[PATCH 3.2 02/52] PCI: Use function 0 VPD for identical functions, regular VPD for others

[Ben Hutchings <ben@decadent.org.uk>]

3.2.74-rc1 review patch.  If anyone has any objections, please let me know.

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

From: Alex Williamson <alex.williamson@redhat.com>

commit da2d03ea27f6ed9d2005a67b20dd021ddacf1e4d upstream.

932c435caba8 ("PCI: Add dev_flags bit to access VPD through function 0")
added PCI_DEV_FLAGS_VPD_REF_F0.  Previously, we set the flag on every
non-zero function of quirked devices.  If a function turned out to be
different from function 0, i.e., it had a different class, vendor ID, or
device ID, the flag remained set but we didn't make VPD accessible at all.

Flip this around so we only set PCI_DEV_FLAGS_VPD_REF_F0 for functions that
are identical to function 0, and allow regular VPD access for any other
functions.

[bhelgaas: changelog, stable tag]
Fixes: 932c435caba8 ("PCI: Add dev_flags bit to access VPD through function 0")
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Bjorn Helgaas <helgaas@kernel.org>
Acked-by: Myron Stowe <myron.stowe@redhat.com>
Acked-by: Mark Rustad <mark.d.rustad@intel.com>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
 drivers/pci/access.c | 22 ----------------------
 drivers/pci/quirks.c | 20 ++++++++++++++++++--
 2 files changed, 18 insertions(+), 24 deletions(-)

--- a/drivers/pci/access.c
+++ b/drivers/pci/access.c
@@ -391,23 +391,6 @@ static const struct pci_vpd_ops pci_vpd_
 	.release = pci_vpd_pci22_release,
 };
 
-static int pci_vpd_f0_dev_check(struct pci_dev *dev)
-{
-	struct pci_dev *tdev = pci_get_slot(dev->bus,
-					    PCI_DEVFN(PCI_SLOT(dev->devfn), 0));
-	int ret = 0;
-
-	if (!tdev)
-		return -ENODEV;
-	if (!tdev->vpd || !tdev->multifunction ||
-	    dev->class != tdev->class || dev->vendor != tdev->vendor ||
-	    dev->device != tdev->device)
-		ret = -ENODEV;
-
-	pci_dev_put(tdev);
-	return ret;
-}
-
 int pci_vpd_pci22_init(struct pci_dev *dev)
 {
 	struct pci_vpd_pci22 *vpd;
@@ -416,12 +399,7 @@ int pci_vpd_pci22_init(struct pci_dev *d
 	cap = pci_find_capability(dev, PCI_CAP_ID_VPD);
 	if (!cap)
 		return -ENODEV;
-	if (dev->dev_flags & PCI_DEV_FLAGS_VPD_REF_F0) {
-		int ret = pci_vpd_f0_dev_check(dev);
 
-		if (ret)
-			return ret;
-	}
 	vpd = kzalloc(sizeof(*vpd), GFP_ATOMIC);
 	if (!vpd)
 		return -ENOMEM;
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -1941,12 +1941,28 @@ static void __devinit quirk_netmos(struc
 }
 DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_NETMOS, PCI_ANY_ID, quirk_netmos);
 
+/*
+ * Quirk non-zero PCI functions to route VPD access through function 0 for
+ * devices that share VPD resources between functions.  The functions are
+ * expected to be identical devices.
+ */
 static void quirk_f0_vpd_link(struct pci_dev *dev)
 {
+	struct pci_dev *f0;
+
 	if ((dev->class >> 8) != PCI_CLASS_NETWORK_ETHERNET ||
-	    !dev->multifunction || !PCI_FUNC(dev->devfn))
+	    !PCI_FUNC(dev->devfn))
+		return;
+
+	f0 = pci_get_slot(dev->bus, PCI_DEVFN(PCI_SLOT(dev->devfn), 0));
+	if (!f0)
 		return;
-	dev->dev_flags |= PCI_DEV_FLAGS_VPD_REF_F0;
+
+	if (f0->vpd && dev->class == f0->class &&
+	    dev->vendor == f0->vendor && dev->device == f0->device)
+		dev->dev_flags |= PCI_DEV_FLAGS_VPD_REF_F0;
+
+	pci_dev_put(f0);
 }
 DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, PCI_ANY_ID, quirk_f0_vpd_link);