[PATCH 1/4] blk-mq: support at_head inserations for blk_execute_rq

Christoph Hellwig
2014-02-07T18:22:36Z

[-- Attachment #1: 0001-blk-mq-support-at_head-inserations-for-blk_execute_r.patch --]
[-- Type: text/plain, Size: 3493 bytes --]

This is neede for proper SG_IO operation as well as various uses of
blk_execute_rq from the SCSI midlayer.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
block/blk-exec.c | 2 +-
block/blk-mq.c | 17 ++++++++++-------
include/linux/blk-mq.h | 3 ++-
3 files changed, 13 insertions(+), 9 deletions(-)

diff --git a/block/blk-exec.c b/block/blk-exec.c
index bbfc072..c68613b 100644
--- a/block/blk-exec.c
+++ b/block/blk-exec.c
@@ -65,7 +65,7 @@ void blk_execute_rq_nowait(struct request_queue *q, struct gendisk *bd_disk,
* be resued after dying flag is set
*/
if (q->mq_ops) {
- blk_mq_insert_request(q, rq, true);
+ blk_mq_insert_request(q, rq, at_head, true);
return;
}

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 57039fc..40fc4dd 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -693,13 +693,16 @@ static void blk_mq_work_fn(struct work_struct *work)
}

static void __blk_mq_insert_request(struct blk_mq_hw_ctx *hctx,
- struct request *rq)
+ struct request *rq, bool at_head)
{
struct blk_mq_ctx *ctx = rq->mq_ctx;

trace_block_rq_insert(hctx->queue, rq);

- list_add_tail(&rq->queuelist, &ctx->rq_list);
+ if (at_head)
+ list_add(&rq->queuelist, &ctx->rq_list);
+ else
+ list_add_tail(&rq->queuelist, &ctx->rq_list);
blk_mq_hctx_mark_pending(hctx, ctx);

/*
@@ -709,7 +712,7 @@ static void __blk_mq_insert_request(struct blk_mq_hw_ctx *hctx,
}

void blk_mq_insert_request(struct request_queue *q, struct request *rq,
- bool run_queue)
+ bool at_head, bool run_queue)
{
struct blk_mq_hw_ctx *hctx;
struct blk_mq_ctx *ctx, *current_ctx;
@@ -728,7 +731,7 @@ void blk_mq_insert_request(struct request_queue *q, struct request *rq,
rq->mq_ctx = ctx;
}
spin_lock(&ctx->lock);
- __blk_mq_insert_request(hctx, rq);
+ __blk_mq_insert_request(hctx, rq, at_head);
spin_unlock(&ctx->lock);

blk_mq_put_ctx(current_ctx);
@@ -760,7 +763,7 @@ void blk_mq_run_request(struct request *rq, bool run_queue, bool async)

/* ctx->cpu might be offline */
spin_lock(&ctx->lock);
- __blk_mq_insert_request(hctx, rq);
+ __blk_mq_insert_request(hctx, rq, false);
spin_unlock(&ctx->lock);

blk_mq_put_ctx(current_ctx);
@@ -798,7 +801,7 @@ static void blk_mq_insert_requests(struct request_queue *q,
rq = list_first_entry(list, struct request, queuelist);
list_del_init(&rq->queuelist);
rq->mq_ctx = ctx;
- __blk_mq_insert_request(hctx, rq);
+ __blk_mq_insert_request(hctx, rq, false);
}
spin_unlock(&ctx->lock);

@@ -950,7 +953,7 @@ static void blk_mq_make_request(struct request_queue *q, struct bio *bio)
__blk_mq_free_request(hctx, ctx, rq);
else {
blk_mq_bio_to_request(rq, bio);
- __blk_mq_insert_request(hctx, rq);
+ __blk_mq_insert_request(hctx, rq, false);
}

spin_unlock(&ctx->lock);
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index 161b231..8e6e710 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -119,7 +119,8 @@ void blk_mq_init_commands(struct request_queue *, void (*init)(void *data, struc

void blk_mq_flush_plug_list(struct blk_plug *plug, bool from_schedule);

-void blk_mq_insert_request(struct request_queue *, struct request *, bool);
+void blk_mq_insert_request(struct request_queue *, struct request *,
+ bool, bool);
void blk_mq_run_queues(struct request_queue *q, bool async);
void blk_mq_free_request(struct request *rq);
bool blk_mq_can_queue(struct blk_mq_hw_ctx *);
--
1.7.10.4