul.burton@imgtec.com>

    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.

    Signed-off-by: Paul Burton <paul.burton@imgtec.com>
    Signed-off-by: David S. Miller <davem@davemloft.net>
    Cc: Arnd Bergmann <arnd@arndb.de>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
    ---
    drivers/net/ethernet/ti/cpmac.c | 5 +++--
    1 file changed, 3 insertions(+), 2 deletions(-)

    --- a/drivers/net/ethernet/ti/cpmac.c
    +++ b/drivers/net/ethernet/ti/cpmac.c
    @@ -543,7 +543,8 @@ 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);

    @@ -553,7 +554,7 @@ 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);

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