Re: [PATCH v5 7/9] PCI: PCI: Add pcie_link_is_active() to determine if the PCIe link is active

[Lukas Wunner]

On Sat, Apr 12, 2025 at 07:19:56AM +0530, Krishna Chaitanya Chundru wrote:
> Introduce a common API to check if the PCIe link is active, replacing
> duplicate code in multiple locations.
> 
> Signed-off-by: Krishna Chaitanya Chundru <krishna.chundru@xxxxxxxxxxxxxxxx>

Reviewed-by: Lukas Wunner <lukas@xxxxxxxxx>

One heads-up and one nit:

> --- a/drivers/pci/hotplug/pciehp_hpc.c
> +++ b/drivers/pci/hotplug/pciehp_hpc.c
> @@ -584,7 +557,7 @@ static void pciehp_ignore_dpc_link_change(struct controller *ctrl,
>  	 * Synthesize it to ensure that it is acted on.
>  	 */
>  	down_read_nested(&ctrl->reset_lock, ctrl->depth);
> -	if (!pciehp_check_link_active(ctrl))
> +	if (!pcie_link_is_active(ctrl_dev(ctrl)))
>  		pciehp_request(ctrl, PCI_EXP_SLTSTA_DLLSC);
>  	up_read(&ctrl->reset_lock);
>  }

Heads-up:  There's a trivial merge conflict here with what's queued on
pci.git/hotplug.  No need for you to respin because I expect this will be
merged through a different topic branch anyway, but Bjorn and the other
maintainers will see the merge conflict when generating the next branch.


> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -1945,6 +1945,7 @@ pci_release_mem_regions(struct pci_dev *pdev)
>  			    pci_select_bars(pdev, IORESOURCE_MEM));
>  }
>  
> +bool pcie_link_is_active(struct pci_dev *dev);
>  #else /* CONFIG_PCI is not enabled */
>  
>  static inline void pci_set_flags(int flags) { }
> @@ -2093,6 +2094,9 @@ pci_alloc_irq_vectors(struct pci_dev *dev, unsigned int min_vecs,
>  {
>  	return -ENOSPC;
>  }
> +
> +static inline bool pcie_link_is_active(struct pci_dev *dev)
> +{ return false; }
>  #endif /* CONFIG_PCI */

Nit:  Seems like this would still fit within 80 chars:

static inline bool pcie_link_is_active(struct pci_dev *dev) { return false; }

That said, all existing callers of this function as well as the new one
introduced by this series are only compiled in the CONFIG_PCI=y case,
so I'm not sure the inline stub is necessary at all?

Thanks,

Lukas