diff mbox series

[net,1/1] r8169: fix memory corruption on retrieval of hardware statistics.

Message ID 20180126005326.GA15234@electric-eye.fr.zoreil.com
State Accepted, archived
Delegated to: David Miller
Headers show
Series [net,1/1] r8169: fix memory corruption on retrieval of hardware statistics. | expand

Commit Message

Francois Romieu Jan. 26, 2018, 12:53 a.m. UTC 
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>
---
 drivers/net/ethernet/realtek/r8169.c | 9 ++-------
 1 file changed, 2 insertions(+), 7 deletions(-)

Comments

David Miller Jan. 26, 2018, 2:34 a.m. UTC | #1 
From: Francois Romieu <romieu@fr.zoreil.com>
Date: Fri, 26 Jan 2018 01:53:26 +0100

> 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>

Applied and queued up for -stable, thanks Francois.
diff mbox series

Patch

diff --git a/drivers/net/ethernet/realtek/r8169.c b/drivers/net/ethernet/realtek/r8169.c
index 272c5962e4f7..8e91274174f1 100644
--- a/drivers/net/ethernet/realtek/r8169.c
+++ b/drivers/net/ethernet/realtek/r8169.c
@@ -2235,19 +2235,14 @@  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)