linux-kernel - Re: [PATCH v9 2/7] PCI/AER: factor out error reporting from AER

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Date:   Thu, 22 Feb 2018 11:23:41 -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 2/7] PCI/AER: factor out error reporting from AER

On 02/21/2018 11:46 PM, Oza Pawandeep wrote:

Hi,
Just minor stuff:

> diff --git a/drivers/pci/pcie/pcie-err.c b/drivers/pci/pcie/pcie-err.c
> new file mode 100644
> index 0000000..a532fe0
> --- /dev/null
> +++ b/drivers/pci/pcie/pcie-err.c
> @@ -0,0 +1,334 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * This file implements the error recovery as a core part of PCIe error reporting.
> + * When a PCIe error is delivered, an error message will be collected and printed
> + * to console, then, an error recovery procedure will be executed by following
> + * the PCI error recovery rules.
> + *
> + * Copyright (C) 2006 Intel Corp.
> + *	Tom Long Nguyen (tom.l.nguyen@...el.com)
> + *	Zhang Yanmin (yanmin.zhang@...el.com)
> + *
> + */
> +
> +#include <linux/pci.h>
> +#include <linux/module.h>
> +#include <linux/pci.h>
> +#include <linux/kernel.h>
> +#include <linux/errno.h>
> +#include <linux/aer.h>
> +#include <linux/pcieport_if.h>
> +#include "portdrv.h"

> +static int report_error_detected(struct pci_dev *dev, void *data)
> +{
> +	pci_ers_result_t vote;
> +	const struct pci_error_handlers *err_handler;
> +	struct aer_broadcast_data *result_data;
> +
> +	result_data = (struct aer_broadcast_data *) data;
> +
> +	device_lock(&dev->dev);
> +	dev->error_state = result_data->state;
> +
> +	if (!dev->driver ||
> +		!dev->driver->err_handler ||
> +		!dev->driver->err_handler->error_detected) {
> +		if (result_data->state == pci_channel_io_frozen &&
> +			dev->hdr_type != PCI_HEADER_TYPE_BRIDGE) {
> +			/*
> +			 * In case of fatal recovery, if one of down-
> +			 * stream device has no driver. We might be
> +			 * unable to recover because a later insmod
> +			 * of a driver for this device is unaware of
> +			 * its hw state.
> +			 */
> +			dev_printk(KERN_DEBUG, &dev->dev, "device has %s\n",
> +				   dev->driver ?
> +				   "no error-aware driver" : "no driver");

or:
			dev_printk(KERN_DEBUG, &dev->dev, "device has no%s driver\n",
				   dev->driver ? " error-aware" : "");

> +		}
> +
> +		/*
> +		 * If there's any device in the subtree that does not
> +		 * have an error_detected callback, returning
> +		 * PCI_ERS_RESULT_NO_AER_DRIVER prevents calling of
> +		 * the subsequent mmio_enabled/slot_reset/resume
> +		 * callbacks of "any" device in the subtree. All the
> +		 * devices in the subtree are left in the error state
> +		 * without recovery.
> +		 */
> +
> +		if (dev->hdr_type != PCI_HEADER_TYPE_BRIDGE)
> +			vote = PCI_ERS_RESULT_NO_AER_DRIVER;
> +		else
> +			vote = PCI_ERS_RESULT_NONE;
> +	} else {
> +		err_handler = dev->driver->err_handler;
> +		vote = err_handler->error_detected(dev, result_data->state);
> +	}
> +
> +	result_data->result = merge_result(result_data->result, vote);
> +	device_unlock(&dev->dev);
> +	return 0;
> +}

> +/**
> + * broadcast_error_message - handle message broadcast to downstream drivers
> + * @dev: pointer to from where in a hierarchy message is broadcasted down

            I would drop ^^ "from" ...                   is broadcast downstream

> + * @state: error state
> + * @error_mesg: message to print
> + * @cb: callback to be broadcasted

                    to be broadcast

> + *
> + * Invoked during error recovery process. Once being invoked, the content
> + * of error severity will be broadcasted to all downstream drivers in a

                        will be broadcast

> + * hierarchy in question.
> + */
> +static pci_ers_result_t broadcast_error_message(struct pci_dev *dev,
> +	enum pci_channel_state state,
> +	char *error_mesg,
> +	int (*cb)(struct pci_dev *, void *))
> +{
> +	struct aer_broadcast_data result_data;


-- 
~Randy