diff options
Diffstat (limited to 'block/blk-mq-sched.c')
| -rw-r--r-- | block/blk-mq-sched.c | 15 |
1 files changed, 12 insertions, 3 deletions
diff --git a/block/blk-mq-sched.c b/block/blk-mq-sched.c index 4ee7cb043812..9e8d6795a8c1 100644 --- a/block/blk-mq-sched.c +++ b/block/blk-mq-sched.c @@ -175,6 +175,8 @@ void blk_mq_sched_put_request(struct request *rq) void blk_mq_sched_dispatch_requests(struct blk_mq_hw_ctx *hctx) { struct elevator_queue *e = hctx->queue->elevator; + const bool has_sched_dispatch = e && e->type->ops.mq.dispatch_request; + bool did_work = false; LIST_HEAD(rq_list); if (unlikely(blk_mq_hctx_stopped(hctx))) @@ -204,11 +206,18 @@ void blk_mq_sched_dispatch_requests(struct blk_mq_hw_ctx *hctx) */ if (!list_empty(&rq_list)) { blk_mq_sched_mark_restart(hctx); - blk_mq_dispatch_rq_list(hctx, &rq_list); - } else if (!e || !e->type->ops.mq.dispatch_request) { + did_work = blk_mq_dispatch_rq_list(hctx, &rq_list); + } else if (!has_sched_dispatch) { blk_mq_flush_busy_ctxs(hctx, &rq_list); blk_mq_dispatch_rq_list(hctx, &rq_list); - } else { + } + + /* + * We want to dispatch from the scheduler if we had no work left + * on the dispatch list, OR if we did have work but weren't able + * to make progress. + */ + if (!did_work && has_sched_dispatch) { do { struct request *rq; |