[PATCH 2/2] PCI: Support PCIe Capability Slot registers only forports with slots

[Bjorn Helgaas]

Commit 6d3a1741f1e648cfbd5a0cc94477a0d5004c6f5e upstream.

Previously we allowed callers to access Slot Capabilities, Status, and
Control for Root Ports even if the Root Port did not implement a slot.
This seems dubious because the spec only requires these registers if a
slot is implemented.

It's true that even Root Ports without slots must have *space* for these
slot registers, because the Root Capabilities, Status, and Control
registers are after the slot registers in the capability.  However,
for a v1 PCIe Capability, the *semantics* of the slot registers are
undefined unless a slot is implemented.

Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
Reviewed-By: Jiang Liu <jiang.liu@xxxxxxxxxx>
CC: stable@xxxxxxxxxxxxxxx	# 3.10.x 3.11.x
---
 drivers/pci/access.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/access.c b/drivers/pci/access.c
index e26c3bd9aca4..bcd92b629d3c 100644
--- a/drivers/pci/access.c
+++ b/drivers/pci/access.c
@@ -499,8 +499,8 @@ static inline bool pcie_cap_has_sltctl(const struct pci_dev *dev)
 	int type = pci_pcie_type(dev);
 
 	return pcie_cap_version(dev) > 1 ||
-	       type == PCI_EXP_TYPE_ROOT_PORT ||
-	       (type == PCI_EXP_TYPE_DOWNSTREAM &&
+	       ((type == PCI_EXP_TYPE_ROOT_PORT ||
+	         type == PCI_EXP_TYPE_DOWNSTREAM) &&
 		pcie_caps_reg(dev) & PCI_EXP_FLAGS_SLOT);
 }
 

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/