Re: [PATCH v5 1/3] uacce: supports device isolation feature

[Greg KH <gregkh@linuxfoundation.org>]

On Fri, Jul 08, 2022 at 03:08:18PM +0800, Kai Ye wrote:
> UACCE adds the hardware error isolation API. Users can configure
> the isolation frequency by this sysfs node. UACCE reports the device
> isolate state to the user space. If the AER error frequency exceeds
> the value of setting for a certain period of time, the device will be
> isolated.
> 
> Signed-off-by: Kai Ye <yekai13@huawei.com>
> ---
>  drivers/misc/uacce/uacce.c | 55 ++++++++++++++++++++++++++++++++++++++
>  include/linux/uacce.h      | 11 ++++++++
>  2 files changed, 66 insertions(+)
> 
> diff --git a/drivers/misc/uacce/uacce.c b/drivers/misc/uacce/uacce.c
> index 281c54003edc..d07b5f1f0596 100644
> --- a/drivers/misc/uacce/uacce.c
> +++ b/drivers/misc/uacce/uacce.c
> @@ -7,6 +7,8 @@
>  #include <linux/slab.h>
>  #include <linux/uacce.h>
>  
> +#define MAX_ERR_ISOLATE_COUNT		65535
> +
>  static struct class *uacce_class;
>  static dev_t uacce_devt;
>  static DEFINE_MUTEX(uacce_mutex);
> @@ -339,12 +341,63 @@ static ssize_t region_dus_size_show(struct device *dev,
>  		       uacce->qf_pg_num[UACCE_QFRT_DUS] << PAGE_SHIFT);
>  }
>  
> +static ssize_t isolate_show(struct device *dev,
> +			    struct device_attribute *attr, char *buf)
> +{
> +	struct uacce_device *uacce = to_uacce_device(dev);
> +
> +	if (!uacce->ops->get_isolate_state)
> +		return -ENODEV;

If there is no callback, why is this sysfs even created at all?  Please
do not create it if it can not be accessed.

Use the is_visable() callback for the group to do this.

> +
> +	return sysfs_emit(buf, "%d\n", uacce->ops->get_isolate_state(uacce));
> +}
> +
> +static ssize_t isolate_strategy_show(struct device *dev,
> +				     struct device_attribute *attr, char *buf)
> +{
> +	struct uacce_device *uacce = to_uacce_device(dev);
> +	u32 val;
> +
> +	if (!uacce->ops->isolate_strategy_read)
> +		return -ENODEV;

Same here, don't have a sysfs file that does nothing.

> +
> +	val = uacce->ops->isolate_strategy_read(uacce);
> +	if (val > MAX_ERR_ISOLATE_COUNT)
> +		return -EINVAL;
> +
> +	return sysfs_emit(buf, "%u\n", val);
> +}
> +
> +static ssize_t isolate_strategy_store(struct device *dev,
> +				      struct device_attribute *attr,
> +				      const char *buf, size_t count)
> +{
> +	struct uacce_device *uacce = to_uacce_device(dev);
> +	unsigned long val;
> +	int ret;
> +
> +	if (!uacce->ops->isolate_strategy_write)
> +		return -ENODEV;

Same here.

thanks,

greg k-h