PCI: Return -ENOSYS for SR-IOV operations on non-SR-IOV devices

Change the return value to -ENOSYS if a device is not an SR-IOV PF.
Previously we returned either -ENODEV or -EINVAL.

Also have pci_sriov_get_totalvfs() return 0 in the error case to make the
behaviour consistent whether CONFIG_PCI_IOV is enabled or not.
Signed-off-by: Stefan Assmann <sassmann@kpanic.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

drivers/pci/iov.c

@@ -323,7 +323,7 @@ static int sriov_enable(struct pci_dev *dev, int nr_virtfn)
 
 		if (!pdev->is_physfn) {
 			pci_dev_put(pdev);
-			return -ENODEV;
+			return -ENOSYS;
 		}
 
 		rc = sysfs_create_link(&dev->dev.kobj,
@@ -664,7 +664,7 @@ int pci_enable_sriov(struct pci_dev *dev, int nr_virtfn)
 	might_sleep();
 
 	if (!dev->is_physfn)
-		return -ENODEV;
+		return -ENOSYS;
 
 	return sriov_enable(dev, nr_virtfn);
 }
@@ -724,7 +724,7 @@ EXPORT_SYMBOL_GPL(pci_num_vf);
  * @dev: the PCI device
  *
  * Returns number of VFs belonging to this device that are assigned to a guest.
- * If device is not a physical function returns -ENODEV.
+ * If device is not a physical function returns 0.
  */
 int pci_vfs_assigned(struct pci_dev *dev)
 {
@@ -769,12 +769,15 @@ EXPORT_SYMBOL_GPL(pci_vfs_assigned);
  * device's mutex held.
  *
  * Returns 0 if PF is an SRIOV-capable device and
- * value of numvfs valid. If not a PF with VFS, return -EINVAL;
+ * value of numvfs valid. If not a PF return -ENOSYS;
+ * if numvfs is invalid return -EINVAL;
  * if VFs already enabled, return -EBUSY.
  */
 int pci_sriov_set_totalvfs(struct pci_dev *dev, u16 numvfs)
 {
-	if (!dev->is_physfn || (numvfs > dev->sriov->total_VFs))
+	if (!dev->is_physfn)
+		return -ENOSYS;
+	if (numvfs > dev->sriov->total_VFs)
 		return -EINVAL;
 
 	/* Shouldn't change if VFs already enabled */
@@ -793,12 +796,12 @@ EXPORT_SYMBOL_GPL(pci_sriov_set_totalvfs);
  *
  * For a PCIe device with SRIOV support, return the PCIe
  * SRIOV capability value of TotalVFs or the value of driver_max_VFs
- * if the driver reduced it.  Otherwise, -EINVAL.
+ * if the driver reduced it.  Otherwise 0.
  */
 int pci_sriov_get_totalvfs(struct pci_dev *dev)
 {
 	if (!dev->is_physfn)
-		return -EINVAL;
+		return 0;
 
 	if (dev->sriov->driver_max_VFs)
 		return dev->sriov->driver_max_VFs;