From f31dc1cd490539e2b62a126bc4dc2495b165d772 Mon Sep 17 00:00:00 2001 From: "Martin K. Petersen" Date: Tue, 18 Sep 2012 12:19:26 -0400 Subject: block: Consolidate command flag and queue limit checks for merges - blk_check_merge_flags() verifies that cmd_flags / bi_rw are compatible. This function is called for both req-req and req-bio merging. - blk_rq_get_max_sectors() and blk_queue_get_max_sectors() can be used to query the maximum sector count for a given request or queue. The calls will return the right value from the queue limits given the type of command (RW, discard, write same, etc.) Signed-off-by: Martin K. Petersen Acked-by: Mike Snitzer Signed-off-by: Jens Axboe --- block/blk-merge.c | 30 ++++++++++++------------------ 1 file changed, 12 insertions(+), 18 deletions(-) (limited to 'block/blk-merge.c') diff --git a/block/blk-merge.c b/block/blk-merge.c index 86710ca408b8..642b862608a1 100644 --- a/block/blk-merge.c +++ b/block/blk-merge.c @@ -275,14 +275,8 @@ no_merge: int ll_back_merge_fn(struct request_queue *q, struct request *req, struct bio *bio) { - unsigned short max_sectors; - - if (unlikely(req->cmd_type == REQ_TYPE_BLOCK_PC)) - max_sectors = queue_max_hw_sectors(q); - else - max_sectors = queue_max_sectors(q); - - if (blk_rq_sectors(req) + bio_sectors(bio) > max_sectors) { + if (blk_rq_sectors(req) + bio_sectors(bio) > + blk_rq_get_max_sectors(req)) { req->cmd_flags |= REQ_NOMERGE; if (req == q->last_merge) q->last_merge = NULL; @@ -299,15 +293,8 @@ int ll_back_merge_fn(struct request_queue *q, struct request *req, int ll_front_merge_fn(struct request_queue *q, struct request *req, struct bio *bio) { - unsigned short max_sectors; - - if (unlikely(req->cmd_type == REQ_TYPE_BLOCK_PC)) - max_sectors = queue_max_hw_sectors(q); - else - max_sectors = queue_max_sectors(q); - - - if (blk_rq_sectors(req) + bio_sectors(bio) > max_sectors) { + if (blk_rq_sectors(req) + bio_sectors(bio) > + blk_rq_get_max_sectors(req)) { req->cmd_flags |= REQ_NOMERGE; if (req == q->last_merge) q->last_merge = NULL; @@ -338,7 +325,8 @@ static int ll_merge_requests_fn(struct request_queue *q, struct request *req, /* * Will it become too large? */ - if ((blk_rq_sectors(req) + blk_rq_sectors(next)) > queue_max_sectors(q)) + if ((blk_rq_sectors(req) + blk_rq_sectors(next)) > + blk_rq_get_max_sectors(req)) return 0; total_phys_segments = req->nr_phys_segments + next->nr_phys_segments; @@ -417,6 +405,9 @@ static int attempt_merge(struct request_queue *q, struct request *req, if (!rq_mergeable(req) || !rq_mergeable(next)) return 0; + if (!blk_check_merge_flags(req->cmd_flags, next->cmd_flags)) + return 0; + /* * not contiguous */ @@ -512,6 +503,9 @@ bool blk_rq_merge_ok(struct request *rq, struct bio *bio) if (!rq_mergeable(rq) || !bio_mergeable(bio)) return false; + if (!blk_check_merge_flags(rq->cmd_flags, bio->bi_rw)) + return false; + /* different data direction or already started, don't merge */ if (bio_data_dir(bio) != rq_data_dir(rq)) return false; -- cgit v1.2.1