netdev - [PATCH 08/17] net/mlx5: Use pcie_lnkctl_clear_and

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Date: Thu, 11 May 2023 16:14:32 +0300
From: Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
To: linux-pci@...r.kernel.org,
	Bjorn Helgaas <helgaas@...nel.org>,
	Rob Herring <robh@...nel.org>,
	Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
	Krzysztof Wilczyński <kw@...ux.com>,
	Lukas Wunner <lukas@...ner.de>,
	Saeed Mahameed <saeedm@...dia.com>,
	Leon Romanovsky <leon@...nel.org>,
	"David S. Miller" <davem@...emloft.net>,
	Eric Dumazet <edumazet@...gle.com>,
	Jakub Kicinski <kuba@...nel.org>,
	Paolo Abeni <pabeni@...hat.com>,
	netdev@...r.kernel.org,
	linux-rdma@...r.kernel.org,
	linux-kernel@...r.kernel.org
Cc: Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
Subject: [PATCH 08/17] net/mlx5: Use pcie_lnkctl_clear_and_set() for changing LNKCTL

Don't assume that only the driver would be accessing LNKCTL of the
upstream (bridge). ASPM policy changes can trigger write to LNKCTL
outside of driver's control.

Use pcie_lnkctl_clear_and_set() which does proper locking to avoid
losing concurrent updates to the register value.

Suggested-by: Lukas Wunner <lukas@...ner.de>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
---
 drivers/net/ethernet/mellanox/mlx5/core/fw_reset.c | 9 ++-------
 1 file changed, 2 insertions(+), 7 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/fw_reset.c b/drivers/net/ethernet/mellanox/mlx5/core/fw_reset.c
index 50022e7565f1..2c3d69f3a107 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/fw_reset.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/fw_reset.c
@@ -332,16 +332,11 @@ static int mlx5_pci_link_toggle(struct mlx5_core_dev *dev)
 		pci_cfg_access_lock(sdev);
 	}
 	/* PCI link toggle */
-	err = pci_read_config_word(bridge, cap + PCI_EXP_LNKCTL, &reg16);
-	if (err)
-		return err;
-	reg16 |= PCI_EXP_LNKCTL_LD;
-	err = pci_write_config_word(bridge, cap + PCI_EXP_LNKCTL, reg16);
+	err = pcie_lnkctl_clear_and_set(bridge, 0, PCI_EXP_LNKCTL_LD);
 	if (err)
 		return err;
 	msleep(500);
-	reg16 &= ~PCI_EXP_LNKCTL_LD;
-	err = pci_write_config_word(bridge, cap + PCI_EXP_LNKCTL, reg16);
+	err = pcie_lnkctl_clear_and_set(bridge, PCI_EXP_LNKCTL_LD, 0);
 	if (err)
 		return err;
 
-- 
2.30.2