Bluetooth: Host: Move tx_processor to bt_taskq

The Bluetooth Host itself performs operations on the system workqueue
which are blocking waiting for the tx_processor to run. This results in
deadlocks.

TX processor is supposed to be non-blocking, so this change puts it on
the new bt_taskq.

This effectively gives tx_processor its own thread, like the BT TX
thread that used to exist. But, this time this thread is intended to be
shared with any other non-blocking Bluetooth Host tasks.

Signed-off-by: Aleksander Wasaznik <[email protected]>

Author: alwa-nordic

subsys/bluetooth/host/bt_taskq.c

@@ -16,10 +16,8 @@ struct k_work_q bt_taskq;
 
 static int bt_taskq_init(void)
 {
-	const struct k_work_queue_config cfg = {
+	struct k_work_queue_config cfg = {
 		.name = "bt_taskq",
-		/* Enable CONFIG_WORKQUEUE_WORK_TIMEOUT to detect tasks that take too long. */
-		.work_timeout_ms = 10,
 	};
 
 	k_work_queue_start(&bt_taskq, bt_taskq_stack, K_THREAD_STACK_SIZEOF(bt_taskq_stack),

subsys/bluetooth/host/hci_core.c

@@ -48,6 +48,7 @@
 
 #include "addr_internal.h"
 #include "adv.h"
+#include "bt_taskq.h"
 #include "common/hci_common_internal.h"
 #include "common/bt_str.h"
 #include "common/rpa.h"
@@ -282,8 +283,6 @@ void bt_send_one_host_num_completed_packets(uint16_t handle)
 	BT_ASSERT_MSG(err == 0, "Unable to send Host NCP (err %d)", err);
 }
 
-#include "bt_taskq.h"
-
 #if defined(CONFIG_BT_TESTING)
 __weak void bt_testing_trace_event_acl_pool_destroy(struct net_buf *buf)
 {
@@ -5038,5 +5037,5 @@ static K_WORK_DEFINE(tx_work, tx_processor);
 void bt_tx_irq_raise(void)
 {
 	LOG_DBG("kick TX");
-	k_work_submit(&tx_work);
+	k_work_submit_to_queue(&bt_taskq, &tx_work);
 }