[ptxdist] [PATCH] systemd: make default-net-naming-scheme configurable

[Michael Tretter <m.tretter@pengutronix.de>]

The default-net-naming-scheme parameter allows to preserve the naming
scheme of a previous systemd version on a newer version. It may be
necessary to preserve a naming scheme if other system components rely on
certain network interface names generated by some naming scheme.

The default is "latest" to use the naming scheme of the currently used
systemd version.

Signed-off-by: Michael Tretter <m.tretter@pengutronix.de>
---
 rules/systemd.in   | 8 ++++++++
 rules/systemd.make | 2 +-
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/rules/systemd.in b/rules/systemd.in
index 0818bf535866..17997574b62e 100644
--- a/rules/systemd.in
+++ b/rules/systemd.in
@@ -158,6 +158,14 @@ config SYSTEMD_NSPAWN
 	bool
 	prompt "install systemd-nspawn"
 
+config SYSTEMD_DEFAULT_NET_NAMING_SCHEME
+	string
+	prompt "default net.naming-scheme= value"
+	default "latest"
+	help
+	  Preserve the naming scheme for network interfaces of the given
+	  systemd version.
+
 menu "journald                    "
 
 config SYSTEMD_XZ
diff --git a/rules/systemd.make b/rules/systemd.make
index e5a6b26a5c55..69b044bb8123 100644
--- a/rules/systemd.make
+++ b/rules/systemd.make
@@ -78,7 +78,7 @@ SYSTEMD_CONF_OPT	:= \
 	-Ddefault-llmnr=yes \
 	-Ddefault-locale=C \
 	-Ddefault-mdns=yes \
-	-Ddefault-net-naming-scheme=latest \
+	-Ddefault-net-naming-scheme=$(call remove_quotes,$(PTXCONF_SYSTEMD_DEFAULT_NET_NAMING_SCHEME)) \
 	-Ddev-kvm-mode=0660 \
 	-Ddns-over-tls=false \
 	-Ddns-servers= \
-- 
2.30.2