linux-kernel - Re: [PATCH v9 7/7] PCI/DPC: Enumerate the devices after DPC trigger event

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Date:   Thu, 22 Feb 2018 11:23:28 -0800
From:   Randy Dunlap <rdunlap@...radead.org>
To:     Oza Pawandeep <poza@...eaurora.org>,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        Philippe Ombredanne <pombredanne@...b.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Kate Stewart <kstewart@...uxfoundation.org>,
        linux-pci@...r.kernel.org, linux-kernel@...r.kernel.org,
        Dongdong Liu <liudongdong3@...wei.com>,
        Keith Busch <keith.busch@...el.com>, Wei Zhang <wzhang@...com>,
        Sinan Kaya <okaya@...eaurora.org>,
        Timur Tabi <timur@...eaurora.org>
Subject: Re: [PATCH v9 7/7] PCI/DPC: Enumerate the devices after DPC trigger
 event

On 02/21/2018 11:46 PM, Oza Pawandeep wrote:
> Implement error_resume callback in DPC so, after DPC trigger event
> enumerates the devices beneath.
> 
> Signed-off-by: Oza Pawandeep <poza@...eaurora.org>
> 
> diff --git a/drivers/pci/pcie/pcie-dpc.c b/drivers/pci/pcie/pcie-dpc.c
> index fce4518..59c01c7 100644
> --- a/drivers/pci/pcie/pcie-dpc.c
> +++ b/drivers/pci/pcie/pcie-dpc.c
> @@ -129,6 +129,23 @@ static void dpc_wait_link_inactive(struct dpc_dev *dpc)
>  }
>  
>  /**
> + * dpc_error_resume - enumerate the devices beneath
> + * @dev: pointer to Root Port's pci_dev data structure

    * @pdev: ...

> + *
> + * Invoked by Port Bus driver during nonfatal recovery.
> + */
> +static void dpc_error_resume(struct pci_dev *pdev)
> +{
> +	bool active = true;
> +
> +	if (pci_wait_for_link(pdev, active)) {
> +		pci_lock_rescan_remove();
> +		pci_rescan_bus(pdev->bus);
> +		pci_unlock_rescan_remove();
> +	}
> +}
> +
> +/**
>   * dpc_reset_link - reset link DPC  routine
>   * @dev: pointer to Root Port's pci_dev data structure
>   *
> diff --git a/drivers/pci/pcie/pcie-err.c b/drivers/pci/pcie/pcie-err.c
> index 6844347..4950f49 100644
> --- a/drivers/pci/pcie/pcie-err.c
> +++ b/drivers/pci/pcie/pcie-err.c
> @@ -256,6 +258,15 @@ static pci_ers_result_t broadcast_error_message(struct pci_dev *dev,
>  		result_data.result = PCI_ERS_RESULT_RECOVERED;
>  
>  	if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE) {
> +		/* If DPC is triggered, call resume error hanlder

		                                          handler

Kernel multi-line comment style is:
		/*
		 * Begin comment here.
		 * foo bar blah
		 */

> +		 * because, at this point we can safely assume that
> +		 * link recovery has happened.
> +		 */
> +		if ((severity == DPC_FATAL) &&
> +			(cb == report_resume)) {
> +			cb(dev, NULL);
> +			return PCI_ERS_RESULT_RECOVERED;
> +		}
>  		/*
>  		 * If the error is reported by a bridge, we think this error
>  		 * is related to the downstream link of the bridge, so we

thanks,
-- 
~Randy