Fix submission ring overflow & ring_data_t reuse conflicts

ringloop.cpp

@@ -7,16 +7,23 @@ ring_loop_t::ring_loop_t(int qd)
     {
         throw std::runtime_error(std::string("io_uring_queue_init: ") + strerror(-ret));
     }
-    ring_data = (struct ring_data_t*)malloc(sizeof(ring_data_t) * ring.sq.ring_sz);
-    if (!ring_data)
+    free_ring_data_ptr = *ring.cq.kring_entries;
+    ring_datas = (struct ring_data_t*)malloc(sizeof(ring_data_t) * free_ring_data_ptr);
+    free_ring_data = (int*)malloc(sizeof(int) * free_ring_data_ptr);
+    if (!ring_datas || !free_ring_data)
     {
         throw std::bad_alloc();
     }
+    for (int i = 0; i < free_ring_data_ptr; i++)
+    {
+        free_ring_data[i] = i;
+    }
 }
 
 ring_loop_t::~ring_loop_t()
 {
-    free(ring_data);
+    free(free_ring_data);
+    free(ring_datas);
     io_uring_queue_exit(&ring);
 }
 
@@ -52,6 +59,7 @@ void ring_loop_t::loop()
             d->res = cqe->res;
             d->callback(d);
         }
+        free_ring_data[free_ring_data_ptr++] = d - ring_datas;
         io_uring_cqe_seen(&ring, cqe);
     }
     do
@@ -63,3 +71,18 @@ void ring_loop_t::loop()
         }
     } while (loop_again);
 }
+
+unsigned ring_loop_t::save()
+{
+    return ring.sq.sqe_tail;
+}
+
+void ring_loop_t::restore(unsigned sqe_tail)
+{
+    assert(ring.sq.sqe_tail >= sqe_tail);
+    for (unsigned i = sqe_tail; i < ring.sq.sqe_tail; i++)
+    {
+        free_ring_data[free_ring_data_ptr++] = ((ring_data_t*)ring.sq.sqes[i & *ring.sq.kring_mask].user_data) - ring_datas;
+    }
+    ring.sq.sqe_tail = sqe_tail;
+}