net: selftest: fix build issue if INET is disabled

In case ethernet driver is enabled and INET is disabled, selftest will
fail to build.

Reported-by: Randy Dunlap <rdunlap@infradead.org>
Fixes: 3e1e58d64c ("net: add generic selftest support")
Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Acked-by: Randy Dunlap <rdunlap@infradead.org> # build-tested
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Link: https://lore.kernel.org/r/20210428130947.29649-1-o.rempel@pengutronix.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/atheros/Kconfig

@@ -20,8 +20,8 @@ if NET_VENDOR_ATHEROS
 config AG71XX
 	tristate "Atheros AR7XXX/AR9XXX built-in ethernet mac support"
 	depends on ATH79
-	select NET_SELFTESTS
 	select PHYLINK
+	imply NET_SELFTESTS
 	help
 	  If you wish to compile a kernel for AR7XXX/91XXX and enable
 	  ethernet support, then you should always answer Y to this.

drivers/net/ethernet/freescale/Kconfig

@@ -26,8 +26,8 @@ config FEC
 		   ARCH_MXC || SOC_IMX28 || COMPILE_TEST)
 	default ARCH_MXC || SOC_IMX28 if ARM
 	select CRC32
-	select NET_SELFTESTS
 	select PHYLIB
+	imply NET_SELFTESTS
 	imply PTP_1588_CLOCK
 	help
 	  Say Y here if you want to use the built-in 10/100 Fast ethernet

include/net/selftests.h

@@ -4,9 +4,28 @@
 
 #include <linux/ethtool.h>
 
+#if IS_ENABLED(CONFIG_NET_SELFTESTS)
+
 void net_selftest(struct net_device *ndev, struct ethtool_test *etest,
 		  u64 *buf);
 int net_selftest_get_count(void);
 void net_selftest_get_strings(u8 *data);
 
+#else
+
+static inline void net_selftest(struct net_device *ndev, struct ethtool_test *etest,
+				u64 *buf)
+{
+}
+
+static inline int net_selftest_get_count(void)
+{
+	return 0;
+}
+
+static inline void net_selftest_get_strings(u8 *data)
+{
+}
+
+#endif
 #endif /* _NET_SELFTESTS */

net/Kconfig

@@ -431,7 +431,7 @@ config SOCK_VALIDATE_XMIT
 
 config NET_SELFTESTS
 	def_tristate PHYLIB
-	depends on PHYLIB
+	depends on PHYLIB && INET
 
 config NET_SOCK_MSG
 	bool

net/core/Makefile

@@ -21,6 +21,7 @@ obj-$(CONFIG_NETPOLL) += netpoll.o
 obj-$(CONFIG_FIB_RULES) += fib_rules.o
 obj-$(CONFIG_TRACEPOINTS) += net-traces.o
 obj-$(CONFIG_NET_DROP_MONITOR) += drop_monitor.o
+obj-$(CONFIG_NET_SELFTESTS) += selftests.o
 obj-$(CONFIG_NETWORK_PHY_TIMESTAMPING) += timestamping.o
 obj-$(CONFIG_NET_PTP_CLASSIFY) += ptp_classifier.o
 obj-$(CONFIG_CGROUP_NET_PRIO) += netprio_cgroup.o
@@ -33,7 +34,6 @@ obj-$(CONFIG_NET_DEVLINK) += devlink.o
 obj-$(CONFIG_GRO_CELLS) += gro_cells.o
 obj-$(CONFIG_FAILOVER) += failover.o
 ifeq ($(CONFIG_INET),y)
-obj-$(CONFIG_NET_SELFTESTS) += selftests.o
 obj-$(CONFIG_NET_SOCK_MSG) += skmsg.o
 obj-$(CONFIG_BPF_SYSCALL) += sock_map.o
 endif

net/dsa/Kconfig

@@ -9,7 +9,7 @@ menuconfig NET_DSA
 	select NET_SWITCHDEV
 	select PHYLINK
 	select NET_DEVLINK
-	select NET_SELFTESTS
+	imply NET_SELFTESTS
 	help
 	  Say Y if you want to enable support for the hardware switches supported
 	  by the Distributed Switch Architecture.