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-rw-r--r--block/blk-mq.c29
1 files changed, 27 insertions, 2 deletions
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 68929bad9a6..7e530382045 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -680,6 +680,8 @@ static void __blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx)
struct request_queue *q = hctx->queue;
struct request *rq;
LIST_HEAD(rq_list);
+ LIST_HEAD(driver_list);
+ struct list_head *dptr;
int queued;
WARN_ON(!cpumask_test_cpu(raw_smp_processor_id(), hctx->cpumask));
@@ -706,16 +708,27 @@ static void __blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx)
}
/*
+ * Start off with dptr being NULL, so we start the first request
+ * immediately, even if we have more pending.
+ */
+ dptr = NULL;
+
+ /*
* Now process all the entries, sending them to the driver.
*/
queued = 0;
while (!list_empty(&rq_list)) {
+ struct blk_mq_queue_data bd;
int ret;
rq = list_first_entry(&rq_list, struct request, queuelist);
list_del_init(&rq->queuelist);
- ret = q->mq_ops->queue_rq(hctx, rq, list_empty(&rq_list));
+ bd.rq = rq;
+ bd.list = dptr;
+ bd.last = list_empty(&rq_list);
+
+ ret = q->mq_ops->queue_rq(hctx, &bd);
switch (ret) {
case BLK_MQ_RQ_QUEUE_OK:
queued++;
@@ -734,6 +747,13 @@ static void __blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx)
if (ret == BLK_MQ_RQ_QUEUE_BUSY)
break;
+
+ /*
+ * We've done the first request. If we have more than 1
+ * left in the list, set dptr to defer issue.
+ */
+ if (!dptr && rq_list.next != rq_list.prev)
+ dptr = &driver_list;
}
if (!queued)
@@ -1153,6 +1173,11 @@ static void blk_mq_make_request(struct request_queue *q, struct bio *bio)
}
if (is_sync) {
+ struct blk_mq_queue_data bd = {
+ .rq = rq,
+ .list = NULL,
+ .last = 1
+ };
int ret;
blk_mq_bio_to_request(rq, bio);
@@ -1162,7 +1187,7 @@ static void blk_mq_make_request(struct request_queue *q, struct bio *bio)
* error (busy), just add it to our list as we previously
* would have done
*/
- ret = q->mq_ops->queue_rq(data.hctx, rq, true);
+ ret = q->mq_ops->queue_rq(data.hctx, &bd);
if (ret == BLK_MQ_RQ_QUEUE_OK)
goto done;
else {