linux-kernel - Re: [PATCH v7 05/13] PCI/ERR: Use "bridge" for clarity in pcie_do

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Date:   Thu, 01 Oct 2020 14:04:49 -0700
From:   "Sean V Kelley" <sean.v.kelley@...el.com>
To:     "Jonathan Cameron" <Jonathan.Cameron@...wei.com>
Cc:     "Sean V Kelley" <seanvk.dev@...gontracks.org>, bhelgaas@...gle.com,
        rafael.j.wysocki@...el.com, ashok.raj@...el.com,
        tony.luck@...el.com, sathyanarayanan.kuppuswamy@...el.com,
        qiuxu.zhuo@...el.com, linux-pci@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v7 05/13] PCI/ERR: Use "bridge" for clarity in
 pcie_do_recovery()

On 1 Oct 2020, at 2:06, Jonathan Cameron wrote:

> On Wed, 30 Sep 2020 14:58:12 -0700
> Sean V Kelley <seanvk.dev@...gontracks.org> wrote:
>
>> From: Sean V Kelley <sean.v.kelley@...el.com>
>>
>> The term "dev" is being applied to root ports, switch
>> upstream ports, switch downstream ports, and the upstream
>> ports on endpoints. While endpoint upstream ports don't have
>> subordinate buses, a generic term such as "bridge" may be used
>
> This sentence is a bit confusing.  The bit before the comma
> seems only slightly connected. Perhaps 2 sentences?

I agree.  Will reword.
>
>> for something with a subordinate bus. The current conditional
>> logic in pcie_do_recovery() would also benefit from some
>> simplification with use of pci_upstream_bridge() in place of
>> dev->bus->self. Reverse the pcie_do_recovery() conditional logic
>> and replace use of "dev" with "bridge" for greater clarity.
>>
>> Suggested-by: Bjorn Helgaas <bhelgaas@...gle.com>
>> Signed-off-by: Sean V Kelley <sean.v.kelley@...el.com>
>
> Acked-by: Jonathan Cameron <Jonathan.Cameron@...wei.com>

Thanks,

Sean

>
>> ---
>>  drivers/pci/pcie/err.c | 20 +++++++++++++-------
>>  1 file changed, 13 insertions(+), 7 deletions(-)
>>
>> diff --git a/drivers/pci/pcie/err.c b/drivers/pci/pcie/err.c
>> index 950612342f1c..c6922c099c76 100644
>> --- a/drivers/pci/pcie/err.c
>> +++ b/drivers/pci/pcie/err.c
>> @@ -152,16 +152,22 @@ pci_ers_result_t pcie_do_recovery(struct 
>> pci_dev *dev,
>>  {
>>  	pci_ers_result_t status = PCI_ERS_RESULT_CAN_RECOVER;
>>  	struct pci_bus *bus;
>> +	struct pci_dev *bridge;
>> +	int type;
>>
>>  	/*
>> -	 * Error recovery runs on all subordinates of the first downstream 
>> port.
>> -	 * If the downstream port detected the error, it is cleared at the 
>> end.
>> +	 * Error recovery runs on all subordinates of the first downstream
>> +	 * bridge. If the downstream bridge detected the error, it is
>> +	 * cleared at the end.
>>  	 */
>> -	if (!(pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT ||
>> -	      pci_pcie_type(dev) == PCI_EXP_TYPE_DOWNSTREAM))
>> -		dev = dev->bus->self;
>> -	bus = dev->subordinate;
>> -
>> +	type = pci_pcie_type(dev);
>> +	if (type == PCI_EXP_TYPE_ROOT_PORT ||
>> +	    type == PCI_EXP_TYPE_DOWNSTREAM)
>> +		bridge = dev;
>> +	else
>> +		bridge = pci_upstream_bridge(dev);
>> +
>> +	bus = bridge->subordinate;
>>  	pci_dbg(dev, "broadcast error_detected message\n");
>>  	if (state == pci_channel_io_frozen) {
>>  		pci_walk_bus(bus, report_frozen_detected, &status);