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>

1 files changed, 16 insertions, 15 deletions

diff --git a/drivers/net/ethernet/freescale/gianfar.h b/drivers/net/ethernet/freescale/gianfar.h
index 61b1785c9ca7..78125f1f870e 100644
--- a/drivers/net/ethernet/freescale/gianfar.h
+++ b/drivers/net/ethernet/freescale/gianfar.h
@@ -627,24 +627,25 @@ struct rmon_mib
 };
 
 struct gfar_extra_stats {
-	u64 kernel_dropped;
-	u64 rx_large;
-	u64 rx_short;
-	u64 rx_nonoctet;
-	u64 rx_crcerr;
-	u64 rx_overrun;
-	u64 rx_bsy;
-	u64 rx_babr;
-	u64 rx_trunc;
-	u64 eberr;
-	u64 tx_babt;
-	u64 tx_underrun;
-	u64 rx_skbmissing;
-	u64 tx_timeout;
+	atomic64_t kernel_dropped;
+	atomic64_t rx_large;
+	atomic64_t rx_short;
+	atomic64_t rx_nonoctet;
+	atomic64_t rx_crcerr;
+	atomic64_t rx_overrun;
+	atomic64_t rx_bsy;
+	atomic64_t rx_babr;
+	atomic64_t rx_trunc;
+	atomic64_t eberr;
+	atomic64_t tx_babt;
+	atomic64_t tx_underrun;
+	atomic64_t rx_skbmissing;
+	atomic64_t tx_timeout;
 };
 
 #define GFAR_RMON_LEN ((sizeof(struct rmon_mib) - 16)/sizeof(u32))
-#define GFAR_EXTRA_STATS_LEN (sizeof(struct gfar_extra_stats)/sizeof(u64))
+#define GFAR_EXTRA_STATS_LEN \
+	(sizeof(struct gfar_extra_stats)/sizeof(atomic64_t))
 
 /* Number of stats exported via ethtool */
 #define GFAR_STATS_LEN (GFAR_RMON_LEN + GFAR_EXTRA_STATS_LEN)