[PATCH 3.16 175/192] PCI: Support PCIe devices with short cfg_size

Ben Hutchings
2017-10-09T13:59:58Z

From: "Jason S. McMullan" <jason.mcmullan@netronome.com>

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@netronome.com>
[simon: edited changelog]
Signed-off-by: Simon Horman <simon.horman@netronome.com>
[bhelgaas: more changelog edits]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
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
@@ -1367,10 +1367,10 @@ 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;

@@ -1422,10 +1422,10 @@ 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;
}
@@ -1459,10 +1459,10 @@ 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);