Re: [PATCH 7/9] bus: add helper to find a bus from a device name

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

On Wed, Jun 07, 2017 at 07:28:07PM +0200, Jan Blunck wrote:
> On Wed, May 24, 2017 at 5:12 PM, Gaetan Rivet <gaetan.rivet@6wind.com> wrote:
> > Find which bus should be able to parse this device name into an internal
> > device representation.
> >
> 
> No, please don't add this. One should know to what bus a device
> belongs to before plugging it. Artificially encoding the parent bus
> into the device name is not the right thing to do. Please keep those
> things separate.
> 

The EAL has no way to know this currently. As you noted, it has to know
onto which bus a device belongs before plugging it.

> > Signed-off-by: Gaetan Rivet <gaetan.rivet@6wind.com>
> > ---
> >  lib/librte_eal/bsdapp/eal/rte_eal_version.map   |  1 +
> >  lib/librte_eal/common/eal_common_bus.c          | 15 +++++++++++++++
> >  lib/librte_eal/common/include/rte_bus.h         | 12 ++++++++++++
> >  lib/librte_eal/linuxapp/eal/rte_eal_version.map |  1 +
> >  4 files changed, 29 insertions(+)
> >
> > diff --git a/lib/librte_eal/bsdapp/eal/rte_eal_version.map b/lib/librte_eal/bsdapp/eal/rte_eal_version.map
> > index 3517d74..04fa882 100644
> > --- a/lib/librte_eal/bsdapp/eal/rte_eal_version.map
> > +++ b/lib/librte_eal/bsdapp/eal/rte_eal_version.map
> > @@ -202,5 +202,6 @@ DPDK_17.08 {
> >         global:
> >
> >         rte_bus_from_name;
> > +       rte_bus_from_dev;
> >
> >  } DPDK_17.05;
> > diff --git a/lib/librte_eal/common/eal_common_bus.c b/lib/librte_eal/common/eal_common_bus.c
> > index 7977190..08fff60 100644
> > --- a/lib/librte_eal/common/eal_common_bus.c
> > +++ b/lib/librte_eal/common/eal_common_bus.c
> > @@ -242,3 +242,18 @@ rte_bus_from_name(const char *str)
> >                 return NULL;
> >         return rte_bus_find(bus_cmp_name, str);
> >  }
> > +
> > +static int
> > +bus_can_parse(const struct rte_bus *bus, const void *_name)
> > +{
> > +       const char *name = _name;
> > +
> > +       return (bus->parse && !bus->parse(name, NULL));
> > +}
> > +
> > +/* find a bus capable of parsing a device description */
> > +struct rte_bus *
> > +rte_bus_from_dev(const char *str)
> > +{
> > +       return rte_bus_find(bus_can_parse, str);
> > +}
> > diff --git a/lib/librte_eal/common/include/rte_bus.h b/lib/librte_eal/common/include/rte_bus.h
> > index 5b87ac4..0b48e66 100644
> > --- a/lib/librte_eal/common/include/rte_bus.h
> > +++ b/lib/librte_eal/common/include/rte_bus.h
> > @@ -251,6 +251,18 @@ struct rte_bus *rte_bus_find_by_device(const struct rte_device *dev);
> >  struct rte_bus *rte_bus_from_name(const char *str);
> >
> >  /**
> > + * Find a bus capable of identifying a device.
> > + *
> > + * @param str
> > + *   A device identifier (PCI address, virtual PMD name, ...).
> > + *
> > + * @return
> > + *   A valid bus structure if found.
> > + *   NULL if no bus is able to parse this device.
> > + */
> > +struct rte_bus *rte_bus_from_dev(const char *str);
> > +
> > +/**
> >   * Helper for Bus registration.
> >   * The constructor has higher priority than PMD constructors.
> >   */
> > diff --git a/lib/librte_eal/linuxapp/eal/rte_eal_version.map b/lib/librte_eal/linuxapp/eal/rte_eal_version.map
> > index 6607acc..a5127d6 100644
> > --- a/lib/librte_eal/linuxapp/eal/rte_eal_version.map
> > +++ b/lib/librte_eal/linuxapp/eal/rte_eal_version.map
> > @@ -206,5 +206,6 @@ DPDK_17.08 {
> >         global:
> >
> >         rte_bus_from_name;
> > +       rte_bus_from_dev;
> >
> >  } DPDK_17.05;
> > --
> > 2.1.4
> >

-- 
Gaëtan Rivet
6WIND