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SubjectRe: [PATCH 1/2] PCI: Add support for VF Resizable Bar extended cap
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On 16.12.2021 01:21, Krzysztof Wilczyński wrote:
> Hi Michał,
>
> [...]
>> +static int pci_memory_decoding(struct pci_dev *dev)
>> +{
>> + u16 cmd;
>> +
>> + pci_read_config_word(dev, PCI_COMMAND, &cmd);
>> + if (cmd & PCI_COMMAND_MEMORY)
>> + return -EBUSY;
>> +
>> + return 0;
>> +}
>> +
>> +#ifdef CONFIG_PCI_IOV
>> +static int pci_vf_memory_decoding(struct pci_dev *dev)
>> +{
>> + u16 cmd;
>> +
>> + pci_read_config_word(dev, dev->sriov->pos + PCI_SRIOV_CTRL, &cmd);
>> + if (cmd & PCI_SRIOV_CTRL_MSE)
>> + return -EBUSY;
>> +
>> + return 0;
>> +}
>> +#endif
>> +
>> int pci_resize_resource(struct pci_dev *dev, int resno, int size)
>> {
>> struct resource *res = dev->resource + resno;
>> struct pci_host_bridge *host;
>> int old, ret;
>> u32 sizes;
>> - u16 cmd;
>>
>> /* Check if we must preserve the firmware's resource assignment */
>> host = pci_find_host_bridge(dev->bus);
>> @@ -424,9 +447,14 @@ int pci_resize_resource(struct pci_dev *dev, int resno, int size)
>> if (!(res->flags & IORESOURCE_UNSET))
>> return -EBUSY;
>>
>> - pci_read_config_word(dev, PCI_COMMAND, &cmd);
>> - if (cmd & PCI_COMMAND_MEMORY)
>> - return -EBUSY;
>> +#ifdef CONFIG_PCI_IOV
>> + if (resno >= PCI_IOV_RESOURCES)
>> + ret = pci_vf_memory_decoding(dev);
>> + else
>> +#endif
>> + ret = pci_memory_decoding(dev);
>> + if (ret)
>> + return ret;
>
> The above else works, however, it does trip our static analysis tools, and
> lack of the indentation makes it slightly confusing to read, at least at
> the first glance. Thus, I wonder whether it would be possible to combine
> the pci_vf_memory_decoding() and pci_memory_decoding() somehow neatly into
> a private helper that takes a boolean to indicate whether it's a VF or not.
> Then, we could drop the if-statement, since some of the logic could live
> within the helper.
>
> What do you think?

Sure - implementing a helper in a way that Christian suggested (the
helper still takes resno though) should also take care of that.

Thanks
-Michał

>
> Krzysztof

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