block: Introduce elevator features
[linux-2.6-microblaze.git] / block / blk-settings.c
index a058997..6bd1e3b 100644 (file)
@@ -832,6 +832,22 @@ void blk_queue_write_cache(struct request_queue *q, bool wc, bool fua)
 }
 EXPORT_SYMBOL_GPL(blk_queue_write_cache);
 
+/**
+ * blk_queue_required_elevator_features - Set a queue required elevator features
+ * @q:         the request queue for the target device
+ * @features:  Required elevator features OR'ed together
+ *
+ * Tell the block layer that for the device controlled through @q, only the
+ * only elevators that can be used are those that implement at least the set of
+ * features specified by @features.
+ */
+void blk_queue_required_elevator_features(struct request_queue *q,
+                                         unsigned int features)
+{
+       q->required_elevator_features = features;
+}
+EXPORT_SYMBOL_GPL(blk_queue_required_elevator_features);
+
 static int __init blk_settings_init(void)
 {
        blk_max_low_pfn = max_low_pfn - 1;