bluetooth: hci: userchan: Improve RX allocation handling

This makes userchan transport behavior similar to other HCI
transports (eg IPC). Improved logging gives clear overview
of what RX events are discarded helping for configuration
tuning.

Signed-off-by: Szymon Janc <[email protected]>

Author: sjanc

drivers/bluetooth/hci/userchan.c

@@ -93,24 +93,70 @@ static bool is_hci_event_discardable(const uint8_t *evt_data)
 	}
 }
 
-static struct net_buf *get_rx(const uint8_t *buf)
+static struct net_buf *get_rx_evt(const uint8_t *data)
 {
-	bool discardable = false;
-	k_timeout_t timeout = K_FOREVER;
+	bool discardable = is_hci_event_discardable(data);
+	struct net_buf *buf;
+
+	do {
+		buf = bt_buf_get_evt(data[1], discardable, discardable ? K_NO_WAIT : K_SECONDS(1));
+		if (buf == NULL) {
+			if (discardable) {
+				LOG_DBG("Discardable buffer pool full, ignoring event");
+				return buf;
+			}
+			LOG_WRN("Couldn't allocate a buffer after waiting 1 second.");
+		}
+	} while (!buf);
 
-	switch (buf[0]) {
-	case BT_HCI_H4_EVT:
-		if (is_hci_event_discardable(buf)) {
-			discardable = true;
-			timeout = K_NO_WAIT;
+	return buf;
+}
+
+static struct net_buf *get_rx_acl(const uint8_t *data)
+{
+	struct net_buf *buf;
+
+	buf = bt_buf_get_rx(BT_BUF_ACL_IN, K_NO_WAIT);
+	if (buf == NULL) {
+		LOG_ERR("No available ACL buffers!");
+	}
+
+	return buf;
+}
+
+static struct net_buf *get_rx_iso(const uint8_t *data)
+{
+	static unsigned int fail_cnt;
+	struct net_buf *buf;
+
+	buf = bt_buf_get_rx(BT_BUF_ISO_IN, K_NO_WAIT);
+	if (buf == NULL) {
+		if (fail_cnt == 0) {
+			LOG_ERR("No available ISO buffers!");
 		}
 
-		return bt_buf_get_evt(buf[1], discardable, timeout);
+		fail_cnt++;
+	} else {
+		if (fail_cnt) {
+			LOG_INF("ISO buffer available (%u dropped)!", fail_cnt);
+		}
+
+		fail_cnt = 0;
+	}
+
+	return buf;
+}
+
+static struct net_buf *get_rx(const uint8_t *buf)
+{
+	switch (buf[0]) {
+	case BT_HCI_H4_EVT:
+		return get_rx_evt(buf);
 	case BT_HCI_H4_ACL:
-		return bt_buf_get_rx(BT_BUF_ACL_IN, K_FOREVER);
+		return get_rx_acl(buf);
 	case BT_HCI_H4_ISO:
 		if (IS_ENABLED(CONFIG_BT_ISO)) {
-			return bt_buf_get_rx(BT_BUF_ISO_IN, K_FOREVER);
+			return get_rx_iso(buf);
 		}
 		__fallthrough;
 	default:
@@ -281,7 +327,6 @@ static void rx_thread(void *p1, void *p2, void *p3)
 			frame_start += decoded_len;
 
 			if (!buf) {
-				LOG_DBG("Discard adv report due to insufficient buf");
 				continue;
 			}