Re: [PATCH 05/14] cxl/mem: Register CXL memX devices

[Christoph Hellwig]

> diff --git a/drivers/base/core.c b/drivers/base/core.c
> index 25e08e5f40bd..33432a4cbe23 100644
> --- a/drivers/base/core.c
> +++ b/drivers/base/core.c
> @@ -3179,6 +3179,20 @@ struct device *get_device(struct device *dev)
>  }
>  EXPORT_SYMBOL_GPL(get_device);
>  
> +/**
> + * get_live_device() - increment reference count for device iff !dead
> + * @dev: device.
> + *
> + * Forward the call to get_device() if the device is still alive. If
> + * this is called with the device_lock() held then the device is
> + * guaranteed to not die until the device_lock() is dropped.
> + */
> +struct device *get_live_device(struct device *dev)
> +{
> +	return dev && !dev->p->dead ? get_device(dev) : NULL;
> +}
> +EXPORT_SYMBOL_GPL(get_live_device);

Err, if you want to add new core functionality that needs to be in a
separate well documented prep patch, and also CCed to the relevant
maintainers.

>  	mutex_unlock(&cxlm->mbox.mutex);
>  }
>  
> +static int cxl_memdev_open(struct inode *inode, struct file *file)
> +{
> +	struct cxl_memdev *cxlmd =
> +		container_of(inode->i_cdev, typeof(*cxlmd), cdev);
> +
> +	file->private_data = cxlmd;

There is no good reason to ever mirror stuff from the inode into
file->private_data, as you can just trivially get at the original
location using file_inode(file).