linux-kernel - [PATCH 3.12 02/38] PCI: Fix devfn for VPD access through function 0

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Date:   Tue, 13 Dec 2016 20:52:28 +0100
From:   Jiri Slaby <jslaby@...e.cz>
To:     stable@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org,
        Alex Williamson <alex.williamson@...hat.com>,
        Bjorn Helgaas <helgaas@...nel.org>, Jiri Slaby <jslaby@...e.cz>
Subject: [PATCH 3.12 02/38] PCI: Fix devfn for VPD access through function 0

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

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

===============

commit 9d9240756e63dd87d6cbf5da8b98ceb8f8192b55 upstream.

Commit 932c435caba8 ("PCI: Add dev_flags bit to access VPD through function
0") passes PCI_SLOT(devfn) for the devfn parameter of pci_get_slot().
Generally this works because we're fairly well guaranteed that a PCIe
device is at slot address 0, but for the general case, including
conventional PCI, it's incorrect.  We need to get the slot and then convert
it back into a devfn.

Fixes: 932c435caba8 ("PCI: Add dev_flags bit to access VPD through function 0")
Signed-off-by: Alex Williamson <alex.williamson@...hat.com>
Signed-off-by: Bjorn Helgaas <helgaas@...nel.org>
Acked-by: Myron Stowe <myron.stowe@...hat.com>
Acked-by: Mark Rustad <mark.d.rustad@...el.com>
Signed-off-by: Jiri Slaby <jslaby@...e.cz>
---
 drivers/pci/access.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/pci/access.c b/drivers/pci/access.c
index 6bc9b12ba42a..16a022ee54a6 100644
--- a/drivers/pci/access.c
+++ b/drivers/pci/access.c
@@ -362,7 +362,8 @@ static const struct pci_vpd_ops pci_vpd_pci22_ops = {
 static ssize_t pci_vpd_f0_read(struct pci_dev *dev, loff_t pos, size_t count,
 			       void *arg)
 {
-	struct pci_dev *tdev = pci_get_slot(dev->bus, PCI_SLOT(dev->devfn));
+	struct pci_dev *tdev = pci_get_slot(dev->bus,
+					    PCI_DEVFN(PCI_SLOT(dev->devfn), 0));
 	ssize_t ret;
 
 	if (!tdev)
@@ -376,7 +377,8 @@ static ssize_t pci_vpd_f0_read(struct pci_dev *dev, loff_t pos, size_t count,
 static ssize_t pci_vpd_f0_write(struct pci_dev *dev, loff_t pos, size_t count,
 				const void *arg)
 {
-	struct pci_dev *tdev = pci_get_slot(dev->bus, PCI_SLOT(dev->devfn));
+	struct pci_dev *tdev = pci_get_slot(dev->bus,
+					    PCI_DEVFN(PCI_SLOT(dev->devfn), 0));
 	ssize_t ret;
 
 	if (!tdev)
@@ -395,7 +397,8 @@ static const struct pci_vpd_ops pci_vpd_f0_ops = {
 
 static int pci_vpd_f0_dev_check(struct pci_dev *dev)
 {
-	struct pci_dev *tdev = pci_get_slot(dev->bus, PCI_SLOT(dev->devfn));
+	struct pci_dev *tdev = pci_get_slot(dev->bus,
+					    PCI_DEVFN(PCI_SLOT(dev->devfn), 0));
 	int ret = 0;
 
 	if (!tdev)
-- 
2.11.0