rng: move request queue cleanup from RngEgd to RngBackend

RngBackend is now in charge of cleaning up the linked list on
instance finalization. It also exposes a function to finalize
individual RngRequest instances, called by its child classes.

Signed-off-by: Ladi Prosek <lprosek@redhat.com>
Reviewed-by: Amit Shah <amit.shah@redhat.com>
Message-Id: <1456994238-9585-4-git-send-email-lprosek@redhat.com>
Signed-off-by: Amit Shah <amit.shah@redhat.com>

backends/rng-egd.c

@@ -58,12 +58,6 @@ static void rng_egd_request_entropy(RngBackend *b, size_t size,
     s->parent.requests = g_slist_append(s->parent.requests, req);
 }
 
-static void rng_egd_free_request(RngRequest *req)
-{
-    g_free(req->data);
-    g_free(req);
-}
-
 static int rng_egd_chr_can_read(void *opaque)
 {
     RngEgd *s = RNG_EGD(opaque);
@@ -93,28 +87,13 @@ static void rng_egd_chr_read(void *opaque, const uint8_t *buf, int size)
         size -= len;
 
         if (req->offset == req->size) {
-            s->parent.requests = g_slist_remove_link(s->parent.requests,
-                                                     s->parent.requests);
-
             req->receive_entropy(req->opaque, req->data, req->size);
 
-            rng_egd_free_request(req);
+            rng_backend_finalize_request(&s->parent, req);
         }
     }
 }
 
-static void rng_egd_free_requests(RngEgd *s)
-{
-    GSList *i;
-
-    for (i = s->parent.requests; i; i = i->next) {
-        rng_egd_free_request(i->data);
-    }
-
-    g_slist_free(s->parent.requests);
-    s->parent.requests = NULL;
-}
-
 static void rng_egd_opened(RngBackend *b, Error **errp)
 {
     RngEgd *s = RNG_EGD(b);
@@ -183,8 +162,6 @@ static void rng_egd_finalize(Object *obj)
     }
 
     g_free(s->chr_name);
-
-    rng_egd_free_requests(s);
 }
 
 static void rng_egd_class_init(ObjectClass *klass, void *data)

backends/rng.c

@@ -64,6 +64,30 @@ static void rng_backend_prop_set_opened(Object *obj, bool value, Error **errp)
     s->opened = true;
 }
 
+static void rng_backend_free_request(RngRequest *req)
+{
+    g_free(req->data);
+    g_free(req);
+}
+
+static void rng_backend_free_requests(RngBackend *s)
+{
+    GSList *i;
+
+    for (i = s->requests; i; i = i->next) {
+        rng_backend_free_request(i->data);
+    }
+
+    g_slist_free(s->requests);
+    s->requests = NULL;
+}
+
+void rng_backend_finalize_request(RngBackend *s, RngRequest *req)
+{
+    s->requests = g_slist_remove(s->requests, req);
+    rng_backend_free_request(req);
+}
+
 static void rng_backend_init(Object *obj)
 {
     object_property_add_bool(obj, "opened",
@@ -72,6 +96,13 @@ static void rng_backend_init(Object *obj)
                              NULL);
 }
 
+static void rng_backend_finalize(Object *obj)
+{
+    RngBackend *s = RNG_BACKEND(obj);
+
+    rng_backend_free_requests(s);
+}
+
 static void rng_backend_class_init(ObjectClass *oc, void *data)
 {
     UserCreatableClass *ucc = USER_CREATABLE_CLASS(oc);
@@ -84,6 +115,7 @@ static const TypeInfo rng_backend_info = {
     .parent = TYPE_OBJECT,
     .instance_size = sizeof(RngBackend),
     .instance_init = rng_backend_init,
+    .instance_finalize = rng_backend_finalize,
     .class_size = sizeof(RngBackendClass),
     .class_init = rng_backend_class_init,
     .abstract = true,

include/sysemu/rng.h

@@ -60,6 +60,7 @@ struct RngBackend
     GSList *requests;
 };
 
+
 /**
  * rng_backend_request_entropy:
  * @s: the backend to request entropy from
@@ -78,4 +79,15 @@ struct RngBackend
 void rng_backend_request_entropy(RngBackend *s, size_t size,
                                  EntropyReceiveFunc *receive_entropy,
                                  void *opaque);
+
+/**
+ * rng_backend_free_request:
+ * @s: the backend that created the request
+ * @req: the request to finalize
+ *
+ * Used by child rng backend classes to finalize requests once they've been
+ * processed. The request is removed from the list of active requests and
+ * deleted.
+ */
+void rng_backend_finalize_request(RngBackend *s, RngRequest *req);
 #endif