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From:   =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= <ilpo.jarvinen@linux.intel.com>
To:     linux-pci@vger.kernel.org, Bjorn Helgaas <helgaas@kernel.org>,
        Rob Herring <robh@kernel.org>,
        Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
        =?UTF-8?q?Krzysztof=20Wilczy=C5=84ski?= <kw@linux.com>,
        Lukas Wunner <lukas@wunner.de>,
        Jesse Brandeburg <jesse.brandeburg@intel.com>,
        Tony Nguyen <anthony.l.nguyen@intel.com>,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        intel-wired-lan@lists.osuosl.org, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
Cc:     =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= <ilpo.jarvinen@linux.intel.com>
Subject: [PATCH 07/17] e1000e: Use pcie_lnkctl_clear_and_set() for changing LNKCTL
Date:   Thu, 11 May 2023 16:14:31 +0300
Message-Id: <20230511131441.45704-8-ilpo.jarvinen@linux.intel.com>
In-Reply-To: <20230511131441.45704-1-ilpo.jarvinen@linux.intel.com>
References: <20230511131441.45704-1-ilpo.jarvinen@linux.intel.com>
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Don't assume that only the driver would be accessing LNKCTL. ASPM
policy changes can trigger write to LNKCTL outside of driver's control.
And in the case of upstream (parent), the driver does not even own the
device it's changing LNKCTL for.

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

Suggested-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
---
 drivers/net/ethernet/intel/e1000e/netdev.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/intel/e1000e/netdev.c b/drivers/net/ethernet/intel/e1000e/netdev.c
index bd7ef59b1f2e..29d50aeb2c3e 100644
--- a/drivers/net/ethernet/intel/e1000e/netdev.c
+++ b/drivers/net/ethernet/intel/e1000e/netdev.c
@@ -6829,11 +6829,9 @@ static void __e1000e_disable_aspm(struct pci_dev *pdev, u16 state, int locked)
 	/* Both device and parent should have the same ASPM setting.
 	 * Disable ASPM in downstream component first and then upstream.
 	 */
-	pcie_capability_clear_word(pdev, PCI_EXP_LNKCTL, aspm_dis_mask);
-
+	pcie_lnkctl_clear_and_set(pdev, aspm_dis_mask, 0);
 	if (parent)
-		pcie_capability_clear_word(parent, PCI_EXP_LNKCTL,
-					   aspm_dis_mask);
+		pcie_lnkctl_clear_and_set(parent, aspm_dis_mask, 0);
 }
 
 /**
-- 
2.30.2