Re: [PATCH v3 5/5] powernv:cpufreq: Implement the driver->get() method

[Gautham R Shenoy <ego@linux.vnet.ibm.com>]

On Fri, Mar 21, 2014 at 12:01:07PM +0000, David Laight wrote:
> From: Viresh Kumar
>  
> > On 21 March 2014 16:34, Gautham R Shenoy <ego@linux.vnet.ibm.com> wrote:
> > > Heh! Well, that wasn't the reason why this was sent out as a separate
> > > patch, but never mind. Though I don't understand why it would be
> > > difficult to review the patch though.
> > 
> > Because the initial driver wasn't complete earlier. There were 2-3 patches
> > after the first one which are changing what the first patch has added.
> > Nothing else :)
> > 
> > >> > +static void powernv_read_cpu_freq(void *ret_freq)
> > >> > +{
> > >> > +       unsigned long pmspr_val;
> > >> > +       s8 local_pstate_id;
> > >> > +       int *cur_freq, freq, pstate_id;
> > >> > +
> > >> > +       cur_freq = (int *)ret_freq;
> > >>
> > >> You don't need cur_freq variable at all..
> > >
> > > I don't like it either. But the compiler complains without this hack
> > > :-(
> > 
> > Why would the compiler warn for doing this?:
> > 
> > *(int *)ret_freq = freq;
> 
> Because it is very likely to be wrong.
> In general casts of pointers to integer types are dangerous.
> In this case why not make the function return the value?

Because this function is called via an smp_call_function(). And we
need a way of returning the value to the caller.

> 
> 	David
> 
>