Re: [PATCH v7 2/6] bus: introduce parsing functionality

["Gaëtan Rivet" <gaetan.rivet@6wind.com>]

On Thu, Jul 06, 2017 at 02:49:41PM +0530, santosh wrote:
> Hi Gaetan,
> 
> On Wednesday 05 July 2017 05:25 AM, Gaetan Rivet wrote:
> 
> > This operation can be used either to validate that a device
> > representation can be understood by a bus, as well as store the resulting
> > specialized device representation in any format determined by the bus.
> >
> > Signed-off-by: Gaetan Rivet <gaetan.rivet@6wind.com>
> > ---
> >  lib/librte_eal/common/include/rte_bus.h | 21 +++++++++++++++++++++
> >  1 file changed, 21 insertions(+)
> >
> > diff --git a/lib/librte_eal/common/include/rte_bus.h b/lib/librte_eal/common/include/rte_bus.h
> > index 773b0d7..aebf57e 100644
> > --- a/lib/librte_eal/common/include/rte_bus.h
> > +++ b/lib/librte_eal/common/include/rte_bus.h
> > @@ -138,6 +138,26 @@ typedef int (*rte_bus_plug_t)(struct rte_device *dev,
> >  typedef int (*rte_bus_unplug_t)(struct rte_device *dev);
> >  
> >  /**
> > + * Bus specific parsing function.
> > + * Validates the syntax used in the textual representation of a device,
> > + * If the syntax is valid and ``addr`` is not NULL, writes the bus-specific
> > + * device representation to ``addr``.
> > + *
> > + * @param[in] name
> > + *	device textual description
> > + *
> > + * @param[out] addr
> > + *	device information location address, into which parsed info
> > + *	should be written. If NULL, nothing should be written, which
> > + *	is not an error.
> > + *
> 
> r / is not a error/ is valid?
> 

I'm partial to "is not an error" here, but it doesn't matter that much
and I can change it if you prefer.

> > + * @return
> > + *	0 if parsing was successful.
> > + *	!0 for any error.
> > + */
> > +typedef int (*rte_bus_parse_t)(const char *name, void *addr);
> > +
> 
> _parse handler in _common_vdev or common_pci file return boolean value 
> i.e..0 for success and 1 for error, right? if so then
> !0 for any error would be like '1' for error case.. make sense?
> 

I thought of that yes, and actually your suggestion was the first
version I used.

Ultimately however, this function is not only saying "can parse": it is
not merely a test of being able to process the input, but also the
process itself. The test value is then a byproduct.

As such, I decided to settle on the standard "0 means nothing of note
happened, carry on".

-- 
Gaëtan Rivet
6WIND