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.
1bfe60e...
by
=?utf-8?q?J=C3=A9r=C3=A9mie_Galarneau?= <email address hidden>
Fix: Don't print ring-buffer's records count when it is not used
The teardown of a ring buffer causes a number of diagnostic messages
to be printed using printk. One of those contains the "records
count", which is only updated when lttng-modules is built with
LTTNG_RING_BUFFER_COUNT_EVENTS defined.
Move the "records count" printing to a different function and stub it
out when LTTNG_RING_BUFFER_COUNT_EVENTS is not defined
(default configuration).
This eliminates messages of the following form from the dmesg output
when an LTTng session is torn down.
[...] ring buffer relay-discard, cpu 0: 0 records written, 0 records overrun
