1. Patchew
  2. linux
  3. [PATCH net-next 0/7] net: stmmac: fixes and new features
  4. View patch

[PATCH net-next 4/7] net: stmmac: enable ARP Offload on mac_link_up()

Konrad Leszczynski posted 7 patches 5 months, 2 weeks ago
[PATCH net-next 4/7] net: stmmac: enable ARP Offload on mac_link_up()
Posted by Konrad Leszczynski 5 months, 2 weeks ago 
From: Karol Jurczenia <karol.jurczenia@intel.com>

Add Address Resolution Protocol (ARP) Offload support in
stmmac_mac_link_up() to enable ARP Offload beside the selftests.

Introduce STMMAC_FLAG_ARP_OFFLOAD_EN flag, which is used to enable the
feature with the stmmac_set_arp_offload().

Reviewed-by: Konrad Leszczynski <konrad.leszczynski@intel.com>
Reviewed-by: Sebastian Basierski <sebastian.basierski@intel.com>
Signed-off-by: Karol Jurczenia <karol.jurczenia@intel.com>
---
 .../net/ethernet/stmicro/stmmac/stmmac_main.c   | 17 +++++++++++++++++
 include/linux/stmmac.h                          |  1 +
 2 files changed, 18 insertions(+)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index 9cf7f85c10b6..e000dc7f0349 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -39,6 +39,7 @@
 #include <linux/phylink.h>
 #include <linux/udp.h>
 #include <linux/bpf_trace.h>
+#include <linux/inetdevice.h>
 #include <net/page_pool/helpers.h>
 #include <net/pkt_cls.h>
 #include <net/xdp_sock_drv.h>
@@ -963,6 +964,8 @@ static void stmmac_mac_link_up(struct phylink_config *config,
 			       bool tx_pause, bool rx_pause)
 {
 	struct stmmac_priv *priv = netdev_priv(to_net_dev(config->dev));
+	struct in_device *in_dev;
+	struct in_ifaddr *ifa;
 	unsigned int flow_ctrl;
 	u32 old_ctrl, ctrl;
 	int ret;
@@ -1075,6 +1078,20 @@ static void stmmac_mac_link_up(struct phylink_config *config,
 
 	if (priv->plat->flags & STMMAC_FLAG_HWTSTAMP_CORRECT_LATENCY)
 		stmmac_hwtstamp_correct_latency(priv, priv);
+
+	if (priv->plat->flags & STMMAC_FLAG_ARP_OFFLOAD_EN) {
+		in_dev = in_dev_get(priv->dev);
+		if (!in_dev)
+			return;
+
+		ifa = in_dev->ifa_list;
+		if (!ifa)
+			return;
+
+		stmmac_set_arp_offload(priv, priv->hw, true,
+				       ntohl(ifa->ifa_address));
+		in_dev_put(in_dev);
+	}
 }
 
 static void stmmac_mac_disable_tx_lpi(struct phylink_config *config)
diff --git a/include/linux/stmmac.h b/include/linux/stmmac.h
index 26ddf95d23f9..aae522f37710 100644
--- a/include/linux/stmmac.h
+++ b/include/linux/stmmac.h
@@ -185,6 +185,7 @@ struct dwmac4_addrs {
 #define STMMAC_FLAG_EN_TX_LPI_CLOCKGATING	BIT(11)
 #define STMMAC_FLAG_EN_TX_LPI_CLK_PHY_CAP	BIT(12)
 #define STMMAC_FLAG_HWTSTAMP_CORRECT_LATENCY	BIT(13)
+#define STMMAC_FLAG_ARP_OFFLOAD_EN		BIT(14)
 
 struct plat_stmmacenet_data {
 	int bus_id;
-- 
2.34.1
Re: [PATCH net-next 4/7] net: stmmac: enable ARP Offload on mac_link_up()
Posted by Simon Horman 5 months, 2 weeks ago 
On Tue, Aug 26, 2025 at 01:32:44PM +0200, Konrad Leszczynski wrote:
> From: Karol Jurczenia <karol.jurczenia@intel.com>
> 
> Add Address Resolution Protocol (ARP) Offload support in
> stmmac_mac_link_up() to enable ARP Offload beside the selftests.
> 
> Introduce STMMAC_FLAG_ARP_OFFLOAD_EN flag, which is used to enable the
> feature with the stmmac_set_arp_offload().
> 
> Reviewed-by: Konrad Leszczynski <konrad.leszczynski@intel.com>
> Reviewed-by: Sebastian Basierski <sebastian.basierski@intel.com>
> Signed-off-by: Karol Jurczenia <karol.jurczenia@intel.com>

Konrad,

AFAIK, as you are posting this patches, your SoB line needs to go here.
(And correspondingly, your Reviewed-by line should be removed.)

...

> @@ -1075,6 +1078,20 @@ static void stmmac_mac_link_up(struct phylink_config *config,
>  
>  	if (priv->plat->flags & STMMAC_FLAG_HWTSTAMP_CORRECT_LATENCY)
>  		stmmac_hwtstamp_correct_latency(priv, priv);
> +
> +	if (priv->plat->flags & STMMAC_FLAG_ARP_OFFLOAD_EN) {
> +		in_dev = in_dev_get(priv->dev);
> +		if (!in_dev)
> +			return;
> +
> +		ifa = in_dev->ifa_list;

ifa_list is protected by RCU, so I think the code needs to take that into
account. E.g. by doing the following and making sure that the RCU read lock
is held.

		ifa = rcu_dereference(idev->ifa_list);

Flagged by Sparse.


> +		if (!ifa)
> +			return;
> +
> +		stmmac_set_arp_offload(priv, priv->hw, true,
> +				       ntohl(ifa->ifa_address));
> +		in_dev_put(in_dev);
> +	}
>  }
>  
>  static void stmmac_mac_disable_tx_lpi(struct phylink_config *config)
> diff --git a/include/linux/stmmac.h b/include/linux/stmmac.h
> index 26ddf95d23f9..aae522f37710 100644
> --- a/include/linux/stmmac.h
> +++ b/include/linux/stmmac.h
> @@ -185,6 +185,7 @@ struct dwmac4_addrs {
>  #define STMMAC_FLAG_EN_TX_LPI_CLOCKGATING	BIT(11)
>  #define STMMAC_FLAG_EN_TX_LPI_CLK_PHY_CAP	BIT(12)
>  #define STMMAC_FLAG_HWTSTAMP_CORRECT_LATENCY	BIT(13)
> +#define STMMAC_FLAG_ARP_OFFLOAD_EN		BIT(14)

I see that the following patch in this series also makes use of this bit.
But I don't see any thing (platform) that sets this bit. Perhaps I'm
missing something. But I think that would be best included in the patchset
that adds this bit.

>  
>  struct plat_stmmacenet_data {
>  	int bus_id;
> -- 
> 2.34.1
> 
>
Re: [PATCH net-next 4/7] net: stmmac: enable ARP Offload on mac_link_up()
Posted by kernel test robot 5 months, 2 weeks ago 
Hi Konrad,

kernel test robot noticed the following build errors:

[auto build test ERROR on net-next/main]

url:    https://github.com/intel-lab-lkp/linux/commits/Konrad-Leszczynski/net-stmmac-replace-memcpy-with-strscpy-in-ethtool/20250826-193732
base:   net-next/main
patch link:    https://lore.kernel.org/r/20250826113247.3481273-5-konrad.leszczynski%40intel.com
patch subject: [PATCH net-next 4/7] net: stmmac: enable ARP Offload on mac_link_up()
config: arm-randconfig-004-20250826 (https://download.01.org/0day-ci/archive/20250827/202508270007.sExKFhrN-lkp@intel.com/config)
compiler: arm-linux-gnueabi-gcc (GCC) 10.5.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250827/202508270007.sExKFhrN-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202508270007.sExKFhrN-lkp@intel.com/

All errors (new ones prefixed by >>, old ones prefixed by <<):

>> ERROR: modpost: "in_dev_finish_destroy" [drivers/net/ethernet/stmicro/stmmac/stmmac.ko] undefined!

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

Patchew 2.1-devel-b67e4c2

© 2016 - 2026 Red Hat, Inc.