diff --git a/[refs] b/[refs]
index 422e3f62eb4d..f8b462253b31 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 06d2188644c85c56d243efab914f368d1d23c4a3
+refs/heads/master: 3c5820c743479285ce2678fd3c12b1fd39fe998f
diff --git a/trunk/block/blk-settings.c b/trunk/block/blk-settings.c
index 476d87065073..83413ff83739 100644
--- a/trunk/block/blk-settings.c
+++ b/trunk/block/blk-settings.c
@@ -427,6 +427,25 @@ void blk_queue_io_min(struct request_queue *q, unsigned int min)
 }
 EXPORT_SYMBOL(blk_queue_io_min);
 
+/**
+ * blk_limits_io_opt - set optimal request size for a device
+ * @limits: the queue limits
+ * @opt:  smallest I/O size in bytes
+ *
+ * Description:
+ *   Storage devices may report an optimal I/O size, which is the
+ *   device's preferred unit for sustained I/O.  This is rarely reported
+ *   for disk drives.  For RAID arrays it is usually the stripe width or
+ *   the internal track size.  A properly aligned multiple of
+ *   optimal_io_size is the preferred request size for workloads where
+ *   sustained throughput is desired.
+ */
+void blk_limits_io_opt(struct queue_limits *limits, unsigned int opt)
+{
+	limits->io_opt = opt;
+}
+EXPORT_SYMBOL(blk_limits_io_opt);
+
 /**
  * blk_queue_io_opt - set optimal request size for the queue
  * @q:	the request queue for the device
@@ -442,7 +461,7 @@ EXPORT_SYMBOL(blk_queue_io_min);
  */
 void blk_queue_io_opt(struct request_queue *q, unsigned int opt)
 {
-	q->limits.io_opt = opt;
+	blk_limits_io_opt(&q->limits, opt);
 }
 EXPORT_SYMBOL(blk_queue_io_opt);
 
diff --git a/trunk/drivers/md/dm-stripe.c b/trunk/drivers/md/dm-stripe.c
index fde658ccbcec..e0efc1adcaff 100644
--- a/trunk/drivers/md/dm-stripe.c
+++ b/trunk/drivers/md/dm-stripe.c
@@ -336,7 +336,7 @@ static void stripe_io_hints(struct dm_target *ti,
 	unsigned chunk_size = (sc->chunk_mask + 1) << 9;
 
 	blk_limits_io_min(limits, chunk_size);
-	limits->io_opt = chunk_size * sc->stripes;
+	blk_limits_io_opt(limits, chunk_size * sc->stripes);
 }
 
 static struct target_type stripe_target = {
diff --git a/trunk/include/linux/blkdev.h b/trunk/include/linux/blkdev.h
index 8bf1a10e4d88..86c2bdff3b89 100644
--- a/trunk/include/linux/blkdev.h
+++ b/trunk/include/linux/blkdev.h
@@ -935,6 +935,7 @@ extern void blk_queue_alignment_offset(struct request_queue *q,
 				       unsigned int alignment);
 extern void blk_limits_io_min(struct queue_limits *limits, unsigned int min);
 extern void blk_queue_io_min(struct request_queue *q, unsigned int min);
+extern void blk_limits_io_opt(struct queue_limits *limits, unsigned int opt);
 extern void blk_queue_io_opt(struct request_queue *q, unsigned int opt);
 extern void blk_set_default_limits(struct queue_limits *lim);
 extern int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,