Re: [PATCH v2 1/8] [PATCH 1/8] drivers/peci: Add support for PECI bus driver core

From: Andrew Lunn
Date: Wed Feb 21 2018 - 16:52:05 EST


> >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.

> >>+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.

> >>+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