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authorArnd Bergmann <arnd@arndb.de>2012-02-28 12:39:56 +0000
committerArnd Bergmann <arnd@arndb.de>2012-02-28 12:40:01 +0000
commit4d8cfec692e988b844dcaeaeb76b5780b7ef9d28 (patch)
tree67d43adab2afd18a74d08f347e3676ae1a64193f /block/blk-merge.c
parenta3a3c4664184f86ef964323d106c62158e2b3f25 (diff)
parent1d8c38c3d1b48eeb9cfaa42a8be13a1423569eb2 (diff)
Merge branch 'cleanup-3.4' of git://github.com/hzhuang1/linux into next/cleanup
* 'cleanup-3.4' of git://github.com/hzhuang1/linux: (2 commits) rtc: sa1100: remove verification code of alarm rtc: sa1100: remove periodic code (update to v3.3-rc5)
Diffstat (limited to 'block/blk-merge.c')
-rw-r--r--block/blk-merge.c37
1 files changed, 37 insertions, 0 deletions
diff --git a/block/blk-merge.c b/block/blk-merge.c
index cfcc37cb222b..160035f54882 100644
--- 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;
+}