Subject: Re: [PATCH V10 06/12] powerpc/powernv: EEH device for VF

From: Alexey Kardashevskiy <[email-masked]>
Date: Fri, 30 Oct 2015 18:36:01 +1100

On 10/30/2015 05:52 PM, Wei Yang wrote:
> On Fri, Oct 30, 2015 at 02:33:49PM +1100, Alexey Kardashevskiy wrote:
>> On 10/26/2015 02:15 PM, Wei Yang wrote:
>>> VFs and their corresponding pci_dn instances are created and released
>>> dynamically as their PF's SRIOV capability is enabled and disabled.
>>> The patch creates and releases EEH devices for VFs when creating and
>>> releasing their pci_dn instances, which means EEH devices and pci_dn
>>> instances have same life cycle. Also, VF's EEH device is identified
>>> by (struct eeh_dev::physfn).
>>
>>
>> The add_dev_pci_data() helper (the one you hack) does not create pci_dn
>> instances. The add_one_dev_pci_data() helper does.
>>
>
> Yes, you are right. The patch here create edev after the pci_dn is created.
>
> So which part in the log you think is not accurate?

The commit log is ok, I just thought loud that eeh_dev_init() could go to 
add_one_dev_pci_data() to make things more clear.

>>
>>>
>>> [gwshan: changelog and removed CONFIG_PCI_IOV]
>>> Signed-off-by: Wei Yang <[email-masked]>
>>> Acked-by: Gavin Shan <[email-masked]>
>>> ---
>>>   arch/powerpc/include/asm/eeh.h |  1 +
>>>   arch/powerpc/kernel/pci_dn.c   | 12 ++++++++++++
>>>   2 files changed, 13 insertions(+)
>>>
>>> diff --git a/arch/powerpc/include/asm/eeh.h b/arch/powerpc/include/asm/eeh.h
>>> index c5eb86f..6c383ad 100644
>>> --- a/arch/powerpc/include/asm/eeh.h
>>> +++ b/arch/powerpc/include/asm/eeh.h
>>> @@ -140,6 +140,7 @@ struct eeh_dev {
>>>   	struct pci_controller *phb;	/* Associated PHB		*/
>>>   	struct pci_dn *pdn;		/* Associated PCI device node	*/
>>>   	struct pci_dev *pdev;		/* Associated PCI device	*/
>>> +	struct pci_dev *physfn;		/* Associated PF PORT		*/
>>>   	struct pci_bus *bus;		/* PCI bus for partial hotplug	*/
>>>   };
>>>
>>> diff --git a/arch/powerpc/kernel/pci_dn.c b/arch/powerpc/kernel/pci_dn.c
>>> index f771130..f0ddde7 100644
>>> --- a/arch/powerpc/kernel/pci_dn.c
>>> +++ b/arch/powerpc/kernel/pci_dn.c
>>> @@ -180,7 +180,9 @@ static struct pci_dn *add_one_dev_pci_data(struct pci_dn *parent,
>>>   struct pci_dn *add_dev_pci_data(struct pci_dev *pdev)
>>>   {
>>>   #ifdef CONFIG_PCI_IOV
>>> +	struct pci_controller *hose = pci_bus_to_host(pdev->bus);
>>>   	struct pci_dn *parent, *pdn;
>>> +	struct eeh_dev *edev;
>>>   	int i;
>>>
>>>   	/* Only support IOV for now */
>>> @@ -206,6 +208,9 @@ struct pci_dn *add_dev_pci_data(struct pci_dev *pdev)
>>>   				 __func__, i);
>>>   			return NULL;
>>>   		}
>>> +		eeh_dev_init(pdn, hose);
>>> +		edev = pdn_to_eeh_dev(pdn);
>>
>>
>> In theory, pdn_to_eeh_dev() can return NULL. In this patch, it is not clear
>> if pdn->edev gets initialized before or after add_dev_pci_data().
>>
>
> Yep, the return value should be checked.

May be BUG_ON will be enough, up to you.

>
> pdn->edev is initialized in eeh_dev_init() which is called in
> add_dev_pci_data(). The order is not clear?
>
>>
>>
>>> +		edev->physfn = pdev;
>>>   	}
>>>   #endif /* CONFIG_PCI_IOV */
>>>
>>> @@ -254,10 +259,17 @@ void remove_dev_pci_data(struct pci_dev *pdev)
>>>   	for (i = 0; i < pci_sriov_get_totalvfs(pdev); i++) {
>>>   		list_for_each_entry_safe(pdn, tmp,
>>>   			&parent->child_list, list) {
>>> +			struct eeh_dev *edev;
>>>   			if (pdn->busno != pci_iov_virtfn_bus(pdev, i) ||
>>>   			    pdn->devfn != pci_iov_virtfn_devfn(pdev, i))
>>>   				continue;
>>>
>>> +			edev = pdn_to_eeh_dev(pdn);
>>> +			if (edev) {
>>> +				pdn->edev = NULL;
>>> +				kfree(edev);
>>> +			}
>>> +
>>>   			if (!list_empty(&pdn->list))
>>>   				list_del(&pdn->list);
>>>
>>>
>>

-- 
Alexey