[PATCH 4.19 077/138] PCI: cpqphp: Use PCI_POSSIBLE_ERROR() to check config reads

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4.19-stable review patch.  If anyone has any objections, please let me know.

------------------

From: weiyufeng <weiyufeng@xxxxxxxxxx>

[ Upstream commit a18a025c2fb5fbf2d1d0606ea0d7441ac90e9c39 ]

When config pci_ops.read() can detect failed PCI transactions, the data
returned to the CPU is PCI_ERROR_RESPONSE (~0 or 0xffffffff).

Obviously a successful PCI config read may *also* return that data if a
config register happens to contain ~0, so it doesn't definitively indicate
an error unless we know the register cannot contain ~0.

Use PCI_POSSIBLE_ERROR() to check the response we get when we read data
from hardware.  This unifies PCI error response checking and makes error
checks consistent and easier to find.

Link: https://lore.kernel.org/r/b12005c0d57bb9d4c8b486724d078b7bd92f8321.1637243717.git.naveennaidu479@xxxxxxxxx
Signed-off-by: Naveen Naidu <naveennaidu479@xxxxxxxxx>
Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
Stable-dep-of: e2226dbc4a49 ("PCI: cpqphp: Fix PCIBIOS_* return value confusion")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/pci/hotplug/cpqphp_pci.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/hotplug/cpqphp_pci.c b/drivers/pci/hotplug/cpqphp_pci.c
index 1b2b3f3b648bc..a20875da4ec70 100644
--- a/drivers/pci/hotplug/cpqphp_pci.c
+++ b/drivers/pci/hotplug/cpqphp_pci.c
@@ -138,7 +138,7 @@ static int PCI_RefinedAccessConfig(struct pci_bus *bus, unsigned int devfn, u8 o
 
 	if (pci_bus_read_config_dword(bus, devfn, PCI_VENDOR_ID, &vendID) == -1)
 		return -1;
-	if (vendID == 0xffffffff)
+	if (PCI_POSSIBLE_ERROR(vendID))
 		return -1;
 	return pci_bus_read_config_dword(bus, devfn, offset, value);
 }
@@ -251,7 +251,7 @@ static int PCI_GetBusDevHelper(struct controller *ctrl, u8 *bus_num, u8 *dev_num
 			*dev_num = tdevice;
 			ctrl->pci_bus->number = tbus;
 			pci_bus_read_config_dword(ctrl->pci_bus, *dev_num, PCI_VENDOR_ID, &work);
-			if (!nobridge || (work == 0xffffffff))
+			if (!nobridge || PCI_POSSIBLE_ERROR(work))
 				return 0;
 
 			dbg("bus_num %d devfn %d\n", *bus_num, *dev_num);
-- 
2.43.0







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