linux-kernel - Re: [PATCH v2 2/2] Improve container_notify

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Message-ID: <50889A14.9030607@huawei.com>
Date:	Thu, 25 Oct 2012 09:47:00 +0800
From:	Jiang Liu <jiang.liu@...wei.com>
To:	Tang Chen <tangchen@...fujitsu.com>
CC:	Toshi Kani <toshi.kani@...com>, <yinghai@...nel.org>,
	<bhelgaas@...gle.com>, <lenb@...nel.org>,
	<izumi.taku@...fujitsu.com>, <isimatu.yasuaki@...fujitsu.com>,
	<mihailm@...allels.com>, <linux-acpi@...r.kernel.org>,
	<linux-pci@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 2/2] Improve container_notify_cb() to support container
 hot-remove.

On 2012-10-25 9:31, Tang Chen wrote:
> Hi Toshi,
> 
> On 10/25/2012 01:14 AM, Toshi Kani wrote:
>> On Wed, 2012-10-24 at 14:05 +0800, Tang Chen wrote:
>>> +static int container_device_remove(struct acpi_device *device)
>>> +{
>>> +    int ret;
>>> +    struct acpi_eject_event *ej_event;
>>> +
>>> +    /* stop container device at first */
>>> +    ret = acpi_bus_trim(device, 0);
>>
>> Hi Tang,
>>
>> Why do you need to call acpi_bus_trim(device,0) to stop the container
>> device first?
> 
> This issue was introduced by Lu Yinghai, I think he could give a better
> answer than me. :)
> Please refer to the following url:
> 
> http://www.spinics.net/lists/linux-pci/msg17667.html
> 
> However, this is not applied into the pci tree yet.
We have worked out a patch set to clean up the logic for PCI/ACPI binding
relationship. It updates PCI/ACPI binding relationship by registering bus
notification onto pci_bus_type instead of hooking into the ACPI/glue.c.

To accommodate that patch set, the ACPI device destroy process has been
split into two steps:
1) acpi_bus_trim(device,0) to unbind ACPI drivers
2) acpi_bus_trim(device,1) to destroy ACPI devices

> 
>>
>>> +    printk(KERN_WARNING "acpi_bus_trim stop return %x\n", ret);
>>
>> Do you need this message in the normal case?  If so, I'd suggest to use
>> pr_debug().
>>
>>> +    if (ret)
>>> +        return ret;
>>> +
>>> +    /* event originated from ACPI eject notification */
>>> +    device->flags.eject_pending = 1;
>>
>> You do not need to set the eject_pending flag when the handler calls
>> acpi_bus_hot_remove_device().  It was set before because the handler did
>> not initiate the hot-remove operation.
> 
> I just set it to keep the logic the same as before.
> And thanks for telling me this. :)
> 
>>
> ...
>>> +        printk(KERN_WARNING "Container driver received %s event\n",
>>> +            "ACPI_NOTIFY_EJECT_REQUEST");
>>
>> Same as other comment.  Suggest to use pr_debug().
> 
> OK. :)
> 
>>
>>> +
>>> +        if (!present || ACPI_FAILURE(status) || !device)
>>> +            break;
>>> +
>>> +        result = container_device_remove(device);
>>> +        if (result) {
>>> +            printk(KERN_WARNING "Failed to remove container\n");
>>
>> Please use pr_warn().
>>
>> Thanks,
>> -Toshi
>>
>>> +            break;
>>>           }
>>> -        break;
>>> +
>>> +        return;
>>>
>>>       default:
>>>           /* non-hotplug event; possibly handled by other handler */
>>
>>
>> -- 
>> To unsubscribe from this list: send the line "unsubscribe linux-acpi" in
>> the body of a message to majordomo@...r.kernel.org
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>>
> 
> 
> .
> 


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