Remove the left over worker thread from ::load() call.

The logic is called as callback invoked by virtio interrupts.

In addition, polish the test code. Before all of the write request
had filled the ring and left no space for the read requests. Now I rotate
between the two.

drivers/virtio-blk.cc

@@ -99,9 +99,6 @@ struct driver virtio_blk_driver = {
                       sizeof(_config.capacity));
         debug(fmt("capacity of the device is %x") % (u64)_config.capacity);
 
-        thread* worker = new thread([this] { this->response_worker(); });
-        worker->wake(); // just to keep gcc happy about unused var
-
         _dev->add_dev_status(VIRTIO_CONFIG_S_DRIVER_OK);
 
         _dev->register_callback([this] { this->response_worker();});
@@ -117,10 +114,14 @@ struct driver virtio_blk_driver = {
             prv = reinterpret_cast<struct virtio_blk_priv*>(dev->private_data);
             prv->drv = this;
 
-            for (int i=0;i<2000;i++) {
+            for (int i=0;i<6;i++) {
                 debug(fmt("Running test %d") % i);
                 test();
-                //sched::thread::current()->yield();
+                timespec ts = {};
+                ts.tv_sec = 1;
+                nanosleep(&ts, nullptr);
+
+                sched::thread::current()->yield();
             }
         }
 
@@ -174,37 +175,42 @@ struct driver virtio_blk_driver = {
 
     void virtio_blk::test() {
         int i;
+        static bool is_write = true; // keep changing the type every call
 
         debug("test virtio blk");
         vring* queue = _dev->get_virt_queue(0);
         virtio_blk_req* req;
         const int iterations = 100;
 
-        debug(" write several requests");
-        for (i=0;i<iterations;i++) {
-            req = make_virtio_req(i*8, VIRTIO_BLK_T_OUT,i);
-            if (!queue->add_buf(req->payload,2,1,req)) {
-                break;
+        if (is_write) {
+            is_write = false;
+            debug(" write several requests");
+            for (i=0;i<iterations;i++) {
+                req = make_virtio_req(i*8, VIRTIO_BLK_T_OUT,i);
+                if (!queue->add_buf(req->payload,2,1,req)) {
+                    break;
+                }
             }
-        }
-
-        debug(fmt(" Let the host know about the %d requests") % i);
-        queue->kick();
 
-        sched::thread::current()->yield();
+            debug(fmt(" Let the host know about the %d requests") % i);
+            queue->kick();
+        } else {
+            is_write = true;
+            debug(" read several requests");
+            for (i=0;i<iterations;i++) {
+                req = make_virtio_req(i*8, VIRTIO_BLK_T_IN,0);
+                if (!queue->add_buf(req->payload,1,2,req)) {
+                    break;
+                }
+                if (i%2) queue->kick(); // should be out of the loop but I like plenty of irqs for the test
 
-        debug(" read several requests");
-        for (i=0;i<iterations;i++) {
-            req = make_virtio_req(i*8, VIRTIO_BLK_T_IN,0);
-            if (!queue->add_buf(req->payload,1,2,req)) {
-                break;
             }
-            if (i%2) queue->kick(); // should be out of the loop but I like plenty of irqs for the test
 
+            debug(fmt(" Let the host know about the %d requests") % i);
+            queue->kick();
         }
 
-        debug(fmt(" Let the host know about the %d requests") % i);
-        queue->kick();
+        //sched::thread::current()->yield();
 
         debug("test virtio blk end");
     }
@@ -215,14 +221,14 @@ struct driver virtio_blk_driver = {
 
         while (1) {
 
-            debug("\t ----> virtio_blk: response worker main loop");
+            debug("\t ----> virtio_blk: IRQ: response worker main loop");
 
             thread::wait_until([this] {
                 vring* queue = this->_dev->get_virt_queue(0);
-                return queue->used_ring_not_empy();
+                return queue->used_ring_not_empty();
             });
 
-            debug("\t ----> debug - blk thread awaken");
+            debug("\t ----> IRQ: debug - blk thread awaken");
 
             int i = 0;