Commit 9a0f830f authored by Jakub Kicinski's avatar Jakub Kicinski Committed by Paolo Abeni
Browse files

ethtool: linkstate: add a statistic for PHY down events 

The previous attempt to augment carrier_down (see Link)
was not met with much enthusiasm so let's do the simple
thing of exposing what some devices already maintain.
Add a common ethtool statistic for link going down.
Currently users have to maintain per-driver mapping
to extract the right stat from the vendor-specific ethtool -S
stats. carrier_down does not fit the bill because it counts
a lot of software related false positives.

Add the statistic to the extended link state API to steer
vendors towards implementing all of it.

Implement for bnxt and all Linux-controlled PHYs. mlx5 and (possibly)
enic also have a counter for this but I leave the implementation
to their maintainers.

Link: https://lore.kernel.org/r/20220520004500.2250674-1-kuba@kernel.org


Reviewed-by: default avatarFlorian Fainelli <f.fainelli@gmail.com>
Reviewed-by: default avatarMichael Chan <michael.chan@broadcom.com>
Reviewed-by: default avatarAndrew Lunn <andrew@lunn.ch>
Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
Link: https://lore.kernel.org/r/20221104190125.684910-1-kuba@kernel.org


Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
parent 91c596cc

Documentation/networking/ethtool-netlink.rst

+1 −0
Original line number Diff line number Diff line
@@ -491,6 +491,7 @@ Kernel response contents: 
  ``ETHTOOL_A_LINKSTATE_SQI_MAX``       u32     Max support SQI value

  ``ETHTOOL_A_LINKSTATE_EXT_STATE``     u8      link extended state

  ``ETHTOOL_A_LINKSTATE_EXT_SUBSTATE``  u8      link extended substate

  ``ETHTOOL_A_LINKSTATE_EXT_DOWN_CNT``  u32     count of link down events

  ====================================  ======  ============================



For most NIC drivers, the value of ``ETHTOOL_A_LINKSTATE_LINK`` returns

drivers/net/ethernet/broadcom/bnxt/bnxt_ethtool.c

+15 −0
Original line number Diff line number Diff line
@@ -4112,6 +4112,20 @@ static void bnxt_get_rmon_stats(struct net_device *dev, 
	*ranges = bnxt_rmon_ranges;

}



static void bnxt_get_link_ext_stats(struct net_device *dev,

				    struct ethtool_link_ext_stats *stats)

{

	struct bnxt *bp = netdev_priv(dev);

	u64 *rx;



	if (BNXT_VF(bp) || !(bp->flags & BNXT_FLAG_PORT_STATS_EXT))

		return;



	rx = bp->rx_port_stats_ext.sw_stats;

	stats->link_down_events =

		*(rx + BNXT_RX_STATS_EXT_OFFSET(link_down_events));

}



void bnxt_ethtool_free(struct bnxt *bp)

{

	kfree(bp->test_info);
@@ -4161,6 +4175,7 @@ const struct ethtool_ops bnxt_ethtool_ops = { 
	.get_eeprom             = bnxt_get_eeprom,

	.set_eeprom		= bnxt_set_eeprom,

	.get_link		= bnxt_get_link,

	.get_link_ext_stats	= bnxt_get_link_ext_stats,

	.get_eee		= bnxt_get_eee,

	.set_eee		= bnxt_set_eee,

	.get_module_info	= bnxt_get_module_info,

drivers/net/phy/phy.c

+1 −0
Original line number Diff line number Diff line
@@ -67,6 +67,7 @@ static void phy_link_down(struct phy_device *phydev) 
{

	phydev->phy_link_change(phydev, false);

	phy_led_trigger_change_speed(phydev);

	WRITE_ONCE(phydev->link_down_events, phydev->link_down_events + 1);

}



static const char *phy_pause_str(struct phy_device *phydev)

include/linux/ethtool.h

+17 −0
Original line number Diff line number Diff line
@@ -125,6 +125,20 @@ struct ethtool_link_ext_state_info { 
	};

};



struct ethtool_link_ext_stats {

	/* Custom Linux statistic for PHY level link down events.

	 * In a simpler world it should be equal to netdev->carrier_down_count

	 * unfortunately netdev also counts local reconfigurations which don't

	 * actually take the physical link down, not to mention NC-SI which,

	 * if present, keeps the link up regardless of host state.

	 * This statistic counts when PHY _actually_ went down, or lost link.

	 *

	 * Note that we need u64 for ethtool_stats_init() and comparisons

	 * to ETHTOOL_STAT_NOT_SET, but only u32 is exposed to the user.

	 */

	u64 link_down_events;

};



/**

 * ethtool_rxfh_indir_default - get default value for RX flow hash indirection

 * @index: Index in RX flow hash indirection table
@@ -481,6 +495,7 @@ struct ethtool_module_power_mode_params { 
 *	do not attach ext_substate attribute to netlink message). If link_ext_state

 *	and link_ext_substate are unknown, return -ENODATA. If not implemented,

 *	link_ext_state and link_ext_substate will not be sent to userspace.

 * @get_link_ext_stats: Read extra link-related counters.

 * @get_eeprom_len: Read range of EEPROM addresses for validation of

 *	@get_eeprom and @set_eeprom requests.

 *	Returns 0 if device does not support EEPROM access.
@@ -652,6 +667,8 @@ struct ethtool_ops { 
	u32	(*get_link)(struct net_device *);

	int	(*get_link_ext_state)(struct net_device *,

				      struct ethtool_link_ext_state_info *);

	void	(*get_link_ext_stats)(struct net_device *dev,

				      struct ethtool_link_ext_stats *stats);

	int	(*get_eeprom_len)(struct net_device *);

	int	(*get_eeprom)(struct net_device *,

			      struct ethtool_eeprom *, u8 *);

include/linux/phy.h

+3 −0
Original line number Diff line number Diff line
@@ -600,6 +600,7 @@ struct macsec_ops; 
 * @psec: Pointer to Power Sourcing Equipment control struct

 * @lock:  Mutex for serialization access to PHY

 * @state_queue: Work queue for state machine

 * @link_down_events: Number of times link was lost

 * @shared: Pointer to private data shared by phys in one package

 * @priv: Pointer to driver private data

 *
@@ -723,6 +724,8 @@ struct phy_device { 


	int pma_extable;



	unsigned int link_down_events;



	void (*phy_link_change)(struct phy_device *phydev, bool up);

	void (*adjust_link)(struct net_device *dev);