Add 'discard' request handling

[linux-2.6-omap-h63xx.git] / block / blk-settings.c

diff --git a/block/blk-settings.c b/block/blk-settings.c
index dfc77012843ffbf9e67fa8996d40099f2db667fe..539d873c820dc3781314a6161d8664d438a7ff8c 100644 (file)
--- a/block/blk-settings.c
+++ b/block/blk-settings.c
@@ -32,6 +32,23 @@ void blk_queue_prep_rq(struct request_queue *q, prep_rq_fn *pfn)
 }
 EXPORT_SYMBOL(blk_queue_prep_rq);
 
+/**
+ * blk_queue_set_discard - set a discard_sectors function for queue
+ * @q:         queue
+ * @dfn:       prepare_discard function
+ *
+ * It's possible for a queue to register a discard callback which is used
+ * to transform a discard request into the appropriate type for the
+ * hardware. If none is registered, then discard requests are failed
+ * with %EOPNOTSUPP.
+ *
+ */
+void blk_queue_set_discard(struct request_queue *q, prepare_discard_fn *dfn)
+{
+       q->prepare_discard_fn = dfn;
+}
+EXPORT_SYMBOL(blk_queue_set_discard);
+
 /**
  * blk_queue_merge_bvec - set a merge_bvec function for queue
  * @q:         queue