Re: [PATCH v4 3/5] PCI/AER: clean all untracked pci_ops_aer when rmmod aer_inject

[Yijing Wang <wangyijing@huawei.com>]

On 2012/9/21 13:13, Huang Ying wrote:
> On Fri, 2012-09-21 at 11:44 +0800, Yijing Wang wrote:
>> When we do hot plug for pci devices that were injected aer errors, some newly created child buses'
>> pci_ops will be assigned to pci_ops_aer. Aer_inject module will not track these pci_ops_aer(not
>> list in pci_bus_ops_list),so we should clean all of these when rmmod aer_inject module.
>>
>> Signed-off-by: Yijing Wang <wangyijing@huawei.com>
>> Signed-off-by: Huang Ying <ying.huang@intel.com>
>> ---
>>  drivers/pci/pcie/aer/aer_inject.c |   24 ++++++++++++++++++++++++
>>  1 files changed, 24 insertions(+), 0 deletions(-)
>>
>> diff --git a/drivers/pci/pcie/aer/aer_inject.c b/drivers/pci/pcie/aer/aer_inject.c
>> index 0123120..e04cf24 100644
>> --- a/drivers/pci/pcie/aer/aer_inject.c
>> +++ b/drivers/pci/pcie/aer/aer_inject.c
>> @@ -299,6 +299,29 @@ 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*/
>> +static void clean_untracked_pci_ops_aer(void)
>> +{
>> +	struct pci_bus_ops *bus_ops;
>> +
>> +	list_for_each_entry(bus_ops, &pci_bus_ops_list, list) {
>> +		if (pci_is_root_bus(bus_ops->bus))
> 
> Why do cleanup only for root bus?
> 

Because the bus with untracked pci_ops_aer always is the child bus of the root bus
whose pci_ops_aer is tracked in pci_bus_ops_list. So here only do cleanup for root bus to
avoid unnecessary pci_clean_child_aer_ops() called.
eg.
If inject aer errors into 0000:46:00.0, so the pci_ops of bus 0000:40 and bus 0000:46 will be assign to pci_ops_aer
hot remove and hot add 0000:46:00.0, so newly created bus 0000:47 0000:48 and 0000:49 have untracked pci_ops_aer;
In this case 0000:40 and 0000:46 are tracked in pci_bus_ops_list, but 0000:47 0000:48 and 0000:49 are not.
So when we clean untracked pci_ops_aer, I think only cleanup root bus's child bus is enough. cleanup bus 0000:46's child bus
is unnecessary.

 |           +-07.0-[0000:46-49]----00.0-[0000:47-49]--+-02.0-[0000:48]--+-00.0  Intel Corporation 82576 Gigabit Network Connection
 |           |                                         |                 \-00.1  Intel Corporation 82576 Gigabit Network Connection
 |           |                                         \-04.0-[0000:49]--+-00.0  Intel Corporation 82576 Gigabit Network Connection
 |           |                                                           \-00.1  Intel Corporation 82576 Gigabit Network Connection

Thanks
Yijing


> Best Regards,
> Huang Ying
> 
>> +			pci_clean_child_aer_ops(bus_ops->bus);
>> +	}
>> +}
>> +
>>  static int pci_bus_set_aer_ops(struct pci_bus *bus)
>>  {
>>  	struct pci_ops *ops;
>> @@ -560,6 +583,7 @@ static void __exit aer_inject_exit(void)
>>  	while ((bus_ops = pci_bus_ops_get(bus_ops)))
>>  		pci_bus_set_ops(bus_ops->bus, bus_ops->ops);
>>  
>> +	clean_untracked_pci_ops_aer();
>>  	while ((bus_ops = pci_bus_ops_pop()))
>>  		kfree(bus_ops);
>>  
> 
> 
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> .
> 


-- 
Thanks!
Yijing