[PATCH 4.4 018/113] PCI: Support PCIe devices with short cfg_size

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Jason S. McMullan <jason.mcmullan@xxxxxxxxxxxxx>

commit c20aecf6963d1273d8f6d61c042b4845441ca592 upstream.

If a device quirk modifies the pci_dev->cfg_size to be less than
PCI_CFG_SPACE_EXP_SIZE (4096), but greater than PCI_CFG_SPACE_SIZE (256),
the PCI sysfs interface truncates the readable size to PCI_CFG_SPACE_SIZE.

Allow sysfs access to config space up to cfg_size, even if the device
doesn't support the entire 4096-byte PCIe config space.

Note that pci_read_config() and pci_write_config() limit access to
dev->cfg_size even though pcie_config_attr contains 4096 (the maximum
size).

Signed-off-by: Jason S. McMullan <jason.mcmullan@xxxxxxxxxxxxx>
[simon: edited changelog]
Signed-off-by: Simon Horman <simon.horman@xxxxxxxxxxxxx>
[bhelgaas: more changelog edits]
Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/pci/pci-sysfs.c |   18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

--- a/drivers/pci/pci-sysfs.c
+++ b/drivers/pci/pci-sysfs.c
@@ -1372,10 +1372,10 @@ int __must_check pci_create_sysfs_dev_fi
 	if (!sysfs_initialized)
 		return -EACCES;
 
-	if (pdev->cfg_size < PCI_CFG_SPACE_EXP_SIZE)
-		retval = sysfs_create_bin_file(&pdev->dev.kobj, &pci_config_attr);
-	else
+	if (pdev->cfg_size > PCI_CFG_SPACE_SIZE)
 		retval = sysfs_create_bin_file(&pdev->dev.kobj, &pcie_config_attr);
+	else
+		retval = sysfs_create_bin_file(&pdev->dev.kobj, &pci_config_attr);
 	if (retval)
 		goto err;
 
@@ -1427,10 +1427,10 @@ err_rom_file:
 err_resource_files:
 	pci_remove_resource_files(pdev);
 err_config_file:
-	if (pdev->cfg_size < PCI_CFG_SPACE_EXP_SIZE)
-		sysfs_remove_bin_file(&pdev->dev.kobj, &pci_config_attr);
-	else
+	if (pdev->cfg_size > PCI_CFG_SPACE_SIZE)
 		sysfs_remove_bin_file(&pdev->dev.kobj, &pcie_config_attr);
+	else
+		sysfs_remove_bin_file(&pdev->dev.kobj, &pci_config_attr);
 err:
 	return retval;
 }
@@ -1464,10 +1464,10 @@ void pci_remove_sysfs_dev_files(struct p
 
 	pci_remove_capabilities_sysfs(pdev);
 
-	if (pdev->cfg_size < PCI_CFG_SPACE_EXP_SIZE)
-		sysfs_remove_bin_file(&pdev->dev.kobj, &pci_config_attr);
-	else
+	if (pdev->cfg_size > PCI_CFG_SPACE_SIZE)
 		sysfs_remove_bin_file(&pdev->dev.kobj, &pcie_config_attr);
+	else
+		sysfs_remove_bin_file(&pdev->dev.kobj, &pci_config_attr);
 
 	pci_remove_resource_files(pdev);