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Date: Mon, 19 Jan 2015 11:12:50 +0800
From: Yijing Wang <wangyijing@huawei.com>
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To: Arnd Bergmann <arnd@arndb.de>,
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CC: Bjorn Helgaas <bhelgaas@google.com>,
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	Thomas Gleixner <tglx@linutronix.de>,
	"Guan Xuetao" <gxt@mprc.pku.edu.cn>,
	Yinghai Lu <yinghai@kernel.org>,
	Jiang Liu <jiang.liu@linux.intel.com>
Subject: Re: [PATCH 10/28] PCI: Save sysdata in pci_host_bridge drvdata
References: <1421372666-12288-1-git-send-email-wangyijing@huawei.com> <1421372666-12288-11-git-send-email-wangyijing@huawei.com> <18973877.BYCS6vtzoq@wuerfel>
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On 2015/1/16 17:18, Arnd Bergmann wrote:
> On Friday 16 January 2015 09:44:08 Yijing Wang wrote:
>> @@ -2066,11 +2064,11 @@ struct pci_bus *pci_scan_root_bus(struct device *parent, u32 db,
>>  {
>>         struct pci_host_bridge *host;
>>  
>> -       host = pci_create_host_bridge(parent, db, resources);
>> +       host = pci_create_host_bridge(parent, db, resources, sysdata);
>>         if (!host)
>>                 return NULL;
>>  
>> -       return __pci_scan_root_bus(host, ops, sysdata);
>> +       return __pci_scan_root_bus(host, ops);
>>  }
>>  EXPORT_SYMBOL(pci_scan_root_bus);
>>
> 
> How about keeping the sysdata out of the pci_create_host_bridge interface, and
> refactoring it so that the call sequence becomes
> 
> 	host = pci_create_host_bridge(parent, db, resources);
> 	host->sysdata = sysdata;
> 	__pci_scan_root_bus(host, ops);
> 
> This way, we can make sysdata completely option. I assume that more of the
> fields we have in sysdata today can get moved into pci_host_bridge
> over time, so a host bridge driver can just assign those members individually
> between pci_create_host_bridge and __pci_scan_root_bus.

I put the sysdata in pci_host_bridge, because some platforms x86/ia64
need to call pcibios_root_bridge_prepare() before pci_host_bridge registration
in pci_create_host_bridge(), and pcibios_root_bridge_prepare() need the companion
acpi device pointer which is stored in sysdata.

I like you idea, but I haven't find a better way yet.

Thanks!
Yijing.

> 
> 	Arnd
> 
> .
> 


-- 
Thanks!
Yijing