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>
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>

diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c
index e91d73c8aa4e3e241ba89ad51f559f69fe1b3062..94be6c32fa7d9359c984349dce845720acefe795 100644 (file)
--- a/drivers/net/ethernet/intel/igb/igb_main.c
+++ b/drivers/net/ethernet/intel/igb/igb_main.c
@@ -5012,7 +5012,8 @@ 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,