infra: disable say_logging by default

kernel/brick_say.c

@@ -160,7 +160,7 @@ struct say_channel *find_channel(const void *id)
 	struct say_channel *res = default_channel;
 	struct say_channel *ch;
 
-	if (cannot_schedule())
+	if (!default_channel || cannot_schedule())
 		return res;
 
 	down_read(&say_mutex);
@@ -197,7 +197,7 @@ void bind_to_channel(struct say_channel *ch, struct task_struct *whom)
 {
 	int i;
 
-	if (cannot_schedule())
+	if (!default_channel || !ch || cannot_schedule())
 		return;
 
 	down_write(&say_mutex);
@@ -230,7 +230,7 @@ struct say_channel *get_binding(struct task_struct *whom)
 	struct say_channel *ch;
 	int i;
 
-	if (cannot_schedule())
+	if (!default_channel || cannot_schedule())
 		return NULL;
 
 	down_read(&say_mutex);
@@ -253,7 +253,7 @@ void remove_binding_from(struct say_channel *ch, struct task_struct *whom)
 	bool found = false;
 	int i;
 
-	if (cannot_schedule())
+	if (!default_channel || !ch || cannot_schedule())
 		return;
 
 	down_write(&say_mutex);
@@ -273,7 +273,7 @@ EXPORT_SYMBOL_GPL(remove_binding_from);
 
 void remove_binding(struct task_struct *whom)
 {
-	if (cannot_schedule())
+	if (!default_channel || cannot_schedule())
 		return;
 
 	down_write(&say_mutex);
@@ -284,6 +284,9 @@ EXPORT_SYMBOL_GPL(remove_binding);
 
 void rollover_channel(struct say_channel *ch)
 {
+	if (!default_channel || cannot_schedule())
+		return;
+
 	if (!ch) {
 		ch = find_channel(current);
 	}
@@ -296,7 +299,7 @@ void rollover_all(void)
 {
 	struct say_channel *ch;
 
-	if (cannot_schedule())
+	if (!default_channel || cannot_schedule())
 		return;
 
 	down_read(&say_mutex);
@@ -428,6 +431,9 @@ struct say_channel *make_channel(const char *name, bool must_exist)
 	struct say_channel *res = NULL;
 	struct say_channel *ch;
 
+	if (must_exist && !default_channel)
+		return NULL;
+
 	if (cannot_schedule()) {
 		printk(KERN_ERR "trying to make channel in atomic\n");
 		return NULL;
@@ -480,6 +486,9 @@ void _say(struct say_channel *ch, int class, va_list args, bool use_args, const
 	int rest;
 	int written;
 
+	if (!default_channel)
+		return;
+
 	if (unlikely(!ch))
 		return;
 	if (unlikely(ch->ch_delete && ch != default_channel)) {
@@ -520,6 +529,9 @@ void say_to(struct say_channel *ch, int class, const char *fmt, ...)
 	va_list args;
 	unsigned long flags;
 
+	if (!default_channel)
+		return;
+
 	if (!class && !brick_say_debug)
 		return;
 
@@ -569,6 +581,9 @@ void brick_say_to(struct say_channel *ch, int class, bool dump, const char *pref
 	va_list args;
 	unsigned long flags;
 
+	if (!default_channel)
+		return;
+
 	if (!class && !brick_say_debug)
 		return;
 
@@ -884,8 +899,16 @@ int _say_thread(void *data)
 
 void init_say(void)
 {
-	default_channel = make_channel(CONFIG_MARS_LOGDIR, true);
-	say_thread = kthread_create(_say_thread, NULL, "brick_say");
+	/* Only initialize once */
+	if (default_channel)
+		return;
+
+	default_channel = make_channel(CONFIG_MARS_LOGDIR, false);
+	if (!default_channel)
+		return;
+
+	if (!say_thread)
+		say_thread = kthread_create(_say_thread, NULL, "brick_say");
 	if (IS_ERR(say_thread)) {
 		say_thread = NULL;
 	} else {

kernel/sy_old/mars_main.c

@@ -3334,7 +3334,7 @@ int make_log_init(void *buf, struct mars_dent *dent)
 	if (unlikely(!rot->log_say)) {
 		char *name = path_make("%s/logstatus-%s", parent_path, my_id());
 		if (likely(name)) {
-			rot->log_say = make_channel(name, false);
+			rot->log_say = make_channel(name, true);
 			brick_string_free(name);
 		}
 	}
@@ -6250,6 +6250,8 @@ static int main_worker(struct mars_global *global, struct mars_dent *dent, bool
 	return 0;
 }
 
+#define SAY_TEST_STR CONFIG_MARS_LOGDIR "/5.total.log"
+
 static int _main_thread(void *data)
 {
 	long long last_rollover = jiffies;
@@ -6276,11 +6278,17 @@ static int _main_thread(void *data)
 			(void *)&bio_brick_type,
 			NULL
 		};
+		struct kstat dummy;
+		int say_status;
 		struct list_head *tmp;
 		int trigger_mode;
 		int status;
 		loff_t memlimit;
 
+		say_status = mars_stat(SAY_TEST_STR, &dummy, true);
+		if (!say_status)
+			init_say();
+
 		MARS_DBG("-------- NEW ROUND %d ---------\n", atomic_read(&server_handler_count));
 
 		/* Static memlimit */
@@ -6528,6 +6536,11 @@ static int __init init_main(void)
 		return -ENOENT;
 	}
 
+	/* This must come first to be effective */
+	status = mars_stat(SAY_TEST_STR, &dummy, true);
+	if (!status)
+		init_say();
+
 #ifdef MARS_HAS_PREPATCH
 	// bump the min_free limit
 	if (min_free_kbytes < new_limit)
@@ -6536,8 +6549,6 @@ static int __init init_main(void)
 
 	printk(KERN_INFO "loading MARS, BUILDTAG=%s BUILDHOST=%s BUILDDATE=%s\n", BUILDTAG, BUILDHOST, BUILDDATE);
 
-	init_say(); // this must come first
-
 	/* be careful: order is important!
 	 */
 	DO_INIT(brick_mem);

kernel/sy_old/sy_generic.c

@@ -1058,7 +1058,8 @@ void bind_to_dent(struct mars_dent *dent, struct say_channel **ch)
 				break;
 			}
 			if (test->d_use_channel && test->d_path) {
-				dent->d_say_channel = make_channel(test->d_path, true);
+				dent->d_say_channel = make_channel(test->d_path,
+								   true);
 				break;
 			}
 			test = test->d_parent;