write_queue: Enable updating max_length field
Dequeue and free any excess messages, in case the new queue length
is shorter than the old.
Related: OS#5774
Change-Id: Ibfe51a2faf29f8ae160a9c330c9af0d09b5a9002
diff --git a/src/core/libosmocore.map b/src/core/libosmocore.map
index c0e164b..30814c3 100644
--- a/src/core/libosmocore.map
+++ b/src/core/libosmocore.map
@@ -565,6 +565,7 @@
osmo_wqueue_clear;
osmo_wqueue_enqueue;
osmo_wqueue_enqueue_quiet;
+osmo_wqueue_set_maxlen;
osmo_wqueue_init;
rate_ctr_add;
rate_ctr_difference;
diff --git a/src/core/write_queue.c b/src/core/write_queue.c
index 884cebd..ffa7704 100644
--- a/src/core/write_queue.c
+++ b/src/core/write_queue.c
@@ -147,4 +147,24 @@
queue->bfd.when &= ~OSMO_FD_WRITE;
}
+/* Update write queue length & drop excess messages.
+ * \param[in] queue linked list header of message queue
+ * \param[in] len new max. wqueue length
+ * \returns Number of messages dropped.
+ *
+ * Messages beyond the new maximum message queue size will be dropped.
+ */
+size_t osmo_wqueue_set_maxlen(struct osmo_wqueue *queue, unsigned int len)
+{
+ size_t dropped_msgs = 0;
+ struct msgb *msg;
+ queue->max_length = len;
+ while (queue->current_length > queue->max_length) {
+ msg = msgb_dequeue_count(&queue->msg_queue, &queue->current_length);
+ msgb_free(msg);
+ dropped_msgs++;
+ }
+ return dropped_msgs;
+}
+
/*! @} */