[PATCH net-next v6 1/6] net: dcb: add new pcp selector to app object

[Petr Machata]

Daniel Machon <daniel.machon at microchip.com> writes:

> Add new PCP selector for the 8021Qaz APP managed object.
>
> As the PCP selector is not part of the 8021Qaz standard, a new non-std
> extension attribute DCB_ATTR_DCB_APP has been introduced. Also two
> helper functions to translate between selector and app attribute type
> has been added. The new selector has been given a value of 255, to
> minimize the risk of future overlap of std- and non-std attributes.
>
> The new DCB_ATTR_DCB_APP is sent alongside the ieee std attribute in the
> app table. This means that the dcb_app struct can now both contain std-
> and non-std app attributes. Currently there is no overlap between the
> selector values of the two attributes.
>
> The purpose of adding the PCP selector, is to be able to offload
> PCP-based queue classification to the 8021Q Priority Code Point table,
> see 6.9.3 of IEEE Std 802.1Q-2018.
>
> PCP and DEI is encoded in the protocol field as 8*dei+pcp, so that a
> mapping of PCP 2 and DEI 1 to priority 3 is encoded as {255, 10, 3}.
>
> Signed-off-by: Daniel Machon <daniel.machon at microchip.com>

Reviewed-by: Petr Machata <petrm at nvidia.com>