Re: [Xen-devel] [PATCH v9 08/25] x86: refactor psr: L3 CAT: implement get value flow.

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 28.03.17 at 04:13, <yi.y.sun@xxxxxxxxxxxxxxx> wrote:
> On 17-03-27 07:34:43, Jan Beulich wrote:
>> >>> On 27.03.17 at 14:59, <yi.y.sun@xxxxxxxxxxxxxxx> wrote:
>> > On 17-03-27 03:23:08, Jan Beulich wrote:
>> >> >>> On 16.03.17 at 12:07, <yi.y.sun@xxxxxxxxxxxxxxx> wrote:
>> >> > @@ -504,21 +515,30 @@ static struct psr_socket_info 
>> >> > *get_socket_info(unsigned int socket)
>> >> >      return socket_info + socket;
>> >> >  }
>> >> >  
>> >> > -int psr_get_info(unsigned int socket, enum cbm_type type,
>> >> > -                 uint32_t data[], unsigned int array_len)
>> >> > +static const struct feat_node * psr_get_feat(unsigned int socket,
>> >> > +                                             enum cbm_type type)
>> >> >  {
>> >> >      const struct psr_socket_info *info = get_socket_info(socket);
>> >> >      const struct feat_node *feat;
>> >> >      enum psr_feat_type feat_type;
>> >> >  
>> >> >      if ( IS_ERR(info) )
>> >> > -        return PTR_ERR(info);
>> >> > +        return NULL;
>> >> 
>> >> You're losing the error information here - is that intentional?
>> >> 
>> > This function returns the 'struct feat_node *' object. If error happens, it
>> > returns NULL. The caller handles the error.
>> 
>> You didn't understand: Your callee has handed you error
>> information (a -E... value encoded as a pointer), which you
>> discard.
>> 
> Thanks for explanation! I will modify the type of 'psr_get_feat' to be able to
> return such error back.

Why would you need to modify its type? Just pass on the error
indicator, instead of returning NULL. It's the caller(s) who need(s)
to change.

Jan


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