Re: [PATCH 2/5 V2] PCI: pciehp: check and wait port status out of DPC before handling DLLSC and PDC

[Sinan Kaya]

On 9/26/2020 11:28 PM, Ethan Zhao wrote:
> diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_hpc.c
> index 53433b37e181..6f271160f18d 100644
> --- a/drivers/pci/hotplug/pciehp_hpc.c
> +++ b/drivers/pci/hotplug/pciehp_hpc.c
> @@ -710,8 +710,10 @@ static irqreturn_t pciehp_ist(int irq, void *dev_id)
>  	down_read(&ctrl->reset_lock);
>  	if (events & DISABLE_SLOT)
>  		pciehp_handle_disable_request(ctrl);
> -	else if (events & (PCI_EXP_SLTSTA_PDC | PCI_EXP_SLTSTA_DLLSC))
> +	else if (events & (PCI_EXP_SLTSTA_PDC | PCI_EXP_SLTSTA_DLLSC)) {
> +		pci_wait_port_outdpc(pdev);
>  		pciehp_handle_presence_or_link_change(ctrl, events);
> +	}
>  	up_read(&ctrl->reset_lock);

This looks like a hack TBH.

Lukas, Keith;

What is your take on this?
Why is device lock not protecting this situation?

Is there a lock missing in hotplug driver?

Sinan