Merge blk_mq_try_issue_directly and __blk_mq_try_issue_directly
into one interface which is able to handle the return value from
.queue_rq callback. Due to we can only issue directly w/o io
scheduler, so remove the blk_mq_get_driver_tag.
Signed-off-by: Jianchao Wang <jianchao.w.w...@oracle.com>
---
block/blk-mq.c | 109 ++++++++++++++++++++++++++-------------------------------
1 file changed, 50 insertions(+), 59 deletions(-)
diff --git a/block/blk-mq.c b/block/blk-mq.c
index dcf10e3..a81d2ca 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1700,8 +1700,6 @@ static blk_status_t __blk_mq_issue_directly(struct
blk_mq_hw_ctx *hctx,
blk_qc_t new_cookie;
blk_status_t ret;
- new_cookie = request_to_qc_t(hctx, rq);
-
/*
* For OK queue, we are done. For error, caller may kill it.
* Any other error (busy), just add it to our list as we
@@ -1711,7 +1709,7 @@ static blk_status_t __blk_mq_issue_directly(struct
blk_mq_hw_ctx *hctx,
switch (ret) {
case BLK_STS_OK:
blk_mq_update_dispatch_busy(hctx, false);
- *cookie = new_cookie;
+ new_cookie = request_to_qc_t(hctx, rq);
break;
case BLK_STS_RESOURCE:
case BLK_STS_DEV_RESOURCE:
@@ -1720,86 +1718,79 @@ static blk_status_t __blk_mq_issue_directly(struct
blk_mq_hw_ctx *hctx,
break;
default:
blk_mq_update_dispatch_busy(hctx, false);
- *cookie = BLK_QC_T_NONE;
+ new_cookie = BLK_QC_T_NONE;
break;
}
+ if (cookie)
+ *cookie = new_cookie;
return ret;
}
-static blk_status_t __blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx,
+/*
+ * When the bypass is true, the caller is responsible for handling the
+ * request if it is not issued. The only exception is that io scheduler
+ * is set.
+ */
+static blk_status_t blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx,
struct request *rq,
blk_qc_t *cookie,
- bool bypass_insert)
+ bool bypass)
{
struct request_queue *q = rq->q;
- bool run_queue = true;
+ blk_status_t ret = BLK_STS_OK;
+ bool insert = true;
+ int srcu_idx;
+
+ if (q->elevator)
+ goto out;
+ hctx_lock(hctx, &srcu_idx);
/*
- * RCU or SRCU read lock is needed before checking quiesced flag.
+ * hctx_lock is needed before checking quiesced flag.
*
- * When queue is stopped or quiesced, ignore 'bypass_insert' from
- * blk_mq_request_issue_directly(), and return BLK_STS_OK to caller,
- * and avoid driver to try to dispatch again.
+ * When queue is stopped or quiesced, ignore 'bypass', insert and return
+ * BLK_STS_OK to caller, and avoid driver to try to dispatch again.
*/
- if (blk_mq_hctx_stopped(hctx) || blk_queue_quiesced(q)) {
- run_queue = false;
- bypass_insert = false;
- goto insert;
- }
-
- if (q->elevator && !bypass_insert)
- goto insert;
+ if (blk_mq_hctx_stopped(hctx) || blk_queue_quiesced(q))
+ goto out_unlock;
- if (!blk_mq_get_dispatch_budget(hctx))
- goto insert;
-
- if (!blk_mq_get_driver_tag(rq)) {
- blk_mq_put_dispatch_budget(hctx);
- goto insert;
+ if (!blk_mq_get_dispatch_budget(hctx)) {
+ insert = !bypass;
+ ret = bypass ? BLK_STS_RESOURCE : BLK_STS_OK;
+ goto out_unlock;
}
- return __blk_mq_issue_directly(hctx, rq, cookie);
-insert:
- if (bypass_insert)
- return BLK_STS_RESOURCE;
-
- blk_mq_sched_insert_request(rq, false, run_queue, false);
- return BLK_STS_OK;
-}
-
-static void blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx,
- struct request *rq, blk_qc_t *cookie)
-{
- blk_status_t ret;
- int srcu_idx;
-
- might_sleep_if(hctx->flags & BLK_MQ_F_BLOCKING);
-
- hctx_lock(hctx, &srcu_idx);
-
- ret = __blk_mq_try_issue_directly(hctx, rq, cookie, false);
- if (ret == BLK_STS_RESOURCE || ret == BLK_STS_DEV_RESOURCE)
- blk_mq_sched_insert_request(rq, false, true, false);
- else if (ret != BLK_STS_OK)
- blk_mq_end_request(rq, ret);
+ ret = __blk_mq_issue_directly(hctx, rq, cookie);
+ switch(ret) {
+ case BLK_STS_OK:
+ insert = false;
+ break;
+ case BLK_STS_DEV_RESOURCE:
+ case BLK_STS_RESOURCE:
+ insert = !bypass;
+ break;
+ default:
+ if (!bypass)
+ blk_mq_end_request(rq, ret);
+ insert = false;
+ break;
+ }
+out_unlock:
hctx_unlock(hctx, srcu_idx);
+out:
+ if (insert)
+ blk_mq_sched_insert_request(rq, false, true, false);
+ return ret;
}
blk_status_t blk_mq_request_issue_directly(struct request *rq)
{
- blk_status_t ret;
- int srcu_idx;
- blk_qc_t unused_cookie;
struct blk_mq_ctx *ctx = rq->mq_ctx;
struct blk_mq_hw_ctx *hctx = blk_mq_map_queue(rq->q, ctx->cpu);
- hctx_lock(hctx, &srcu_idx);
- ret = __blk_mq_try_issue_directly(hctx, rq, &unused_cookie, true);
- hctx_unlock(hctx, srcu_idx);
-
- return ret;
+ return blk_mq_try_issue_directly(hctx, rq, NULL, true);
}
void blk_mq_try_issue_list_directly(struct blk_mq_hw_ctx *hctx,
@@ -1921,13 +1912,13 @@ static blk_qc_t blk_mq_make_request(struct
request_queue *q, struct bio *bio)
data.hctx = blk_mq_map_queue(q,
same_queue_rq->mq_ctx->cpu);
blk_mq_try_issue_directly(data.hctx, same_queue_rq,
- &cookie);
+ &cookie, false);
}
} else if ((q->nr_hw_queues > 1 && is_sync) || (!q->elevator &&
!data.hctx->dispatch_busy)) {
blk_mq_put_ctx(data.ctx);
blk_mq_bio_to_request(rq, bio);
- blk_mq_try_issue_directly(data.hctx, rq, &cookie);
+ blk_mq_try_issue_directly(data.hctx, rq, &cookie, false);
} else {
blk_mq_put_ctx(data.ctx);
blk_mq_bio_to_request(rq, bio);
--
2.7.4
