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SubjectRe: [PATCH v6 21/30] PCI: Introduce pci_bus_child_max_busnr()
On 2015/3/12 11:33, Bjorn Helgaas wrote:
> On Mon, Mar 09, 2015 at 10:34:18AM +0800, Yijing Wang wrote:
>> Sometimes, we need to know the highest reserved
>> busnr for children bus. Because parent's
>> bus->busn_res could have padding in it.
>> This function return the max child busnr as
>> pci_scan_child_bus().
>
> I'm not convinced about this one. The fact that it's only used by parisc
> lba_pci.c and acpiphp makes me suspicious that either they're doing
> something funny, or other drivers *should* be using it, too.

Yes, what lba_pci.c do looks some strange, I did this patch just try to
keep the original logic, but it seems to make code more complex, I would
consider this again and try to find a better solution, thanks.

>
>> Signed-off-by: Yijing Wang <wangyijing@huawei.com>
>> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
>> Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
>> ---
>> drivers/pci/hotplug/acpiphp_glue.c | 29 +----------------------------
>> drivers/pci/pci.c | 27 +++++++++++++++++++++++++--
>> include/linux/pci.h | 2 +-
>> 3 files changed, 27 insertions(+), 31 deletions(-)
>>
>> diff --git a/drivers/pci/hotplug/acpiphp_glue.c b/drivers/pci/hotplug/acpiphp_glue.c
>> index bcb90e4..84f2584 100644
>> --- a/drivers/pci/hotplug/acpiphp_glue.c
>> +++ b/drivers/pci/hotplug/acpiphp_glue.c
>> @@ -397,33 +397,6 @@ static void cleanup_bridge(struct acpiphp_bridge *bridge)
>> acpi_unlock_hp_context();
>> }
>>
>> -/**
>> - * acpiphp_max_busnr - return the highest reserved bus number under the given bus.
>> - * @bus: bus to start search with
>> - */
>> -static unsigned char acpiphp_max_busnr(struct pci_bus *bus)
>> -{
>> - struct pci_bus *tmp;
>> - unsigned char max, n;
>> -
>> - /*
>> - * pci_bus_max_busnr will return the highest
>> - * reserved busnr for all these children.
>> - * that is equivalent to the bus->subordinate
>> - * value. We don't want to use the parent's
>> - * bus->subordinate value because it could have
>> - * padding in it.
>> - */
>> - max = bus->busn_res.start;
>> -
>> - list_for_each_entry(tmp, &bus->children, node) {
>> - n = pci_bus_max_busnr(tmp);
>> - if (n > max)
>> - max = n;
>> - }
>> - return max;
>> -}
>> -
>> static void acpiphp_set_acpi_region(struct acpiphp_slot *slot)
>> {
>> struct acpiphp_func *func;
>> @@ -489,7 +462,7 @@ static void enable_slot(struct acpiphp_slot *slot)
>> LIST_HEAD(add_list);
>>
>> acpiphp_rescan_slot(slot);
>> - max = acpiphp_max_busnr(bus);
>> + max = pci_bus_child_max_busnr(bus);
>> for (pass = 0; pass < 2; pass++) {
>> list_for_each_entry(dev, &bus->devices, bus_list) {
>> if (PCI_SLOT(dev->devfn) != slot->device)
>> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
>> index c49eec1..0001896 100644
>> --- a/drivers/pci/pci.c
>> +++ b/drivers/pci/pci.c
>> @@ -108,7 +108,7 @@ static bool pcie_ari_disabled;
>> * Given a PCI bus, returns the highest PCI bus number present in the set
>> * including the given PCI bus and its list of child PCI buses.
>> */
>> -unsigned char pci_bus_max_busnr(struct pci_bus *bus)
>> +static unsigned char pci_bus_max_busnr(struct pci_bus *bus)
>> {
>> struct pci_bus *tmp;
>> unsigned char max, n;
>> @@ -121,7 +121,30 @@ unsigned char pci_bus_max_busnr(struct pci_bus *bus)
>> }
>> return max;
>> }
>> -EXPORT_SYMBOL_GPL(pci_bus_max_busnr);
>> +
>> +unsigned char pci_bus_child_max_busnr(struct pci_bus *bus)
>> +{
>> + struct pci_bus *tmp;
>> + unsigned char max, n;
>> +
>> + /*
>> + * pci_bus_max_busnr will return the highest
>> + * reserved busnr for all these children.
>> + * that is equivalent to the bus->subordinate
>> + * value. We don't want to use the parent's
>> + * bus->subordinate value because it could have
>> + * padding in it.
>> + */
>> + max = bus->busn_res.start;
>> +
>> + list_for_each_entry(tmp, &bus->children, node) {
>> + n = pci_bus_max_busnr(tmp);
>> + if (n > max)
>> + max = n;
>> + }
>> + return max;
>> +}
>> +EXPORT_SYMBOL_GPL(pci_bus_child_max_busnr);
>>
>> #ifdef CONFIG_HAS_IOMEM
>> void __iomem *pci_ioremap_bar(struct pci_dev *pdev, int bar)
>> diff --git a/include/linux/pci.h b/include/linux/pci.h
>> index cfaf217..261b8de 100644
>> --- a/include/linux/pci.h
>> +++ b/include/linux/pci.h
>> @@ -1181,7 +1181,7 @@ int pci_scan_bridge(struct pci_bus *bus, struct pci_dev *dev, int max,
>> void pci_walk_bus(struct pci_bus *top, int (*cb)(struct pci_dev *, void *),
>> void *userdata);
>> int pci_cfg_space_size(struct pci_dev *dev);
>> -unsigned char pci_bus_max_busnr(struct pci_bus *bus);
>> +unsigned char pci_bus_child_max_busnr(struct pci_bus *bus);
>> void pci_setup_bridge(struct pci_bus *bus);
>> resource_size_t pcibios_window_alignment(struct pci_bus *bus,
>> unsigned long type);
>> --
>> 1.7.1
>>
>
> .
>


--
Thanks!
Yijing



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