Re: [dpdk-dev] [PATCH 1/3] rawdev: allow calling info function for unknown rawdevs

[Bruce Richardson <bruce.richardson@intel.com>]

On Tue, Jul 07, 2020 at 02:18:31PM +0200, Thomas Monjalon wrote:
> 06/07/2020 12:31, Bruce Richardson:
> > To call the rte_rawdev_info_get() function, the user currently has to
> > know the underlying type of the device in order to pass an appropriate
> > structure or buffer as the dev_private pointer in the info structure.
> > By allowing a NULL value for this field, we can skip getting the
> > device-specific info and just return the generic info - including the
> > device name and driver, which can be used to determine the device type
> > - to the user.
> > 
> > This ensures that basic info can be get for all rawdevs, without
> > knowing the type, and even if the info driver API call has not been
> > implemented for the device.
> > 
> > Cc: stable@dpdk.org
> 
> This is a new feature. Why should it be backported?
> 

I'd largely leave it up to the stable maintainers, but IMHO it should be
backported as its not a big change and I don't see the existing rawdev APIs
as very usable without it. I think the current API leaves the user in a bit
of a catch 22, since info_get() is the API you'd expect to call to find out
the actual type of a rawdev, but unfortunately, to call the info_get API
you need to know the type to pass in the appropriate type-specific
structure parameter. Therefore I see this as fixing a usability bug. :-)

Regards,
/Bruce