Re: [PATCH v2 2/4] PCI/AER: clean all untracked pci_ops_aer when rmmod aer_inject

[Yijing Wang <wangyijing@huawei.com>]

On 2012/9/14 8:56, Huang Ying wrote:
> On Thu, 2012-09-13 at 18:54 +0800, Yijing Wang wrote:
>> On 2012/9/13 9:43, Huang Ying wrote:
>>> On Wed, 2012-09-12 at 20:33 +0800, Yijing Wang wrote:
>>>> Since hot plug for pci devices while doing aer inject, some newly created child buses'
>>>> pci_ops will be assigned to pci_ops_aer. Aer_inject does not track these pci_ops_aer(not
>>>> list in pci_bus_ops_list),we should clean all of these when rmmod aer_inject module.
>>>>
>>>> Signed-off-by: Yijing Wang <wangyijing@huawei.com>
>>>> ---
>>>>  drivers/pci/pcie/aer/aer_inject.c |   32 ++++++++++++++++++++++++++++++++
>>>>  1 files changed, 32 insertions(+), 0 deletions(-)
>>>>
>>>> diff --git a/drivers/pci/pcie/aer/aer_inject.c b/drivers/pci/pcie/aer/aer_inject.c
>>>> index 0816483..9d195ae 100644
>>>> --- a/drivers/pci/pcie/aer/aer_inject.c
>>>> +++ b/drivers/pci/pcie/aer/aer_inject.c
>>>> @@ -283,6 +283,28 @@ static void pci_bus_ops_init(struct pci_bus_ops *bus_ops,
>>>>  	bus_ops->ops = ops;
>>>>  }
>>>>  
>>>> +static void pci_clean_child_aer_ops(struct pci_bus *bus)
>>>> +{
>>>> +	struct pci_bus *child;
>>>> +
>>>> +	list_for_each_entry(child, &bus->children, node) {
>>>> +		if (child->ops == &pci_ops_aer)
>>>> +			pci_bus_set_ops(child, bus->ops);
>>>> +		pci_clean_child_aer_ops(child);
>>>> +	}
>>>> +}
>>>> +
>>>> +/* find pci_ops_aer from root bus, and replace it by parent bus's pci_ops.
>>>> + * pci_ops of root bus won't be pci_ops_aer here*/
>>>
>>> Why scan all pci buses?  Is it possible just to check buses in
>>> pci_bus_ops_list.
>>>
>>
>> Hi Huang Ying,
>>    Some buses' pci_ops_aer may be not assigned by pci_bus_set_aer_ops() function,
>> As the first patch [PATCH v2 1/4] said. Some newly created buses' pci_ops assigned to
>> pci_ops_aer because their parent just doing aer inject, parent bus's pci_ops was pci_ops_aer.
>> So when we rmmod aer_inject module, these buses' pci_ops_aer will be invalid.
>>
>> 1、Tracked pci_ops_aer will be cleaned and pci_ops will reassign to their original pci_ops saved in pci_bus_ops_list.
>> 2、Un-tracked pci_ops_aer won't be cleaned.so we need to fix it.
> 
> Can we just check all bus and its children in pci_bus_ops_list?  If my
> understanding were correct, bus itself or some of its parents should be
> saved in pci_bus_ops_list?
> 

Yes, good idea! I think the buses that owned untracked pci_ops_aer always are child buses of the root buses
tracked in the pci_bus_ops_list. I will improve this patch in this way.

Thanks
Yijing

> Best Regards,
> Huang Ying
> 
>>>
>>>> +static void clean_untracked_pci_ops_aer(void)
>>>> +{
>>>> +	struct pci_bus *bus = NULL;
>>>> +
>>>> +	while ((bus = pci_find_next_bus(bus)) != NULL)
>>>> +		pci_clean_child_aer_ops(bus);
>>>> +}
>>>> +
>>>> +
>>>>  static int pci_bus_set_aer_ops(struct pci_bus *bus)
>>>>  {
>>>>  	struct pci_ops *ops;
>>>> @@ -546,6 +568,8 @@ static void __exit aer_inject_exit(void)
>>>>  		pci_bus_set_ops(bus_ops->bus, bus_ops->ops);
>>>>  		kfree(bus_ops);
>>>>  	}
>>>> +
>>>> +	clean_untracked_pci_aer_ops();
>>>>  
>>>>  	spin_lock_irqsave(&inject_lock, flags);
>>>>  	list_for_each_entry_safe(err, err_next, &einjected, list) {
>>>> @@ -553,6 +577,14 @@ static void __exit aer_inject_exit(void)
>>>>  		kfree(err);
>>>>  	}
>>>>  	spin_unlock_irqrestore(&inject_lock, flags);
>>>> +
>>>> +	/* Inject aer errors and hotplug the same pcie device
>>>> +	 * maybe assign some newly created buses' pci_ops pci_ops_aer.
>>>> +	 * Since these pci_ops_aer are not tracked in pci_bus_ops_list,
>>>> +	 * we need to find and clean untracked pci_ops_aer before aer_inject
>>>> +	 * module exit
>>>> +	 */
>>>> +	clean_untracked_pci_ops_aer();
>>>>  }
>>>>  
>>>>  module_init(aer_inject_init);
>>>
>>>
>>>
>>> .
>>>
>>
>>
> 
> 
> 
> .
> 


-- 
Thanks!
Yijing