On Tue, Sep 18 2012 at 12:19pm -0400,
Martin K. Petersen <martin.petersen@xxxxxxxxxx> wrote:
> From: "Martin K. Petersen" <martin.petersen@xxxxxxxxxx>
>
> - 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 <martin.petersen@xxxxxxxxxx>
> ---
> 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 5cc2929..33eded0 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 86710ca..642b862 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 3a6fea7..90f7abe 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;
Any reason not to use queue_max_sectors() here?
> +}
> +
> +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;
Or queue_max_hw_sectors() here?
> + return blk_queue_get_max_sectors(q, rq->cmd_flags);
> +}
> +
But I don't feel that strongly on these nits. So regardless:
Acked-by: Mike Snitzer <snitzer@xxxxxxxxxx>
(thanks for getting this patchset together Martin)
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