At 10/13/2012 03:10 AM, KOSAKI Motohiro Wrote:
>>>> -static int acpi_memory_disable_device(struct acpi_memory_device *mem_device)
>>>> +static int acpi_memory_remove_memory(struct acpi_memory_device *mem_device)
>>>> {
>>>> int result;
>>>> struct acpi_memory_info *info, *n;
>>>>
>>>> + list_for_each_entry_safe(info, n, &mem_device->res_list, list) {
>>>
>>> Which lock protect this loop?
>>
>> There is no any lock to protect it now...
>
> When iterate an item removal list, you should use lock for protecting from
> memory corruption.
>
>
>
>
>>>> +static int acpi_memory_disable_device(struct acpi_memory_device *mem_device)
>>>> +{
>>>> + int result;
>>>>
>>>> /*
>>>> * Ask the VM to offline this memory range.
>>>> * Note: Assume that this function returns zero on success
>>>> */
>>>
>>> Write function comment instead of this silly comment.
>>>
>>>> - list_for_each_entry_safe(info, n, &mem_device->res_list, list) {
>>>> - if (info->enabled) {
>>>> - result = remove_memory(info->start_addr, info->length);
>>>> - if (result)
>>>> - return result;
>>>> - }
>>>> - kfree(info);
>>>> - }
>>>> + result = acpi_memory_remove_memory(mem_device);
>>>> + if (result)
>>>> + return result;
>>>>
>>>> /* Power-off and eject the device */
>>>> result = acpi_memory_powerdown_device(mem_device);
>>>
>>> This patch move acpi_memory_powerdown_device() from ACPI_NOTIFY_EJECT_REQUEST
>>> to release callback, but don't explain why.
>>
>> Hmm, it doesn't move the code. It just reuse the code in acpi_memory_powerdown_device().
>
> Even if reuse or not reuse, you changed the behavior. If any changes
> has no good rational, you cannot get an ack.
I don't understand this? IIRC, the behavior isn't changed.
Thanks
Wen Congyang
>
>
>
>
>>>> @@ -473,12 +486,23 @@ static int acpi_memory_device_add(struct
>>>> static int acpi_memory_device_remove(struct acpi_device *device, int type)
>>>> {
>>>> struct acpi_memory_device *mem_device = NULL;
>>>> -
>>>> + int result;
>>>>
>>>> if (!device || !acpi_driver_data(device))
>>>> return -EINVAL;
>>>>
>>>> mem_device = acpi_driver_data(device);
>>>> +
>>>> + if (type == ACPI_BUS_REMOVAL_EJECT) {
>>>> + /*
>>>> + * offline and remove memory only when the memory device is
>>>> + * ejected.
>>>> + */
>>>
>>> This comment explain nothing. A comment should describe _why_ should we do.
>>> e.g. Why REMOVAL_NORMAL and REMOVEL_EJECT should be ignored. Why
>>> we need remove memory here instead of ACPI_NOTIFY_EJECT_REQUEST.
>>
>> Hmm, we have 2 ways to remove a memory:
>> 1. SCI
>> 2. echo 1 >/sys/bus/acpi/devices/PNP0C80:XX/eject
>>
>> In the 2nd case, there is no ACPI_NOTIFY_EJECT_REQUEST. We should offline
>> the memory and remove it from kernel in the release callback. We will poweroff
>> the memory device in acpi_bus_hot_remove_device(), so we must offline
>> and remove it if the type is ACPI_BUS_REMOVAL_EJECT.
>>
>> I guess we should not poweroff the memory device when we fail to offline it.
>> But device_release_driver() doesn't returns any error...
>
> 1) I think /sys/bus/acpi/devices/PNP0C80:XX/eject should emulate acpi
> eject. Can't
> you make a pseudo acpi eject event and detach device by acpi regular path?
>
> 2) Your explanation didn't explain why we should ignore REMOVAL_NORMAL
> and REMOVEL_EJECT. As far as reviewers can't track your intention, we
> can't maintain
> the code and can't ack them.
>
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