net: dcb: use obj-$(CONFIG_DCB) form in net/Makefile

CONFIG_DCB is a bool option. Change the ifeq conditional to the
standard obj-$(CONFIG_DCB) form.

Use obj-y in net/dcb/Makefile because Kbuild visits this Makefile
only when CONFIG_DCB=y.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Link: https://lore.kernel.org/r/20210125231659.106201-2-masahiroy@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

treewide: Add SPDX license identifier - Makefile/Kconfig

Add SPDX license identifiers to all Make/Kconfig files which:

- Have no license information of any form

These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:

GPL-2.0-only

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

net_dcb: add application notifiers

DCBx applications priorities can be changed dynamically. If
application stacks are expected to keep the skb priority
consistent with the dcbx priority the stack will need to
be notified when these changes occur.

This patch adds application notifiers for the stack to register
with.

Signed-off-by: John Fastabend <john.r.fastabend@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ixgbe: this patch adds support for DCB to the kernel and ixgbe driver

This adds support for Data Center Bridging (DCB) features in the ixgbe
driver and adds an rtnetlink interface for configuring DCB to the
kernel. The DCB feature support included are Priority Grouping (PG) -
which allows bandwidth guarantees to be allocated to groups to traffic
based on the 802.1q priority, and Priority Based Flow Control (PFC) -
which introduces a new MAC control PAUSE frame which works at
granularity of the 802.1p priority instead of the link (IEEE 802.3x).

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: Peter P Waskiewicz Jr <peter.p.waskiewicz.jr@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>