From: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Date: Fri, 4 Sep 2020 15:09:04 +0100
Subject: PCI: rockchip: Fix bus checks in rockchip_pcie_valid_device()
Git-commit: e338eecf3fe79054e8a31b8c39a1234b5acfdabe
Patch-mainline: v5.9-rc8
References: bsc#1179344
The root bus checks rework in d84c572de1a3 ("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: d84c572de1a3 ("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.com
Reported-by: Samuel Dionne-Riel <samuel@dionne-riel.com>
Tested-by: Samuel Dionne-Riel <samuel@dionne-riel.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Cc: Shawn Lin <shawn.lin@rock-chips.com>
Signed-off-by: Mian Yousaf Kaukab <yousaf.kaukab@suse.com>
---
drivers/pci/controller/pcie-rockchip-host.c | 11 ++++-------
1 file changed, 4 insertions(+), 7 deletions(-)
diff --git a/drivers/pci/controller/pcie-rockchip-host.c b/drivers/pci/controller/pcie-rockchip-host.c
index 0bb2fb3e8a0b..9705059523a6 100644
--- a/drivers/pci/controller/pcie-rockchip-host.c
+++ b/drivers/pci/controller/pcie-rockchip-host.c
@@ -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,
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.
*/
- if (pci_is_root_bus(bus->parent) && dev > 0)
- return 0;
+ if (pci_is_root_bus(bus) || pci_is_root_bus(bus->parent))
+ return dev == 0;
return 1;
}
--
2.26.2