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/elevator.c | 55 ++++--------------------------------------------------- 1 file changed, 4 insertions(+), 51 deletions(-) (limited to 'block/elevator.c') diff --git a/block/elevator.c b/block/elevator.c index 91e18f8af9be..f016855a46b0 100644 --- a/block/elevator.c +++ b/block/elevator.c @@ -70,39 +70,9 @@ static int elv_iosched_allow_merge(struct request *rq, struct bio *bio) /* * can we safely merge with this request? */ -int elv_rq_merge_ok(struct request *rq, struct bio *bio) +bool elv_rq_merge_ok(struct request *rq, struct bio *bio) { - if (!rq_mergeable(rq)) - return 0; - - /* - * Don't merge file system requests and discard requests - */ - if ((bio->bi_rw & REQ_DISCARD) != (rq->bio->bi_rw & REQ_DISCARD)) - return 0; - - /* - * Don't merge discard requests and secure discard requests - */ - if ((bio->bi_rw & REQ_SECURE) != (rq->bio->bi_rw & REQ_SECURE)) - return 0; - - /* - * different data direction or already started, don't merge - */ - if (bio_data_dir(bio) != rq_data_dir(rq)) - return 0; - - /* - * must be same device and not a special request - */ - 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)) + if (!blk_rq_merge_ok(rq, bio)) return 0; if (!elv_iosched_allow_merge(rq, bio)) @@ -112,23 +82,6 @@ int elv_rq_merge_ok(struct request *rq, struct bio *bio) } EXPORT_SYMBOL(elv_rq_merge_ok); -int elv_try_merge(struct request *__rq, struct bio *bio) -{ - int ret = ELEVATOR_NO_MERGE; - - /* - * we can merge and sequence is ok, check if it's possible - */ - if (elv_rq_merge_ok(__rq, bio)) { - if (blk_rq_pos(__rq) + blk_rq_sectors(__rq) == bio->bi_sector) - ret = ELEVATOR_BACK_MERGE; - else if (blk_rq_pos(__rq) - bio_sectors(bio) == bio->bi_sector) - ret = ELEVATOR_FRONT_MERGE; - } - - return ret; -} - static struct elevator_type *elevator_find(const char *name) { struct elevator_type *e; @@ -478,8 +431,8 @@ int elv_merge(struct request_queue *q, struct request **req, struct bio *bio) /* * First try one-hit cache. */ - if (q->last_merge) { - ret = elv_try_merge(q->last_merge, bio); + if (q->last_merge && elv_rq_merge_ok(q->last_merge, bio)) { + ret = blk_try_merge(q->last_merge, bio); if (ret != ELEVATOR_NO_MERGE) { *req = q->last_merge; return ret; -- cgit v1.2.3-59-g8ed1b