Re: [Xen-devel] [PATCH v3 05/27] PCI: tegra: Save msi chip in pci_sys_data

[Yijing Wang <wangyijing@xxxxxxxxxx>]

On 2014/10/23 13:18, Bjorn Helgaas wrote:
> On Wed, Oct 15, 2014 at 11:06:53AM +0800, Yijing Wang wrote:
>> Save msi chip in pci_sys_data instead of assign
>> msi chip to every pci bus in .add_bus().
>>
>> Signed-off-by: Yijing Wang <wangyijing@xxxxxxxxxx>
>> ---
>>  drivers/pci/host/pci-tegra.c |   13 +++----------
>>  1 files changed, 3 insertions(+), 10 deletions(-)
>>
>> diff --git a/drivers/pci/host/pci-tegra.c b/drivers/pci/host/pci-tegra.c
>> index 3d43874..5af0525 100644
>> --- a/drivers/pci/host/pci-tegra.c
>> +++ b/drivers/pci/host/pci-tegra.c
>> @@ -694,15 +694,6 @@ static int tegra_pcie_map_irq(const struct pci_dev 
>> *pdev, u8 slot, u8 pin)
>>      return irq;
>>  }
>>  
>> -static void tegra_pcie_add_bus(struct pci_bus *bus)
>> -{
>> -    if (IS_ENABLED(CONFIG_PCI_MSI)) {
>> -            struct tegra_pcie *pcie = sys_to_pcie(bus->sysdata);
>> -
>> -            bus->msi = &pcie->msi.chip;
>> -    }
>> -}
>> -
>>  static struct pci_bus *tegra_pcie_scan_bus(int nr, struct pci_sys_data *sys)
>>  {
>>      struct tegra_pcie *pcie = sys_to_pcie(sys);
>> @@ -1881,11 +1872,13 @@ static int tegra_pcie_enable(struct tegra_pcie *pcie)
>>  
>>      memset(&hw, 0, sizeof(hw));
>>  
>> +#ifdef CONFIG_PCI_MSI
>> +    hw.msi_chip = &pcie->msi.chip;
>> +#endif
> 
> Why did you use "#ifdef CONFIG_PCI_MSI" instead of the
> "IS_ENABLED(CONFIG_PCI_MSI)" used previously?

Just personal habit. :)

> 
> It's true that CONFIG_PCI_MSI will never be a tristate symbol, so we don't
> really *need* the extra smarts of IS_ENABLED(), but I'm fairly sympathetic
> to James' argument [1] that we should just use IS_ENABLED() all the time
> because it's simpler overall.
> 
> If you want to change the #ifdef to IS_ENABLED(), that should be a separate
> patch from your msi_chip change, and we can debate the merits of that by
> itself.
> 
> [1] http://lkml.iu.edu//hypermail/linux/kernel/1204.3/00081.html

Hi Bjorn, thanks for your guidance. I will use IS_ENABLED() instead of #ifdef 
for simplification
in a separate patch.

> 
>>      hw.nr_controllers = 1;
>>      hw.private_data = (void **)&pcie;
>>      hw.setup = tegra_pcie_setup;
>>      hw.map_irq = tegra_pcie_map_irq;
>> -    hw.add_bus = tegra_pcie_add_bus;
>>      hw.scan = tegra_pcie_scan_bus;
>>      hw.ops = &tegra_pcie_ops;
>>  
>> -- 
>> 1.7.1
>>
>> --
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> 
> .
> 


-- 
Thanks!
Yijing


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