commit 212079df6d77c0daada96b1d906f4b7749871411
author Paul Gortmaker <paul.gortmaker@windriver.com> Tue Feb 12 15:38:19 2013 -0500
committer Paul Gortmaker <paul.gortmaker@windriver.com> Tue Feb 12 19:08:27 2013 -0500
tree 2c4f2b31b6bdc2a6ea1a22617fd840c19ff90882
parent 68719786cba169f93b6cb5a53f5dd6ea1bdbb9f3

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>

drivers/net/ethernet/freescale/gianfar_ethtool.c

diff --git a/drivers/net/ethernet/freescale/gianfar_ethtool.c b/drivers/net/ethernet/freescale/gianfar_ethtool.c
index 172acb9..75e89ac 100644
--- a/drivers/net/ethernet/freescale/gianfar_ethtool.c
+++ b/drivers/net/ethernet/freescale/gianfar_ethtool.c
@@ -149,10 +149,10 @@
 	int i;
 	struct gfar_private *priv = netdev_priv(dev);
 	struct gfar __iomem *regs = priv->gfargrp[0].regs;
-	u64 *extra = (u64 *) & priv->extra_stats;
+	atomic64_t *extra = (atomic64_t *)&priv->extra_stats;
 
 	for (i = 0; i < GFAR_EXTRA_STATS_LEN; i++)
-		buf[i] = extra[i];
+		buf[i] = atomic64_read(&extra[i]);
 
 	if (priv->device_flags & FSL_GIANFAR_DEV_HAS_RMON) {
 		u32 __iomem *rmon = (u32 __iomem *) &regs->rmon;