block: Block layer data integrity support
Some block devices support verifying the integrity of requests by way
of checksums or other protection information that is submitted along
with the I/O.
This patch implements support for generating and verifying integrity
metadata, as well as correctly merging, splitting and cloning bios and
requests that have this extra information attached.
See Documentation/block/data-integrity.txt for more information.
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/block/elevator.c b/block/elevator.c
index 902dd13..1f5bfe6 100644
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -86,6 +86,12 @@
if (rq->rq_disk != bio->bi_bdev->bd_disk || rq->special)
return 0;
+ /*
+ * only merge integrity protected bio into ditto rq
+ */
+ if (bio_integrity(bio) != blk_integrity_rq(rq))
+ return 0;
+
if (!elv_iosched_allow_merge(rq, bio))
return 0;