Re: [PATCH v2 07/37] PCI: pci_bus_size_bridges() should not size own bridge

From: Bjorn Helgaas
Date: Mon Mar 12 2012 - 22:48:09 EST


On Sat, Mar 10, 2012 at 12:00 AM, Yinghai Lu <yinghai@xxxxxxxxxx> wrote:
> During checking acpiphp code, found following sequence:
>        pci_bus_size_bridges(bus);
>        pci_bus_assign_resources(bus);
>        pci_enable_bridges(bus);

One of these lines is indented with tab, the others with spaces, which
makes it not line up when using "git log". Try it sometime.

> The problem is that when bus is not root bus, pci_bus_size_bridges would also size
> own pci bridge bus->self if that bridge resource is not inserted before.
> but later pci_bus_assign_resources will not allocate those size bridge res.
>
> So try make it less confusing, let it does not include self sizing.
> and add with_self parameter info __pci_bus_size_bridge()

You failed to make this less confusing. Adding words to function
names, adding "__" prefixes, adding flags to say "include self" or not
-- they all make things hard to read.

> Fixes caller in pci hotplug componets.

"components"

>
> Signed-off-by: Yinghai Lu <yinghai@xxxxxxxxxx>
> ---
>  drivers/pci/hotplug/acpiphp_glue.c     |    2 +-
>  drivers/pci/hotplug/cpci_hotplug_pci.c |    2 +-
>  drivers/pci/hotplug/shpchp_pci.c       |    2 +-
>  drivers/pci/setup-bus.c                |   24 +++++++++++++++---------
>  include/linux/pci.h                    |    1 +
>  5 files changed, 19 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/pci/hotplug/acpiphp_glue.c b/drivers/pci/hotplug/acpiphp_glue.c
> index 806c44f..10b2122 100644
> --- a/drivers/pci/hotplug/acpiphp_glue.c
> +++ b/drivers/pci/hotplug/acpiphp_glue.c
> @@ -816,7 +816,7 @@ static int __ref enable_device(struct acpiphp_slot *slot)
>                            dev->hdr_type == PCI_HEADER_TYPE_CARDBUS) {
>                                max = pci_scan_bridge(bus, dev, max, pass);
>                                if (pass && dev->subordinate)
> -                                       pci_bus_size_bridges(dev->subordinate);
> +                                       pci_bus_size_bridges_with_self(dev->subordinate);
>                        }
>                }
>        }
> diff --git a/drivers/pci/hotplug/cpci_hotplug_pci.c b/drivers/pci/hotplug/cpci_hotplug_pci.c
> index ae853cc..4ef80ad 100644
> --- a/drivers/pci/hotplug/cpci_hotplug_pci.c
> +++ b/drivers/pci/hotplug/cpci_hotplug_pci.c
> @@ -313,7 +313,7 @@ int __ref cpci_configure_slot(struct slot *slot)
>                                continue;
>                        }
>                        child->subordinate = pci_do_scan_bus(child);
> -                       pci_bus_size_bridges(child);
> +                       pci_bus_size_bridges_with_self(child);
>                }
>                pci_dev_put(dev);
>        }
> diff --git a/drivers/pci/hotplug/shpchp_pci.c b/drivers/pci/hotplug/shpchp_pci.c
> index df7e4bf..d92807b 100644
> --- a/drivers/pci/hotplug/shpchp_pci.c
> +++ b/drivers/pci/hotplug/shpchp_pci.c
> @@ -85,7 +85,7 @@ int __ref shpchp_configure_device(struct slot *p_slot)
>                                continue;
>                        }
>                        child->subordinate = pci_do_scan_bus(child);
> -                       pci_bus_size_bridges(child);
> +                       pci_bus_size_bridges_with_self(child);
>                }
>                pci_configure_slot(dev);
>                pci_dev_put(dev);
> diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
> index f35a679..ec2026c 100644
> --- a/drivers/pci/setup-bus.c
> +++ b/drivers/pci/setup-bus.c
> @@ -982,8 +982,8 @@ handle_done:
>        ;
>  }
>
> -void __ref __pci_bus_size_bridges(struct pci_bus *bus,
> -                       struct list_head *realloc_head)
> +static void __ref __pci_bus_size_bridges(struct pci_bus *bus,
> +                       struct list_head *realloc_head, bool with_self)
>  {
>        struct pci_dev *dev;
>        unsigned long mask, prefmask;
> @@ -1001,13 +1001,13 @@ void __ref __pci_bus_size_bridges(struct pci_bus *bus,
>
>                case PCI_CLASS_BRIDGE_PCI:
>                default:
> -                       __pci_bus_size_bridges(b, realloc_head);
> +                       __pci_bus_size_bridges(b, realloc_head, true);
>                        break;
>                }
>        }
>
> -       /* The root bus? */
> -       if (!bus->self)
> +       /* Is root bus or not wanted? */
> +       if (!bus->self || !with_self)
>                return;
>
>        switch (bus->self->class >> 8) {
> @@ -1047,9 +1047,15 @@ void __ref __pci_bus_size_bridges(struct pci_bus *bus,
>        }
>  }
>
> +void __ref pci_bus_size_bridges_with_self(struct pci_bus *bus)
> +{
> +       __pci_bus_size_bridges(bus, NULL, true);
> +}
> +EXPORT_SYMBOL(pci_bus_size_bridges_with_self);
> +
>  void __ref pci_bus_size_bridges(struct pci_bus *bus)
>  {
> -       __pci_bus_size_bridges(bus, NULL);
> +       __pci_bus_size_bridges(bus, NULL, false);
>  }
>  EXPORT_SYMBOL(pci_bus_size_bridges);
>
> @@ -1362,7 +1368,7 @@ again:
>        /* Depth first, calculate sizes and alignments of all
>           subordinate buses. */
>        list_for_each_entry(bus, &pci_root_buses, node)
> -               __pci_bus_size_bridges(bus, add_list);
> +               __pci_bus_size_bridges(bus, add_list, false);
>
>        /* Depth last, allocate resources and update the hardware. */
>        list_for_each_entry(bus, &pci_root_buses, node)
> @@ -1439,7 +1445,7 @@ void pci_assign_unassigned_bridge_resources(struct pci_dev *bridge)
>                                  IORESOURCE_PREFETCH;
>
>  again:
> -       __pci_bus_size_bridges(parent, &add_list);
> +       __pci_bus_size_bridges(parent, &add_list, true);
>        __pci_bridge_assign_resources(bridge, &add_list, &fail_head);
>        BUG_ON(!list_empty(&add_list));
>        tried_times++;
> @@ -1500,7 +1506,7 @@ void pci_assign_unassigned_bus_resources(struct pci_bus *bus)
>                    dev->hdr_type == PCI_HEADER_TYPE_CARDBUS)
>                        if (dev->subordinate)
>                                __pci_bus_size_bridges(dev->subordinate,
> -                                                        &add_list);
> +                                                &add_list, true);
>        up_read(&pci_bus_sem);
>        __pci_bus_assign_resources(bus, &add_list, NULL);
>        BUG_ON(!list_empty(&add_list));
> diff --git a/include/linux/pci.h b/include/linux/pci.h
> index 634bbf5..87dceca 100644
> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -906,6 +906,7 @@ int pci_vpd_truncate(struct pci_dev *dev, size_t size);
>  resource_size_t pcibios_retrieve_fw_addr(struct pci_dev *dev, int idx);
>  void pci_bus_assign_resources(const struct pci_bus *bus);
>  void pci_bus_size_bridges(struct pci_bus *bus);
> +void pci_bus_size_bridges_with_self(struct pci_bus *bus);
>  int pci_claim_resource(struct pci_dev *, int);
>  void pci_assign_unassigned_resources(void);
>  void pci_assign_unassigned_bridge_resources(struct pci_dev *bridge);
> --
> 1.7.7
>
--
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/