PCI: Disable VF decoding before pcibios_sriov_disable() updates resources

A struct resource represents the address space consumed by a device. We
should not modify that resource while the device is actively using the
address space. For VFs, pci_iov_update_resource() enforces this by
printing a warning and doing nothing if the VFE (VF Enable) and MSE (VF
Memory Space Enable) bits are set.

Previously, both sriov_enable() and sriov_disable() called the
pcibios_sriov_disable() arch hook, which may update the struct resource,
while VFE and MSE were enabled. This effectively dropped the resource
update pcibios_sriov_disable() intended to do.

Disable VF memory decoding before calling pcibios_sriov_disable().

Reported-by: Carol L Soto <[e-mail]>
Tested-by: Carol L Soto <[e-mail]>
Signed-off-by: Gavin Shan <[e-mail]>
Signed-off-by: Alexey Kardashevskiy <[e-mail]>
[bhelgaas: changelog]
Signed-off-by: Bjorn Helgaas <[e-mail]>
Cc: [e-mail]
Cc: Benjamin Herrenschmidt <[e-mail]>
Cc: Paul Mackerras <[e-mail]>

drivers/pci/iov.c

···
 	while (i--)
 		pci_iov_remove_virtfn(dev, i, 0);
 
-	pcibios_sriov_disable(dev);
 err_pcibios:
 	iov->ctrl &= ~(PCI_SRIOV_CTRL_VFE | PCI_SRIOV_CTRL_MSE);
 	pci_cfg_access_lock(dev);
 	pci_write_config_word(dev, iov->pos + PCI_SRIOV_CTRL, iov->ctrl);
 	ssleep(1);
 	pci_cfg_access_unlock(dev);
+
+	pcibios_sriov_disable(dev);
 
 	if (iov->link != dev->devfn)
 		sysfs_remove_link(&dev->dev.kobj, "dep_link");
···
 	for (i = 0; i < iov->num_VFs; i++)
 		pci_iov_remove_virtfn(dev, i, 0);
 
-	pcibios_sriov_disable(dev);
-
 	iov->ctrl &= ~(PCI_SRIOV_CTRL_VFE | PCI_SRIOV_CTRL_MSE);
 	pci_cfg_access_lock(dev);
 	pci_write_config_word(dev, iov->pos + PCI_SRIOV_CTRL, iov->ctrl);
 	ssleep(1);
 	pci_cfg_access_unlock(dev);
+
+	pcibios_sriov_disable(dev);
 
 	if (iov->link != dev->devfn)
 		sysfs_remove_link(&dev->dev.kobj, "dep_link");