[PATCH] s390: enable write barriers in the dasd driver

The DASD device driver never reorders the I/O requests and relies on the
hardware to write all data to nonvolatile storage before signaling a
successful write.  Hence, the only thing we have to do to support write
barriers is to set the queue ordered flag.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/drivers/s390/block/dasd.c b/drivers/s390/block/dasd.c
index 826fd238034d45f22d30b37f55d81bc562c6eeb8..02cfe244e069777219e3ef4450e05634badafcc9 100644 (file)
--- a/drivers/s390/block/dasd.c
+++ b/drivers/s390/block/dasd.c
@@ -1635,6 +1635,7 @@ dasd_setup_queue(struct dasd_device * device)
        blk_queue_max_hw_segments(device->request_queue, -1L);
        blk_queue_max_segment_size(device->request_queue, -1L);
        blk_queue_segment_boundary(device->request_queue, -1L);
+       blk_queue_ordered(device->request_queue, 1);
 }
 
 /*