Re: [PATCH part1 v6 5/7] PCI: Add pci_dummy_ops to isolate pci device temporarily

[Yijing Wang <wangyijing@huawei.com>]

>> +void pci_bus_unfreeze_device(struct pci_bus *bus)
>> +{
>> +	unsigned long flags;
>> +
>> +	BUG_ON(!bus->save_ops);
>> +	spin_lock_irqsave(&pci_freeze_lock, flags);
>> +	if (!bus->is_frozen)
>> +		goto out;
> 
> It seems that the BUG_ON() should placed here, otherwise it will be
> triggered if we try to unfreeze the same bus multiply.
> 

Oh, right, I should move it down, thanks for the good catch.


> 
>> +	pci_bus_set_ops(bus, bus->save_ops);
>> +	bus->save_ops = NULL;
>> +	bus->is_frozen = 0;
>> +out:
>> +	spin_unlock_irqrestore(&pci_freeze_lock, flags);
>> +}
>> +
>>  /**
>>   * pci_configure_ari - enable or disable ARI forwarding
>>   * @dev: the PCI device
>> diff --git a/include/linux/pci.h b/include/linux/pci.h
>> index d60c0b6..e3dd4ea 100644
>> --- a/include/linux/pci.h
>> +++ b/include/linux/pci.h
>> @@ -442,6 +442,7 @@ struct pci_bus {
>>  	struct resource busn_res;	/* bus numbers routed to this bus */
>>  
>>  	struct pci_ops	*ops;		/* configuration access functions */
>> +	struct pci_ops	*save_ops; /* save configuration access functions */
>>  	struct msi_chip	*msi;		/* MSI controller */
>>  	void		*sysdata;	/* hook for sys-specific extension */
>>  	struct proc_dir_entry *procdir;	/* directory entry in /proc/bus/pci */
>> @@ -460,6 +461,7 @@ struct pci_bus {
>>  	struct bin_attribute	*legacy_io; /* legacy I/O for this bus */
>>  	struct bin_attribute	*legacy_mem; /* legacy mem */
>>  	unsigned int		is_added:1;
>> +	unsigned int		is_frozen:1;
>>  };
>>  
>>  #define pci_bus_b(n)	list_entry(n, struct pci_bus, node)
>> @@ -1026,6 +1028,8 @@ ssize_t pci_read_vpd(struct pci_dev *dev, loff_t pos, size_t count, void *buf);
>>  ssize_t pci_write_vpd(struct pci_dev *dev, loff_t pos, size_t count, const void *buf);
>>  
>>  bool pci_serial_number_changed(struct pci_dev *pdev);
>> +void pci_bus_freeze_device(struct pci_bus *bus);
>> +void pci_bus_unfreeze_device(struct pci_bus *bus);
>>  
>>  /* Helper functions for low-level code (drivers/pci/setup-[bus,res].c) */
>>  resource_size_t pcibios_retrieve_fw_addr(struct pci_dev *dev, int idx);
> 
> 
> 
> .
> 


-- 
Thanks!
Yijing