Unlock the GIL while accessing queues

Keeping the GIL locked while sending to full queues or receiving from
empty queues results in a deadlock, because no other Python code can
execute to put() or get() from the queue.

Author: Sympatron

esp32/mods/moduqueue.c

@@ -91,10 +91,13 @@ STATIC mp_obj_t mp_queue_put(mp_uint_t n_args, const mp_obj_t *pos_args, mp_map_
     mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
     mp_arg_parse_all(n_args - 1, pos_args + 1, kw_args, MP_ARRAY_SIZE(args), allowed_args, args);
 
+    MP_THREAD_GIL_EXIT();
     uint32_t timeout_ms = (args[2].u_obj == mp_const_none) ? portMAX_DELAY : mp_obj_get_int_truncated(args[2].u_obj);
     if (!xQueueSend(self->handle, (void *)&args[0].u_obj, args[1].u_bool ? (TickType_t)(timeout_ms / portTICK_PERIOD_MS) : 0)) {
+        MP_THREAD_GIL_ENTER();
         nlr_raise(mp_obj_new_exception_msg(&mp_type_OSError, "Full"));
     }
+    MP_THREAD_GIL_ENTER();
 
     return mp_const_none;
 }
@@ -113,9 +116,12 @@ STATIC mp_obj_t mp_queue_get(mp_uint_t n_args, const mp_obj_t *pos_args, mp_map_
 
     uint32_t timeout_ms = (args[1].u_obj == mp_const_none) ? portMAX_DELAY : mp_obj_get_int_truncated(args[1].u_obj);
     mp_obj_t item;
+    MP_THREAD_GIL_EXIT();
     if (!xQueueReceive(self->handle, (void *)&item, args[0].u_bool ? (TickType_t)(timeout_ms / portTICK_PERIOD_MS) : 0)) {
+        MP_THREAD_GIL_ENTER();
         nlr_raise(mp_obj_new_exception_msg(&mp_type_OSError, "Empty"));
     }
+    MP_THREAD_GIL_ENTER();
 
     return item;
 }