osdblk: Adjust queue limits to lower device's limits

call blk_queue_stack_limits() to copy queue limits from
the underline osd scsi_device. This is absolutely needed
because osdblk cannot sleep when allocating a lower-request and
therefore cannot be bouncing.

TODO: Dynamic changes of limits to the lower device queue
will not reflect in the upper driver
Signed-off-by: NBoaz Harrosh <bharrosh@panasas.com>

drivers/block/osdblk.c

@@ -66,6 +66,7 @@
 #include <scsi/osd_initiator.h>
 #include <scsi/osd_attributes.h>
 #include <scsi/osd_sec.h>
+#include <scsi/scsi_device.h>
 
 #define DRV_NAME "osdblk"
 #define PFX DRV_NAME ": "
@@ -437,6 +438,12 @@ static int osdblk_init_disk(struct osdblk_device *osdev)
 		return rc;
 	}
 
+	/* Set our limits to the lower device limits, because osdblk cannot
+	 * sleep when allocating a lower-request and therefore cannot be
+	 * bouncing.
+	 */
+	blk_queue_stack_limits(q, osd_request_queue(osdev->osd));
+
 	blk_queue_prep_rq(q, blk_queue_start_tag);
 	blk_queue_ordered(q, QUEUE_ORDERED_DRAIN_FLUSH, osdblk_prepare_flush);