Commit bcf54e5d authored by Mohsin Bashir's avatar Mohsin Bashir Committed by Jakub Kicinski
Browse files

eth: fbnic: Reset MAC stats 



Reset the MAC stats as part of the hardware stats reset to ensure
consistency. Currently, hardware stats are reset during device bring-up
and upon experiencing PCI errors; however, MAC stats are being skipped
during these resets.

When fbnic_reset_hw_stats() is called upon recovering from PCI error,
MAC stats are accessed outside the rtnl_lock. The only other access to
MAC stats is via the ethtool API, which is protected by rtnl_lock. This
can result in concurrent access to MAC stats and a potential race. Protect
the fbnic_reset_hw_stats() call in __fbnic_pm_attach() with rtnl_lock to
avoid this.

Note that fbnic_reset_hw_mac_stats() is called outside the hardware
stats lock which protects access to the fbnic_hw_stats. This is intentional
because MAC stats are fetched from the device outside this lock and are
exclusively read via the ethtool API.

Signed-off-by: default avatarMohsin Bashir <mohsin.bashr@gmail.com>
Reviewed-by: default avatarJacob Keller <jacob.e.keller@intel.com>
Link: https://patch.msgid.link/20250825200206.2357713-4-kuba@kernel.org


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent b1161b18

drivers/net/ethernet/meta/fbnic/fbnic_hw_stats.c

+22 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0

/* Copyright (c) Meta Platforms, Inc. and affiliates. */



#include <linux/rtnetlink.h>



#include "fbnic.h"



static void fbnic_hw_stat_rst32(struct fbnic_dev *fbd, u32 reg,
@@ -510,6 +512,16 @@ static void fbnic_get_pcie_stats_asic64(struct fbnic_dev *fbd, 
			   &pcie->ob_rd_no_np_cred);

}



static void fbnic_reset_hw_mac_stats(struct fbnic_dev *fbd,

				     struct fbnic_mac_stats *mac_stats)

{

	const struct fbnic_mac *mac = fbd->mac;



	mac->get_eth_mac_stats(fbd, true, &mac_stats->eth_mac);

	mac->get_eth_ctrl_stats(fbd, true, &mac_stats->eth_ctrl);

	mac->get_rmon_stats(fbd, true, &mac_stats->rmon);

}



void fbnic_reset_hw_stats(struct fbnic_dev *fbd)

{

	spin_lock(&fbd->hw_stats.lock);
@@ -520,6 +532,16 @@ void fbnic_reset_hw_stats(struct fbnic_dev *fbd) 
	fbnic_reset_hw_rxq_stats(fbd, fbd->hw_stats.hw_q);

	fbnic_reset_pcie_stats_asic(fbd, &fbd->hw_stats.pcie);

	spin_unlock(&fbd->hw_stats.lock);



	/* Once registered, the only other access to MAC stats is via the

	 * ethtool API which is protected by the rtnl_lock. The call to

	 * fbnic_reset_hw_stats() during PCI recovery is also protected

	 * by the rtnl_lock hence, we don't need the spinlock to access

	 * the MAC stats.

	 */

	if (fbd->netdev)

		ASSERT_RTNL();

	fbnic_reset_hw_mac_stats(fbd, &fbd->hw_stats.mac);

}



void fbnic_init_hw_stats(struct fbnic_dev *fbd)

drivers/net/ethernet/meta/fbnic/fbnic_pci.c

+2 −0
Original line number Diff line number Diff line
@@ -491,7 +491,9 @@ static void __fbnic_pm_attach(struct device *dev) 
	struct net_device *netdev = fbd->netdev;

	struct fbnic_net *fbn;



	rtnl_lock();

	fbnic_reset_hw_stats(fbd);

	rtnl_unlock();



	if (fbnic_init_failure(fbd))

		return;