From 050c8ea80e3e90019d9e981c6a117ef614e882ed Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Wed, 8 Feb 2012 09:19:38 +0100 Subject: block: separate out blk_rq_merge_ok() and blk_try_merge() from elevator functions blk_rq_merge_ok() is the elevator-neutral part of merge eligibility test. blk_try_merge() determines merge direction and expects the caller to have tested elv_rq_merge_ok() previously. elv_rq_merge_ok() now wraps blk_rq_merge_ok() and then calls elv_iosched_allow_merge(). elv_try_merge() is removed and the two callers are updated to call elv_rq_merge_ok() explicitly followed by blk_try_merge(). While at it, make rq_merge_ok() functions return bool. This is to prepare for plug merge update and doesn't introduce any behavior change. This is based on Jens' patch to skip elevator_allow_merge_fn() from plug merge. Signed-off-by: Tejun Heo LKML-Reference: <4F16F3CA.90904@kernel.dk> Original-patch-by: Jens Axboe Signed-off-by: Jens Axboe --- block/blk-merge.c | 37 +++++++++++++++++++++++++++++++++++++ 1 file changed, 37 insertions(+) (limited to 'block/blk-merge.c') diff --git a/block/blk-merge.c b/block/blk-merge.c index cfcc37cb222..160035f5488 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; +} -- cgit v1.2.3