wqueue: Reject messges if queue is considered full

The write queue was always meant to not queue more than the
max_length messages but the implementation never rejected a
message.

Begin to log and enforce the queue size limit, add a testcase
to verify the code and initialize except_cb as part of a fix
for that new test case.

Real applications might now run into the queue limit and drop
messages where they just queued them before. It is unfortunate
but I still think it is good to implement the routine as it was
intended. We need to review osmo_wqueue_enqueue once more to
see that no msgb is leaked.

Change-Id: I1e6aef30f3e73d4bcf2967bc49f0783aa65395ae

1 files changed, 1 insertions, 0 deletions

diff --git a/tests/write_queue/wqueue_test.ok b/tests/write_queue/wqueue_test.ok
new file mode 100644
index 00000000..a965a70e
--- /dev/null
+++ b/tests/write_queue/wqueue_test.ok
@@ -0,0 +1 @@
+Done