@@ -255,6 +255,63 @@ static void bdrv_drain_invoke(BlockDriverState *bs, bool begin,
}
}
+/* TODO: Actually use this function and drop this forward declaration */
+static void bdrv_poll_drain_data_objs(GSList **data_objs, bool acquire_ctx)
+ __attribute__((unused));
+
+/*
+ * Poll the AioContexts in the given list of BdrvCoDrainData objects
+ * until all of those objects are "done" (i.e. their .done field is
+ * true).
+ * Also, free all objects and the list.
+ *
+ * If @acquire_ctx is true, the AioContexts are locked while they are
+ * polled.
+ */
+static void bdrv_poll_drain_data_objs(GSList **data_objs, bool acquire_ctx)
+{
+ GSList *contexts = NULL;
+ GSList *iter;
+
+ /* First collect the contexts while the BDSs are not gone */
+ for (iter = *data_objs; iter; iter = iter->next) {
+ BdrvCoDrainData *drain_data = iter->data;
+ contexts = g_slist_prepend(contexts,
+ bdrv_get_aio_context(drain_data->bs));
+ }
+
+ /*
+ * Reverse the list so it is in the same order as *data_objs
+ * (prepend and then reverse has better performance than appending)
+ */
+ contexts = g_slist_reverse(contexts);
+
+ /* The BDSs may disappear here, but we only need their contexts */
+ while (*data_objs) {
+ GSList *next;
+ BdrvCoDrainData *drain_data = (*data_objs)->data;
+ AioContext *ctx = contexts->data;
+
+ if (acquire_ctx) {
+ aio_context_acquire(ctx);
+ }
+ AIO_WAIT_WHILE(ctx, !drain_data->done);
+ if (acquire_ctx) {
+ aio_context_release(ctx);
+ }
+
+ g_free(drain_data);
+
+ next = (*data_objs)->next;
+ g_slist_free_1(*data_objs);
+ *data_objs = next;
+
+ next = contexts->next;
+ g_slist_free_1(contexts);
+ contexts = next;
+ }
+}
+
/* Returns true if BDRV_POLL_WHILE() should go into a blocking aio_poll() */
bool bdrv_drain_poll(BlockDriverState *bs, bool recursive,
BdrvChild *ignore_parent, bool ignore_bds_parents)
This function polls all of the involved AioContexts for a GSList of BdrvCoDrainData objects until all objects' .done is true. Signed-off-by: Max Reitz <mreitz@redhat.com> --- block/io.c | 57 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 57 insertions(+)