igb: fix vf lookup

Recent addition of code to find already allocated VFs failed to take
account that systems with 2 or more multi-port SR-IOV capable controllers
might have already enabled VFs.  Make sure that the VFs the function is
finding are actually subordinate to the particular instance of the adapter
that is looking for them and not subordinate to some device that has
previously enabled SR-IOV.

This is applicable to 3.2+ kernels.

CC: stable@vger.kernel.org
Reported-by: David Ahern <daahern@cisco.com>
(cherry picked from commit 0629292117572a60465f38cdedde2f8164c3df0b)
Signed-off-by: Greg Rose <gregory.v.rose@intel.com>
Tested-by: Robert E Garrett <robertX.e.garrett@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: Joe Jin <joe.jin@oracle.com>

diff --git a/drivers/net/igb/igb_main.c b/drivers/net/igb/igb_main.c
index d1580916995d33857347da3ccdbaf805fdde0f9f..9cc19a4242ea792641e809c0b9a0a357646826e8 100644 (file)
--- a/drivers/net/igb/igb_main.c
+++ b/drivers/net/igb/igb_main.c
@@ -5008,7 +5008,8 @@ static int igb_find_enabled_vfs(struct igb_adapter *adapter)
        vf_devfn = pdev->devfn + 0x80;
        pvfdev = pci_get_device(hw->vendor_id, device_id, NULL);
        while (pvfdev) {
-               if (pvfdev->devfn == vf_devfn)
+               if (pvfdev->devfn == vf_devfn &&
+                   (pvfdev->bus->number >= pdev->bus->number))
                        vfs_found++;
                vf_devfn += vf_stride;
                pvfdev = pci_get_device(hw->vendor_id,