[PATCH net-next] net: build all switchdev drivers as modules when the bridge is a module

From: Vladimir Oltean <vladimir.oltean@nxp.com>
To: netdev@vger.kernel.org, Jakub Kicinski <kuba@kernel.org>,
	"David S. Miller" <davem@davemloft.net>
Cc: Naresh Kamboju <naresh.kamboju@linaro.org>,
	Grygorii Strashko <grygorii.strashko@ti.com>,
	Lars Povlsen <lars.povlsen@microchip.com>,
	Steen Hegelund <Steen.Hegelund@microchip.com>,
	UNGLinuxDriver@microchip.com,
	Florian Fainelli <f.fainelli@gmail.com>,
	Andrew Lunn <andrew@lunn.ch>,
	Vivien Didelot <vivien.didelot@gmail.com>,
	Ido Schimmel <idosch@nvidia.com>, Jiri Pirko <jiri@nvidia.com>,
	Roopa Prabhu <roopa@nvidia.com>,
	Nikolay Aleksandrov <nikolay@nvidia.com>,
	Linux Kernel Functional Testing <lkft@linaro.org>
Subject: [PATCH net-next] net: build all switchdev drivers as modules when the bridge is a module
Date: Mon, 26 Jul 2021 17:25:36 +0300	[thread overview]
Message-ID: <20210726142536.1223744-1-vladimir.oltean@nxp.com> (raw)

Currently, all drivers depend on the bool CONFIG_NET_SWITCHDEV, but only
the drivers that call some sort of function exported by the bridge, like
br_vlan_enabled() or whatever, have an extra dependency on CONFIG_BRIDGE.

Since the blamed commit, all switchdev drivers have a functional
dependency upon switchdev_bridge_port_{,un}offload(), which is a pair of
functions exported by the bridge module and not by the bridge-independent
part of CONFIG_NET_SWITCHDEV.

Problems appear when we have:

CONFIG_BRIDGE=m
CONFIG_NET_SWITCHDEV=y
CONFIG_TI_CPSW_SWITCHDEV=y

because cpsw, am65_cpsw and sparx5 will then be built-in but they will
call a symbol exported by a loadable module. This is not possible and
will result in the following build error:

drivers/net/ethernet/ti/cpsw_new.o: in function `cpsw_netdevice_event':
drivers/net/ethernet/ti/cpsw_new.c:1520: undefined reference to
					`switchdev_bridge_port_offload'
drivers/net/ethernet/ti/cpsw_new.c:1537: undefined reference to
					`switchdev_bridge_port_unoffload'

As mentioned, the other switchdev drivers don't suffer from this because
switchdev_bridge_port_offload() is not the first symbol exported by the
bridge that they are calling, so they already needed to deal with this
in the same way.

Fixes: 2f5dc00f7a3e ("net: bridge: switchdev: let drivers inform which bridge ports are offloaded")
Reported-by: Linux Kernel Functional Testing <lkft@linaro.org>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
---
 drivers/net/ethernet/microchip/sparx5/Kconfig | 1 +
 drivers/net/ethernet/ti/Kconfig               | 2 ++
 2 files changed, 3 insertions(+)

diff --git a/drivers/net/ethernet/microchip/sparx5/Kconfig b/drivers/net/ethernet/microchip/sparx5/Kconfig
index 7bdbb2d09a14..d39ae2a6fb49 100644
--- a/drivers/net/ethernet/microchip/sparx5/Kconfig
+++ b/drivers/net/ethernet/microchip/sparx5/Kconfig
@@ -1,5 +1,6 @@
 config SPARX5_SWITCH
 	tristate "Sparx5 switch driver"
+	depends on BRIDGE || BRIDGE=n
 	depends on NET_SWITCHDEV
 	depends on HAS_IOMEM
 	depends on OF
diff --git a/drivers/net/ethernet/ti/Kconfig b/drivers/net/ethernet/ti/Kconfig
index affcf92cd3aa..7ac8e5ecbe97 100644
--- a/drivers/net/ethernet/ti/Kconfig
+++ b/drivers/net/ethernet/ti/Kconfig
@@ -64,6 +64,7 @@ config TI_CPSW
 config TI_CPSW_SWITCHDEV
 	tristate "TI CPSW Switch Support with switchdev"
 	depends on ARCH_DAVINCI || ARCH_OMAP2PLUS || COMPILE_TEST
+	depends on BRIDGE || BRIDGE=n
 	depends on NET_SWITCHDEV
 	depends on TI_CPTS || !TI_CPTS
 	select PAGE_POOL
@@ -109,6 +110,7 @@ config TI_K3_AM65_CPSW_NUSS
 config TI_K3_AM65_CPSW_SWITCHDEV
 	bool "TI K3 AM654x/J721E CPSW Switch mode support"
 	depends on TI_K3_AM65_CPSW_NUSS
+	depends on BRIDGE || BRIDGE=n
 	depends on NET_SWITCHDEV
 	help
 	 This enables switchdev support for TI K3 CPSWxG Ethernet
-- 
2.25.1

