From f31dc1cd490539e2b62a126bc4dc2495b165d772 Mon Sep 17 00:00:00 2001 From: "Martin K. Petersen" Date: Tue, 18 Sep 2012 12:19:26 -0400 Subject: [PATCH] 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-core.c | 3 +-- block/blk-merge.c | 30 ++++++++++++------------------ include/linux/blkdev.h | 31 +++++++++++++++++++++++++++++++ 3 files changed, 44 insertions(+), 20 deletions(-) diff --git a/block/blk-core.c b/block/blk-core.c index 5cc29299f6ac..33eded00c5b1 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -1866,8 +1866,7 @@ int blk_rq_check_limits(struct request_queue *q, struct request *rq) if (!rq_mergeable(rq)) return 0; - if (blk_rq_sectors(rq) > queue_max_sectors(q) || - blk_rq_bytes(rq) > queue_max_hw_sectors(q) << 9) { + if (blk_rq_sectors(rq) > blk_queue_get_max_sectors(q, rq->cmd_flags)) { printk(KERN_ERR "%s: over max size limit.\n", __func__); return -EIO; } 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; diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 3a6fea7460f1..90f7abe8f183 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -605,6 +605,18 @@ static inline bool rq_mergeable(struct request *rq) return true; } +static inline bool blk_check_merge_flags(unsigned int flags1, + unsigned int flags2) +{ + if ((flags1 & REQ_DISCARD) != (flags2 & REQ_DISCARD)) + return false; + + if ((flags1 & REQ_SECURE) != (flags2 & REQ_SECURE)) + return false; + + return true; +} + /* * q->prep_rq_fn return values */ @@ -800,6 +812,25 @@ static inline unsigned int blk_rq_cur_sectors(const struct request *rq) return blk_rq_cur_bytes(rq) >> 9; } +static inline unsigned int blk_queue_get_max_sectors(struct request_queue *q, + unsigned int cmd_flags) +{ + if (unlikely(cmd_flags & REQ_DISCARD)) + return q->limits.max_discard_sectors; + + return q->limits.max_sectors; +} + +static inline unsigned int blk_rq_get_max_sectors(struct request *rq) +{ + struct request_queue *q = rq->q; + + if (unlikely(rq->cmd_type == REQ_TYPE_BLOCK_PC)) + return q->limits.max_hw_sectors; + + return blk_queue_get_max_sectors(q, rq->cmd_flags); +} + /* * Request issue related functions. */