Patch "PCI: cpqphp: Use PCI_POSSIBLE_ERROR() to check config reads" has been added to the 5.15-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    PCI: cpqphp: Use PCI_POSSIBLE_ERROR() to check config reads

to the 5.15-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     pci-cpqphp-use-pci_possible_error-to-check-config-re.patch
and it can be found in the queue-5.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 10ade12a4ba77207f4764eccff000a17e713bb05
Author: weiyufeng <weiyufeng@xxxxxxxxxx>
Date:   Tue Aug 6 14:50:50 2024 +0800

    PCI: cpqphp: Use PCI_POSSIBLE_ERROR() to check config reads
    
    [ 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>

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);