[PATCH iwl-next] i40e: add link_down_events statistic

[PATCH iwl-next] i40e: add link_down_events statistic

[Dawid Osuchowski]

Introduce a link_down_events counter to the i40e driver, incremented
each time the link transitions from up to down.
This counter can help diagnose issues related to link stability,
such as port flapping or unexpected link drops.

The value is exposed via ethtool's get_link_ext_stats() interface.

Co-developed-by: Martyna Szapar-Mudlaw <martyna.szapar-mudlaw@linux.intel.com>
Signed-off-by: Martyna Szapar-Mudlaw <martyna.szapar-mudlaw@linux.intel.com>
Reviewed-by: Michal Swiatkowski <michal.swiatkowski@linux.intel.com>
Signed-off-by: Dawid Osuchowski <dawid.osuchowski@linux.intel.com>
---
Based on series [1] from Martyna where this was implemented for ixgbe
and ice drivers.

[1] https://lore.kernel.org/netdev/20250515105011.1310692-1-martyna.szapar-mudlaw@linux.intel.com/
---
 drivers/net/ethernet/intel/i40e/i40e.h         |  1 +
 drivers/net/ethernet/intel/i40e/i40e_ethtool.c | 10 ++++++++++
 drivers/net/ethernet/intel/i40e/i40e_main.c    |  3 +++
 3 files changed, 14 insertions(+)

diff --git a/drivers/net/ethernet/intel/i40e/i40e.h b/drivers/net/ethernet/intel/i40e/i40e.h
index c67963bfe14e..54d5fdc303ca 100644
--- a/drivers/net/ethernet/intel/i40e/i40e.h
+++ b/drivers/net/ethernet/intel/i40e/i40e.h
@@ -548,6 +548,7 @@ struct i40e_pf {
 	u16 empr_count; /* EMP reset count */
 	u16 pfr_count; /* PF reset count */
 	u16 sw_int_count; /* SW interrupt count */
+	u32 link_down_events;
 
 	struct mutex switch_mutex;
 	u16 lan_vsi;       /* our default LAN VSI */
diff --git a/drivers/net/ethernet/intel/i40e/i40e_ethtool.c b/drivers/net/ethernet/intel/i40e/i40e_ethtool.c
index 21dd70125a16..adcf068202b0 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_ethtool.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_ethtool.c
@@ -2749,6 +2749,15 @@ static void i40e_diag_test(struct net_device *netdev,
 	netif_info(pf, drv, netdev, "testing failed\n");
 }
 
+static void i40e_get_link_ext_stats(struct net_device *netdev,
+				    struct ethtool_link_ext_stats *stats)
+{
+	struct i40e_netdev_priv *np = netdev_priv(netdev);
+	struct i40e_pf *pf = np->vsi->back;
+
+	stats->link_down_events = pf->link_down_events;
+}
+
 static void i40e_get_wol(struct net_device *netdev,
 			 struct ethtool_wolinfo *wol)
 {
@@ -5807,6 +5816,7 @@ static const struct ethtool_ops i40e_ethtool_ops = {
 	.get_regs		= i40e_get_regs,
 	.nway_reset		= i40e_nway_reset,
 	.get_link		= ethtool_op_get_link,
+	.get_link_ext_stats	= i40e_get_link_ext_stats,
 	.get_wol		= i40e_get_wol,
 	.set_wol		= i40e_set_wol,
 	.set_eeprom		= i40e_set_eeprom,
diff --git a/drivers/net/ethernet/intel/i40e/i40e_main.c b/drivers/net/ethernet/intel/i40e/i40e_main.c
index e421156717a4..d7368fa31ec8 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_main.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_main.c
@@ -9933,6 +9933,9 @@ static void i40e_link_event(struct i40e_pf *pf)
 	     new_link == netif_carrier_ok(vsi->netdev)))
 		return;
 
+	if (!new_link && old_link)
+		pf->link_down_events++;
+
 	i40e_print_link_message(vsi, new_link);
 
 	/* Notify the base of the switch tree connected to
-- 
2.47.0

Re: [PATCH iwl-next] i40e: add link_down_events statistic

[Simon Horman]

On Wed, May 21, 2025 at 04:23:32PM +0200, Dawid Osuchowski wrote:
> Introduce a link_down_events counter to the i40e driver, incremented
> each time the link transitions from up to down.
> This counter can help diagnose issues related to link stability,
> such as port flapping or unexpected link drops.
> 
> The value is exposed via ethtool's get_link_ext_stats() interface.
> 
> Co-developed-by: Martyna Szapar-Mudlaw <martyna.szapar-mudlaw@linux.intel.com>
> Signed-off-by: Martyna Szapar-Mudlaw <martyna.szapar-mudlaw@linux.intel.com>
> Reviewed-by: Michal Swiatkowski <michal.swiatkowski@linux.intel.com>
> Signed-off-by: Dawid Osuchowski <dawid.osuchowski@linux.intel.com>
> ---
> Based on series [1] from Martyna where this was implemented for ixgbe
> and ice drivers.
> 
> [1] https://lore.kernel.org/netdev/20250515105011.1310692-1-martyna.szapar-mudlaw@linux.intel.com/

Reviewed-by: Simon Horman <horms@kernel.org>

RE: [Intel-wired-lan] [PATCH iwl-next] i40e: add link_down_events statistic

[Rinitha, SX]

> -----Original Message-----
> From: Intel-wired-lan <intel-wired-lan-bounces@osuosl.org> On Behalf Of Dawid Osuchowski
> Sent: 21 May 2025 19:54
> To: intel-wired-lan@lists.osuosl.org
> Cc: netdev@vger.kernel.org; Dawid Osuchowski <dawid.osuchowski@linux.intel.com>; Martyna Szapar-Mudlaw <martyna.szapar-mudlaw@linux.intel.com>; Michal Swiatkowski <michal.swiatkowski@linux.intel.com>
> Subject: [Intel-wired-lan] [PATCH iwl-next] i40e: add link_down_events statistic
>
> Introduce a link_down_events counter to the i40e driver, incremented each time the link transitions from up to down.
> This counter can help diagnose issues related to link stability, such as port flapping or unexpected link drops.
>
> The value is exposed via ethtool's get_link_ext_stats() interface.
>
> Co-developed-by: Martyna Szapar-Mudlaw <martyna.szapar-mudlaw@linux.intel.com>
> Signed-off-by: Martyna Szapar-Mudlaw <martyna.szapar-mudlaw@linux.intel.com>
> Reviewed-by: Michal Swiatkowski <michal.swiatkowski@linux.intel.com>
> Signed-off-by: Dawid Osuchowski <dawid.osuchowski@linux.intel.com>
> ---
> Based on series [1] from Martyna where this was implemented for ixgbe and ice drivers.
>
> [1] https://lore.kernel.org/netdev/20250515105011.1310692-1-martyna.szapar-mudlaw@linux.intel.com/
> ---
> drivers/net/ethernet/intel/i40e/i40e.h         |  1 +
> drivers/net/ethernet/intel/i40e/i40e_ethtool.c | 10 ++++++++++
> drivers/net/ethernet/intel/i40e/i40e_main.c    |  3 +++
> 3 files changed, 14 insertions(+)
>

Tested-by: Rinitha S <sx.rinitha@intel.com> (A Contingent worker at Intel)