quoted

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.

quoted

quoted

+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.

quoted

quoted

+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