RE: [PATCH v4] net: stmmac: fix 'ethtool -P' return -EBUSY

-----Original Message-----
From: Hao Chen <redacted>
Sent: 2021年7月19日 17:32
To: peppe.cavallaro@st.com
Cc: alexandre.torgue@foss.st.com; joabreu@synopsys.com;
davem@davemloft.net; kuba@kernel.org; mcoquelin.stm32@gmail.com;
linux@armlinux.org.uk; netdev@vger.kernel.org;
linux-stm32@st-md-mailman.stormreply.com; linux-kernel@vger.kernel.org;
Hao Chen [off-list ref]
Subject: [PATCH v4] net: stmmac: fix 'ethtool -P' return -EBUSY

The permanent mac address should be available for query when the device is
not up.
NetworkManager, the system network daemon, uses 'ethtool -P' to obtain the
permanent address after the kernel start. When the network device is not up,
it will return the device busy error with 'ethtool -P'. At that time, it is unable to
access the Internet through the permanent address by NetworkManager.
I think that the '.begin' is not used to check if the device is up.

Signed-off-by: Hao Chen <redacted>
---
 .../ethernet/stmicro/stmmac/stmmac_ethtool.c  | 19 +++++++++++++++----
 1 file changed, 15 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c

b/drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c
index d0ce608b81c3..25c44c1ecbd6 100644

--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c

@@ -15,6 +15,7 @@
 #include <linux/phylink.h>
 #include <linux/net_tstamp.h>
 #include <asm/io.h>
+#include <linux/pm_runtime.h>

 #include "stmmac.h"
 #include "dwmac_dma.h"

@@ -410,13 +411,22 @@ static void stmmac_ethtool_setmsglevel(struct

net_device *dev, u32 level)

 }

-static int stmmac_check_if_running(struct net_device *dev)
+static int stmmac_ethtool_begin(struct net_device *dev)
 {
-	if (!netif_running(dev))
-		return -EBUSY;
+	struct stmmac_priv *priv = netdev_priv(dev);
+
+	pm_runtime_get_sync(priv->device);
+
 	return 0;
 }