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

["yekai(A)" <yekai13@huawei.com>]

On 2022/7/8 15:28, Greg KH wrote:
> 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.
>

If is_visable() is used as the judgment, all uacce device nodes cannot 
be registered if there is no callback by test.

>> +
>> +	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
> .
>