Re: [PATCH v2 1/1] scsi: ufs: Fix unexpected values get from ufshcd_read_desc_param()

[Can Guo <cang@codeaurora.org>]

On 2020-10-26 13:22, Avri Altman wrote:
>> On 2020-10-22 14:37, Avri Altman wrote:
>> >> Since WB feature has been added, WB related sysfs entries can be
>> >> accessed
>> >> even when an UFS device does not support WB feature. In that case, the
>> >> descriptors which are not supported by the UFS device may be wrongly
>> >> reported when they are accessed from their corrsponding sysfs entries.
>> >> Fix it by adding a sanity check of parameter offset against the actual
>> >> decriptor length.s
>> > This should be a bug fix IMO, and be dealt with similarly like
>> > ufshcd_is_wb_attrs or ufshcd_is_wb_flag.
>> > Thanks,
>> > Avri
>> 
>> Could you please elaborate on ufshcd_is_wb_attrs or ufshcd_is_wb_flag?
>> Sorry that I don't quite get it.
> Since this change is only protecting illegal access from sysfs entries,
> I am suggesting to handle it there, just like ufshcd_is_wb_attrs or
> ufshcd_is_wb_flag
> Are doing it for flags and attributes.
> 
> Thanks,
> Avri

This is a general problem - if later we have HPB entries added into 
sysfs,
we will hit it again. We cannot keep adding checks like 
ufshcd_is_xxx_attrs
or ufshcd_is_xxx_flag to block them, right?

Thanks,

Can Guo.