On Wed, Nov 13, 2024 at 03:54:17PM -0600, Terry Bowman wrote:
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -5038,6 +5038,20 @@ static u16 cxl_port_dvsec(struct pci_dev *dev)
> PCI_DVSEC_CXL_PORT);
> }
>
> +bool pcie_is_cxl_port(struct pci_dev *dev)
> +{
> + if (!pcie_is_cxl(dev))
> + return false;
> +
> + if ((pci_pcie_type(dev) != PCI_EXP_TYPE_ROOT_PORT) &&
> + (pci_pcie_type(dev) != PCI_EXP_TYPE_UPSTREAM) &&
> + (pci_pcie_type(dev) != PCI_EXP_TYPE_DOWNSTREAM))
> + return false;
> +
> + return cxl_port_dvsec(dev);
> +}
> +EXPORT_SYMBOL_GPL(pcie_is_cxl_port);
This doesn't need to be exported because the only caller introduced
in this series is in drivers/pci/pcie/aer.c (in patch 05/15), which
is dependent on CONFIG_PCIEAER, which is bool not tristate.
The "!pcie_is_cxl(dev)" check at the top of the function is identical
to the return value "cxl_port_dvsec(dev)". This looks redundant.
However one cannot call pci_pcie_type() without first checking
pci_is_pcie(). So I'm wondering if the "!pcie_is_cxl(dev)" check
is actually erroneous and supposed to be "!pci_is_pcie(dev)"?
That would make more sense to me.
Alternatively, just return true instead of "cxl_port_dvsec(dev)".
That would probably be the simplest solution here.
> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -443,6 +443,7 @@ struct pci_dev {
> unsigned int is_hotplug_bridge:1;
> unsigned int shpc_managed:1; /* SHPC owned by shpchp */
> unsigned int is_thunderbolt:1; /* Thunderbolt controller */
> + unsigned int is_cxl:1; /* CXL alternate protocol */
I suspect the audience consists mostly of CXL-unaware PCI developers,
so spelling out Compute Express Link here (and omitting "alternate
protocol" if it doesn't fit) might be more appropriate.
Thanks,
Lukas
