Re: [PATCH] Staging: TIDSPBRIDGE: Remove UUID helper

[Ivajlo Dimitrov]

On 01.12.2013 21:06, Joe Perches wrote:
> On Sun, 2013-12-01 at 19:07 +0200, Ivaylo DImitrov wrote:
> > From: Ivaylo Dimitrov <freemangordon@xxxxxx>
> >
> > Custom uuid helper function is needed only in rmgr/dbdcd.c and doesn't
> > need to be exported. It can also be made way simpler by using sscanf.
> []
> > diff --git a/drivers/staging/tidspbridge/rmgr/dbdcd.c b/drivers/staging/tidspbridge/rmgr/dbdcd.c
> []
> > @@ -74,6 +74,40 @@ static int get_dep_lib_info(struct dcd_manager *hdcd_mgr,
> >   				   enum nldr_phase phase);
> >   
> >   /*
> > + *  ======== dcd_uuid_from_string ========
> > + *  Purpose:
> > + *      Converts an ANSI string to a dsp_uuid.
> > + *  Parameters:
> > + *      sz_uuid:    Pointer to a string that represents a dsp_uuid object.
> > + *      uuid_obj:      Pointer to a dsp_uuid object.
> > + *  Returns:
> > + *  Requires:
> > + *      uuid_obj & sz_uuid are non-NULL values.
> > + *  Ensures:
> > + *  Details:
> > + *      We assume the string representation of a UUID has the following format:
> > + *      "12345678_1234_1234_1234_123456789abc".
> > + */
> > +static void dcd_uuid_from_string(char *sz_uuid, struct dsp_uuid *uuid_obj)
> > +{
> > +	char c;
> > +	u64 t;
> > +
> > +	/*
> > +	 * sscanf implementation cannot deal with hh format modifier
> > +	 * if the converted value doesn't fit in u32. So, convert the
> > +	 * last six bytes to u64 and memcpy what is needed
> > +	 */
> > +	sscanf(sz_uuid, "%8x%c%4hx%c%4hx%c%2hhx%2hhx%c%llx",
> > +	       &uuid_obj->data1, &c, &uuid_obj->data2, &c,
> > +	       &uuid_obj->data3, &c, &uuid_obj->data4,
> > +	       &uuid_obj->data5, &c, &t);
> > +
> > +	t = cpu_to_be64(t);
> > +	memcpy(&uuid_obj->data6[0], ((char*)&t) + 2, 6);
> > +}
> It'd probably be better to return true or false on
> successful conversion, use a temporary struct dsp_uuid,
> check the sscanf return is 10 and only copy to uuid_obj
> on success.
>
> Something like:
>
> static bool dcd_uuid_from_string(char *sz_uuid, struct dsp_uuid *uuid_obj)
> {
> 	char c;
> 	u64 t;
> 	struct dsp_uuid tmp;
>
> 	/*
> 	 * sscanf implementation cannot deal with hh format modifier
> 	 * if the converted value doesn't fit in u32. So, convert the
> 	 * last six bytes to u64 and memcpy what is needed
> 	 */
> 	if (sscanf(sz_uuid, "%8x%c%4hx%c%4hx%c%2hhx%2hhx%c%llx",
> 		   &tmp.data1, &c, &tmp.data2, &c,
> 		   &tmp.data3, &c, &tmp.data4,
> 		   &tmp.data5, &c, &t) != 10)
> 		return false;
>
> 	t = cpu_to_be64(t);
> 	memcpy(&tmp.data6[0], ((char*)&t) + 2, 6);
> 	*uuid_obj =  tmp;
>
> 	return true;
> }
If there is to be a return value from that function, it is better to be 
int (-EINVAL/0), IMO. And I am not sure that makes much of a sense, as 
(afaik) uuids are read from baseimage.dof and codec nodes, if those are 
broken I suspect wrong uuids will be our least problem.
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