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SubjectRe: [PATCH v2 1/8] [PATCH 1/8] drivers/peci: Add support for PECI bus driver core
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On 2/21/2018 1:51 PM, Andrew Lunn wrote:
>>> Is there a real need to do transfers in atomic context, or with
>>> interrupts disabled?
>>>
>>
>> Actually, no. Generally, this function will be called in sleep-able context
>> so this code is for an exceptional case handling.
>>
>> I'll rewrite this code like below:
>> if (in_atomic() || irqs_disabled()) {
>> dev_dbg(&adapter->dev,
>> "xfer in non-sleepable context is not supported\n");
>> return -EWOULDBLOCK;
>> }
>
> I would not even do that. Just add a call to
> might_sleep(). CONFIG_DEBUG_ATOMIC_SLEEP will then find bad calls.
>

Thanks for the suggestion. I've learned one thing. :)

>>>> +static int peci_ioctl_get_temp(struct peci_adapter *adapter, void *vmsg)
>>>> +{
>>>> + struct peci_get_temp_msg *umsg = vmsg;
>>>> + struct peci_xfer_msg msg;
>>>> + int rc;
>>>> +
>>>
>>> Is this getting the temperature?
>>>
>>
>> Yes, this is getting the 'die' temperature of a processor package.
>
> So the hwmon driver provides this. No need to have both.
>

This this common API in core driver of PECI bus. The hwmon is also uses
it through peci_command call.

>>>> +static long peci_ioctl(struct file *file, unsigned int iocmd, unsigned long arg)
>>>> +{
>>>> + struct peci_adapter *adapter = file->private_data;
>>>> + void __user *argp = (void __user *)arg;
>>>> + unsigned int msg_len;
>>>> + enum peci_cmd cmd;
>>>> + u8 *msg;
>>>> + int rc = 0;
>>>> +
>>>> + dev_dbg(&adapter->dev, "ioctl, cmd=0x%x, arg=0x%lx\n", iocmd, arg);
>>>> +
>>>> + switch (iocmd) {
>>>> + case PECI_IOC_PING:
>>>> + case PECI_IOC_GET_DIB:
>>>> + case PECI_IOC_GET_TEMP:
>>>> + case PECI_IOC_RD_PKG_CFG:
>>>> + case PECI_IOC_WR_PKG_CFG:
>>>> + case PECI_IOC_RD_IA_MSR:
>>>> + case PECI_IOC_RD_PCI_CFG:
>>>> + case PECI_IOC_RD_PCI_CFG_LOCAL:
>>>> + case PECI_IOC_WR_PCI_CFG_LOCAL:
>>>> + cmd = _IOC_TYPE(iocmd) - PECI_IOC_BASE;
>>>> + msg_len = _IOC_SIZE(iocmd);
>>>> + break;
>>>
>>> Adding new ioctl calls is pretty frowned up. Can you export this info
>>> via /sysfs?
>>>
>>
>> Most of these are not simple IOs so ioctl is better suited, I think.
>
> Lets see what other reviewers say, but i think ioctls are
> wrong.
>
> Andrew
>

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