Commit e338eecf authored by Lorenzo Pieralisi's avatar Lorenzo Pieralisi Committed by Bjorn Helgaas

PCI: rockchip: Fix bus checks in rockchip_pcie_valid_device()

The root bus checks rework in d84c572d ("PCI: rockchip: Use
pci_is_root_bus() to check if bus is root bus") caused a regression whereby
in rockchip_pcie_valid_device() if the bus parameter is the root bus and
the dev value == 0, the function should return 1 (ie true) without checking
if the bus->parent pointer is a root bus because that triggers a NULL
pointer dereference.

Fix this by streamlining the root bus detection.

Fixes: d84c572d ("PCI: rockchip: Use pci_is_root_bus() to check if bus is root bus")
Link: https://lore.kernel.org/r/20200904140904.944-1-lorenzo.pieralisi@arm.comReported-by: default avatarSamuel Dionne-Riel <samuel@dionne-riel.com>
Tested-by: default avatarSamuel Dionne-Riel <samuel@dionne-riel.com>
Signed-off-by: default avatarLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: default avatarBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: default avatarRob Herring <robh@kernel.org>
Cc: Shawn Lin <shawn.lin@rock-chips.com>
parent 7c2308f7
...@@ -71,16 +71,13 @@ static void rockchip_pcie_update_txcredit_mui(struct rockchip_pcie *rockchip) ...@@ -71,16 +71,13 @@ static void rockchip_pcie_update_txcredit_mui(struct rockchip_pcie *rockchip)
static int rockchip_pcie_valid_device(struct rockchip_pcie *rockchip, static int rockchip_pcie_valid_device(struct rockchip_pcie *rockchip,
struct pci_bus *bus, int dev) struct pci_bus *bus, int dev)
{ {
/* access only one slot on each root port */
if (pci_is_root_bus(bus) && dev > 0)
return 0;
/* /*
* do not read more than one device on the bus directly attached * Access only one slot on each root port.
* Do not read more than one device on the bus directly attached
* to RC's downstream side. * to RC's downstream side.
*/ */
if (pci_is_root_bus(bus->parent) && dev > 0) if (pci_is_root_bus(bus) || pci_is_root_bus(bus->parent))
return 0; return dev == 0;
return 1; return 1;
} }
......
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