Fix: lttng-tracepoint module notifier should return NOTIFY_OK

Module notifiers should return NOTIFY_OK on success rather than the
value 0. The return value 0 does not seem to have any ill side-effects
in the notifier chain caller, but it is preferable to respect the API
requirements in case this changes in the future.

Notifiers can encapsulate a negative errno value with
notifier_from_errno(), but this is not needed by the LTTng tracepoint
notifier.

The approach taken in this notifier is to just print a console warning
on error, because tracing failure should not prevent loading a module.
So we definitely do not want to stop notifier iteration. Returning
an error without stopping iteration is not really that useful, because
only the return value of the last callback is returned to notifier chain
caller.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

diff --git a/lttng-tracepoint.c b/lttng-tracepoint.c
index bbb2c7a4fdb04a79664f2bd2e5ca679176124d78..8298b3970b6256eb9cdf40ca1e43a416c501c9c3 100644 (file)
--- a/lttng-tracepoint.c
+++ b/lttng-tracepoint.c
@@ -256,7 +256,7 @@ int lttng_tracepoint_coming(struct tp_module *tp_mod)
                }
        }
        mutex_unlock(&lttng_tracepoint_mutex);
-       return 0;
+       return NOTIFY_OK;
 }
 
 static