net/mlx4_en: Use union for BlueFlame WQE

When BlueFlame is turned on, control segment of the TX WQE is changed,
and the second line of it is used for QPN.
Changed code to use a union in the mlx4_wqe_ctrl_seg instead of casting.
This makes the code clearer and solves the static checker warning:

drivers/net/ethernet/mellanox/mlx4/en_tx.c:839 mlx4_en_xmit()
	warn: potential memory corrupting cast 4 vs 2 bytes

CC: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Amir Vadai <amirv@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/mellanox/mlx4/en_tx.c b/drivers/net/ethernet/mellanox/mlx4/en_tx.c
index 56e8fbc128f864daafc462aec17069cf3d9f7e55..69c2fcef9d4cb79209a97b27f81e3fad27a776fd 100644 (file)
--- a/drivers/net/ethernet/mellanox/mlx4/en_tx.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_tx.c
@@ -876,7 +876,8 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
        skb_tx_timestamp(skb);
 
        if (ring->bf_enabled && desc_size <= MAX_BF && !bounce && !vlan_tx_tag_present(skb)) {
-               *(__be32 *) (&tx_desc->ctrl.vlan_tag) |= cpu_to_be32(ring->doorbell_qpn);
+               tx_desc->ctrl.bf_qpn |= cpu_to_be32(ring->doorbell_qpn);
+
                op_own |= htonl((bf_index & 0xffff) << 8);
                /* Ensure new descirptor hits memory
                * before setting ownership of this descriptor to HW */

diff --git a/include/linux/mlx4/qp.h b/include/linux/mlx4/qp.h
index 59f8ba84568bef4a4e17ed21240c163d6953a912..b66e7610d4eec9f4d67e5f8bbd745bb6cbd3c99a 100644 (file)
--- a/include/linux/mlx4/qp.h
+++ b/include/linux/mlx4/qp.h
@@ -270,9 +270,14 @@ enum {
 
 struct mlx4_wqe_ctrl_seg {
        __be32                  owner_opcode;
-       __be16                  vlan_tag;
-       u8                      ins_vlan;
-       u8                      fence_size;
+       union {
+               struct {
+                       __be16                  vlan_tag;
+                       u8                      ins_vlan;
+                       u8                      fence_size;
+               };
+               __be32                  bf_qpn;
+       };
        /*
         * High 24 bits are SRC remote buffer; low 8 bits are flags:
         * [7]   SO (strong ordering)