From: Mohsin Bashir 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: Mohsin Bashir Signed-off-by: Jakub Kicinski --- .../net/ethernet/meta/fbnic/fbnic_hw_stats.c | 22 +++++++++++++++++++ drivers/net/ethernet/meta/fbnic/fbnic_pci.c | 2 ++ 2 files changed, 24 insertions(+) diff --git a/drivers/net/ethernet/meta/fbnic/fbnic_hw_stats.c b/drivers/net/ethernet/meta/fbnic/fbnic_hw_stats.c index 77182922f018..8aa9a0e286bb 100644 --- a/drivers/net/ethernet/meta/fbnic/fbnic_hw_stats.c +++ b/drivers/net/ethernet/meta/fbnic/fbnic_hw_stats.c @@ -1,6 +1,8 @@ // SPDX-License-Identifier: GPL-2.0 /* Copyright (c) Meta Platforms, Inc. and affiliates. */ +#include + #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) diff --git a/drivers/net/ethernet/meta/fbnic/fbnic_pci.c b/drivers/net/ethernet/meta/fbnic/fbnic_pci.c index 953297f667a2..ef7928b18ac0 100644 --- a/drivers/net/ethernet/meta/fbnic/fbnic_pci.c +++ b/drivers/net/ethernet/meta/fbnic/fbnic_pci.c @@ -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; -- 2.51.0