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: Boaz Harrosh <bharrosh@panasas.com>

1 files changed, 7 insertions, 0 deletions

diff --git a/drivers/block/osdblk.c b/drivers/block/osdblk.c
index 3565d0dd123f..13c1aee6aa3f 100644
--- a/drivers/block/osdblk.c
+++ b/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);