gianfar: convert u64 status counters to atomic64_t

While looking at some asm dump for an unrelated change, Eric
noticed in the following stats count increment code:

    50b8:       81 3c 01 f8     lwz     r9,504(r28)
    50bc:       81 5c 01 fc     lwz     r10,508(r28)
    50c0:       31 4a 00 01     addic   r10,r10,1
    50c4:       7d 29 01 94     addze   r9,r9
    50c8:       91 3c 01 f8     stw     r9,504(r28)
    50cc:       91 5c 01 fc     stw     r10,508(r28)

that a 64 bit counter was used on ppc-32 without sync
and hence the "ethtool -S" output was racy.

Here we convert all the values to use atomic64_t so that
the output will always be consistent.

Reported-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
diff --git a/drivers/net/ethernet/freescale/gianfar.c b/drivers/net/ethernet/freescale/gianfar.c
index ab32bd0..c82f677 100644
--- a/drivers/net/ethernet/freescale/gianfar.c
+++ b/drivers/net/ethernet/freescale/gianfar.c
@@ -2648,7 +2648,7 @@
 	if (status & RXBD_TRUNCATED) {
 		stats->rx_length_errors++;
 
-		estats->rx_trunc++;
+		atomic64_inc(&estats->rx_trunc);
 
 		return;
 	}
@@ -2657,20 +2657,20 @@
 		stats->rx_length_errors++;
 
 		if (status & RXBD_LARGE)
-			estats->rx_large++;
+			atomic64_inc(&estats->rx_large);
 		else
-			estats->rx_short++;
+			atomic64_inc(&estats->rx_short);
 	}
 	if (status & RXBD_NONOCTET) {
 		stats->rx_frame_errors++;
-		estats->rx_nonoctet++;
+		atomic64_inc(&estats->rx_nonoctet);
 	}
 	if (status & RXBD_CRCERR) {
-		estats->rx_crcerr++;
+		atomic64_inc(&estats->rx_crcerr);
 		stats->rx_crc_errors++;
 	}
 	if (status & RXBD_OVERRUN) {
-		estats->rx_overrun++;
+		atomic64_inc(&estats->rx_overrun);
 		stats->rx_crc_errors++;
 	}
 }
@@ -2744,7 +2744,7 @@
 	ret = napi_gro_receive(napi, skb);
 
 	if (GRO_DROP == ret)
-		priv->extra_stats.kernel_dropped++;
+		atomic64_inc(&priv->extra_stats.kernel_dropped);
 
 	return 0;
 }
@@ -2812,7 +2812,7 @@
 			} else {
 				netif_warn(priv, rx_err, dev, "Missing skb!\n");
 				rx_queue->stats.rx_dropped++;
-				priv->extra_stats.rx_skbmissing++;
+				atomic64_inc(&priv->extra_stats.rx_skbmissing);
 			}
 
 		}
@@ -3245,7 +3245,7 @@
 			netif_dbg(priv, tx_err, dev,
 				  "TX FIFO underrun, packet dropped\n");
 			dev->stats.tx_dropped++;
-			priv->extra_stats.tx_underrun++;
+			atomic64_inc(&priv->extra_stats.tx_underrun);
 
 			local_irq_save(flags);
 			lock_tx_qs(priv);
@@ -3260,7 +3260,7 @@
 	}
 	if (events & IEVENT_BSY) {
 		dev->stats.rx_errors++;
-		priv->extra_stats.rx_bsy++;
+		atomic64_inc(&priv->extra_stats.rx_bsy);
 
 		gfar_receive(irq, grp_id);
 
@@ -3269,19 +3269,19 @@
 	}
 	if (events & IEVENT_BABR) {
 		dev->stats.rx_errors++;
-		priv->extra_stats.rx_babr++;
+		atomic64_inc(&priv->extra_stats.rx_babr);
 
 		netif_dbg(priv, rx_err, dev, "babbling RX error\n");
 	}
 	if (events & IEVENT_EBERR) {
-		priv->extra_stats.eberr++;
+		atomic64_inc(&priv->extra_stats.eberr);
 		netif_dbg(priv, rx_err, dev, "bus error\n");
 	}
 	if (events & IEVENT_RXC)
 		netif_dbg(priv, rx_status, dev, "control frame\n");
 
 	if (events & IEVENT_BABT) {
-		priv->extra_stats.tx_babt++;
+		atomic64_inc(&priv->extra_stats.tx_babt);
 		netif_dbg(priv, tx_err, dev, "babbling TX error\n");
 	}
 	return IRQ_HANDLED;