Bluetooth: Add dedicated pool for HCI_Num_Completed_Packets HCI event

This event is a priority one, so it's not safe to have it use the RX
buffer pool which may be depleted due to non-priority events (e.g.
advertising events). Since the event is consumed synchronously it's
safe to have a single-buffer pool for it. Also introduce a new
bt_buf_get_evt() API for HCI drivers to simplify the driver-side code,
this effectively also deprecates bt_buf_get_cmd_complete() which now
has no in-tree HCI driver users anymore.

Fixes #16864

Signed-off-by: Johan Hedberg <[email protected]>

Author: Johan Hedberg

drivers/bluetooth/hci/h4.c

@@ -161,16 +161,11 @@ static struct net_buf *get_rx(int timeout)
 {
 	BT_DBG("type 0x%02x, evt 0x%02x", rx.type, rx.evt.evt);
 
-	if (rx.type == H4_EVT && (rx.evt.evt == BT_HCI_EVT_CMD_COMPLETE ||
-				  rx.evt.evt == BT_HCI_EVT_CMD_STATUS)) {
-		return bt_buf_get_cmd_complete(timeout);
+	if (rx.type == H4_EVT) {
+		return bt_buf_get_evt(rx.evt.evt, timeout);
 	}
 
-	if (rx.type == H4_ACL) {
-		return bt_buf_get_rx(BT_BUF_ACL_IN, timeout);
-	} else {
-		return bt_buf_get_rx(BT_BUF_EVT, timeout);
-	}
+	return bt_buf_get_rx(BT_BUF_ACL_IN, timeout);
 }
 
 static void rx_thread(void *p1, void *p2, void *p3)

drivers/bluetooth/hci/h5.c

@@ -408,16 +408,7 @@ static inline struct net_buf *get_evt_buf(u8_t evt)
 {
 	struct net_buf *buf;
 
-	switch (evt) {
-	case BT_HCI_EVT_CMD_COMPLETE:
-	case BT_HCI_EVT_CMD_STATUS:
-		buf = bt_buf_get_cmd_complete(K_NO_WAIT);
-		break;
-	default:
-		buf = bt_buf_get_rx(BT_BUF_EVT, K_NO_WAIT);
-		break;
-	}
-
+	buf = bt_buf_get_evt(evt, K_NO_WAIT);
 	if (buf) {
 		net_buf_add_u8(h5.rx_buf, evt);
 	}

drivers/bluetooth/hci/ipm_stm32wb.c

@@ -114,12 +114,8 @@ void TM_EvtReceivedCb(TL_EvtPacket_t *hcievt)
 			BT_ERR("Unknown evtcode type 0x%02x",
 			       hcievt->evtserial.evt.evtcode);
 			goto out;
-		case BT_HCI_EVT_CMD_COMPLETE:
-		case BT_HCI_EVT_CMD_STATUS:
-			buf = bt_buf_get_cmd_complete(K_FOREVER);
-			break;
 		default:
-			buf = bt_buf_get_rx(BT_BUF_EVT, K_FOREVER);
+			buf = bt_buf_get_evt(evtserial.evt.evtcode, K_FOREVER);
 			break;
 		}
 		net_buf_add_mem(buf, &hcievt->evtserial.evt,

drivers/bluetooth/hci/spi.c

@@ -353,12 +353,9 @@ static void bt_spi_rx_thread(void)
 					/* Vendor events are currently unsupported */
 					bt_spi_handle_vendor_evt(rxmsg);
 					continue;
-				case BT_HCI_EVT_CMD_COMPLETE:
-				case BT_HCI_EVT_CMD_STATUS:
-					buf = bt_buf_get_cmd_complete(K_FOREVER);
-					break;
 				default:
-					buf = bt_buf_get_rx(BT_BUF_EVT, K_FOREVER);
+					buf = bt_buf_get_evt(rxmsg[EVT_HEADER_EVENT],
+							     K_FOREVER);
 					break;
 				}
 

drivers/bluetooth/hci/userchan.c

@@ -57,16 +57,11 @@ static int bt_dev_index = -1;
 
 static struct net_buf *get_rx(const u8_t *buf)
 {
-	if (buf[0] == H4_EVT && (buf[1] == BT_HCI_EVT_CMD_COMPLETE ||
-				 buf[1] == BT_HCI_EVT_CMD_STATUS)) {
-		return bt_buf_get_cmd_complete(K_FOREVER);
+	if (buf[0] == H4_EVT) {
+		return bt_buf_get_evt(buf[1], K_FOREVER);
 	}
 
-	if (buf[0] == H4_ACL) {
-		return bt_buf_get_rx(BT_BUF_ACL_IN, K_FOREVER);
-	} else {
-		return bt_buf_get_rx(BT_BUF_EVT, K_FOREVER);
-	}
+	return bt_buf_get_rx(BT_BUF_ACL_IN, K_FOREVER);
 }
 
 static bool uc_ready(void)

include/bluetooth/buf.h

@@ -64,6 +64,18 @@ struct net_buf *bt_buf_get_rx(enum bt_buf_type type, s32_t timeout);
  */
 struct net_buf *bt_buf_get_cmd_complete(s32_t timeout);
 
+/** Allocate a buffer for an HCI Event
+ *
+ *  This will set the buffer type so bt_buf_set_type() does not need to
+ *  be explicitly called before bt_recv_prio() or bt_recv().
+ *
+ *  @param evt     HCI event code
+ *  @param timeout Timeout in milliseconds, or one of the special values
+ *                 K_NO_WAIT and K_FOREVER.
+ *  @return A new buffer.
+ */
+struct net_buf *bt_buf_get_evt(u8_t evt, s32_t timeout);
+
 /** Set the buffer type
  *
  *  @param buf   Bluetooth buffer

subsys/bluetooth/controller/hci/hci.c

@@ -120,7 +120,7 @@ void *hci_cmd_complete(struct net_buf **buf, u8_t plen)
 {
 	struct bt_hci_evt_cmd_complete *cc;
 
-	*buf = bt_buf_get_cmd_complete(K_FOREVER);
+	*buf = bt_buf_get_evt(BT_HCI_EVT_CMD_COMPLETE, K_FOREVER);
 
 	hci_evt_create(*buf, BT_HCI_EVT_CMD_COMPLETE, sizeof(*cc) + plen);
 
@@ -137,7 +137,7 @@ static struct net_buf *cmd_status(u8_t status)
 	struct bt_hci_evt_cmd_status *cs;
 	struct net_buf *buf;
 
-	buf = bt_buf_get_cmd_complete(K_FOREVER);
+	buf = bt_buf_get_evt(BT_HCI_EVT_CMD_STATUS, K_FOREVER);
 	hci_evt_create(buf, BT_HCI_EVT_CMD_STATUS, sizeof(*cs));
 
 	cs = net_buf_add(buf, sizeof(*cs));

subsys/bluetooth/controller/hci/hci_driver.c

@@ -90,7 +90,8 @@ static void prio_recv_thread(void *p1, void *p2, void *p3)
 #if defined(CONFIG_BT_CONN)
 			struct net_buf *buf;
 
-			buf = bt_buf_get_rx(BT_BUF_EVT, K_FOREVER);
+			buf = bt_buf_get_evt(BT_HCI_EVT_NUM_COMPLETED_PACKETS,
+					     K_FOREVER);
 			hci_num_cmplt_encode(buf, handle, num_cmplt);
 			BT_DBG("Num Complete: 0x%04x:%u", handle, num_cmplt);
 			bt_recv_prio(buf);

subsys/bluetooth/host/hci_core.c

@@ -138,6 +138,16 @@ NET_BUF_POOL_DEFINE(hci_cmd_pool, CONFIG_BT_HCI_CMD_COUNT,
 NET_BUF_POOL_DEFINE(hci_rx_pool, CONFIG_BT_RX_BUF_COUNT,
 		    BT_BUF_RX_SIZE, BT_BUF_USER_DATA_MIN, NULL);
 
+#if defined(CONFIG_BT_CONN)
+/* Dedicated pool for HCI_Number_of_Completed_Packets. This event is always
+ * consumed synchronously by bt_recv_prio() so a single buffer is enough.
+ * Having a dedicated pool for it ensures that exhaustion of the RX pool
+ * cannot block the delivery of this priority event.
+ */
+NET_BUF_POOL_DEFINE(num_complete_pool, 1, BT_BUF_RX_SIZE,
+		    BT_BUF_USER_DATA_MIN, NULL);
+#endif /* CONFIG_BT_CONN */
+
 struct event_handler {
 	u8_t event;
 	u8_t min_len;
@@ -5662,6 +5672,31 @@ struct net_buf *bt_buf_get_cmd_complete(s32_t timeout)
 	return bt_buf_get_rx(BT_BUF_EVT, timeout);
 }
 
+struct net_buf *bt_buf_get_evt(u8_t evt, s32_t timeout)
+{
+	switch (evt) {
+#if defined(CONFIG_BT_CONN)
+	case BT_HCI_EVT_NUM_COMPLETED_PACKETS:
+		{
+			struct net_buf *buf;
+
+			buf = net_buf_alloc(&num_complete_pool, timeout);
+			if (buf) {
+				net_buf_reserve(buf, CONFIG_BT_HCI_RESERVE);
+				bt_buf_set_type(buf, BT_BUF_EVT);
+			}
+
+			return buf;
+		}
+#endif /* CONFIG_BT_CONN */
+	case BT_HCI_EVT_CMD_COMPLETE:
+	case BT_HCI_EVT_CMD_STATUS:
+		return bt_buf_get_cmd_complete(timeout);
+	default:
+		return bt_buf_get_rx(BT_BUF_EVT, timeout);
+	}
+}
+
 #if defined(CONFIG_BT_BREDR)
 static int br_start_inquiry(const struct bt_br_discovery_param *param)
 {

subsys/bluetooth/host/hci_ecc.c

@@ -84,7 +84,7 @@ static void send_cmd_status(u16_t opcode, u8_t status)
 
 	BT_DBG("opcode %x status %x", opcode, status);
 
-	buf = bt_buf_get_cmd_complete(K_FOREVER);
+	buf = bt_buf_get_evt(BT_HCI_EVT_CMD_STATUS, K_FOREVER);
 	bt_buf_set_type(buf, BT_BUF_EVT);
 
 	hdr = net_buf_add(buf, sizeof(*hdr));