tg3: fix 64 bit counter for ethtool stats

Ethtool stats are 64-bits in length.  net_device_stats members are
unsigned long types.  When gathering information for
a get_ethtool_stats call, the driver will call a driver-private,
inlined get_stat64() function, which returns an unsigned long value.
This call will inadvertently mask off the upper 32-bits of a stat on
32-bit machines.

This patch defines a new get_estat() inline function and modifies the
ESTAT_ADD() macro to use it.
Signed-off-by: Stefan Buehler <stbuehler@web.de>
Signed-off-by: Matt Carlson <mcarlson@broadcom.com>
Signed-off-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/tg3.c

@@ -8466,6 +8466,11 @@ static inline unsigned long get_stat64(tg3_stat64_t *val)
 	return ret;
 }
 
+static inline u64 get_estat64(tg3_stat64_t *val)
+{
+       return ((u64)val->high << 32) | ((u64)val->low);
+}
+
 static unsigned long calc_crc_errors(struct tg3 *tp)
 {
 	struct tg3_hw_stats *hw_stats = tp->hw_stats;
@@ -8494,7 +8499,7 @@ static unsigned long calc_crc_errors(struct tg3 *tp)
 
 #define ESTAT_ADD(member) \
 	estats->member =	old_estats->member + \
-				get_stat64(&hw_stats->member)
+				get_estat64(&hw_stats->member)
 
 static struct tg3_ethtool_stats *tg3_get_estats(struct tg3 *tp)
 {