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 4cfec38502f54fe74de19c13ad8e8b8a1694d6f6..f2909aced270216e80b5e970d5ed476fb7964df1 100644 (file)
--- a/lttng-tracepoint.c
+++ b/lttng-tracepoint.c
@@ -269,7 +269,7 @@ int lttng_tracepoint_coming(struct tp_module *tp_mod)
                }
        }
        mutex_unlock(&lttng_tracepoint_mutex);
-       return 0;
+       return NOTIFY_OK;
 }
 
 static