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authorMike Snitzer <snitzer@redhat.com>2018-01-17 11:25:56 -0500
committerJens Axboe <axboe@kernel.dk>2018-01-17 09:46:50 -0700
commit0f95549c0ea1e8075ae049202088b2c6a0cb40ad (patch)
treec1f1bf9a15df938a4ac525f7d02efd17f825a71a /block
parent7df938fbc4ee641e70e05002ac67c24b19e86e74 (diff)
blk-mq: factor out a few helpers from __blk_mq_try_issue_directly
No functional change. Just makes code flow more logically. In following commit, __blk_mq_try_issue_directly() will be used to return the dispatch result (blk_status_t) to DM. DM needs this information to improve IO merging. Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block')
-rw-r--r--block/blk-mq.c79
1 files changed, 52 insertions, 27 deletions
diff --git a/block/blk-mq.c b/block/blk-mq.c
index ec429be05729..ddc46f215bfa 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1738,9 +1738,9 @@ static blk_qc_t request_to_qc_t(struct blk_mq_hw_ctx *hctx, struct request *rq)
return blk_tag_to_qc_t(rq->internal_tag, hctx->queue_num, true);
}
-static void __blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx,
- struct request *rq,
- blk_qc_t *cookie)
+static blk_status_t __blk_mq_issue_directly(struct blk_mq_hw_ctx *hctx,
+ struct request *rq,
+ blk_qc_t *cookie)
{
struct request_queue *q = rq->q;
struct blk_mq_queue_data bd = {
@@ -1749,6 +1749,43 @@ static void __blk_mq_try_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
+ * previously would have done.
+ */
+ ret = q->mq_ops->queue_rq(hctx, &bd);
+ switch (ret) {
+ case BLK_STS_OK:
+ *cookie = new_cookie;
+ break;
+ case BLK_STS_RESOURCE:
+ __blk_mq_requeue_request(rq);
+ break;
+ default:
+ *cookie = BLK_QC_T_NONE;
+ break;
+ }
+
+ return ret;
+}
+
+static void __blk_mq_fallback_to_insert(struct blk_mq_hw_ctx *hctx,
+ struct request *rq,
+ bool run_queue)
+{
+ blk_mq_sched_insert_request(rq, false, run_queue, false,
+ hctx->flags & BLK_MQ_F_BLOCKING);
+}
+
+static blk_status_t __blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx,
+ struct request *rq,
+ blk_qc_t *cookie)
+{
+ struct request_queue *q = rq->q;
bool run_queue = true;
/* RCU or SRCU read lock is needed before checking quiesced flag */
@@ -1768,41 +1805,29 @@ static void __blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx,
goto insert;
}
- new_cookie = request_to_qc_t(hctx, rq);
-
- /*
- * For OK queue, we are done. For error, kill it. Any other
- * error (busy), just add it to our list as we previously
- * would have done
- */
- ret = q->mq_ops->queue_rq(hctx, &bd);
- switch (ret) {
- case BLK_STS_OK:
- *cookie = new_cookie;
- return;
- case BLK_STS_RESOURCE:
- __blk_mq_requeue_request(rq);
- goto insert;
- default:
- *cookie = BLK_QC_T_NONE;
- blk_mq_end_request(rq, ret);
- return;
- }
-
+ return __blk_mq_issue_directly(hctx, rq, cookie);
insert:
- blk_mq_sched_insert_request(rq, false, run_queue, false,
- hctx->flags & BLK_MQ_F_BLOCKING);
+ __blk_mq_fallback_to_insert(hctx, rq, run_queue);
+
+ 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);
- __blk_mq_try_issue_directly(hctx, rq, cookie);
+
+ ret = __blk_mq_try_issue_directly(hctx, rq, cookie);
+ if (ret == BLK_STS_RESOURCE)
+ __blk_mq_fallback_to_insert(hctx, rq, true);
+ else if (ret != BLK_STS_OK)
+ blk_mq_end_request(rq, ret);
+
hctx_unlock(hctx, srcu_idx);
}

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