This patch moves write-hint-to-stream-id conversion in block-layer. Earlier this was done by driver (nvme). For user write-hints, conversion is of the form "streamid = write-hint - 1". For kernel write-hints, streams are allocated in top-to-bottom fashion. This has the effect of mapping user-hints to lower range of stream-ids and kernel-hints to upper range of stream-ids. Conversion takes stream limit (maintained in request queue) into account. Write-hints beyond the exposed limit turn to 0. A new field 'streamid' has been added in request, while 'write-hint' field has been removed. For merging checks, 'bi_write_hint' (of bio) is used instead.
Signed-off-by: Kanchan Joshi <[email protected]> --- block/blk-core.c | 29 ++++++++++++++++++++++++++++- block/blk-merge.c | 4 ++-- drivers/nvme/host/core.c | 7 ++----- include/linux/blkdev.h | 2 +- 4 files changed, 33 insertions(+), 9 deletions(-) diff --git a/block/blk-core.c b/block/blk-core.c index a55389b..0485c20 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -730,6 +730,33 @@ bool blk_attempt_plug_merge(struct request_queue *q, struct bio *bio, return false; } +enum rw_hint blk_write_hint_to_streamid(struct request *req, + struct bio *bio) +{ + enum rw_hint streamid, write_hint, nr_streams; + struct request_queue *q = req->q; + + nr_streams = q->limits.nr_streams; + + write_hint = bio->bi_write_hint; + + if (!nr_streams || write_hint == WRITE_LIFE_NOT_SET || + write_hint == WRITE_LIFE_NONE) + streamid = 0; + else if (write_hint < WRITE_LIFE_KERN_MIN) { /*user-space hints*/ + streamid = write_hint - 1; + if (streamid > nr_streams) + streamid = 0; + } else { /* kernel hints */ + streamid = write_hint - WRITE_LIFE_KERN_MIN + 1; + if (streamid > (nr_streams - BLK_MAX_USER_HINTS)) + streamid = 0; + else + streamid = nr_streams - streamid + 1; + } + return streamid; +} + void blk_init_request_from_bio(struct request *req, struct bio *bio) { if (bio->bi_opf & REQ_RAHEAD) @@ -737,7 +764,7 @@ void blk_init_request_from_bio(struct request *req, struct bio *bio) req->__sector = bio->bi_iter.bi_sector; req->ioprio = bio_prio(bio); - req->write_hint = bio->bi_write_hint; + req->streamid = blk_write_hint_to_streamid(req, bio); blk_rq_bio_prep(req->q, req, bio); } EXPORT_SYMBOL_GPL(blk_init_request_from_bio); diff --git a/block/blk-merge.c b/block/blk-merge.c index 1c9d4f0..1435634 100644 --- a/block/blk-merge.c +++ b/block/blk-merge.c @@ -832,7 +832,7 @@ static struct request *attempt_merge(struct request_queue *q, * Don't allow merge of different write hints, or for a hint with * non-hint IO. */ - if (req->write_hint != next->write_hint) + if (req->bio->bi_write_hint != next->bio->bi_write_hint) return NULL; if (req->ioprio != next->ioprio) @@ -964,7 +964,7 @@ bool blk_rq_merge_ok(struct request *rq, struct bio *bio) * Don't allow merge of different write hints, or for a hint with * non-hint IO. */ - if (rq->write_hint != bio->bi_write_hint) + if (rq->bio->bi_write_hint != bio->bi_write_hint) return false; if (rq->ioprio != bio_prio(bio)) diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c index 2c43e12..f3000d9 100644 --- a/drivers/nvme/host/core.c +++ b/drivers/nvme/host/core.c @@ -530,12 +530,9 @@ static void nvme_assign_write_stream(struct nvme_ctrl *ctrl, struct request *req, u16 *control, u32 *dsmgmt) { - enum rw_hint streamid = req->write_hint; + enum rw_hint streamid = req->streamid; - if (streamid == WRITE_LIFE_NOT_SET || streamid == WRITE_LIFE_NONE) - streamid = 0; - else { - streamid--; + if (streamid != 0) { if (WARN_ON_ONCE(streamid > ctrl->nr_streams)) return; diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 5b6cb9747..9cf8a40 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -216,7 +216,7 @@ struct request { unsigned short nr_integrity_segments; #endif - unsigned short write_hint; + unsigned short streamid; unsigned short ioprio; unsigned int extra_len; /* length of alignment and padding */ -- 2.7.4
