netconsole: add oops_only module option

Some people wants to log only oops messages via netconsole,
(this is also why netoops was invented)
so add a module option for netconsole. This can be tuned
via /sys/module/netconsole/parameters/oops_only at run time
as well.

Cc: David Miller <davem@davemloft.net>
Signed-off-by: Cong Wang <amwang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/netconsole.c

@@ -56,6 +56,10 @@ static char config[MAX_PARAM_LENGTH];
 module_param_string(netconsole, config, MAX_PARAM_LENGTH, 0);
 MODULE_PARM_DESC(netconsole, " netconsole=[src-port]@[src-ip]/[dev],[tgt-port]@<tgt-ip>/[tgt-macaddr]");
 
+static bool oops_only = false;
+module_param(oops_only, bool, 0600);
+MODULE_PARM_DESC(oops_only, "Only log oops messages");
+
 #ifndef	MODULE
 static int __init option_setup(char *opt)
 {
@@ -683,6 +687,8 @@ static void write_msg(struct console *con, const char *msg, unsigned int len)
 	struct netconsole_target *nt;
 	const char *tmp;
 
+	if (oops_only && !oops_in_progress)
+		return;
 	/* Avoid taking lock and disabling interrupts unnecessarily */
 	if (list_empty(&target_list))
 		return;