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From:   Meng Tang <tangmeng@uniontech.com>
To:     netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
        stable@vger.kernel.org
Cc:     Vinicius Costa Gomes <vinicius.gomes@intel.com>,
        Bjorn Helgaas <bhelgaas@google.com>,
        Tony Nguyen <anthony.l.nguyen@intel.com>,
        Meng Tang <tangmeng@uniontech.com>
Subject: [PATCH 5.10 1/2] commit 1d71eb53e451 ("Revert "PCI: Make pci_enable_ptm() private"")
Date:   Tue, 14 Jun 2022 09:15:27 +0800
Message-Id: <20220614011528.32118-1-tangmeng@uniontech.com>
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From: Vinicius Costa Gomes <vinicius.gomes@intel.com>

Make pci_enable_ptm() accessible from the drivers.

Exposing this to the driver enables the driver to use the
'ptm_enabled' field of 'pci_dev' to check if PTM is enabled or not.

This reverts commit ac6c26da29c1 ("PCI: Make pci_enable_ptm() private").

In the 5.10 kernel version, even to the latest confirmed version,
the following error will still be reported when I225-V network card
is used.

kernel: [    1.031581] igc: probe of 0000:01:00.0 failed with error -2
kernel: [    1.066574] igc: probe of 0000:02:00.0 failed with error -2
kernel: [    1.096152] igc: probe of 0000:03:00.0 failed with error -2
kernel: [    1.127251] igc: probe of 0000:04:00.0 failed with error -2

Even though I confirmed that 7c496de538eebd8212dc2a3c9a468386b2640d4
and 47bca7de6a4fb8dcb564c7ca4d885c91ed19e03 have been merged into the
kernel 5.10, the bug is still occurred, and the
"commit 1b5d73fb8624 ("igc: Enable PCIe PTM")" can fixes it.

And this patch is the pre-patch of
1b5d73fb862414106cf270a1a7300ce8ae77de83.

Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
Signed-off-by: Meng Tang <tangmeng@uniontech.com>
---
 drivers/pci/pci.h   | 3 ---
 include/linux/pci.h | 7 +++++++
 2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index a96dc6f53076..4084764bf0b1 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -585,11 +585,8 @@ static inline void pcie_ecrc_get_policy(char *str) { }
 
 #ifdef CONFIG_PCIE_PTM
 void pci_ptm_init(struct pci_dev *dev);
-int pci_enable_ptm(struct pci_dev *dev, u8 *granularity);
 #else
 static inline void pci_ptm_init(struct pci_dev *dev) { }
-static inline int pci_enable_ptm(struct pci_dev *dev, u8 *granularity)
-{ return -EINVAL; }
 #endif
 
 struct pci_dev_reset_methods {
diff --git a/include/linux/pci.h b/include/linux/pci.h
index bc5a1150f072..692ce678c5f1 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1599,6 +1599,13 @@ static inline bool pci_aer_available(void) { return false; }
 
 bool pci_ats_disabled(void);
 
+#ifdef CONFIG_PCIE_PTM
+int pci_enable_ptm(struct pci_dev *dev, u8 *granularity);
+#else
+static inline int pci_enable_ptm(struct pci_dev *dev, u8 *granularity)
+{ return -EINVAL; }
+#endif
+
 void pci_cfg_access_lock(struct pci_dev *dev);
 bool pci_cfg_access_trylock(struct pci_dev *dev);
 void pci_cfg_access_unlock(struct pci_dev *dev);
-- 
2.20.1