Re: [PATCH] X86/acpi: remove redundant logic of acpi memory hotadd

[Wen Congyang <wency@cn.fujitsu.com>]

At 12/08/2012 06:19 AM, Rafael J. Wysocki Wrote:
> On Tuesday, December 04, 2012 01:39:54 AM Liu, Jinsong wrote:
>> Resend it, add Rafael and linux-acpi@vger.kernel.org
> 
> I wonder what memory hotplug people think about that.
> 
> Thanks,
> Rafael
> 
> 
>> ===============
>> From 1d39279e45c54ce531691da5ffe261e7689dd92c Mon Sep 17 00:00:00 2001
>> From: Liu Jinsong <jinsong.liu@intel.com>
>> Date: Wed, 14 Nov 2012 18:52:06 +0800
>> Subject: [PATCH] X86/acpi: remove redundant logic of acpi memory hotadd
>>
>> When memory hotadd, acpi_memory_enable_device has already been done
>> at drv->ops.add (acpi_memory_device_add), no need to do it again
>> at notify callback.
>>
>> At acpi_memory_enable_device, acpi_memory_get_device_resources
>> is also a redundant action, since it has been done at drv->ops.add.
>>
>> Signed-off-by: Liu Jinsong <jinsong.liu@intel.com>
>> ---
>>  drivers/acpi/acpi_memhotplug.c |   17 -----------------
>>  1 files changed, 0 insertions(+), 17 deletions(-)
>>
>> diff --git a/drivers/acpi/acpi_memhotplug.c b/drivers/acpi/acpi_memhotplug.c
>> index 24c807f..a6489fd 100644
>> --- a/drivers/acpi/acpi_memhotplug.c
>> +++ b/drivers/acpi/acpi_memhotplug.c
>> @@ -220,15 +220,6 @@ static int acpi_memory_enable_device(struct acpi_memory_device *mem_device)
>>  	struct acpi_memory_info *info;
>>  	int node;
>>  
>> -
>> -	/* Get the range from the _CRS */
>> -	result = acpi_memory_get_device_resources(mem_device);
>> -	if (result) {
>> -		printk(KERN_ERR PREFIX "get_device_resources failed\n");
>> -		mem_device->state = MEMORY_INVALID_STATE;
>> -		return result;
>> -	}
>> -
>>  	node = acpi_get_node(mem_device->device->handle);
>>  	/*
>>  	 * Tell the VM there is more memory here...
>> @@ -357,14 +348,6 @@ static void acpi_memory_device_notify(acpi_handle handle, u32 event, void *data)
>>  			break;
>>  		}
>>  
>> -		if (acpi_memory_check_device(mem_device))
>> -			break;

Hmm, if acpi_memory_check_device() fails, it means the memory device disappears
I don't know if a real hardware uses this way to remove memory device.

>> -
>> -		if (acpi_memory_enable_device(mem_device)) {
>> -			printk(KERN_ERR PREFIX "Cannot enable memory device\n");
>> -			break;
>> -		}

If acpi_memory_get_device() doesn't fail, it means that the device has been managed
by this driver, so I think we can do this cleanup.

Thanks
Wen Congyang

>> -
>>  		ost_code = ACPI_OST_SC_SUCCESS;
>>  		break;
>>  
>>