Merge branch 'netconsole-enable-compile-time-configuration'

Breno Leitao says:

====================
netconsole: Enable compile time configuration

Enable netconsole features to be set at compilation time. Create two
Kconfig options that allow users to set extended logs and release
prepending features at compilation time.

The first patch de-duplicates the initialization code, and the second
patch adds the support in the de-duplicated code, avoiding touching two
different functions with the same change.
====================

Link: https://lore.kernel.org/r/20230811093158.1678322-1-leitao@debian.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

2 files changed, 50 insertions, 20 deletions

diff --git a/drivers/net/Kconfig b/drivers/net/Kconfig
index be43cd08027b..44eeb5d61ba9 100644
--- a/drivers/net/Kconfig
+++ b/drivers/net/Kconfig
@@ -332,6 +332,28 @@ config NETCONSOLE_DYNAMIC
 	  at runtime through a userspace interface exported using configfs.
 	  See <file:Documentation/networking/netconsole.rst> for details.
 
+config NETCONSOLE_EXTENDED_LOG
+	bool "Set kernel extended message by default"
+	depends on NETCONSOLE
+	default n
+	help
+	  Set extended log support for netconsole message. If this option is
+	  set, log messages are transmitted with extended metadata header in a
+	  format similar to /dev/kmsg.  See
+	  <file:Documentation/networking/netconsole.rst> for details.
+
+config NETCONSOLE_PREPEND_RELEASE
+	bool "Prepend kernel release version in the message by default"
+	depends on NETCONSOLE_EXTENDED_LOG
+	default n
+	help
+	  Set kernel release to be prepended to each netconsole message by
+	  default. If this option is set, the kernel release is prepended into
+	  the first field of every netconsole message, so, the netconsole
+	  server/peer can easily identify what kernel release is logging each
+	  message.  See <file:Documentation/networking/netconsole.rst> for
+	  details.
+
 config NETPOLL
 	def_bool NETCONSOLE
 
diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c
index 87f18aedd3bd..3111e1648592 100644
--- a/drivers/net/netconsole.c
+++ b/drivers/net/netconsole.c
@@ -167,19 +167,21 @@ static void netconsole_target_put(struct netconsole_target *nt)
 
 #endif	/* CONFIG_NETCONSOLE_DYNAMIC */
 
-/* Allocate new target (from boot/module param) and setup netpoll for it */
-static struct netconsole_target *alloc_param_target(char *target_config)
+/* Allocate and initialize with defaults.
+ * Note that these targets get their config_item fields zeroed-out.
+ */
+static struct netconsole_target *alloc_and_init(void)
 {
-	int err = -ENOMEM;
 	struct netconsole_target *nt;
 
-	/*
-	 * Allocate and initialize with defaults.
-	 * Note that these targets get their config_item fields zeroed-out.
-	 */
 	nt = kzalloc(sizeof(*nt), GFP_KERNEL);
 	if (!nt)
-		goto fail;
+		return nt;
+
+	if (IS_ENABLED(CONFIG_NETCONSOLE_EXTENDED_LOG))
+		nt->extended = true;
+	if (IS_ENABLED(CONFIG_NETCONSOLE_PREPEND_RELEASE))
+		nt->release = true;
 
 	nt->np.name = "netconsole";
 	strscpy(nt->np.dev_name, "eth0", IFNAMSIZ);
@@ -187,6 +189,21 @@ static struct netconsole_target *alloc_param_target(char *target_config)
 	nt->np.remote_port = 6666;
 	eth_broadcast_addr(nt->np.remote_mac);
 
+	return nt;
+}
+
+/* Allocate new target (from boot/module param) and setup netpoll for it */
+static struct netconsole_target *alloc_param_target(char *target_config)
+{
+	struct netconsole_target *nt;
+	int err;
+
+	nt = alloc_and_init();
+	if (!nt) {
+		err = -ENOMEM;
+		goto fail;
+	}
+
 	if (*target_config == '+') {
 		nt->extended = true;
 		target_config++;
@@ -195,6 +212,7 @@ static struct netconsole_target *alloc_param_target(char *target_config)
 	if (*target_config == 'r') {
 		if (!nt->extended) {
 			pr_err("Netconsole configuration error. Release feature requires extended log message");
+			err = -EINVAL;
 			goto fail;
 		}
 		nt->release = true;
@@ -664,23 +682,13 @@ static const struct config_item_type netconsole_target_type = {
 static struct config_item *make_netconsole_target(struct config_group *group,
 						  const char *name)
 {
-	unsigned long flags;
 	struct netconsole_target *nt;
+	unsigned long flags;
 
-	/*
-	 * Allocate and initialize with defaults.
-	 * Target is disabled at creation (!enabled).
-	 */
-	nt = kzalloc(sizeof(*nt), GFP_KERNEL);
+	nt = alloc_and_init();
 	if (!nt)
 		return ERR_PTR(-ENOMEM);
 
-	nt->np.name = "netconsole";
-	strscpy(nt->np.dev_name, "eth0", IFNAMSIZ);
-	nt->np.local_port = 6665;
-	nt->np.remote_port = 6666;
-	eth_broadcast_addr(nt->np.remote_mac);
-
 	/* Initialize the config_item member */
 	config_item_init_type_name(&nt->item, name, &netconsole_target_type);