On Thursday, July 24, 2014 2:53 AM, Lucas Stach wrote:
>
> Use pci_create_root_bus() similar to other pci
> host controller drivers.
>
> The main problem with pci_scan_root_bus() is that
> not only it will create the root bus, but also try
> to activate all devices on the bus. This triggers
> PCI device drivers probe, which try to use the device
> but fail as resource allocation isn't done at that
> point in time.
>
> To work around this we made sure that the host
> controller driver is probed early and finishes resource
> allocation before any other device drivers are registered.
> Switching to pci_create_root_bus() allows us to get rid
> of this special handling.
>
> Signed-off-by: Lucas Stach <l.stach@xxxxxxxxxxxxxx>
> ---
> drivers/pci/host/pcie-designware.c | 15 +++++++--------
> 1 file changed, 7 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/pci/host/pcie-designware.c b/drivers/pci/host/pcie-designware.c
> index b13a830c8b0f..b869e202367c 100644
> --- a/drivers/pci/host/pcie-designware.c
> +++ b/drivers/pci/host/pcie-designware.c
> @@ -801,14 +801,13 @@ static struct pci_bus *dw_pcie_scan_bus(int nr, struct pci_sys_data *sys)
> struct pci_bus *bus;
> struct pcie_port *pp = sys_to_pcie(sys);
>
> - if (pp) {
> - pp->root_bus_nr = sys->busnr;
> - bus = pci_scan_root_bus(pp->dev, sys->busnr, &dw_pcie_ops,
> - sys, &sys->resources);
> - } else {
> - bus = NULL;
> - BUG();
> - }
> + pp->root_bus_nr = sys->busnr;
> + bus = pci_create_root_bus(pp->dev, sys->busnr,
> + &dw_pcie_ops, sys, &sys->resources);
> + if (!bus)
> + return NULL;
> +
> + pci_scan_child_bus(bus);
I think that we still need to check if pp is NULL.
Then, how about adding NULL check as below?
+ if (!pp) {
+ BUG();
+ return NULL;
+ }
+
+ pp->root_bus_nr = sys->busnr;
+ bus = pci_create_root_bus(pp->dev, sys->busnr,
+ &dw_pcie_ops, sys, &sys->resources);
+ if (!bus)
+ return NULL;
+
+ pci_scan_child_bus(bus);
Best regards,
Jingoo Han
>
> return bus;
> }
> --
> 2.0.1
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