PCI: Fix unaligned access in AF transaction pending test

pci_wait_for_pending() uses word access, so we shouldn't be passing
an offset that is only byte aligned.  Use the control register offset
instead, shifting the mask to match.

Fixes: d0b4cc4e3270 ("PCI: Wrong register used to check pending traffic")
Fixes: 157e876ffe0b ("PCI: Add pci_wait_for_pending() (refactor pci_wait_for_pending_transaction())
Reported-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
CC: stable@vger.kernel.org	# v3.14+

1 files changed, 7 insertions, 2 deletions

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 63a54a340863..1c8592b0e146 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -3135,8 +3135,13 @@ static int pci_af_flr(struct pci_dev *dev, int probe)
         if (probe)
                 return 0;
 
-        /* Wait for Transaction Pending bit clean */
-        if (pci_wait_for_pending(dev, pos + PCI_AF_STATUS, PCI_AF_STATUS_TP))
+        /*
+         * Wait for Transaction Pending bit to clear.  A word-aligned test
+         * is used, so we use the conrol offset rather than status and shift
+         * the test bit to match.
+         */
+        if (pci_wait_for_pending(dev, pos + PCI_AF_CTRL,
+                                 PCI_AF_STATUS_TP << 8))
                 goto clear;
 
         dev_err(&dev->dev, "transaction is not cleared; proceeding with reset anyway\n");