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authorLorenzo Pieralisi <lorenzo.pieralisi@arm.com>2020-09-04 17:09:04 +0300
committerBjorn Helgaas <bhelgaas@google.com>2020-09-09 00:52:42 +0300
commite338eecf3fe79054e8a31b8c39a1234b5acfdabe (patch)
tree155e65e0a9fa813e32535dc256fe4330e8b2b8d4 /drivers/pci/controller/pcie-rockchip-host.c
parent7c2308f79fc81ba0bf24ccd2429fb483a91bcd51 (diff)
downloadlinux-e338eecf3fe79054e8a31b8c39a1234b5acfdabe.tar.xz
PCI: rockchip: Fix bus checks in rockchip_pcie_valid_device()
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>
Diffstat (limited to 'drivers/pci/controller/pcie-rockchip-host.c')
-rw-r--r--drivers/pci/controller/pcie-rockchip-host.c11
1 files 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;
}