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 <szymon.janc@codecoup.pl>

Author: sjanc

drivers/bluetooth/hci/userchan.c

@@ -58,26 +58,24 @@ static unsigned int port;
 static char socket_path[UNIX_ADDR_BUFF_SIZE];
 static bool arg_found;
 
-static bool is_hci_event_discardable(const uint8_t *evt_data)
+static bool is_hci_event_discardable(const struct bt_hci_evt_hdr *ev)
 {
-	uint8_t evt_type = evt_data[0];
-
-	switch (evt_type) {
+	switch (ev->evt) {
 #if defined(CONFIG_BT_CLASSIC)
 	case BT_HCI_EVT_INQUIRY_RESULT_WITH_RSSI:
 	case BT_HCI_EVT_EXTENDED_INQUIRY_RESULT:
 		return true;
 #endif
 	case BT_HCI_EVT_LE_META_EVENT: {
-		uint8_t subevt_type = evt_data[sizeof(struct bt_hci_evt_hdr)];
+		const struct bt_hci_evt_le_meta_event *meta_ev = (const void *)ev->data;
 
-		switch (subevt_type) {
+		switch (ev->evt) {
 		case BT_HCI_EVT_LE_ADVERTISING_REPORT:
 			return true;
 #if defined(CONFIG_BT_EXT_ADV)
 		case BT_HCI_EVT_LE_EXT_ADVERTISING_REPORT: {
 			const struct bt_hci_evt_le_ext_advertising_report *ext_adv =
-				(void *)&evt_data[3];
+				(const void *)meta_ev->data;
 
 			return (ext_adv->num_reports == 1) &&
 			       ((ext_adv->adv_info[0].evt_type & BT_HCI_LE_ADV_EVT_TYPE_LEGACY) !=
@@ -93,28 +91,67 @@ static bool is_hci_event_discardable(const uint8_t *evt_data)
 	}
 }
 
+static struct net_buf *get_rx_evt(const uint8_t *data)
+{
+	const struct bt_hci_evt_hdr *ev = (const void *)data;
+	const bool discardable = is_hci_event_discardable(ev);
+	const k_timeout_t timeout = discardable ? K_NO_WAIT : K_SECONDS(1);
+	struct net_buf *buf;
+
+	do {
+		buf = bt_buf_get_evt(ev->evt, discardable, timeout);
+		if (buf == NULL) {
+			if (discardable) {
+				LOG_DBG_RATELIMIT("Discardable buffer pool full, ignoring event");
+				return buf;
+			}
+			LOG_WRN("Couldn't allocate a buffer after waiting 1 second.");
+		}
+	} while (!buf);
+
+	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)
+{
+	struct net_buf *buf;
+
+	buf = bt_buf_get_rx(BT_BUF_ISO_IN, K_NO_WAIT);
+	if (buf == NULL) {
+		LOG_ERR_RATELIMIT("No available ISO buffers!");
+	}
+
+	return buf;
+}
+
 static struct net_buf *get_rx(const uint8_t *buf)
 {
-	bool discardable = false;
-	k_timeout_t timeout = K_FOREVER;
+	uint8_t hci_h4_type = buf[0];
 
-	switch (buf[0]) {
+	switch (hci_h4_type) {
 	case BT_HCI_H4_EVT:
-		if (is_hci_event_discardable(buf)) {
-			discardable = true;
-			timeout = K_NO_WAIT;
-		}
-
-		return bt_buf_get_evt(buf[1], discardable, timeout);
+		return get_rx_evt(&buf[1]);
 	case BT_HCI_H4_ACL:
-		return bt_buf_get_rx(BT_BUF_ACL_IN, K_FOREVER);
+		return get_rx_acl(&buf[1]);
 	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[1]);
 		}
 		__fallthrough;
 	default:
-		LOG_ERR("Unknown packet type: %u", buf[0]);
+		LOG_ERR("Unknown packet type: %u", hci_h4_type);
 	}
 
 	return NULL;
@@ -281,7 +318,6 @@ 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;
 			}