r8169: fix memory corruption on retrieval of hardware statistics.

[ Upstream commit a78e93661c5fd30b9e1dee464b2f62f966883ef7 ]

Hardware statistics retrieval hurts in tight invocation loops.

Avoid extraneous write and enforce strict ordering of writes targeted to
the tally counters dump area address registers.

Signed-off-by: Francois Romieu <romieu@fr.zoreil.com>
Tested-by: Oliver Freyermuth <o.freyermuth@googlemail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/net/ethernet/realtek/r8169.c b/drivers/net/ethernet/realtek/r8169.c
index 2c4350a..298b74e 100644 (file)
--- a/drivers/net/ethernet/realtek/r8169.c
+++ b/drivers/net/ethernet/realtek/r8169.c
@@ -2222,19 +2222,14 @@ static bool rtl8169_do_counters(struct net_device *dev, u32 counter_cmd)
        void __iomem *ioaddr = tp->mmio_addr;
        dma_addr_t paddr = tp->counters_phys_addr;
        u32 cmd;
-       bool ret;
 
        RTL_W32(CounterAddrHigh, (u64)paddr >> 32);
+       RTL_R32(CounterAddrHigh);
        cmd = (u64)paddr & DMA_BIT_MASK(32);
        RTL_W32(CounterAddrLow, cmd);
        RTL_W32(CounterAddrLow, cmd | counter_cmd);
 
-       ret = rtl_udelay_loop_wait_low(tp, &rtl_counters_cond, 10, 1000);
-
-       RTL_W32(CounterAddrLow, 0);
-       RTL_W32(CounterAddrHigh, 0);
-
-       return ret;
+       return rtl_udelay_loop_wait_low(tp, &rtl_counters_cond, 10, 1000);
 }
 
 static bool rtl8169_reset_counters(struct net_device *dev)