PCI: Fix BAR resizing when VF BARs are assigned

__resource_resize_store() attempts to release all resources of the device
before attempting the resize. The loop, however, only covers standard BARs
(< PCI_STD_NUM_BARS). If a device has VF BARs that are assigned,
pci_reassign_bridge_resources() finds the bridge window still has some
assigned child resources and returns -NOENT which makes
pci_resize_resource() to detect an error and abort the resize.

Change the release loop to cover all resources up to VF BARs which allows
the resize operation to release the bridge windows and attempt to assigned
them again with the different size.

If SR-IOV is enabled, disallow resize as it requires releasing also IOV
resources.

Link: https://lore.kernel.org/r/20250320142837.8027-1-ilpo.jarvinen@linux.intel.com
Fixes: 91fa127794ac ("PCI: Expose PCIe Resizable BAR support via sysfs")
Reported-by: Michał Winiarski <michal.winiarski@intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Alex Williamson <alex.williamson@redhat.com>

diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
index b46ce1a2c5542cdea0a3f9df324434fdb7e8a4d2..0e7eb2a42d88d8c21eb9b3999de9609c59410c18 100644 (file)
--- a/drivers/pci/pci-sysfs.c
+++ b/drivers/pci/pci-sysfs.c
@@ -1556,7 +1556,7 @@ static ssize_t __resource_resize_store(struct device *dev, int n,
                return -EINVAL;
 
        device_lock(dev);
-       if (dev->driver) {
+       if (dev->driver || pci_num_vf(pdev)) {
                ret = -EBUSY;
                goto unlock;
        }
@@ -1578,7 +1578,7 @@ static ssize_t __resource_resize_store(struct device *dev, int n,
 
        pci_remove_resource_files(pdev);
 
-       for (i = 0; i < PCI_STD_NUM_BARS; i++) {
+       for (i = 0; i < PCI_BRIDGE_RESOURCES; i++) {
                if (pci_resource_len(pdev, i) &&
                    pci_resource_flags(pdev, i) == flags)
                        pci_release_resource(pdev, i);