Merge tag 'fixes-3.3-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc

[pandora-kernel.git] / block / blk-merge.c

diff --git a/block/blk-merge.c b/block/blk-merge.c
index cfcc37c..160035f 100644 (file)
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -471,3 +471,40 @@ int blk_attempt_req_merge(struct request_queue *q, struct request *rq,
 {
        return attempt_merge(q, rq, next);
 }
+
+bool blk_rq_merge_ok(struct request *rq, struct bio *bio)
+{
+       if (!rq_mergeable(rq))
+               return false;
+
+       /* don't merge file system requests and discard requests */
+       if ((bio->bi_rw & REQ_DISCARD) != (rq->bio->bi_rw & REQ_DISCARD))
+               return false;
+
+       /* don't merge discard requests and secure discard requests */
+       if ((bio->bi_rw & REQ_SECURE) != (rq->bio->bi_rw & REQ_SECURE))
+               return false;
+
+       /* different data direction or already started, don't merge */
+       if (bio_data_dir(bio) != rq_data_dir(rq))
+               return false;
+
+       /* must be same device and not a special request */
+       if (rq->rq_disk != bio->bi_bdev->bd_disk || rq->special)
+               return false;
+
+       /* only merge integrity protected bio into ditto rq */
+       if (bio_integrity(bio) != blk_integrity_rq(rq))
+               return false;
+
+       return true;
+}
+
+int blk_try_merge(struct request *rq, struct bio *bio)
+{
+       if (blk_rq_pos(rq) + blk_rq_sectors(rq) == bio->bi_sector)
+               return ELEVATOR_BACK_MERGE;
+       else if (blk_rq_pos(rq) - bio_sectors(bio) == bio->bi_sector)
+               return ELEVATOR_FRONT_MERGE;
+       return ELEVATOR_NO_MERGE;
+}