Squash to "DO-NOT-MERGE: mptcp: improve code coverage for CI"

And in "DO-NOT-MERGE: mptcp: improve code coverage for CI (net)".

This is similar to commit bc75dcc ("net: rds: add option for GCOV
profiling"), but I don't think we need to upstream that. Or not for the
moment as the selftests don't depend on GCOV support.

If we do, we will also need to update Documentation/dev-tools/gcov.rst.

Link: https://lore.kernel.org/r/20240924-mptcp-gcov-v1-1-b259d5dc5fa6@kernel.org
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>

net/mptcp/Kconfig

@@ -36,4 +36,13 @@ config MPTCP_KUNIT_TEST
 
 	  If unsure, say N.
 
+config GCOV_PROFILE_MPTCP
+	bool "Enable GCOV profiling on MPTCP"
+	depends on GCOV_KERNEL
+	help
+	  Enable GCOV profiling on MPTCP for checking which functions/lines
+	  are executed.
+
+	  If unsure, say N.
+
 endif

net/mptcp/Makefile

@@ -13,3 +13,8 @@ mptcp_token_test-objs := token_test.o
 obj-$(CONFIG_MPTCP_KUNIT_TEST) += mptcp_crypto_test.o mptcp_token_test.o
 
 obj-$(CONFIG_BPF_SYSCALL) += bpf.o
+
+# for GCOV coverage profiling
+ifdef CONFIG_GCOV_PROFILE_MPTCP
+GCOV_PROFILE := y
+endif